Ground Lighting Illusions - Optical Illusions

Ground Lighting Illusions

Lights along a straight path, such as a road, and even lights on moving trains can be mistaken for runway and approach lights. Bright runway and approach lighting systems, especially where few lights illuminate the surrounding terrain, may create the illusion of less distance to the runway. The pilot who does not recognize this illusion will often fly a higher approach.

Of the senses, vision is the most important for safe flight. However, various terrain features and atmospheric conditions can create optical illusions. These illusions are primarily associated with landing. Since pilots must transition from reliance on instruments to visual cues outside the cockpit for landing at the end of an instrument approach, it is imperative they are aware of the potential problems associated with these illusions, and take appropriate corrective action. The major illusions leading to landing errors are described below.

Runway Width Illusion
A narrower-than-usual runway can create an illusion the aircraft is at a higher altitude than it actually is, especially when runway length-to-width relationships are comparable. [Figure 1-5A] The pilot who does not recognize this illusion will fly a lower approach, with the risk of striking objects along the approach path or landing short. A wider-than-usual runway can have the opposite effect, with the risk of leveling out high and landing hard, or overshooting the runway.

Runway and Terrain Slopes Illusion
An up-sloping runway, up-sloping terrain, or both, can create an illusion the aircraft is at a higher altitude than it actually is. [Figure 1-5B] The pilot who does not recognize this illusion will fly a lower approach. Down-sloping runways and Down-sloping approach terrain can have the opposite effect.

Featureless Terrain Illusion
An absence of surrounding ground features, as in an over-water approach, over darkened areas, or terrain made featureless by snow, can create an illusion the aircraft is at a higher altitude than it actually is. This illusion, sometimes referred to as the “black hole approach,” causes pilots to fly a lower approach than is desired.

Water Refraction
Rain on the windscreen can create an illusion of being at a higher altitude due to the horizon appearing lower than it is. This can result in the pilot flying a lower approach.

Atmospheric haze can create an illusion of being at a greater distance from the runway. As a result, the pilot will have a tendency to be high on the approach. Conversely, extremely clear air can give the pilot the illusion of being closer than he/she actually is, resulting in a long, low approach. The diffusion of light due to water particles can adversely affect depth perception. The lights and terrain features normally used to gauge height during landing become less effective for the pilot.

Penetration of fog can create an illusion of pitching up. Pilots who do not recognize this illusion will often steeped the approach quite abruptly.

Optical illusion: (in aircraft flight)
A misleading visual image of features on the ground associated with landing, which causes a pilot to misread the spatial relationships between the aircraft and the runway.

Practice Makes Proficient
Through training and awareness in developing absolute reliance on the instruments, pilots can reduce their susceptibility to disorienting illusions.

TMS turbo installation on Rotax 914

Here is an article about turbo system of the highly modified Rotax:

Interesting web site:

New development at Dubrovnik Airport

Dubrovnik Airport
Dubrovnik Airport is planning to enlarge its apron for private aircraft. The airport’s authorities are also planning on the expansion of the existing lounge for VIP guests at the end of the current tourist season, in late September. The project entails the construction of 20 new parking spaces for aircraft whose owners are willing to pay a bit extra for special treatment. The entire project will amount to 6 million Kunas (818.000 Euros). Currently, one VIP lounge reservation costs more than 150 Euros, so the airport management considers the VIP capacity enlargement necessary because it believes the investment will pay off. Recently, there were 21 private jets at the airport.

The VIP potential is being explored as some other services the airport offers are reporting a slump in business. In another example that the current economic crisis has no boundaries, Dubrovnik Airport’s duty free shop reported an 11.19% fall in sales in the first 7 months of 2009 compared with the same period last year. Trade department manager of the state-owned duty free store Nikša Milanović said: It is recognised everywhere that we are in a recession. At our airport, British customers continue to be the number one cistomers but still there is a problem with the exchange rate after the Pound fell in value by 33% last year against the Euro, and the British are still cautious about spending as the Euro is still over valued”, he said

Currently Dobrovnik Airport is in the midst of an expansion. A new 36.500 square meter terminal and four jet bridges are under construction. The new terminal will have a projected annual capacity of 3.5 million passengers. Further expansion is planned after 2011, with more floor space and 4 additional jetways. This will increase the capacity further to 5.5 million passengers per year. The terminal at Dubrovnik Airport, once completed, will be the largest in Croatia. Future airport plans call for an extensive economic zone and a large four star airport hotel, and long term plans call for a new runway and the conversion of the existing runway to a taxiway.

OE to the land of the rising sun.

Having just been issued with its export C of A is the Schempp-Hirth Discus-2T ZK-GOE2 , c/n 23/159 . It is off to Japan for the pilot who has been coming to Omarama to fly it for the last couple of years. This is possibly Shojiro Hotta whom I have as a previous short term owner.
The Discus 2T is in the 15m class and has a two cylinder Solo sustainer engine (ie, not sufficient grunt for self launching).
It was initially registered in Australia as VH-SHD (hence the SHD letters on the tail) and was with the Waikerie Soaring Centre P/L in South Australia from 17-12-2002.
In NZ it became ZK-GOE2 for Glide Omarama from 19-12-2005.

NZ registration cancelled 31-08-2009. Ready to GOE.

Coping with Spatial Disorientation

Pilots can take action to prevent illusions and their potentially disastrous consequences if they:

1. Understand the causes of these illusions and remain constantly alert for them.
2. Always obtain preflight weather briefings.
3. Do not continue flight into adverse weather conditions or into dusk or darkness unless proficient in the use of flight instruments.
4. Ensure that when outside visual references are used, they are reliable, fixed points on the Earth’s surface.
5. Avoid sudden head movement, particularly during takeoffs, turns, and approaches to landing.
6. Remember that illness, medication, alcohol, fatigue, sleep loss, and mild hypoxia is likely to increase susceptibility to spatial disorientation.
7. Most importantly, become proficient in the use of flight instruments and rely upon them.

The sensations, which lead to illusions during instrument flight conditions, are normal perceptions experienced by pilots. These undesirable sensations cannot be completely prevented, but through training and awareness, pilots can ignore or suppress them by developing absolute reliance on the flight instruments. As pilots gain proficiency in instrument flying, they become less susceptible to these illusions and their effects.

Beginner RC helicopter flying training

In the last beginner rc helicopter flying training lesson we flew large and fast figure of eight in front of your position not around your position. In this lesson you will learn how to nose in hover. This can really be very difficult for so many people but there are many not one way of learning it, we will discuss here the three effective ones.

Since you may well be flying those large figure of eight loops and that will make you think that you are not required to learn the hovering nose. But let me tell you that if you did not give enough attention in learning the rc helicopter controls in all directions and orientations, you will never be able to perform advanced aerobatics. Nose facing your direction is somewhat has been practiced by you in the earlier lesson or it will be felt the way that you are relearning flying rc helicopter. However by putting little extra effort for learning today’s lesson will be more beneficial in the long run and is very essential. Because, even if you are only keeping yourself stick to just basic flying like normal hovering and basic figure of eight loop, your rc helicopter will be forced to face nose in hover. I can be caused by gusting wind or may be a result of an engine failure, radio interference or your own error. Moreover as said earlier, this is essential to learn if you ever want to perform some simple and basic aerobatics.
You must be thinking that why am I rambling to make you understand that nose in hover is very hard. Well the answer is very simple; your rc helicopter cyclic controls get reversed when the helicopter is facing you. Try doing it yourself, turn the face of your rc helicopter towards you and turn on your radio and receiver. When you give a left cyclic the swash plate moves right. So basically the difficulty is in understanding the reversed commands you will be required to give when the rc helicopter is facing towards you. Same thing applies to the tail rotor command, it gets reversed too. But if you get yourself used to taking the tail rotor commands make the rc heli move in clockwise or anti clock wise directions instead of it being turning left or right, the direction of the rc helicopter will not matter.

However, never look at the tail when you are giving tail rotor commands. Some people may tell you to see how the tail rotor swings left when you give the left tail rotor command. Keep your focus on the nose; this is the right way of flying the rc helicopter. Having said that, it is also very easy to learn the counter clock wise and clock wise orientation instead of getting used to left or right tail rotor movement. By the time you come to this point of practicing nose in hover, you must have got the command over throttle control and collective pitch. Moreover, if you just do all the exercises learned earlier with getting the clockwise and counter clock wise orientation for tail command, it will just become a part of your reflexes and you will not face any difficulty just focusing the nose.

Before we start the nose in flying lesson there are few points which require attention:

Keep you training gear on; it will save your rc helicopter from a possible ditch and also will sever as a guide for visualizing roll and pitch movements easily.

Since you are getting another aspect of the command controls, if the cyclic duel rates are set to more or are turned off, you must reset them back to the factory settings, the same when you were doing the basic hovering exercises. This way you will be controlling the radio control heli the way it is supposed to in the hover in nose exercise.

