Nice easy one this week.
What aircraft type do we have here then ?
And what's with the long rod ?

Added for no historic reason - but purely because I like the pic.

As spied at Rotorua water front a while back.

Which leads me to the next Question time !

In the week which will be remembered by countless emergencies in commercial aviation, Croatia Airlines has joined the long list to experience an incident. High scholl graduates who were expected to return home to Zagreb from Barcelona, half an hour after midnight on Thursday their flight OU8221 experienced wheel corrosion after a bird flew into the engine as the aircraft was about to depart. A few birds flew into the engine and the aircraft was forced to come to a halt at full speed. Upon checks the engine was given the green light however one of the wheels was damaged due to the sudden termination of departure.

As the checks on the Airbus A319 took place until 6.30AM the pilots’ and cabin crews working hours ran out. In accordance to Croatian law, which regulates air traffic, the cabin crew, together with the students waited until midnight until they could depart. All of the 106 students spent the extra night in the hotel.

This week there were many incidents which involved Air France (overshot runway), RyanAir (loss of cabin air pressure), Sudan Airways (hijacking) and Itek Air (crash).

Vertical Speed Indicator (VSI) is an instrument that uses static pressure to display a rate of climb or descent in feet per minute. The VSI can also sometimes be called a vertical velocity indicator (VVI).

The vertical speed indicator (VSI), which is sometimes called a vertical velocity indicator (VVI), indicates whether the airplane is climbing, descending, or in level flight. The rate of climb or descent is indicated in feet per minute. If properly calibrated, the VSI indicates zero in level flight.

Although the vertical speed indicator operates solely from static pressure, it is a differential pressure instrument. It contains a diaphragm with connecting linkage and gearing to the indicator pointer inside an airtight case. The inside of the diaphragm is connected directly to the static line of the pitot-static system.

The vertical speed indicator is capable of displaying two different types of information:
Trend information shows an immediate indication of an increase or decrease in the airplane's rate of climb or descent.
Rate information shows a stabilized rate of change in altitude.

For example, if maintaining a steady 500-foot per minute (f.p.m.) climb, and the nose is lowered slightly, the VSI immediately senses this change and indicates a decrease in the rate of climb. This first indication is called the trend. After a short time, the VSI needle stabilizes on the new rate of climb, which in this example, is something less than 500 f.p.m. The time from the initial change in the rate of climb, until the VSI displays an accurate indication of the new rate, is called the lag. Rough control technique and turbulence can extend the lag period and cause erratic and unstable rate indications. Some airplanes are equipped with an instantaneous vertical speed indicator (IVSI), which incorporates accelerometers to compensate for the lag in the typical VSI.

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.

Aircraft that are flown in instrument meteorological conditions (IMC) are equipped with instruments that provide attitude and direction reference, as well as radio navigation instruments that allow precision flight from takeoff to landing with limited or no outside visual reference.

A turn using 30° of bank is seldom necessary, or advisable, in instrument meteorological conditions (IMC) and is considered an unusual attitude in a helicopter.

Tag: Flying instrument, instrument flight, aviation, piloting, instrument rating, instrument flying training, instrument flight rating, instrument rating requirement, instrument rating regulation, aircraft, aero plane, airplane, and aeronautical knowledge.


Pilots should have a basic understanding of GPS approach procedures and practice GPS IAPs under visual meteorological conditions (VMC) until thoroughly proficient with all aspects of their equipment (receiver and installation) prior to attempting flight in instrument meteorological conditions (IMC).

Pilots who fly in familiar uncongested areas, stay continually alert to weather developments, and accept an alternative to their original plan, may not need an Instrument Rating. However, some cross-country destinations may take a pilot to unfamiliar airports and/or through high activity areas in marginal visual or instrument meteorological conditions (IMC). Under these conditions, an Instrument Flying Rating may be an alternative to rerouting, rescheduling, or canceling a flight. Many accidents are the result of pilots who lack the necessary skills or equipment to fly in marginal visual meteorological conditions (VMC) or IMC conditions and attempt flight without outside references.

Aircraft—A device that is used for flight in the air.

Airplane—An engine-driven, fixed-wing aircraft heavier than air that is supported in flight by the dynamic reaction of air against its wings.

FUSELAGE—The section of the airplane that consists of the cabin and/or cockpit, containing seats for the occupants and the controls for the airplane.

WINGS—Airfoils attached to each side of the fuselage and are the main lifting surfaces that support the airplane in flight.

EMPENNAGE—The section of the airplane that consists of the vertical stabilizer, the horizontal stabilizer, and the associated control surfaces.

CONVENTIONAL LANDING GEAR—Landing gear employing a third rear-mounted wheel. These airplanes are also sometimes referred to as tailwheel airplanes.

Nacelle—A streamlined enclosure on an aircraft in which an engine is mounted. On multiengine propeller-driven airplanes, the nacelle is normally mounted on the leading edge of the wing.

Biplane—An airplane that has two main airfoil surfaces or wings on each side of the fuselage, one placed above the other.

Airfoil—An airfoil is any surface, such as a wing, propeller, rudder, or even a trim tab, which provides aerodynamic force when it interacts with a moving stream of air.

Monoplane—An airplane that has only one main lifting surface or wing, usually divided into two parts by the fuselage.

Truss—A fuselage design made up of supporting structural members that resist deformation by applied loads.

Monocoque—A shell-like fuselage design in which the stressed outer skin is used to support the majority of imposed stresses. Monocoque fuselage design may include bulkheads but not stringers.

Semi-Monocoque—A fuselage design that includes a substructure of bulkheads and/or formers, along with stringers, to support flight loads and stresses imposed on the fuselage.

HUNG START - In gas turbine engines, a condition of normal light off but with rpm remaining at some low value rather than increasing to the normal idle rpm. This is often the result of insufficient power to the engine from the starter. In the event of a hung start, the engine should be shut down.

HOT START - In gas turbine engines, a start which occurs with normal engine rotation, but exhaust temperature exceeds prescribed limits. This is usually caused by an excessively rich mixture in the combustor. The fuel to the engine must be terminated immediately to prevent engine damage.

TURBINE ENGINE HOT/HUNG START
A hot start is when the EGT exceeds the safe limit. Too much fuel entering the combustion chamber or insufficient turbine rpm causes hot starts. Any time an engine has a hot start, refer to the AFM, POH, or an appropriate maintenance manual for inspection requirements.

If the engine fails to accelerate to the proper speed after ignition or does not accelerate to idle rpm, a hung start has occurred. A hung start may also be called a false start. A hung start may be caused by an insufficient starting power source or fuel control malfunction.

The agency for privatisation of the Federation of Bosnia and Herzegovina has confirmed that it has received only one offer for the purchase of 49% of the national airline of the country – B&H Airlines. The tender for the submission of offers was closed yesterday at 16.00CET however the agency has stated it will accept offers sent by mail that arrive in the next 3 days as they could have travelled longer than expected and arrived late as a result. The Agency has stated it is disappointed as many announced they would compete in the tender including Croatia Airlines, MyAir from Italy and Turkish Airlines. It is expected that the offer submitted is a joint bid from the Islamic Bank of reconstruction and development and Royal Jordanian Airlines, the national airline of Jordan.