There are three methods for learning the nose in hover, and you will learn three of them one by one. We will start from the same method we are used to i.e. the ground up hover method. Then we will see the flying approach method and finally look into walk around method.

Nose tip in Hover Ground up method:
This method is almost the same as you did in earlier exercise of basic hovering when you were a beginner rc helicopter flyer, but now you already know the controls of collective/throttle and commands of tail rotor. Stand in front of you rc helicopter keeping a distance of around 10 to 12 feet and make sure that the face of your bird is into the wind. To get the feel of the reversed commands in cyclic, safely, just give a little throttle to make your heli lighter on the skids. Just make it comfortable and then hover a little above the ground, up to few inches and practice there. When you feel comfortable start doing the backward/ forward/ sideways and diagonal commands and see how the commands have reversed effect on your rc helicopter when you are standing in front of it having its nose pointed at you. Make sure the heli remains into the wind direction. Once you have got the hang of that, try doing a long figure of eight loop, just at the end of each loop you will turn the rc helicopter towards you instead of turning it away from you as earlier. When you feel that you are comfortable doing the long skinny figure of eight loop, try doing the fast and large figure of eight circuit from the previous exercise. Keep the altitude high enough to get away from any mishap. There are many situations when you see your rc heli ditching at the ground but can avoid it through increasing the collective/ throttle and climbing altitude again to gain time for getting the control over your remote control helicopter.

You will be doing the nose in hover exercise in an open area, preferably a ground. This is good for whatever method you try for learning it but having plenty of room around you will give you enough chances to correct your skills incase you get disoriented. One more tip which is usually overlooked but is very important that choose to do fly in hover lesson in an overcast day. This way you will be able to avoid the scenario when your rc helicopter passes in front of the sun and your position. On that very instant you wilt blinded by the bright sunlight and those few seconds may cost you the expensive rc helicopter. Because losing sight of your heli will make you disoriented and by the time you will acquire the position back, your bird might get the blow of its life.

Nose in Hover Flying Approach Method:
This is another way to get the taste of reversed controls. In this method, the beginner rc heli is already flying, you just turn it slowly towards you to let your brain learn the reversal of controls when the nose is pointed towards you. The more you will practice the approach of rc helicopter towards you, the more you will get comfortable with the reverse control and the time will come when you be able to hover the heli having the nose pointed towards you. There are two advantages learning nose pointed to you while hovering. One is that your rc hlei will be flying high already so, you will be safe even if you make any mistake and the other is that the heli will already be in a forward flight which will make it easier for you to get the hang of it because rc helicopter is more stable in forward flight than in the hover.

The disadvantage to this method is that you get very less time practicing the nose is hover because most of the time the rc heli is flying and the only time you get to practice nose in hover is when the heli is coming towards you. The other disadvantage is the instant when the beginer rc helicopter comes towards you in the first few instances, those are the moments when you can get it or lose it completely, if you didn’t prepare your mind for the reverse control commands when the heli is approaching towards you. This way of learning is good for you if you are in rc airplane flying already. Since rc helicopters behave the same way as rc airplanes when they are in forward flight, it is all natural for an rc airplane flyer.

Walk Around method:
This method is a lot easier to learn nose in hover because you will be standing behind the heli when you start, the same way it was during the basic exercises. You will be at ease doing it just put the rc helicopter into the wind and stand 10 to 12 feet behind it. Start hovering 2-3 feet off the ground and gradually walk from left or right of the heli to come in front of it. This way will give your brain the gradual learning chance and you will be able to learning a better way this way. When in front, practice your left cyclic/ right cyclic/ forward and backwards.

During that practice whenever you feel disorientated, just move your position to a more comfortable one even get behind the heli to be able to control it the way you are used to. You will have to act fast for getting orientation back or you will ditch your rc hlei to ground and that will cost you moolah. And yes, try to be careful when walking to get in front of the rc helicopter because your focus will be on the heli and something may get you trip over. So make sure you clear all the hurdles you can come across. When you get comfortable being in front of the helicopter, practice all the controls i.e. backwards/forward/ sideways and diagonals.

If you have a good flight simulator for rc helicopter, make use of it because it will help you learn faster. The walk around method will not work with the simulator because your position remains fixed in a simulator. However other two methods will work just fine. Whichever method you choose to go for, just stick to it with the rc helicopter simulator too.

Here I will call it the end of the basic rc helicopter flying training lessons. With the last one being nose in front of you hovering, you are now open to some advanced aerobatic maneuvers and are even able to handle large rc helicopters. Look at you! You are now a skilled rc helicopter flyer who is able to fly in whatever direction, in other words you have full control over your rc heli. No more rc helicopter training gear needed for you, great flying there you rc helicopter pilot!

Competition bites

More airlines hurting Jat
This summer Jat Airways is reporting a decline in passenger figures mostly due to the global financial crisis but also because of added competition in comparison to last year. However, it’s not all bad news. The Serbian national carrier has managed to beat some tough competition on certain routes. The airline’s chief of international sales, Jelena Pavlović explains. “The main reason we are reporting a passenger slump is because the number of flights have been greatly reduced compared to last year. The office which is reporting the greatest decline in sales is Sydney which covers the entire Australian market as well as New Zealand. This is because the termination of a special prorate agreement with Emirates Airlines. The office sold 7.9 million Euros worth of tickets in the first 6 months of 2008 while this year it has only managed 1.9 million Euros. In January last year Emirates decided to heavily increase its prices to the point that it was worthless for Jat to partner with the airline anymore. Jat signed a new agreement with Etihad Airways which is a developing airline that still hasn’t covered the entire Australian market like Emirates has. It will take time until the Abu Dhabi – Belgrade service stabilises however, we are extremely happy with the sales from Abu Dhabi this summer”. Pavolvić continues by sayng that the Belgrade – Amsterdam service is experiencing a decline in passengers because Martinair has terminated services from Amsterdam to Toronto leaving Jat without transit passengers. A decline is also being experienced on services to Istanbul compliments of Turkish Airlines which first offered 3 weekly flights to Belgrade but now offers 5 weekly services. The airline’s pains do not end there. Reduced passenger volumes were experienced this summer from Belgrade to Monastir as the charter carrier Nouvelair became the new competitor on this route. Similar results can be seen on the Belgrade – Tunis service with Tunisair becoming the more popular airline.

However it’s not all doom and gloom. The airline is reporting quite large passenger increases on services to Moscow (competing with Aeroflot), Paris (competing with Air France), London (competing with British Airways), Vienna (competing with Austrian Airlines), Zurich (competing with Swiss International Airlines), Stockholm (competing with Norwegian Air Shuttle) and Frankfurt (competing with Lufthansa) despite tough competition. Pavlović says that new code share agreements with some major world carriers will be ready by the end of the year. The airline has recently begun an aggressive campaign to lure passengers from Montenegro. It is offering tickets averaging 50 Euros for passengers travelling from Podgorica or Tivat to a European destination. While the campaign might boost passenger figures it won’t help the piggy bank.

Demonstrating Spatial Disorientation

There are a number of controlled aircraft maneuvers a pilot can perform to experiment with spatial disorientation. While each maneuver will normally create a specific illusion, any false sensation is an effective demonstration of disorientation. Thus, even if there is no sensation during any of these maneuvers, the absence of sensation is still an effective demonstration in that it shows the inability to detect bank or roll. There are several objectives in demonstrating these various maneuvers.

1. They teach pilots to understand the susceptibility of the human system to spatial disorientation.
2. They demonstrate that judgments of aircraft attitude based on bodily sensations are frequently false.
3. They can help to lessen the occurrence and degree of disorientation through a better understanding of the relationship between aircraft motion, head movements, and resulting disorientation.
4. They can help to instill a greater confidence in relying on flight instruments for assessing true aircraft attitude.

A pilot should not attempt any of these maneuvers at low altitudes, or in the absence of an instructor pilot or an appropriate safety pilot.

Climbing While Accelerating
With the pilot’s eyes closed, the instructor pilot maintains approach airspeed in a straight-and-level attitude for several seconds, and then accelerates while maintaining straight-and-level attitude. The usual illusion during this maneuver, without visual references, will be that the aircraft is climbing.

Climbing While Turning
With the pilot’s eyes still closed and the aircraft in a straight-and-level attitude, the instructor pilot now executes, with a relatively slow entry, a well-coordinated turn of about 1.5 positive G (approximately 50bank) for 90. While in the turn, without outside visual references and under the effect of the slight positive G, the usual illusion produced is that of a climb. Upon sensing the climb, the pilot should immediately open the eyes and see that a slowly established, coordinated turn produces the same feeling as a climb.

Diving While Turning
This sensation can be created by repeating the previous procedure, with the exception that the pilot’s eyes should be kept closed until recovery from the turn is approximately one-half completed. With the eyes closed, the usual illusion will be that the aircraft is diving.

Tilting to Right or Left
While in a straight-and-level attitude, with the pilot’s eyes closed, the instructor pilot executes a moderate or slight skid to the left with wings level. The usual illusion is that the body is being tilted to the right.

Reversal of Motion
This illusion can be demonstrated in any of the three planes of motion. While straight-and-level, with the pilot’s eyes closed, the instructor pilot smoothly and positively rolls the aircraft to approximately a 45-bank attitude while maintaining heading and pitch attitude. The usual illusion is a strong sense of rotation in the opposite direction. After this illusion is noted, the pilot should open the eyes and observe that the aircraft is in a banked attitude.

Diving or Rolling Beyond the Vertical Plane
This maneuver may produce extreme disorientation. While in straight-and-level flight, the pilot should sit normally, either with eyes closed or gaze lowered to the floor. The instructor pilot starts a positive, coordinated roll toward a 30 or 40 angle of bank. As this is in progress, the pilot should tilt the head forward, look to the right or left, then immediately return the head to an upright position. The instructor pilot should time the maneuver so the roll is stopped just as the pilot returns his/her head upright. An intense disorientation is usually produced by this maneuver, with the pilot experiencing the sensation of falling downwards into the direction of the roll.

In the descriptions of these maneuvers, the instructor pilot is doing the flying, but having the pilot do the flying can also make a very effective demonstration. The pilot should close his/her eyes and tilt the head to one side. The instructor pilot tells the pilot what control inputs to perform. The pilot then attempts to establish the correct attitude or control input with eyes still closed and head still tilted. While it is clear the pilot has no idea of the actual attitude, he/she will react to what the senses are saying. After a short time, the pilot will become disoriented and the instructor pilot then tells the pilot to look up and recover. The benefit of this exercise is the pilot actually experiences the disorientation while flying the aircraft.

Demonstrating Spatial Disorientation—Safety Check
These demonstrations should never be conducted at low altitudes, or without an instructor pilot or appropriate safety pilot onboard.

Archive files

This is the eighth in a series of archival news items which are being published each Saturday. The news items date back from the late 1970s until the early 1990s. This collection of news articles have been published in various newspapers and official historic publications.

The following article talks about the airline’s large scale plans for the last decade of the 20th century. By the late 1980s JAT had already devised plans to begin a new wave of fleet renewal and a new wave of long haul route launches. Little did the airline’s management know that those years would be the toughest it has ever faced.
Grand plans for the 1990s

After the breakup of the Eastern Bloc and the historic changes that took place in Eastern Europe, as well as the first multi party elections in Yugoslavia, first signs of serious crisis began to show in the country. Nevertheless, JAT continued ahead with its plans to establish itself as one of the largest European carriers. JAT was planning to begin services to Caracas, the capital of Venezuela in 1991. Thus, in April 1990 the airline initiated the signing of an interstate air traffic agreement between Yugoslavia and Venezuela, the first such agreement with a country from South America. JAT had chosen Venezuela as its first South American destination as it was the most sustainable for air traffic development. Thus, from 1991 JAT was expected to connect Yugoslavia with cities from 6 continents. During that year the Yugoslav – Israeli air agreement was also signed and JAT immediately began operating flights to Tel Aviv twice per week. The airline was also planning another surprise for 1991. It was to begin services to Seoul, the capital of South Korea. Thus, in 1990, an interstate agreement between Yugoslavia and the Republic of Korea was signed in Belgrade. As the agreement nominated a number of carriers, JAT and Adria launched talks early on with Korean Air and Asiana Airlines, on joining a broadly based cooperation. As even more agreements were signed in 1990 JAT was also considering the possibility of beginning services to Hong Kong, Shanghai and Tokyo.

The first Gulf War began in August 1990, after which JAT immediately organised an evacuation of all Yugoslav nationals from the area. The Middle East was an extremely lucrative market for JAT and Yugoslavia in general with thousands of Yugoslav citizens working in the region on behalf of Yugoslav companies. Three aircraft from Amman landed in Belgrade on August 14, 1990. These flights were redirected from Baghdad and the war torn Kuwait. A total of 7.000 people were transported on these special flights.

In 1990, JAT carried 3.828.000 passengers and 38.226 tonnes of cargo. Domestic services continued reporting a downward trend, mostly due to added competition. JAT was also preparing itself for the delivery of its first MD11 aircraft in the April 1991. Development considerations had prompted the decision to modernise the airline’s long haul fleet with the addition of 3 MD11 aircraft on March 3, 1988 under a lease purchase agreement. The advance payment was to be secured from the sale of 2 DC9s in 1989 and 1 DC10 in 1990. The MD11 can seat 320 passengers and can reach Los Angeles or Singapore from Belgrade without a stop. Also its fuel consumption is 20% less than that of the DC10. The manufacturing of the aircraft was about to start. JAT would receive its first MD11 in March 1991 and the second in December that same year. In 1990 in Washington JAT signed the 300 million Dollar agreement, under very favourable terms for JAT. Among other things, JAT was to become the owner of the aircraft after the 15 year lease period ended. In 1990 a decision to buy a fourth MD11 was made.

Ticket sales in Yugoslavia in 1990:

RepublicDomestic (%)International (%)
Bosnia & Herzegovina4.686.42

The year 1990 was the last year in which JAT operated more or less with stability. It was the year before the events which would shake the foundations of the common state and bring about its break up, war and destruction took place.

Next week: D-day (part 1)

ZK-VVV has come to grief!

Hot off the wire, Heydecke V16 (I16 replica) ZK-VVV has crashed near Ponga Road, South Auckland, around 1730 today while attempting a spin. Thankfully the aircraft was fitted with a style of ballistic parachute and this has cushioned the ensuing crash with the pilot/owner thankfully ok to tell the tale.....

The Major Illusions Leading to Spatial Disorientation

Leans: An abrupt correction of a banked attitude, entered too slowly to stimulate the motion sensing system in the inner ear, can create the illusion of banking in the opposite direction.

Coriolis illusion: An abrupt head movement, while in a prolonged constant-rate turn that has ceased stimulating the motion sensing system, can create the illusion of rotation or movement in an entirely different axis.

Graveyard spiral: The illusion of the cessation of a turn while actually still in a prolonged coordinated, constant-rate turn, which can lead a disoriented pilot to a loss of control of the aircraft.

Somatogravic illusion: The feeling of being in a nose-up or nose-down attitude, caused by a rapid acceleration or deceleration while in flight situations that lack visual reference.

Inversion illusion: The feeling that the aircraft is tumbling backwards, caused by an abrupt change from climb to straight-andlevel flight while in situations lacking visual reference.

Elevator illusion: The feeling of being in a climb or descent, caused by the kind of abrupt vertical accelerations that result from upor downdrafts.

False horizon: Inaccurate visual information for aligning the aircraft caused by various natural and geometric formations that disorient the pilot from the actual horizon.

Autokinesis: Nighttime visual illusion that a stationary light is moving, which becomes apparent after several seconds of staring at the light.

The sensory system responsible for most of the illusions leading to spatial disorientation is the vestibular system in the inner ear. The major illusions leading to spatial disorientation are covered below.

Inner Ear
The Leans
A condition called the leans can result when a banked attitude, to the left for example, may be entered too slowly to set in motion the fluid in the “roll” semicircular tubes. [Figure 1-2] An abrupt correction of this attitude can now set the fluid in motion, creating the illusion of a banked attitude to the right. The disoriented pilot may make the error of rolling the aircraft into the original left-banked attitude or, if level flight is maintained, will feel compelled to lean to the left until this illusion subsides.

Coriolis Illusion
The pilot has been in a turn long enough for the fluid in the ear canal to move at the same speed as the canal. A movement of the head in a different plane, such as looking at something in a different part of the cockpit, may set the fluid moving thereby creating the strong illusion of turning or accelerating on an entirely different axis. This is called Coriolis illusion. This action causes the pilot to think the aircraft is doing a maneuver that it is not. The disoriented pilot may maneuver the aircraft into a dangerous attitude in an attempt to correct the aircraft’s perceived attitude.

For this reason, it is important that pilots develop an instrument cross-check or scan that involves minimal head movement. Take care when retrieving charts and other objects in the cockpit—if you drop something, retrieve it with minimal head movement and be alert for the Coriolis illusion.

Graveyard Spiral
As in other illusions, a pilot in a prolonged coordinated, constant-rate turn, will have the illusion of not turning. During the recovery to level flight, the pilot will experience the sensation of turning in the opposite direction. The disoriented pilot may return the aircraft to its original turn. Because an aircraft tends to lose altitude in turns unless the pilot compensates for the loss in lift, the pilot may notice a loss of altitude. The absence of any sensation of turning creates the illusion of being in a level descent. The pilot may pull back on the controls in an attempt to climb or stop the descent. This action tightens the spiral and increases the loss of altitude; hence, this illusion is referred to as a graveyard spiral. At some point, this could lead to a loss of control by the pilot.