The best offer, which in this case can only be the one submitted, will be revealed in 30 days (September 29) while final talks between the purchasing party and the government will be held on October 30.

Some numbers from Javafoil using the Drela approximation method (Xfoil after 1991):



NACA 66-020

Parameters: Length 6 meters, diameter from thickest point 1.2 meters:

α Re Cl Cd Cm 0.25 TU TL SU SL L/D A.C.
[°] [-] [-] [-] [-] [-] [-] [-] [-] [-] [-]
0.0 11.60E6 0.000 0.00709 -0.000 0.623 0.623 1.000 1.000 0.000 0.380

So estimated Cd for the fuselage is 0.00709. Doors, antennas, landing gear door, etc. will make it worse.

Bugs and dirt on the fuselage surface and the results becomes:

NACA 66-020

α Re Cl Cd Cm 0.25 TU TL SU SL L/D A.C.
[°] [-] [-] [-] [-] [-] [-] [-] [-] [-] [-]
0.0 11.60E6 0.000 0.01212 -0.000 0.625 0.625 1.000 1.000 0.000 0.380

NACA 66-030 (engine nacelle variant of the laminar body)

m/S = 1
α Re Cl Cd Cm 0.25 TU TL SU SL L/D A.C.
[°] [-] [-] [-] [-] [-] [-] [-] [-] [-] [-]
0.0 11.60E6 0.000 0.00775 -0.000 0.605 0.603 1.000 1.000 0.000 0.456

Cd = 0.00775

With NACA 66-025 the fuselage pod length drops to 4.8 meters.



NACA 66-025

m/S = 1
α Re Cl Cd Cm 0.25 TU TL SU SL L/D A.C.
[°] [-] [-] [-] [-] [-] [-] [-] [-] [-] [-]
0.0 9.28E6 0.000 0.00812 -0.000 0.612 0.612 1.000 1.000 0.000 0.417

Cd = 0.00818

Conclusion: All of these pods provide (according to simulation), a low drag coefficient.

Equivalent drag area for NACA 66-025 assuming body diameter of 1.2 meters:

0.00818*(0.6m*0.6m*3.14159) = 0.00925 m^2 (=0.0823 sq ft)

Hmm. did I calculate correctly? Somehow looks quite small.

Serbian media have responded to the website airlinequality.com which ranks airlines from 1 to 5 stars depending on levels of service and other factors influencing the airlines operations. Although the rankings have been available for more than 4 years, as a Serbian tabloid discovered the website, which is well known amongst aviation fans (website), other more distinguished newspapers picked up the story.

Jat commented on the rankings saying it has motivated them to improve services. The Serbian national airline joins airlines such as SAS, Canadian Airlines, and Iberia and also EX-YU airlines Croatia Airlines and Adria Airways in the 3 star ranking. Jat Airways released a statement saying that “the airline feels proud of its ranking having in mind the extreme difficulties it had faced in the past 17 years. Because of the rankings we will particularly focus on improving customer service”. Jat’s rankings in detail can be seen here.

MAT Macedonian Airlines has received a 2 star rankings while B&H Airlines and Montenegro Airlines have not received rankings as yet. According to the website rankings are reviewed annually. For a full rankings review click here.

I have a bit evolved set of requirements for an aircraft concept to present. They are now as follows:

- safe
* 2 engines
* 2 fuel systems
* 2 propellers
* non-stallable
* non-spinnable
* double avionics
* two batteries
* two electrical systems
* moderate stall speed (<=55 kts)
* good brakes
* good tires and landing gear that does not break from few bounces
- economical
* very low fuel consumption
* must run on autogas or diesel oil
- at least 2 places with side by side seating, in comfort (enough space in cockpit, a lot more than in a Cessna)
- very long endurance
- capable to high altitude flight
- best glide ratio speed as high as feasible (enabling cruising at L/D max).
- very high best L/D ratio (>=1:25)
- low minimum sink rate
- relatively low power required to keep in level flight
- low drag utilizing extensive laminar flow in the fuselage and wings
- lightning strike protection (copper mesh installed to the whole aircraft)
- utility category (+4.4/-2.2G)
- positively stable in all flight conditions (suitable for IFR flight)
- speed brakes / spoilers
- ballistic recovery chute
- strong roll cage around the cockpit, exceeding the current FAR23 requirement at least with factor of two
- keeping aircraft CG on correct place do not require using ballast (no matter if there are two or one person sitting on front seats)
- aircraft can be parked without anyone sitting on it on its normal upright position
- aircraft shall look stylish and out-of-this-worldish
- surface finish has to be smooth
- large enough control panel for fitting IFR instruments (Large EFIS screen + analog backup instruments)
- good visibility outside
- rudder trim
- aileron trim
- elevator trim
- using aircraft systems has to be simple and all procedures has to be very simple and easy to memorize (aircraft shall not be a checklist-machine)

Summary: Different-looking composite aircraft that incorporates extensive laminar flow, does not stall or spin and that you can fly from Europe to Oskosh and back with ease and with peace of mind. Complies or exceeds with FAR23.

The three new MD NOTARS as seen at Christchurch.

ZK-HBC4 c/n LN018, as seen at Heli-Maintenance today.

ZK-HCZ 4. c/n LN106, at Skysales on 29-05-2008

ZK-HYY4 c/n LN107 (not yet registered) at Skysales on 06-07-2008

ZK-HYY & ZK-HCZ as seen today at Skysales.

The bosses signature (Lynn Tilton CEO MDHC) inside the cockpit of ZK-HYY.

During the last year the government of Republika Srpska, an entity wihin Bosnia and Herzegovina, has announced the creation of its own airline to be named Sky Srpska. The project recently received the green light for the government and new developments have since occurred which could see the airline take off from its base in Banja Luka (pictured above) by the beginning of next year. Yesterday the government of Republika Srpska announced that Sky Srpska would soon receive 2 new, smaller, aircraft for which $24.5 million dollars (USD) will be allocated from the entity’s budget. The two aircraft will have a capacity of 50 seats and will be purchased via credit. The manufacturer of the aircraft has not been chosen however the president of Republika Srpska, Milorad Dodik, a few months ago hinted they could come from the American “General electric”. There is no word on which destinations would be served by the airline although whatever destinations are chosen they will have to wait until next year as it will take time until the aircraft are dispatched to the airline. The CEO of Sky Srpska has announced that future development plan of the airline will soon be made public.

The government hopes to, by starting up Sky Srpska, bring life to Banja Luka Airport which despite its renovated runway, control tower and terminal has extremely low traffic – only served by Serbia’s Jat Airways (to Belgrade), Bosnia’s B&H Airlines (to Zurich) and Austrojet (to Salzburg).

Republika Srpska used to have a national airline from 1999 until 2003. Air Srpska was owned by Jat Airways and used two of its ATR72s for operations to Belgrade, St. Gallen/Altenrhein, Vienna and Zurich. However Jat withdrew its aircraft from the airline in 2003 and therefore all operations ceased. Although Air Srpska was not a large airline, it was extremely unique having major agreements with airlines such as Swiss Air as well as being part of IATA (unusual for a small regional airline) , however this was mostly achieved due to Jat’s lobbying and support.