Somatogravic Illusion
A rapid acceleration, such as experienced during takeoff, stimulates the otolith organs in the same way as tilting the head backwards. This action creates the somatogravic illusion of being in a nose-up attitude, especially in situations without good visual references. The disoriented pilot may push the aircraft into a nose-low or dive attitude. A rapid deceleration by quick reduction of the throttle(s) can have the opposite effect, with the disoriented pilot pulling the aircraft into a nose-up or stall attitude.

Inversion Illusion
An abrupt change from climb to straight-and-level flight can stimulate the otolith organs enough to create the illusion of tumbling backwards, or inversion illusion. The disoriented pilot may push the aircraft abruptly into a nose-low attitude, possibly intensifying this illusion.

Elevator Illusion
An abrupt upward vertical acceleration, as can occur in an updraft, can stimulate the otolith organs to create the illusion of being in a climb. This is called elevator illusion. The disoriented pilot may push the aircraft into a nose-low attitude. An abrupt downward vertical acceleration, usually in a downdraft, has the opposite effect, with the disoriented pilot pulling the aircraft into a nose-up attitude.

Two illusions that lead to spatial disorientation, the false horizon and autokinesis, are concerned with the visual system.

False Horizon
A sloping cloud formation, an obscured horizon, an aurora borealis, a dark scene spread with ground lights and stars, and certain geometric patterns of ground lights can provide inaccurate visual information, or false horizon, for aligning the aircraft correctly with the actual horizon. The disoriented pilot may place the aircraft in a dangerous attitude.

In the dark, a stationary light will appear to move about when stared at for many seconds. The disoriented pilot could lose control of the aircraft in attempting to align it with the false movements of this light, called autokinesis.

The postural system sends signals from the skin, joints, and muscles to the brain that are interpreted in relation to the Earth’s gravitational pull. These signals determine posture. Inputs from each movement update the body’s position to the brain on a constant basis. “Seat of the pants” flying is largely dependent upon these signals. Used in conjunction with visual and vestibular clues, these sensations can be fairly reliable. However, because of the forces acting upon the body in certain flight situations, many false sensations can occur due to acceleration forces overpowering gravity. [Figure 1-4] These situations include uncoordinated turns, climbing turns, and turbulence.

Sensory Systems for Orientation

Orientation is the awareness of the position of the aircraft and of oneself in relation to a specific reference point. Disorientation is the lack of orientation, and spatial disorientation specifically refers to the lack of orientation with regard to position in space and to other objects.

Orientation is maintained through the body’s sensory organs in three areas: visual, vestibular, and postural. The eyes maintain visual orientation; the motion sensing system in the inner ear maintains vestibular orientation; and the nerves in the skin, joints, and muscles of the body maintain postural orientation. When human beings are in their natural environment, these three systems work well. However, when the human body is subjected to the forces of flight, these senses can provide misleading information. It is this misleading information that causes pilots to become disoriented.

During flight in visual meteorological conditions (VMC), the eyes are the major orientation source and usually provide accurate and reliable information. Visual cues usually prevail over false sensations from other sensory systems. When these visual cues are taken away, as they are in IMC, false sensations can cause the pilot to quickly become disoriented.

The only effective way to counter these false sensations is to recognize the problem, disregard the false sensations, and while relying totally on the flight instruments, use the eyes to determine the aircraft attitude. The pilot must have an understanding of the problem and the self-confidence to control the aircraft using only instrument indications.

The inner ear has two major parts concerned with orientation, the semicircular canals and the otolith organs. [Figure 1-1] The semicircular canals detect angular acceleration of the body while the otolith organs detect linear acceleration and gravity. The semicircular canals consist of three tubes at right angles to each other, each located on one of the three axes: pitch, roll, or yaw. Each canal is filled with a fluid called endolymph fluid. In the center of the canal is the cupola, a gelatinous structure that rests upon sensory hairs located at the end of the vestibular nerves.

Figure 1-2 illustrates what happens during a turn. When the ear canal is moved in its plane, the relative motion of the fluid moves the cupola, which, in turn, stimulates the sensory hairs to provide the sensation of turning. This effect can be demonstrated by taking a glass filled with water and turning it slowly. The wall of the glass is moving, yet the water is not. If these sensory hairs were attached to the glass, they would be moving in relation to the water, which is still standing still.

The ear was designed to detect turns of a rather short duration. After a short period of time (approximately 20 seconds), the fluid accelerates due to friction between the fluid and the canal wall. Eventually, the fluid will move at the same speed as the ear canal. Since both are moving at the same speed, the sensory hairs detect no relative movement and the sensation of turning ceases. This can also be illustrated with the glass of water. Initially, the glass moved and the water did not. Yet, continually turning the glass would result in the water accelerating and matching the speed of the wall of the glass.

The pilot is now in a turn without any sensation of turning. When the pilot stops turning, the ear canal stops moving but the fluid does not. The motion of the fluid moves the cupola and therefore, the sensory hairs in the opposite direction. This creates the sensation of turning in the opposite direction even though the turn has stopped.

The otolith organs detect linear acceleration and gravity in a similar way. Instead of being filled with a fluid, a gelatinous membrane containing chalk-like crystals covers the sensory hairs. When the pilot tilts his/her head, the weight of these crystals causes this membrane to shift due to gravity and the sensory hairs detect this shift. The brain orients this new position to what it perceives as vertical. Acceleration and deceleration also cause the membrane to shift in a similar manner. Forward acceleration gives the illusion of the head tilting backward. [Figure 1-3]

Nerves in the body’s skin, muscles, and joints constantly send signals to the brain, which signals the body’s relation to gravity. These signals tell the pilot his/her current position. Acceleration will be felt as the pilot is pushed back into the seat. Forces created in turns can lead to false sensations of the true direction of gravity, and may give the pilot a false sense of which way is up.
Uncoordinated turns, especially climbing turns, can cause misleading signals to be sent to the brain. Skids and slips give the sensation of banking or tilting. Turbulence can create motions that confuse the brain as well. Pilots need to be aware that fatigue or illness can exacerbate these sensations and ultimately lead to subtle incapacitation.

Orientation: Awareness of the position of the aircraft and of oneself in relation to a specific reference point.

Spatial disorientation: The state of confusion due to misleading information being sent to the brain from various sensory organs, resulting in a lack of awareness of the aircraft position in relation to a specific reference point.

Vestibular: The central cavity of the bony labyrinth of the ear, or the parts of the membranous labyrinth that it contains.

Flying Instruments Guideline

Is an Instrument Rating Necessary? Instrument Rating Requirements. Training for the Instrument Rating. Maintaining the Instrument Rating. Human Factors, Aerodynamic Factors, Flight Instruments, Airplane Basic Flight Maneuvers, Airplane Attitude Instrument Flying, Helicopter Attitude Instrument Flying, Navigation Systems, The National Airspace System, The Air Traffic Control System, IFR Flight, Emergency Operations.

Human Factors
Human factors is a broad field that studies the interaction between people and machines for the purpose of improving performance and reducing errors. As aircraft became more reliable and less prone to mechanical failure, the percentage of accidents related to human factors increased. Some aspect of human factors now accounts for over 80 percent of all accidents. Pilots who have a good understanding of human factors are better equipped to plan and execute a safe and uneventful flight.

Flying in instrument meteorological conditions (IMC) can result in sensations that are misleading to the body’s sensory system. A safe pilot needs to understand these sensations and effectively counteract them. Instrument flying requires a pilot to make decisions using all available resources.

The elements of human factors covered in this chapter include sensory systems used for orientation, illusions in flight, physiological and psychological factors, medical factors, aeronautical decision making, and crew/cockpit resource management.

Human factors: A multidisciplinary field encompassing the behavioral and social sciences, engineering, and physiology, to consider the variables that influence individual and crew performance for the purpose of reducing errors.

Recovery in sight

Rijeka reports growth
As August draws to a close the Croatian ministry for transportation has published traffic results for Croatian airports during the month of July, one of the two peak tourist season months. Compared to previous months, more airports are reporting passenger growth although this is not the case for Croatia’s largest airport Zagreb. This month Osijek reports the greatest traffic increase compared to July 2009, while Pula continues to report a negative trend and takes the title for the greatest passenger decrease in July.

With 225.102 passengers Zagreb reported a 2.5% passenger decrease compared to last year. However, aircraft movement also declined by a large 13.2%, understandably decreasing passenger numbers, while its transit passenger numbers decreased by 43%. When compared to its main regional competitor Belgrade, Zagreb is still behind although its losses, passenger wise, have been lower compared to Belgrade this year. With 198.172 passengers in July, Split’s performance has diminished by 4.2%, compared to last year. The worst perfumer in July, the same as in June, was Pula Airport. The airport saw passenger movement plummet by 21.2%. The airport had 198.172 passengers this July compared to 206.908 last year. Actual traffic movement at the airport also decreased by 7.9%.