Introduction

Attitude instrument flying may be defined as the control of an aircraft's

spatial position by using instruments rather than outside visual

references.



Any flight, regardless of the aircraft used or route flown, consists of

basic maneuvers. In visual flight, you control aircraft attitude with

relation to the natural horizon by using certain reference points on the

aircraft. In instrument flight, you control aircraft attitude by reference

to the flight instruments. A proper interpretation of the flight

instruments will give you essentially the same information that outside

references do in visual flight. Once you learn the role of all the

instruments in establishing and maintaining a desired aircraft attitude,

you will be better equipped to control the aircraft in emergency situations

involving failure of one or more key instruments.



Two basic methods used for learning attitude instrument flying are "control

and performance" and "primary and supporting." Both methods involve the use

of the same instruments, and both use the same responses for attitude

control. They differ in their reliance on the attitude indicator and

interpretation of other instruments.



Attitude instrument flying: Controlling the aircraft by reference to the

instruments rather than outside visual cues.





Control and Performance Method

Aircraft performance is achieved by controlling the aircraft attitude and

power (angle of attack and thrust to drag relationship). Aircraft attitude

is the relationship of its longitudinal and lateral axes to the Earth's

horizon. An aircraft is flown in instrument flight by controlling the

attitude and power, as necessary, to produce the desired performance. This

is known as the control and performance method of attitude instrument

flying and can be applied to any basic instrument maneuver. [Figure 4-1]

(See attached file: 4-1 Control-Performance cross-check method.jpg) The

three general categories of instruments are control, performance, and

navigation instruments.



Control Instruments

The control instruments display immediate attitude and power indications

and are calibrated to permit attitude and power adjustments in precise

amounts. In this discussion, the term "power" is used in place of the more

technically correct term "thrust or drag relationship." Control is

determined by reference to the attitude indicator and power indicators.

These power indicators vary with aircraft and may include tachometers,

manifold pressure, engine pressure ratio, fuel flow, etc.



Instrument flight fundamental: Attitude + Power = Performance





Performance Instruments

The performance instruments indicate the aircraft's actual performance.

Performance is determined by reference to the altimeter, airspeed or Mach

indicator, vertical speed indicator, heading indicator, angle-of-attack

indicator, and turn-and-slip indicator.



Navigation Instruments

The navigation instruments indicate the position of the aircraft in

relation to a selected navigation facility or fix. This group of

instruments includes various types of course indicators, range indicators,

glide-slope indicators, and bearing pointers.



Procedural Steps

1. Establish—Establish an attitude and power setting on the control

instruments that will result in the desired performance. Known or computed

attitude changes and approximate power settings will help to reduce the

pilot's workload.

2. Trim—Trim until control pressures are neutralized. Trimming for

hands-off flight is essential for smooth, precise aircraft control. It

allows pilots to divert their attention to other cockpit duties with

minimum deviation from the desired attitude.

3. Cross-check—Cross-check the performance instruments to determine if the

established attitude or power setting is providing the desired performance.

The crosscheck involves both seeing and interpreting. If a deviation is

noted, determine the magnitude and direction of adjustment required to

achieve the desired performance.

4. Adjust—Adjust the attitude or power setting on the control instruments

as necessary.





Trim: Adjusting the aerodynamic forces on the control surfaces so that the

aircraft maintains the set attitude without any control input.



Attitude Control

Proper control of aircraft attitude is the result of maintaining a constant

attitude, knowing when and how much to change the attitude, and smoothly

changing the attitude a precise amount. Aircraft attitude control is

accomplished by properly using the attitude indicator. The attitude

reference provides an immediate, direct, and corresponding indication of

any change in aircraft pitch or bank attitude.



Pitch Control

Pitch changes are made by changing the "pitch attitude" of the miniature

aircraft or fuselage dot by precise amounts in relation to the horizon.

These changes are measured in degrees or fractions thereof, or bar widths

depending upon the type of attitude reference. The amount of deviation from

the desired performance will determine the magnitude of the correction.



Bank Control

Bank changes are made by changing the "bank attitude" or bank pointers by

precise amounts in relation to the bank scale. The bank scale is normally

graduated at 0°, 10°, 20°, 30°, 60°, and 90° and may be located at the top

or bottom of the attitude reference. Normally, use a bank angle that

approximates the degrees to turn, not to exceed 30°.



Power Control

Proper power control results from the ability to smoothly establish or

maintain desired airspeeds in coordination with attitude changes. Power

changes are made by throttle adjustments and reference to the power

indicators. Power indicators are not affected by such factors as

turbulence, improper trim, or inadvertent control pressures. Therefore, in

most aircraft little attention is required to ensure the power setting

remains constant.



From experience in an aircraft, you know approximately how far to move the

throttles to change the power a given amount. Therefore, you can make power

changes primarily by throttle movement and then crosscheck the indicators

to establish a more precise setting. The key is to avoid fixating on the

indicators while setting the power. Knowledge of approximate power settings

for various flight configurations will help you avoid over-controlling

power.





Primary and Supporting Method

Another basic method for presenting attitude instrument flying classifies

the instruments as they relate to control function as well as aircraft

performance. All maneuvers involve some degree of motion about the lateral

(pitch), longitudinal (bank/roll), and vertical (yaw) axes. Attitude

control is stressed in this handbook in terms of pitch control, bank

control, power control, and trim control. [Figure 4-2] (See attached file:

4-2 Primary - Supporting crosscheck method.jpg) Instruments are grouped as

they relate to control function and aircraft performance as follows:



Pitch Instruments

Attitude Indicator

Altimeter

Airspeed Indicator

Vertical Speed Indicator



Bank Instruments

Attitude Indicator

Heading Indicator

Magnetic Compass

Turn Coordinator



Power Instruments

Airspeed Indicator

Engine Instruments

Manifold Pressure Gauge (MP)

Tachometer/RPM

Engine Pressure Ratio (EPR)—Jet



For any maneuver or condition of flight, the pitch, bank, and power control

requirements are most clearly indicated by certain key instruments. The

instruments that provide the most pertinent and essential information will

be referred to as primary instruments. Supporting instruments back up and

supplement the information shown on the primary



Fixating: Staring at a single instrument, thereby interrupting the

crosscheck process.



Flight configurations: Adjusting the aircraft controls surfaces (including

flaps and landing gear) in a manner that will achieve a specified attitude.



instruments. Straight-and-level flight at a constant airspeed, for example,

means that an exact altitude is to be maintained with zero bank (constant

heading) at a constant airspeed. The pitch, bank, and power instruments

that tell you whether you are maintaining this flight condition are the:



1. Altimeter—supplies the most pertinent altitude information and is

therefore primary for pitch.

2. Heading Indicator—supplies the most pertinent bank or heading

information, and is primary for bank.

3. Airspeed Indicator—supplies the most pertinent information concerning

performance in level flight in terms of power output, and is primary for

power.



Although the attitude indicator is the basic attitude reference, this

concept of primary and supporting instruments does not devalue any

particular flight instrument. It is the only instrument that portrays

instantly and directly to the actual flight attitude. It should always be

used, when available, in establishing and maintaining pitch-and-bank

attitudes. You will better understand the specific use of primary and

supporting instruments when the basic instrument maneuvers are presented in

detail in Chapter 5, "Airplane Basic Flight Maneuvers."



You will find the terms "direct indicating instrument" and "indirect

indicating instrument" used in the following pages. A "direct" indication

is the true and instantaneous reflection of airplane pitch-and-bank

attitude by the miniature aircraft relative to the horizon bar of the

attitude indicator. The altimeter, airspeed indicator, and vertical speed

indicator give supporting ("indirect") indications of pitch attitude at a

given power setting. The heading indicator and turn needle give supporting

indications for bank attitude.



Fundamental Skills

During attitude instrument training, you must develop three fundamental

skills involved in all instrument flight maneuvers: instrument cross-check,

instrument interpretation, and aircraft control. Although you learn these

skills separately and in deliberate sequence, a measure of your proficiency

in precision flying will be your ability to integrate these skills into

unified, smooth, positive control responses to maintain any prescribed

flight path.



Cross-Check

The first fundamental skill is cross-checking (also called "scanning" or

"instrument coverage"). Cross-checking is the continuous and logical

observation of instruments for attitude and performance information. In

attitude instrument flying, the pilot maintains an attitude by reference to

instruments that will produce the desired result in performance. Due to

human error, instrument error, and airplane performance differences in

various atmospheric and loading conditions, it is impossible to establish

an attitude and have performance remain constant for a long period of time.

These variables make it necessary for the pilot to constantly check the

instruments and make appropriate changes in airplane attitude.



Selected Radial Cross-Check

When you use the selected radial cross-check, your eyes spend 80 to 90

percent of the time looking at the attitude indicator, leaving it only to

take a quick glance at one of the flight instruments (for this discussion,

the five instruments surrounding the attitude indicator will be called the

flight instruments). With this method, your eyes never travel directly

between the flight instruments but move by way of the attitude indicator.

The maneuver being performed determines which instruments to look at in the

pattern. [Figure 4-3] (See attached file: 4-3 Selected radial crosscheck

pattern.jpg)



Inverted-V Cross-Check

Moving your eyes from the attitude indicator down to the turn instrument,

up to the attitude indicator, down to the vertical speed indicator, and

back up to the attitude indicator is called the inverted-V cross-check.

[Figure 4-4] (See attached file: 4-4 Inverted- V cross-check.jpg)



The Rectangular Cross-Check

If you move your eyes across the top three instruments (airspeed indicator,

attitude indicator, and altimeter) and drop them down to scan the bottom

three instruments (vertical speed indicator, heading indicator, and turn

instrument), their path will describe a rectangle (clockwise or

counterclockwise rotation is a personal choice). [Figure 4-5] (See attached

file: 4-5 Rectangular interchange format.jpg)



This cross-checking method gives equal weight to the information from each

instrument, regardless of its importance to the maneuver being performed.

However, this method lengthens the time it takes for your eyes to return to

an instrument critical to the successful completion of the maneuver.



Common Cross-Check Errors

As a beginner, you might cross-check rapidly, looking at the instruments

without knowing exactly what you are looking for. With increasing

experience in basic instrument maneuvers and familiarity with the

instrument indications associated with them, you will learn what to look

for, when to look for it, and what response to make. As proficiency

increases, you cross-check primarily from habit, suiting your scanning rate

and sequence to the demands of the flight situation.



You can expect to make many of the following common scanning errors, both

during training and at any subsequent time, if you fail to maintain basic

instrument proficiency through practice:



1. Fixation, or staring at a single instrument, usually occurs for a good

reason, but has poor results. For instance, you may find yourself staring

at your altimeter, which reads 200 feet below the assigned altitude,

wondering how the needle got there. While you gaze at the instrument,

perhaps with increasing tension on the controls, a heading change occurs

unnoticed, and more errors accumulate. Another common fixation is likely

when you initiate an attitude change. For example, you establish a shallow

bank for a 90° turn and stare at the heading indicator throughout the turn,

instead of maintaining your cross-check of other pertinent instruments. You

know the aircraft is turning and you do not need to recheck the heading

indicator for approximately 25 seconds after turn entry, yet you cannot

take your eyes off the instrument. The problem here may not be entirely due

to cross-check error. It may be related to difficulties with one or both of

the other fundamental skills. You may be fixating because of uncertainty

about reading the heading indicator (interpretation), or because of

inconsistency in rolling out of turns (control).

2. Omission of an instrument from your cross-check is another likely fault.

It may be caused by failure to anticipate significant instrument

indications following attitude changes. For example, on your roll-out from

a 180° steep turn, you establish straight-and-level flight with reference

to the attitude indicator alone, neglecting to check the heading indicator

for constant heading information. Because of precession error, the attitude

indicator will temporarily show a slight error, correctable by quick

reference to the other flight instruments.

3. Emphasis on a single instrument, instead of on the combination of

instruments necessary for attitude information, is an understandable fault

during the initial stages of training. You naturally tend to rely on the

instrument that you understand most readily, even when it provides

erroneous or inadequate information. Reliance on a single instrument is

poor technique. For example, you can maintain reasonably close altitude

control with the attitude indicator, but you cannot hold altitude with

precision without including the altimeter in your crosscheck.



Instrument Interpretation

The second fundamental skill, instrument interpretation, requires the most

thorough study and analysis. It begins as you understand each instrument's

construction and operating principles. Then you must apply this knowledge

to the performance of the aircraft that you are flying, the particular

maneuvers to be executed, the cross-check and control techniques applicable

to that aircraft, and the flight conditions in which you are operating.



Tension: Maintaining an excessively strong grip on the control column;

usually results in an over controlled situation.



For example, a pilot uses full power in a small airplane for a 5-minute

climb from near sea level, and the attitude indicator shows the miniature

aircraft two bar widths (twice the thickness of the miniature aircraft

wings) above the artificial horizon. [Figure 4-6] (See attached file: 4-6

Power and attitude equal performance.jpg) The airplane is climbing at 500

feet per minute (fpm) as shown on the vertical speed indicator, and at

airspeed of 90 knots, as shown on the airspeed indicator. With the power

available in this particular airplane and the attitude selected by the

pilot, the performance is shown on the instruments.



Now set up the identical picture on the attitude indicator in a jet

airplane. With the same airplane attitude as shown in the first example,

the vertical speed indicator in the jet reads 2,000 fpm, and the airspeed

indicates 300 knots. As you learn the performance capabilities of the

aircraft in which you are training, you will interpret the instrument

indications appropriately in terms of the attitude of the aircraft. If the

pitch attitude is to be determined, the airspeed indicator, altimeter,

vertical speed indicator, and attitude indicator provide the necessary

information. If the bank attitude is to be determined, the heading

indicator, turn coordinator, and attitude indicator must be interpreted.



For each maneuver, you will learn what performance to expect and the

combination of instruments you must interpret in order to control aircraft

attitude during the maneuver.



Aircraft Control

The third fundamental instrument flying skill is aircraft control. When you

use instruments as substitutes for outside references the necessary control

responses and thought processes are the same as those for controlling

aircraft performance by means of outside references. Knowing the desired

attitude of the aircraft with respect to the natural and artificial

horizon, you maintain the attitude or change it by moving the appropriate

controls.