On a brighter note some airports in the country are beginning to recover. Zadar, Osijek, Dubrovnik and Rijeka all managed to see passenger numbers rise. Osijek Airport did exceptionally well with passenger number increasing by a hefty 64.5%. Zadar continued its run of good results with passenger numbers increasing by more than 25%, compliments of the low cost Ryanair. Rijeka also did well in July. The airport handled 24.874 last month compared to 22.324 in July 2008 and thus reported growth of 11.4%. Dubrovnik also improved its results somewhat with passenger numbers increasing by 1.3%.

Passenger figures at Croatian airports:
· January
· February
· March
· April
· May
· June

Possible Kuala Lumpur – Sarajevo link

Soon in Sarajevo?
On Tuesday, the governments of Malaysia and Bosnia and Herzegovina signed an air agreement opening the possibility for Malaysia Airlines to begin services to Sarajevo. The air agreement is expected to be implemented by the beginning of next year with the Bosnian ambassador to Malaysia announcing that Malaysia Airlines would be the first airline to ever connect the two cities. However, there has been no official word or confirmation from the national carrier of Malaysia. "The air transportation agreement is important to both countries to boost air transport", the ambassador said. However whether Malaysia Airlines would actually connect the two cities is questionable as the ambassador said that it is his wish for the two countries to be connected with Malaysia Airlines as B&H Airlines does not have the equipment to do so.

Malaysia Airlines once served many destinations in Europe although has brought its European operations to a minimum, allowing its alliance partners to take care of business. A few years ago Malaysia Airlines ceased operating flights to Zagreb which were established in the mid 1990s via Vienna. Vienna, along with Brussels, Munich, Zurich and Manchester were also scraped recently with Stockholm being the latest victim, to be terminated in October.

Nevertheless, the agreement opens the possibility for air travel cooperation between the 2 countries. Whether the actual service begins next year remains to be seen.

A beautiful piece of kit. Caravan ZK-PMT

Cessna 208 Caravan ZK-PMT , c/n 20800183 , joined the NZ civil register on 28-07-2009 for Skydive Tandem Ltd who operate out of the Pudding Hill strip at the base of Mount Hutt.
A 1990 model which now has all of about 1900 flying hours. It achieved its US airworthiness certificate on 22-03-1990 and was with Carols Planes Inc at Naples, Florida from 05-07-2006 as N165TC. It was fitted out as a seven passenger aircraft. It ferried from Florida across the US to Hollister Municipal then via Hilo, Christmas Island and Apia, reaching Auckland on 01-07-2009. It then hopped over to Ardmore for its NZ certification and moved south in about the first week of August.
These three photos were taken at Avtek at Timaru on Monday the 24th.
The office seems to be well equiped [& still retains its US registration plaque].
All the rear seats have been removed and replaced by squabs along the fuselage side.
The cargo pod has been removed and is seen here alongside a Cessna 185 to give some idea of its size.

A lovely piece of machinery and I imagine a great improvement on the Walter Fletcher.



The term "astronaut" derives from the Greek words meaning "space sailor," and refers to all who have been launched as crew members aboard NASA spacecraft bound for orbit and beyond. Since the inception of NASA's human space flight program, we have also maintained the term "astronaut" as the title for those selected to join the NASA corps of astronauts who make "space sailing" their career profession. The term "cosmonaut" refers to those space sailors who are members of the Russian space program. 

The crew of each launched spacecraft is made up of astronauts or cosmonauts drawn from the various categories described in these pages. The crew assignments and duties of commander, pilot, space shuttle mission specialist, or International Space Station flight engineer are drawn from the NASA professional career astronauts. A special category of astronauts typically titled "payload specialist" refers to individuals selected and trained by commercial or research organizations for flights of a specific payload on a space flight mission. At the present time, these payload specialists may be cosmonauts or astronauts designated by the international partners, individuals selected by the research community, or a company or consortia flying a commercial payload aboard the spacecraft. 



Advanced Solid Rocket Booster

NASA was planning on replacing the post-Challenger SRBs with a new Advanced Solid Rocket Booster (ASRB) to be built by NASA itself at a new facility, on the location of a canceled Tennessee Valley Authority nuclear power plant, at Yellow Creek, Mississippi. The ASRB would have produced additional force in order to increase shuttle payload, so that it could carry modules and construction components to the ISS. After an expenditure of over $2 billion USD, the ASRBs were canceled in favor of the "Super Light-weight Tank" (SLWT) that is in use now, replacing the light-weight tank design that was used on earlier flights.

Two ASRB casings can be found on the Space Shuttle Pathfinder on display at the United States Space & Rocket Center in Huntsville, Alabama.

Filament-wound cases

In the need to provide the necessary thrust to launch polar-orbiting shuttles from the SLC-6 launch pad at Vandenberg Air Force Base in California, SRBs using filament-wound cases (FWC) were designed to be more lightweight than the steel cases used on KSC-launched SRBs.[7] Unlike the regular SRBs, which had the flawed field joint design that led to the Challenger Disaster in 1986, the FWC boosters had the "double tang" joint design (necessary to keep the boosters properly in alignment during the "twang" movement when the SSMEs are ignited prior to liftoff), but used the two O-ring seals. With the closure of SLC-6, the FWC boosters were scrapped by ATK and NASA, but their field joints, albeit modified to incorporate the current three O-ring seals and joint heaters, were later incorporated into the present-day field joints on the current SRMs.

Five-segment booster

Prior to the destruction of the Space Shuttle Columbia in 2003, NASA investigated the replacement of the current 4-segment RSRMs with either a 5-segment SRB design or replacing them altogether with liquid "flyback" boosters using either Atlas V or Delta IV EELV technologies. The 5-segment SRB, which would have required little change to the current shuttle infrastructure, would have allowed the space shuttle to carry an additional 20,000 lb (9,100 kg) of payload in an International Space Station-inclination orbit, eliminate the dangerous "Return-to-Launch Site" and "Trans-Oceanic Abort" modes, and even fly polar-orbiting missions from Kennedy Space Center using a so-called "dog-leg" maneuver over the Atlantic Ocean. With the destruction of the Columbia, NASA has shelved the 5-segment SRB for the shuttle program, but resurrected it for the Ares I and Ares V boosters for Project Constellation.

Future and proposed uses

NASA plans to reuse the SRB designs and infrastructure in several Ares rockets. In 2005, NASA announced the Shuttle-Derived Launch Vehicle slated to carry the Orion Crew Exploration Vehicle into low-Earth orbit and later to the Moon. The SRB-derived Crew Launch Vehicle (CLV), named Ares I, originally featured a modified 4-segment SRB for its first stage, while a liquid-fueled second stage, powered by a single main engine, would have propelled the Orion into orbit. Its current design, initially introduced in 2006, and since modified, is to feature the originally planned, but scrapped 5-segment SRB first-stage, with a second stage powered by an Apollo-derived J-2X rocket engine. In place of the standard SRB nosecone, Ares I will have a tapered interstage assembly connecting the booster proper with the second stage, an inflatable ring to counter the end-over-end spinning, and larger, heavier parachutes to lower the stage into the Atlantic Ocean for recovery.

Also introduced in 2005, was a heavy-lift Cargo Launch Vehicle (CaLV) named Ares V. Early designs of the Ares V utilized five SSMEs and a pair of 5-segment boosters like those planned for the pre-Columbia upgrades, but since then NASA had redesigned the vehicle using first five, and now six RS-68B rocket engines, with either the originally-planned 5-segment boosters or a pair of 5.5-segment boosters (similar to the 5.5-segment booster configuration on the now-retired Titan 34-D/Centaur rocket used to launch the Viking and Voyager spacecrafts in the mid-1970s).

The current redesign will make the booster taller and more powerful than the now-retired Saturn V, N-1, and Energia rockets, and will allow the Ares V to place both the Earth Departure Stage and Altair spacecraft into Low-Earth orbit for later on-orbit assembly. Unlike the 5-segment SRB for the Ares I, the 5 or 5.5-segment boosters for the Ares V are to be identical in design, construction, and function to the current SRBs except for the extra segments. Although there is no final decision on the recovery or reuse of this system, but it is most likely that the standard recovery process like that employed on the shuttle will be used. Like the current shuttle boosters, the Ares V boosters will fly an almost-identical flight trajectory from launch to splashdown.

The DIRECT proposal for a new, shuttle-derived launch vehicle, unlike the Ares I and Ares V boosters, uses a pair of classic 4-segment SRBs with the existing RS-68 engines used on the Delta IV EELV rocket.