Aircraft control is composed of four components: pitch control, bank

control, power control, and trim.



1. Pitch control is controlling the rotation of the aircraft about the

lateral axis by movement of the elevators. After interpreting the pitch

attitude from the proper flight instruments, you exert control pressures to

effect the desired pitch attitude with reference to the horizon.

2. Bank control is controlling the angle made by the wing and the horizon.

After interpreting the bank attitude from the appropriate instruments, you

exert the necessary pressures to move the ailerons and roll the aircraft

about the longitudinal axis.

3. Power control is used when interpretation of the flight instruments

indicates a need for a change in thrust.

4. Trim is used to relieve all control pressures held after a desired

attitude has been attained. An improperly trimmed aircraft requires

constant control pressures, produces tension, distracts your attention from

cross-checking, and contributes to abrupt and erratic attitude control. The

pressures you feel on the controls must be those you apply while

controlling a planned change in aircraft attitude, not pressures held

because you let the aircraft control you.

Climbs

For a given power setting and load condition, there is only one attitude

that will give the most efficient rate of climb. The airspeed and the climb

power setting that will determine this climb attitude are given in the

performance data found in your POH/AFM. Details of the technique for

entering a climb vary according to airspeed on entry and the type of climb

(constant airspeed or constant rate) desired. (Heading and trim control are

maintained as discussed under straight-and-level flight.)



Entry

To enter a constant-airspeed climb from cruising airspeed, raise the

miniature aircraft to the approximate nose-high indication for the

predetermined climb speed. The attitude will vary according to the type of

airplane you are flying. Apply light back-elevator pressure to initiate and

maintain the climb attitude. The pressures will vary as the airplane

decelerates. Power may be advanced to the climb power setting

simultaneously with the pitch change, or after the pitch change is

established and the airspeed approaches climb speed. If the transition from

level flight to climb is smooth, the vertical speed indicator will show an

immediate trend upward, continue to move slowly, then stop at a rate

appropriate to the stabilized airspeed and attitude. (Primary and

supporting instruments for the climb entry are shown in figure 5-25.)



(See attached file: 5-25 Climb entry for constant-airspeed climb.jpg)



Once the airplane stabilizes at a constant airspeed and attitude, the

airspeed indicator is primary for pitch and the heading indicator remains

primary for bank. [Figure 5-26] You will monitor the tachometer or manifold

pressure gauge as the primary power instrument to ensure the proper climb

power setting is being maintained. If the climb attitude is correct for the

power setting selected, the airspeed will stabilize at the desired speed.

If the airspeed is low or high, make an appropriate small pitch correction.



(See attached file: 5-26 Stabilized climb at constant airspeed.jpg)



To enter a constant-airspeed climb, first complete the airspeed reduction

from cruise airspeed to climb speed in straight-and-level flight. The climb

entry is then identical to entry from cruising airspeed, except that power

must be increased simultaneously to the climb setting as the pitch attitude

is increased. Climb entries on partial panel are more easily and accurately

controlled if you enter the maneuver from climbing speed.



The technique for entering a constant-rate climb is very similar to that

used for entry to a constant-airspeed climb from climb airspeed. As the

power is increased to the approximate setting for the desired rate,

simultaneously raise the miniature aircraft to the climbing attitude for

the desired airspeed and rate of climb. As the power is increased, the

airspeed indicator is primary for pitch control until the vertical speed

approaches the desired value. As the vertical-speed needle stabilizes, it

becomes primary for pitch control and the airspeed indicator becomes

primary for power control. [Figure 5-27]



(See attached file: 5-27 Stabilized climb at constant rate.jpg)



Pitch and power corrections must be promptly and closely coordinated. For

example, if the vertical speed is correct, but the airspeed is low, add

power. As the power is increased, the miniature aircraft must be lowered

slightly to maintain constant vertical speed. If the vertical speed is high

and the airspeed is low, lower the miniature aircraft slightly and note the

increase in airspeed to determine whether or not a power change is also

necessary. [Figure 5-28] Familiarity with the approximate power settings

helps to keep your pitch and power corrections at a minimum.



(See attached file: 5-28 Airspeed low and vertical high-reduce pitch.jpg)



Leveling Off

To level off from a climb and maintain an altitude, it is necessary to

start the level off before reaching the desired altitude. The amount of

lead varies with rate of climb and pilot technique. If your airplane is

climbing at 1,000 fpm, it will continue to climb at a decreasing rate

throughout the transition to level flight. An effective practice is to lead

the altitude by 10 percent of the vertical speed shown (500-fpm/ 50-foot

lead, 1,000 fpm/100-foot lead).



To level off at cruising airspeed, apply smooth, steady forward-elevator

pressure toward level-flight attitude for the speed desired. As the

attitude indicator shows the pitch change, the vertical-speed needle will

move slowly toward zero, the altimeter needle will move more slowly, and

the airspeed will show acceleration. [Figure 5-29] Once the altimeter,

attitude indicator, and vertical speed indicator show level flight,

constant changes in pitch and torque control will have to be made as the

airspeed increases. As the airspeed approaches cruising speed, reduce power

to the cruise setting. The amount of lead depends upon the rate of

acceleration of your airplane.



(See attached file: 5-29 Level-off at cruising speed.jpg)



To level off at climbing airspeed, lower the nose to the pitch attitude

appropriate to that airspeed in level flight. Power is simultaneously

reduced to the setting for that airspeed as the pitch attitude is lowered.

If your power reduction is at a rate proportionate to the pitch change, the

airspeed will remain constant.



Descents

A descent can be made at a variety of airspeeds and attitudes by reducing

power, adding drag, and lowering the nose to a predetermined attitude.

Sooner or later the airspeed will stabilize at a constant value. Meanwhile,

the only flight instrument providing a positive attitude reference, by

itself, is the attitude indicator. Without the attitude indicator (such as

during a partial-panel descent) the airspeed indicator, the altimeter, and

the vertical speed indicator will be showing varying rates of change until

the airplane decelerates to a constant airspeed at a constant attitude.

During the transition, changes in control pressure and trim, as well as

cross-check and interpretation, must be very accurate if you expect to

maintain positive control.



Entry

The following method for entering descents is effective either with or

without an attitude indicator. First, reduce airspeed to your selected

descent airspeed while maintaining straight-and-level flight, then make a

further reduction in power (to a predetermined setting). As the power is

adjusted, simultaneously lower the nose to maintain constant airspeed, and

trim off control pressures.



During a constant-airspeed descent, any deviation from the desired airspeed

calls for a pitch adjustment. For a constant rate descent, the entry is the

same, but the vertical-speed indicator is primary for pitch control (after

it stabilizes near the desired rate), and the airspeed indicator is primary

for power control. Pitch and power must be closely coordinated when

corrections are made, as they are in climbs. [Figure 5-30]



(See attached file: 5-30 Constant airspeed descent.jpg)



Leveling Off

The level off from a descent must be started before you reach the desired

altitude. The amount of lead depends upon the rate of descent and control

technique. With too little lead, you will tend to overshoot the selected

altitude unless your technique is rapid. Assuming a 500-fpm rate of

descent, lead the altitude by 100–150 feet for a level off at airspeed

higher than descending speed. At the lead point, add power to the

appropriate level-flight cruise setting. [Figure 5-31] Since the nose will

tend to rise as the airspeed increases, hold forward-elevator pressure to

maintain the vertical speed at the descending rate until approximately 50

feet above the altitude, then smoothly adjust the pitch attitude to the

level flight attitude for the airspeed selected.



(See attached file: 5-31 Level-off airspeed higher than descent

airspeed.jpg)



To level-off from a descent at descent airspeed, lead the desired altitude

by approximately 50 feet, simultaneously adjusting the pitch attitude to

level flight and adding power to a setting that will hold the airspeed

constant. [Figure 5-32] Trim off the control pressures and continue with

the normal straight-and-level flight cross-check.



(See attached file: 5-32 Level-off at descent airspeed.jpg)

Pitch

Pitch errors usually result from the following faults:



Improper adjustment of the attitude indicator's miniature aircraft to

the wings-level attitude. Following your initial level-off from a climb,

check the attitude indicator and make any necessary adjustment in the

miniature aircraft for level flight indication at normal cruise

airspeed.

Insufficient cross-check and interpretation of pitch instruments. For

example, the airspeed indication is low. Believing you are in a

nose-high attitude, you react with forward pressure without noting that

a low power setting is the cause of the airspeed discrepancy. Increase

your cross-check speed to include all relevant instrument indications

before you make a control response.

Uncaging the attitude indicator (if it has a caging feature) when the

airplane is not in level flight. The altimeter and heading indicator

must be stabilized with airspeed indication at normal cruise when you

pull out the caging knob, if you expect the instrument to read

straight-and-level at normal cruise airspeed.

Failure to interpret the attitude indicator in terms of the existing

airspeed.

Late pitch corrections. Pilots commonly like to leave well enough alone.

When the altimeter shows a 20-foot error, there is a reluctance to

correct it, perhaps because of fear of overcontrolling. If

overcontrolling is the error, the more you practice small corrections

and find out the cause of overcontrolling, the closer you will be able

to hold your altitude. If you tolerate a deviation, your errors will

increase.

Chasing the vertical-speed indications. This tendency can be corrected

by proper cross-check of other pitch instruments, as well as by

increasing your understanding of the instrument characteristics.

Using excessive pitch corrections for the altimeter evaluation. Rushing

a pitch correction by making a large pitch change usually aggravates the

existing error and saves neither time nor effort.

Failure to maintain established pitch corrections. This is a common

error associated with cross-check and trim errors. For example, having

established a pitch change to correct an altitude error, you tend to

slow down your crosscheck, waiting for the airplane to stabilize in the

new pitch attitude. To maintain the attitude, you must continue to

cross-check and trim off the pressures you are holding.

Fixations during cross-check. After initiating a heading correction, for

example, you become preoccupied with bank control and neglect to notice

a pitch error. Likewise, during an airspeed change, unnecessary gazing

at the power instrument is common. Bear in mind that a small error in

power setting is of less consequence than large altitude and heading

errors. The airplane will not decelerate any faster if you stare at the

manifold pressure gauge than if you continue your cross-check.



Trim: Adjusting the aerodynamic forces on the control surfaces so that the

aircraft maintains the set attitude without any control input.



Uncaging: Unlocking the gimbals of a gyroscopic instrument, making it

susceptible to damage by abrupt flight maneuvers or rough handling.



Heading

Heading errors usually result from the following faults:



Failure to cross-check the heading indicator, especially during changes

in power or pitch attitude.

Misinterpretation of changes in heading, with resulting corrections in

the wrong direction.

Failure to note, and remember, a preselected heading.

Failure to observe the rate of heading change and its relation to bank

attitude.

Overcontrolling in response to heading changes, especially during

changes in power settings.

Anticipating heading changes with premature application of rudder

control.

Failure to correct small heading deviations. Unless zero error in

heading is your goal, you will find yourself tolerating larger and

larger deviations. Correction of a 1° error takes a lot less time and

concentration than correction of a 20° error.

Correcting with improper bank attitude. If you correct a 10° heading

error with a 20° bank correction, you can roll past the desired heading

before you have the bank established, requiring another correction in

the opposite direction. Do not multiply existing errors with errors in

corrective technique.

Failure to note the cause of a previous heading error and thus repeating

the same error. For example, your airplane is out of trim, with a left

wing low tendency. You repeatedly correct for a slight left turn, yet do

nothing about trim.

Failure to set the heading indicator properly, or failure to uncage it.



Power

Power errors usually result from the following faults:



Failure to know the power settings and pitch attitudes appropriate to

various airspeeds and airplane configurations.

Abrupt use of throttle.

Failure to lead the airspeed when making power changes. For example,

during an airspeed reduction in level flight, especially with gear and

flaps extended, adjust the throttle to maintain the slower speed before

the airspeed reaches the desired speed. Otherwise, the airplane will

decelerate to a speed lower than that desired, resulting in further

power adjustments. How much you lead the airspeed depends upon how fast

the airplane responds to power changes.

Fixation on airspeed or manifold pressure instruments during airspeed

changes, resulting in erratic control of both airspeed and power.



Trim

Trim errors usually result from the following faults:



Improper adjustment of seat or rudder pedals for comfortable position of

legs and feet. Tension in the ankles makes it difficult to relax rudder

pressures.

Confusion as to the operation of trim devices, which differ among

various airplane types. Some trim wheels are aligned appropriately with

the airplane's axes; others are not. Some rotate in a direction contrary

to what you expect.

Faulty sequence in trim technique. Trim should be used, not as a

substitute for control with the wheel (stick) and rudders, but to

relieve pressures already held to stabilize attitude. As you gain

proficiency, you become familiar with trim settings, just as you do with

power settings. With little conscious effort, you trim off pressures

continually as they occur.

Excessive trim control. This induces control pressures that must be held

until you retrim properly. Use trim frequently and in small amounts.

Failure to understand the cause of trim changes. If you do not

understand the basic aerodynamics related to the basic instrument

skills, you will continually lag behind the airplane.

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Introduction

Attitude instrument flying may be defined as the control of an aircraft's

spatial position by using instruments rather than outside visual

references.



Any flight, regardless of the aircraft used or route flown, consists of

basic maneuvers. In visual flight, you control aircraft attitude with

relation to the natural horizon by using certain reference points on the

aircraft. In instrument flight, you control aircraft attitude by reference

to the flight instruments. A proper interpretation of the flight

instruments will give you essentially the same information that outside

references do in visual flight. Once you learn the role of all the

instruments in establishing and maintaining a desired aircraft attitude,

you will be better equipped to control the aircraft in emergency situations

involving failure of one or more key instruments.



Two basic methods used for learning attitude instrument flying are "control

and performance" and "primary and supporting." Both methods involve the use

of the same instruments, and both use the same responses for attitude

control. They differ in their reliance on the attitude indicator and

interpretation of other instruments.



Attitude instrument flying: Controlling the aircraft by reference to the

instruments rather than outside visual cues.