1. Ignition

SRB ignition can occur only when a manual lock pin from each SRB safe and arm device has been removed. The ground crew removes the pin during prelaunch activities. At T minus five minutes, the SRB safe and arm device is rotated to the arm position. The solid rocket motor ignition commands are issued when the three Space Shuttle Main Engines (SSMEs) are at or above 90-percent rated thrust, no SSME fail and/or SRB ignition Pyrotechnic Initiator Controller (PIC) low voltage is indicated and there are no holds from the Launch Processing System (LPS).

The solid rocket motor ignition commands are sent by the orbiter computers through the Master Events Controllers (MECs) to the safe and arm device NSDs in each SRB. A PIC single-channel capacitor discharge device controls the firing of each pyrotechnic device. Three signals must be present simultaneously for the PIC to generate the pyro firing output. These signals — arm, fire 1 and fire 2 — originate in the orbiter general-purpose computers (GPCs) and are transmitted to the MECs. The MECs reformat them to 28 volt DC signals for the PICs. The arm signal charges the PIC capacitor to 40 volts DC (minimum of 20 volts DC).

The GPC launch sequence also controls certain critical main propulsion system valves and monitors the engine ready indications from the SSMEs. The MPS start commands are issued by the onboard computers at T minus 6.6 seconds (staggered start engine three, engine two, engine one all approximately within 0.25 of a second), and the sequence monitors the thrust buildup of each engine. All three SSMEs must reach the required 90% thrust within three seconds; otherwise, an orderly shutdown is commanded and safing functions are initiated.

Normal thrust buildup to the required 90% thrust level will result in the SSMEs being commanded to the lift off position at T minus three seconds as well as the fire 1 command being issued to arm the SRBs. At T minus three seconds, the vehicle base bending load modes are allowed to initialize (movement of approximately 25.5 in (650 mm) measured at the tip of the external tank, with movement towards the external tank).

The fire 2 commands cause the redundant NSDs to fire through a thin barrier seal down a flame tunnel. This ignites a pyro booster charge, which is retained in the safe and arm device behind a perforated plate. The booster charge ignites the propellant in the igniter initiator; and combustion products of this propellant ignite the solid rocket motor initiator, which fires down the entire vertical length of the solid rocket motor igniting the solid rocket motor propellant along its entire surface area instantaneously.

Range safety system

A range safety system (RSS) provides for destruction of a rocket or part of it with on-board explosives by remote command if the rocket is out of control, in order to limit the danger to people on the ground from crashing pieces, explosions, fire, poisonous substances, etc. To date, the RSS has only been activated once - during the Space Shuttle Challenger disaster (37 seconds after the breakup of the vehicle).

The shuttle vehicle has two RSSs, one in each SRB. Both are capable of receiving two command messages (arm and fire) transmitted from the ground station. The RSS is used only when the shuttle vehicle violates a launch trajectory red line.

An RSS consists of two antenna couplers, command receivers/decoders, a dual distributor, a safe and arm device with two NASA standard detonators (NSD), two confined detonating fuse manifolds (CDF), seven CDF assemblies and one linear-shaped charge (LSC).

The antenna couplers provide the proper impedance for radio frequency and ground support equipment commands. The command receivers are tuned to RSS command frequencies and provide the input signal to the distributors when an RSS command is sent. The command decoders use a code plug to prevent any command signal other than the proper command signal from getting into the distributors. The distributors contain the logic to supply valid destruct commands to the RSS pyrotechnics.

The NSDs provide the spark to ignite the CDF, which in turn ignites the LSC for shuttle vehicle destruction. The safe and arm device provides mechanical isolation between the NSDs and the CDF before launch and during the SRB separation sequence.

The first message, called arm, allows the onboard logic to enable a destruct and illuminates a light on the flight deck display and control panel at the commander and pilot station. The second message transmitted is the fire command.

The SRB distributors in the SRBs are cross-strapped together. Thus, if one SRB received an arm or destruct signal, the signal would also be sent to the other SRB.

A command is sent from the orbiter to the SRB just before separation to apply battery power to the recovery logic network. A second, simultaneous command arms the three nose cap thrusters (for deploying the pilot and drogue parachutes), the frustum ring detonator (for main parachute deployment), and the main parachute disconnect ordinance.

The recovery sequence begins with the operation of the high-altitude baroswitch, which triggers the pyrotechnic nose cap thrusters. This ejects the nose cap, which deploys the pilot parachute. Nose cap separation occurs at a nominal altitude of 15,704 ft (4,787 m), about 218 seconds after SRB separation. The 11.5 ft (3.5 m) diameter conical ribbon pilot parachute provides the force to pull lanyards attached to cut knives, which cut the loop securing the drogue retention straps. This allows the pilot chute to pull the drogue pack from the SRB, causing the drogue suspension lines to deploy from their stored position. At full extension of the twelve 105 ft (32 m) suspension lines, the drogue deployment bag is stripped away from the canopy, and the 54 ft (16 m) diameter conical ribbon drogue parachute inflates to its initial reefed condition. The drogue disreefs twice after specified time delays (using redundant 7 and 12-second reefing line cutters), and it reorients/stabilizes the SRB for main chute deployment. The drogue parachute has a design load of approximately 315,000 lb (143,000 kg) and weighs approximately 1,200 lb (540 kg).

After the drogue chute has stabilized the SRB in a tail-first attitude, the frustum is separated from the forward skirt by a pyrotechnic charge triggered by the low-altitude baroswitch at a nominal altitude of 5,500 ft (1,700 m) about 243 seconds after SRB separation. The frustum is then pulled away from the SRB by the drogue chute. The main chute suspension lines are pulled out from deployment bags that remain in the frustum. At full extension of the lines, which are 203 ft (62 m) long, the three main chutes are pulled from their deployment bags and inflate to their first reefed condition. The frustum and drogue parachute continue on a separate trajectory to splashdown. After specified time delays (using redundant 10 and 17-second reefing line cutters), the main chute reefing lines are cut and the chutes inflate to their second reefed and full open configurations. The main chute cluster decelerates the SRB to terminal conditions. Each of the 136 ft (41 m) diameter, 20-degree conical ribbon parachutes have a design load of approximately 195,000 lb (88,000 kg) and each weighs approximately 2,180 lb (990 kg). These chutes are the largest that have ever been used — both in deployed size and load weight. The RSRM nozzle extension is severed by a pyrotechnic charge about 20 seconds after frustum separation.

Water impact occurs about 279 seconds after SRB separation at a nominal velocity of 76 feet per second (23 m/s). The water impact range is approximately 130 nmi (240 km) off the eastern coast of Florida. Because the parachutes provide for a nozzle-first impact, air is trapped in the empty (burned out) motor casing, causing the booster to float with the forward end approximately 30 feet (9.1 m) out of the water.

Solid rocket booster of the STS-114 mission being recovered and transported to Cape Canaveral.

Formerly, the main chutes were released from the SRB at impact using a parachute release nut ordnance system (residual loads in the main chutes would deploy the parachute attach fittings with floats tethered to each fitting). The current design keeps the main chutes attached during water impact (initial impact and slapdown). Salt Water Activated Release (SWAR) devices are now incorporated into the main chute riser lines to simplify recovery efforts and reduce damage to the SRB.The drogue deployment bag/pilot parachutes, drogue parachutes and frustums, each main chute, and the SRBs are buoyant and are recovered.


The Challenger accident originated from one of the SRBs. The cause of the accident was found by the Rogers Commission Report to be due to faulty design of the SRB joints.

During the subsequent downtime, detailed structural analyses were performed on critical structural elements of the SRB. Analyses were primarily focused in areas where anomalies had been noted during postflight inspection of recovered hardware.

One of the areas was the attachment ring where the SRBs are connected to the external tank. Areas of distress were noted in some of the fasteners where the ring attaches to the SRB motor case. This situation was attributed to the high loads encountered during water impact. To correct the situation and ensure higher strength margins during ascent, the attach ring was redesigned to encircle the motor case completely (360 degrees). Previously, the attachment ring formed a 'C' shape and encircled the motor case just 270 degrees.

Additionally, special structural tests were performed on the aft skirt. During this test program, an anomaly occurred in a critical weld between the hold-down post and skin of the skirt. A redesign was implemented to add reinforcement brackets and fittings in the aft ring of the skirt.

These two modifications added approximately 450 lb (200 kg) to the weight of each SRB. The result is called a "Redesigned Solid Rocket Motor" (RSRM).

TAV’s great Macedonian escape

Would Alexander the Great approve?
After speculations weather the Turkish airport management company TAV would takeover Macedonia’s 2 airports and invest millions in them as well as construct a new cargo airport, the company has finally publicly announced it has postponed its takeover until 2010. The delay was announced publically on Monday by Rifat Hisarciklioglu, the President of the Union of Chambers and Commodity Exchanges of Turkey, who is currently in Macedonia. Answering to a journalist’s question, Hisarciklioglu said that TAV's management has assured him in a phone conversation that the company "is not cancelling the project in any case, but it is expected to be launched in early 2010". “TAV is a successful company in Turkey managing and building airports. It manages airports in many other countries including Georgia, Qatar, Egypt and Tunisia”, Hisarciklioglu said.