Control and Performance Method

Aircraft performance is achieved by controlling the aircraft attitude and

power (angle of attack and thrust to drag relationship). Aircraft attitude

is the relationship of its longitudinal and lateral axes to the Earth's

horizon. An aircraft is flown in instrument flight by controlling the

attitude and power, as necessary, to produce the desired performance. This

is known as the control and performance method of attitude instrument

flying and can be applied to any basic instrument maneuver. [Figure 4-1]

(See attached file: 4-1 Control-Performance cross-check method.jpg) The

three general categories of instruments are control, performance, and

navigation instruments.



Control Instruments

The control instruments display immediate attitude and power indications

and are calibrated to permit attitude and power adjustments in precise

amounts. In this discussion, the term "power" is used in place of the more

technically correct term "thrust or drag relationship." Control is

determined by reference to the attitude indicator and power indicators.

These power indicators vary with aircraft and may include tachometers,

manifold pressure, engine pressure ratio, fuel flow, etc.



Instrument flight fundamental: Attitude + Power = Performance





Performance Instruments

The performance instruments indicate the aircraft's actual performance.

Performance is determined by reference to the altimeter, airspeed or Mach

indicator, vertical speed indicator, heading indicator, angle-of-attack

indicator, and turn-and-slip indicator.



Navigation Instruments

The navigation instruments indicate the position of the aircraft in

relation to a selected navigation facility or fix. This group of

instruments includes various types of course indicators, range indicators,

glide-slope indicators, and bearing pointers.



Procedural Steps

1. Establish—Establish an attitude and power setting on the control

instruments that will result in the desired performance. Known or computed

attitude changes and approximate power settings will help to reduce the

pilot's workload.

2. Trim—Trim until control pressures are neutralized. Trimming for

hands-off flight is essential for smooth, precise aircraft control. It

allows pilots to divert their attention to other cockpit duties with

minimum deviation from the desired attitude.

3. Cross-check—Cross-check the performance instruments to determine if the

established attitude or power setting is providing the desired performance.

The crosscheck involves both seeing and interpreting. If a deviation is

noted, determine the magnitude and direction of adjustment required to

achieve the desired performance.

4. Adjust—Adjust the attitude or power setting on the control instruments

as necessary.





Trim: Adjusting the aerodynamic forces on the control surfaces so that the

aircraft maintains the set attitude without any control input.



Attitude Control

Proper control of aircraft attitude is the result of maintaining a constant

attitude, knowing when and how much to change the attitude, and smoothly

changing the attitude a precise amount. Aircraft attitude control is

accomplished by properly using the attitude indicator. The attitude

reference provides an immediate, direct, and corresponding indication of

any change in aircraft pitch or bank attitude.



Pitch Control

Pitch changes are made by changing the "pitch attitude" of the miniature

aircraft or fuselage dot by precise amounts in relation to the horizon.

These changes are measured in degrees or fractions thereof, or bar widths

depending upon the type of attitude reference. The amount of deviation from

the desired performance will determine the magnitude of the correction.



Bank Control

Bank changes are made by changing the "bank attitude" or bank pointers by

precise amounts in relation to the bank scale. The bank scale is normally

graduated at 0°, 10°, 20°, 30°, 60°, and 90° and may be located at the top

or bottom of the attitude reference. Normally, use a bank angle that

approximates the degrees to turn, not to exceed 30°.



Power Control

Proper power control results from the ability to smoothly establish or

maintain desired airspeeds in coordination with attitude changes. Power

changes are made by throttle adjustments and reference to the power

indicators. Power indicators are not affected by such factors as

turbulence, improper trim, or inadvertent control pressures. Therefore, in

most aircraft little attention is required to ensure the power setting

remains constant.



From experience in an aircraft, you know approximately how far to move the

throttles to change the power a given amount. Therefore, you can make power

changes primarily by throttle movement and then crosscheck the indicators

to establish a more precise setting. The key is to avoid fixating on the

indicators while setting the power. Knowledge of approximate power settings

for various flight configurations will help you avoid over-controlling

power.





Primary and Supporting Method

Another basic method for presenting attitude instrument flying classifies

the instruments as they relate to control function as well as aircraft

performance. All maneuvers involve some degree of motion about the lateral

(pitch), longitudinal (bank/roll), and vertical (yaw) axes. Attitude

control is stressed in this handbook in terms of pitch control, bank

control, power control, and trim control. [Figure 4-2] (See attached file:

4-2 Primary - Supporting crosscheck method.jpg) Instruments are grouped as

they relate to control function and aircraft performance as follows:



Pitch Instruments

Attitude Indicator

Altimeter

Airspeed Indicator

Vertical Speed Indicator



Bank Instruments

Attitude Indicator

Heading Indicator

Magnetic Compass

Turn Coordinator



Power Instruments

Airspeed Indicator

Engine Instruments

Manifold Pressure Gauge (MP)

Tachometer/RPM

Engine Pressure Ratio (EPR)—Jet



For any maneuver or condition of flight, the pitch, bank, and power control

requirements are most clearly indicated by certain key instruments. The

instruments that provide the most pertinent and essential information will

be referred to as primary instruments. Supporting instruments back up and

supplement the information shown on the primary



Fixating: Staring at a single instrument, thereby interrupting the

crosscheck process.



Flight configurations: Adjusting the aircraft controls surfaces (including

flaps and landing gear) in a manner that will achieve a specified attitude.



instruments. Straight-and-level flight at a constant airspeed, for example,

means that an exact altitude is to be maintained with zero bank (constant

heading) at a constant airspeed. The pitch, bank, and power instruments

that tell you whether you are maintaining this flight condition are the:



1. Altimeter—supplies the most pertinent altitude information and is

therefore primary for pitch.

2. Heading Indicator—supplies the most pertinent bank or heading

information, and is primary for bank.

3. Airspeed Indicator—supplies the most pertinent information concerning

performance in level flight in terms of power output, and is primary for

power.



Although the attitude indicator is the basic attitude reference, this

concept of primary and supporting instruments does not devalue any

particular flight instrument. It is the only instrument that portrays

instantly and directly to the actual flight attitude. It should always be

used, when available, in establishing and maintaining pitch-and-bank

attitudes. You will better understand the specific use of primary and

supporting instruments when the basic instrument maneuvers are presented in

detail in Chapter 5, "Airplane Basic Flight Maneuvers."



You will find the terms "direct indicating instrument" and "indirect

indicating instrument" used in the following pages. A "direct" indication

is the true and instantaneous reflection of airplane pitch-and-bank

attitude by the miniature aircraft relative to the horizon bar of the

attitude indicator. The altimeter, airspeed indicator, and vertical speed

indicator give supporting ("indirect") indications of pitch attitude at a

given power setting. The heading indicator and turn needle give supporting

indications for bank attitude.



Fundamental Skills

During attitude instrument training, you must develop three fundamental

skills involved in all instrument flight maneuvers: instrument cross-check,

instrument interpretation, and aircraft control. Although you learn these

skills separately and in deliberate sequence, a measure of your proficiency

in precision flying will be your ability to integrate these skills into

unified, smooth, positive control responses to maintain any prescribed

flight path.



Cross-Check

The first fundamental skill is cross-checking (also called "scanning" or

"instrument coverage"). Cross-checking is the continuous and logical

observation of instruments for attitude and performance information. In

attitude instrument flying, the pilot maintains an attitude by reference to

instruments that will produce the desired result in performance. Due to

human error, instrument error, and airplane performance differences in

various atmospheric and loading conditions, it is impossible to establish

an attitude and have performance remain constant for a long period of time.

These variables make it necessary for the pilot to constantly check the

instruments and make appropriate changes in airplane attitude.



Selected Radial Cross-Check

When you use the selected radial cross-check, your eyes spend 80 to 90

percent of the time looking at the attitude indicator, leaving it only to

take a quick glance at one of the flight instruments (for this discussion,

the five instruments surrounding the attitude indicator will be called the

flight instruments). With this method, your eyes never travel directly

between the flight instruments but move by way of the attitude indicator.

The maneuver being performed determines which instruments to look at in the

pattern. [Figure 4-3] (See attached file: 4-3 Selected radial crosscheck

pattern.jpg)



Inverted-V Cross-Check

Moving your eyes from the attitude indicator down to the turn instrument,

up to the attitude indicator, down to the vertical speed indicator, and

back up to the attitude indicator is called the inverted-V cross-check.

[Figure 4-4] (See attached file: 4-4 Inverted- V cross-check.jpg)



The Rectangular Cross-Check

If you move your eyes across the top three instruments (airspeed indicator,

attitude indicator, and altimeter) and drop them down to scan the bottom

three instruments (vertical speed indicator, heading indicator, and turn

instrument), their path will describe a rectangle (clockwise or

counterclockwise rotation is a personal choice). [Figure 4-5] (See attached

file: 4-5 Rectangular interchange format.jpg)



This cross-checking method gives equal weight to the information from each

instrument, regardless of its importance to the maneuver being performed.

However, this method lengthens the time it takes for your eyes to return to

an instrument critical to the successful completion of the maneuver.



Common Cross-Check Errors

As a beginner, you might cross-check rapidly, looking at the instruments

without knowing exactly what you are looking for. With increasing

experience in basic instrument maneuvers and familiarity with the

instrument indications associated with them, you will learn what to look

for, when to look for it, and what response to make. As proficiency

increases, you cross-check primarily from habit, suiting your scanning rate

and sequence to the demands of the flight situation.



You can expect to make many of the following common scanning errors, both

during training and at any subsequent time, if you fail to maintain basic

instrument proficiency through practice:



1. Fixation, or staring at a single instrument, usually occurs for a good

reason, but has poor results. For instance, you may find yourself staring

at your altimeter, which reads 200 feet below the assigned altitude,

wondering how the needle got there. While you gaze at the instrument,

perhaps with increasing tension on the controls, a heading change occurs

unnoticed, and more errors accumulate. Another common fixation is likely

when you initiate an attitude change. For example, you establish a shallow

bank for a 90° turn and stare at the heading indicator throughout the turn,

instead of maintaining your cross-check of other pertinent instruments. You

know the aircraft is turning and you do not need to recheck the heading

indicator for approximately 25 seconds after turn entry, yet you cannot

take your eyes off the instrument. The problem here may not be entirely due

to cross-check error. It may be related to difficulties with one or both of

the other fundamental skills. You may be fixating because of uncertainty

about reading the heading indicator (interpretation), or because of

inconsistency in rolling out of turns (control).

2. Omission of an instrument from your cross-check is another likely fault.

It may be caused by failure to anticipate significant instrument

indications following attitude changes. For example, on your roll-out from

a 180° steep turn, you establish straight-and-level flight with reference

to the attitude indicator alone, neglecting to check the heading indicator

for constant heading information. Because of precession error, the attitude

indicator will temporarily show a slight error, correctable by quick

reference to the other flight instruments.

3. Emphasis on a single instrument, instead of on the combination of

instruments necessary for attitude information, is an understandable fault

during the initial stages of training. You naturally tend to rely on the

instrument that you understand most readily, even when it provides

erroneous or inadequate information. Reliance on a single instrument is

poor technique. For example, you can maintain reasonably close altitude

control with the attitude indicator, but you cannot hold altitude with

precision without including the altimeter in your crosscheck.



Instrument Interpretation

The second fundamental skill, instrument interpretation, requires the most

thorough study and analysis. It begins as you understand each instrument's

construction and operating principles. Then you must apply this knowledge

to the performance of the aircraft that you are flying, the particular

maneuvers to be executed, the cross-check and control techniques applicable

to that aircraft, and the flight conditions in which you are operating.



Tension: Maintaining an excessively strong grip on the control column;

usually results in an over controlled situation.



For example, a pilot uses full power in a small airplane for a 5-minute

climb from near sea level, and the attitude indicator shows the miniature

aircraft two bar widths (twice the thickness of the miniature aircraft

wings) above the artificial horizon. [Figure 4-6] (See attached file: 4-6

Power and attitude equal performance.jpg) The airplane is climbing at 500

feet per minute (fpm) as shown on the vertical speed indicator, and at

airspeed of 90 knots, as shown on the airspeed indicator. With the power

available in this particular airplane and the attitude selected by the

pilot, the performance is shown on the instruments.



Now set up the identical picture on the attitude indicator in a jet

airplane. With the same airplane attitude as shown in the first example,

the vertical speed indicator in the jet reads 2,000 fpm, and the airspeed

indicates 300 knots. As you learn the performance capabilities of the

aircraft in which you are training, you will interpret the instrument

indications appropriately in terms of the attitude of the aircraft. If the

pitch attitude is to be determined, the airspeed indicator, altimeter,

vertical speed indicator, and attitude indicator provide the necessary

information. If the bank attitude is to be determined, the heading

indicator, turn coordinator, and attitude indicator must be interpreted.



For each maneuver, you will learn what performance to expect and the

combination of instruments you must interpret in order to control aircraft

attitude during the maneuver.



Aircraft Control

The third fundamental instrument flying skill is aircraft control. When you

use instruments as substitutes for outside references the necessary control

responses and thought processes are the same as those for controlling

aircraft performance by means of outside references. Knowing the desired

attitude of the aircraft with respect to the natural and artificial

horizon, you maintain the attitude or change it by moving the appropriate

controls.



Aircraft control is composed of four components: pitch control, bank

control, power control, and trim.



1. Pitch control is controlling the rotation of the aircraft about the

lateral axis by movement of the elevators. After interpreting the pitch

attitude from the proper flight instruments, you exert control pressures to

effect the desired pitch attitude with reference to the horizon.

2. Bank control is controlling the angle made by the wing and the horizon.

After interpreting the bank attitude from the appropriate instruments, you

exert the necessary pressures to move the ailerons and roll the aircraft

about the longitudinal axis.

3. Power control is used when interpretation of the flight instruments

indicates a need for a change in thrust.

4. Trim is used to relieve all control pressures held after a desired

attitude has been attained. An improperly trimmed aircraft requires

constant control pressures, produces tension, distracts your attention from

cross-checking, and contributes to abrupt and erratic attitude control. The

pressures you feel on the controls must be those you apply while

controlling a planned change in aircraft attitude, not pressures held

because you let the aircraft control you.