This is the second time that TAV has postponed its project to modernize Macedonia's two airports as a result of the global economic crisis. In December last year, the Turkish company failed to secure credits for the start of the 200 million Euro investments and postponed it for this September. The deal signed between TAV and the Macedonian government means that TAV has to construct a completely new modern terminal at Skopje Airport with the existing runway being enlarged while communal infrastructure, a car park and a cargo building would be built together with the main project. Meanwhile, Ohrid Airport would go under complete reconstruction and modernization with a new car park, cargo building and VIP section to be built. Finally, the project outlines that a cargo terminal would be built in Štip in Eastern Macedonia. Štip Airport which would be built within 3 years, according to the project guidelines, would be an alternative civilian airport for Skopje as well, with the possibility to become the country’s main airport within the next 20 years. The project in Ohrid would take a year to be complete while the Skopje project would take a few years.

The TAV postponement is not good news for certain Macedonian politicians who trumpeted the deal promising new employment for thousands of people. Many believe that TAV’s promise to launch the mass investment next year will also be delayed.

Space Shuttle Solid Rocket Booster

Space Shuttle Solid Rocket Booster:
The Space Shuttle Solid Rocket Boosters (SRBs) are the pair of large solid rockets used by the space shuttle during the first two minutes of powered flight. Together they provide about 83% of liftoff thrust for the Space Shuttle. They are located on either side of the orange external propellant tank. Each SRB produces 80% more liftoff thrust than one F-1 engine, the most powerful single-chamber liquid-fueled rocket engine ever flown — 5 of which powered the Saturn V "moon rocket's" first stage. The SRBs are the largest solid-fuel rocket motors ever flown, and the first to be used for primary propulsion on human spaceflight missions.The spent SRBs are recovered from the ocean, refurbished, reloaded with propellant, and reused for several missions. The prime contractor for the SRBs and the manufacturer of the vital solid fuel rocket segments is the Thiokol Corporation of Brigham City, Utah. SRBs are reused many times, for example a SRB from STS-1 flew 48 times into space over 30 years, and in 2009 was used as an Ares I test engine.
The two reusable SRBs provide the main thrust to lift the shuttle off the launch pad and up to an altitude of about 150,000 ft (28 mi; 46 km). While on the pad, the two SRBs carry the entire weight of the external tank and orbiter and transmit the weight load through their structure to the mobile launch platform. Each booster has a liftoff thrust of approximately 2,800,000 pounds-force (12.5 MN) at sea level, increasing shortly after liftoff to about 3,100,000 lbf (13.8 MN). They are ignited after the three space shuttle main engines' thrust level is verified. Seventy five seconds after SRB separation, SRB apogee occurs at an altitude of approximately 220,000 ft (67 km); parachutes are then deployed and impact occurs in the ocean approximately 122 nautical miles (226 km) downrange, after which the two SRBs are recovered. The SRBs are the largest solid-propellant motors ever flown and the first of such large rockets designed for reuse. Each is 149.16 ft (45.46 m) long and 12.17 ft (3.71 m) in diameter. Each SRB weighs approximately 1,300,000 lb (590,000 kg) at launch. The two SRBs constitute about 60% of the total lift-off mass. The propellant for each solid rocket motor weighs approximately 1,100,000 lb (500,000 kg). The inert weight of each SRB is approximately 200,000 lb (91,000 kg).
Hold-down posts Each solid rocket booster has four hold-down posts that fit into corresponding support posts on the mobile launcher platform. Hold-down bolts hold the SRB and launcher platform posts together. Each bolt has a nut at each end, the top one being a frangible nut. The top nut contains two NASA standard detonators (NSDs), which are ignited at solid rocket motor ignition commands. When the two NSDs are ignited at each hold down, the hold-down bolt travels downward because of the release of tension in the bolt (pretensioned before launch), NSD gas pressure and gravity. The bolt is stopped by the stud deceleration stand, which contains sand. The SRB bolt is 28 in (710 mm) long and is 3.5 in (89 mm) in diameter. The frangible nut is captured in a blast container. In the event of a hold down failure the thrust from SRB ignition is enough to break the bolts, freeing the vehicle. The solid rocket motor ignition commands are issued by the orbiter's computers through the master events controllers to the hold-down pyrotechnic initiator controllers (PICs) on the mobile launcher platform. They provide the ignition to the hold-down NSDs. The launch processing system monitors the SRB hold- down PICs for low voltage during the last 16 seconds before launch. PIC low voltage will initiate a launch hold. Electrical power distribution Electrical power distribution in each SRB consists of orbiter supplied main DC bus power to each SRB via SRB buses labeled A, B and C. orbiter main DC buses A, B and C supply main DC bus power to corresponding SRB buses A, B and C. In addition, orbiter main DC bus C supplies backup power to SRB buses A and B, and orbiter bus B supplies backup power to SRB bus C. This electrical power distribution arrangement allows all SRB buses to remain powered in the event one orbiter main bus fails. The nominal operating voltage is 28±4 volts DC
There are two self-contained, independent Hydraulic Power Units (HPUs) on each SRB. Each HPU consists of an auxiliary power unit (APU), fuel supply module, hydraulic pump, hydraulic reservoir and hydraulic fluid manifold assembly. The APUs are fueled by hydrazine and generate mechanical shaft power to drive a hydraulic pump that produces hydraulic pressure for the SRB hydraulic system. The two separate HPUs and two hydraulic systems are located on the aft end of each SRB between the SRB nozzle and aft skirt. The HPU components are mounted on the aft skirt between the rock and tilt actuators. The two systems operate from T minus 28 seconds until SRB separation from the orbiter and external tank. The two independent hydraulic systems are connected to the rock and tilt servoactuators. The HPU controller electronics are located in the SRB aft integrated electronic assemblies on the aft external tank attach rings. The HPUs and their fuel systems are isolated from each other. Each fuel supply module (tank) contains 22 lb (10.0 kg) of hydrazine. The fuel tank is pressurized with gaseous nitrogen at 400 psi (2.8 MPa), which provides the force to expel (positive expulsion) the fuel from the tank to the fuel distribution line, maintaining a positive fuel supply to the APU throughout its operation. In the APU, a fuel pump boosts the hydrazine pressure and feeds it to a gas generator. The gas generator catalytically decomposes the hydrazine into hot, high-pressure gas; a two-stage turbine converts this into mechanical power, driving a gearbox. The waste gas, now cooler and at low pressure, is passed back over the gas generator housing to cool it before being dumped overboard. The gearbox drives the fuel pump, its own lubrication pump, and the HPU hydraulic pump. As described so far, the system could not self-start, since the fuel pump is driven by the turbine it supplies fuel to. Accordingly, a bypass line goes around the pump and feeds the gas generator using the nitrogen tank pressure until the APU speed is such that the fuel pump outlet pressure exceeds that of the bypass line, at which point all the fuel is supplied to the fuel pump.
Each SRB has two hydraulic gimbal servoactuators: one for roll and one for tilt. The servoactuators provide the force and control to gimbal the nozzle for thrust vector control. The space shuttle ascent thrust vector control portion of the flight control system directs the thrust of the three shuttle main engines and the two SRB nozzles to control shuttle attitude and trajectory during lift- off and ascent. Commands from the guidance system are transmitted to the ATVC (Ascent Thrust Vector Control) drivers, which transmit signals proportional to the commands to each servoactuator of the main engines and SRBs. Four independent flight control system channels and four ATVC channels control six main engine and four SRB ATVC drivers, with each driver controlling one hydraulic port on each main and SRB servoactuator. Each SRB servoactuator consists of four independent, two- stage servovalves that receive signals from the drivers. Each servovalve controls one power spool in each actuator, which positions an actuator ram and the nozzle to control the direction of thrust. The four servovalves in each actuator provide a force summed majority voting arrangement to position the power spool. With four identical commands to the four servovalves, the actuator force-sum action prevents a single erroneous command from affecting power ram motion. If the erroneous command persists for more than a predetermined time, differential pressure sensing activates a selector valve to isolate and remove the defective servovalve hydraulic pressure, permitting the remaining channels and servovalves to control the actuator ram spool. Failure monitors are provided for each channel to indicate which channel has been bypassed. An isolation valve on each channel provides the capability of resetting a failed or bypassed channel.
Rate gyro assemblies Each SRB contains two Rate gyro assemblies (RGAs), with each RGA containing one pitch and one yaw gyro. These provide an output proportional to angular rates about the pitch and yaw axes to the orbiter computers and guidance, navigation and control system during first-stage ascent flight in conjunction with the orbiter roll rate gyros until SRB separation. At SRB separation, a switchover is made from the SRB RGAs to the orbiter RGAs. The SRB RGA rates pass through the orbiter flight aft multiplexers/demultiplexers to the orbiter GPCs. The RGA rates are then mid-value-selected in redundancy management to provide SRB pitch and yaw rates to the user software. The RGAs are designed for 20 missions. Propellant The propellant mixture in each SRB motor consists of ammonium perchlorate (oxidizer, 69.6% by weight), aluminum (fuel, 16%), iron oxide (a catalyst, 0.4%), a polymer (such as PBAN or HTPB, serving as a binder that holds the mixture together and acting as secondary fuel, 12.04%), and an epoxy curing agent (1.96%). This propellant is commonly referred to as Ammonium Perchlorate Composite Propellant, or simply APCP. This mixture develops a specific impulse of 242 seconds at sea level or 268 seconds in a vacuum. The main fuel, aluminum is used because it has a reasonable specific energy density of about 31.0MJ/kg, but having a high volumetric energy density, as well as being difficult to accidentally ignite. The propellant is an 11-point star-shaped perforation in the forward motor segment and a double-truncated-cone perforation in each of the aft segments and aft closure. This configuration provides high thrust at ignition and then reduces the thrust by approximately a third 50 seconds after lift-off to avoid overstressing the vehicle during maximum dynamic pressure



1. It takes only about eight minutes for the Space Shuttle to accelerate to a speed of more than 17,000 miles (27,359 kilometers) per hour. 

2. The Space Shuttle main engine weighs 1/7th as much as a train engine but delivers as much horsepower as 39 locomotives.

3. The turbopump on the Space Shuttle main engine is so powerful it could drain an average family-sized swimming pool in 25 seconds. 

4. The Space Shuttle's three main engines and two solid rocket boosters generate some 7.3 million pounds (3.3 million kilograms) of thrust at liftoff. Compare that with America's first two manned launch vehicles, the Redstone which produced 78,000 pounds (35,380 kilograms) of thrust, and the Atlas, which produced 360,000 pounds (163, 293 kilograms). 

5. The liquid hydrogen in the Space Shuttle main engine is -423 degrees Fahrenheit (-253 degrees Centigrade), the second coldest liquid on Earth, and when burned with liquid oxygen, the temperature in the engine's combustion chamber reaches +6,000 degrees F. (+3,316 degrees C.) 

6. The energy released by the three Space Shuttle main engines is equivalent to the output of 23 Hoover Dams. 

7. Each of the Shuttle's solid rocket motors burns 5 tons (4,536 kilograms) of propellant per second, a total of 1.1 million pounds (498,952 kilograms) in 120 seconds. The speed of the gases exiting the nozzle is more than 6,000 miles (9,656 kilometers) per hour, about five times the speed of sound or three times the speed of a high-powered rifle bullet. The plume of flame ranges up to 500 feet (152 meters) long. 

8. The combustion gases in a solid rocket motor are at a temperature of 6,100 degrees Fahrenheit (3,371 degrees Centigrade), two-thirds the temperature of the surface of the sun. While that temperature is hot enough to boil steel, special insulation inside the motor protects the steel case so well that the outside of the case reaches only about 130 degrees F. (54 degrees C.). 

9.  A stacked booster is the same height as the Statue of Liberty (not including pedestal) -- 151 feet (46 meters) -- but weighs almost three times as much. 

10. The four engines of a Boeing 747 jet produce 188,000 pounds (85,275 kilograms) of thrust, while just one SRM produces more than 17 times as much thrust -- 3.3 million pounds (1.5 million kilograms). A pair of SRM's are more powerful than 35 jumbo jets at takeoff. 

11.If their heat energy could be converted to electric power, two SRMs firing for two minutes would produce 2.2 million kilowatt hours of power, enough to supply the entire power demand of 87,000 homes for a full day. 

12. The Shuttle's Remote Manipulator System (RMS), or robot arm, provided by the Canadian Space Agency, weighs about 905 pounds (411 kilograms) on Earth but can move cargo in space weighing 66,000 pounds (29,937 kilograms), objects about the size of a Greyhound bus.



The Lockheed Martin X-33 was an unmanned, sub-scale technology demonstrator for the VentureStar under the Space Launch Initiative. The VentureStar was planned to be a next-generation, commercially operated reusable launch vehicle. The X-33 would flight-test a range of technologies that NASA believed it needed for single-stage-to-orbit reusable launch vehicles (SSTO RLVs), such as metallic thermal protection systems, composite cryogenic fuel tanks for liquid hydrogen, the aerospike engine, autonomous (unmanned) flight control, rapid flight turn-around times through streamlined operations, and its lifting body aerodynamics.


Through the use of the lifting body shape, composite liquid fuel tanks, and the aerospike engine, NASA and Lockheed Martin hoped to test fly a craft that would demonstrate the viability of a single-stage-to-orbit (SSTO) design. An SSTO craft would not require external fuel tanks or boosters to reach low-earth orbit. Doing away with the need for "staging" with launch vehicles, such as with the Shuttle and the Apollo rockets, would lead to an inherently more reliable and safer space launch vehicle. While the X-33 would not approach airplane-like safety, the X-33 would attempt to demonstrate that 0.997 reliability, or 3 mishaps out of 1,000 launches, which would be an order of magnitude more reliable than the Space Shuttle system, was achievable. The 15 planned experimental X-33 flights could only begin this statistical evaluation.

The unmanned craft would have been launched vertically from a specially designed facility constructed on Edwards Air Force Base,and landed horizontally on a runway at the end of its mission. Initial sub-orbital test flights were planned from Edwards AFB to Dugway Proving Grounds southwest of Salt Lake City, Utah. Once those test flights were completed, further flight tests would be conducted from Edwards AFB to Malmstrom AFB in Great Falls, Montana, to gather more complete data on aircraft heating and engine performance at higher speeds and altitudes.

On July 2, 1996, NASA selected Lockheed Martin Skunk Works of Palmdale, California, to design, build, and test the X-33 experimental vehicle for the RLV program. Lockheed Martin's design concept for the X-33 was selected over competing designs from Boeing and McDonnell Douglas. Boeing featured a Space Shuttle-derived design, and McDonnell Douglas featured a design based on its vertical takeoff and landing DC-XA test vehicle.


Based on the X-33 experience shared with NASA, Lockheed Martin hoped to make the business case for a full-scale SSTO RLV, called VentureStar, that would be developed and operated through commercial means. The intention was that rather than operate space transport systems as it has with the Space Shuttle, NASA would instead look to private industry to operate the reusable launch vehicle and NASA would purchase launch services from the commercial launch provider. Thus, the X-33 was not only about honing space flight technologies, but also about successfully demonstrating the technology required to make a commercial reusable launch vehicle possible.

The VentureStar was to be the first commercial aircraft to fly into space. The unmanned X-33 was slated to fly 15 suborbital hops to near 75.8 km altitude.It also was to be the first aircraft with a ballistic trajectory. It was to be launched upright like a rocket and rather than having a straight flight path it would fly diagonally up for half the flight, reaching extremely high altitudes, and then back down for the rest of the flight. The VentureStar was intended for long inter-continental flights and supposed to be in service by 2012, but this project was never funded or begun.

The decision to design and build the X-33 grew out of an internal NASA study titled "Access to Space". Unlike other space transport studies, "Access to Space" was to result in the design and construction of a vehicle.


Construction of the prototype was some 85% assembled with 96% of the parts and the launch facility 100% complete when the program was canceled by NASA in 2001, after a long series of technical difficulties including flight instability and excess weight.

In particular, the composite liquid hydrogen fuel tank failed during testing in November 1999. The tank was constructed of honeycomb composite walls and internal structures to lower its weight. A lighter tank was needed for the craft to demonstrate necessary technologies for single-stage-to-orbit operations. A hydrogen fueled SSTO craft's mass fraction requires that the weight of the vehicle without fuel be 10% of the fully-fueled weight. This would allow for a vehicle to fly to low earth orbit without the need for the sort of external boosters and fuel tanks used by the Space Shuttle. But, after the composite tank failed on the test stand during fueling and pressure tests, NASA came to the conclusion that the technology of the time was simply not advanced enough for such a design. This conclusion is heavily disputed in the alt-space community, who blame the program's failure on NASA's preference for researching new materials and technologies rather than using older more reliable ones—for example, use of composite hydrogen tanks instead of aluminium-lithium. While the composite tank walls themselves were lighter, the odd hydrogen tank shape resulted in complex joints increasing the total mass of the composite tank to above that of an aluminum-based tank.

NASA had invested $912 million in the project before cancellation and Lockheed Martin a further $357 million. Due to changes in the space launch business—including the challenges faced by companies such as Globalstar, Teledesic, and Iridium and the resulting drop in the number of anticipated commercial satellite launches per year—Lockheed Martin deemed that continuing development of the X-33 privately without government support would not be profitable.

After the cancellation, engineers were able to make a working liquid oxygen tank out of carbon fiber composite.

Blog Archive