Static stability has been defined as the initial tendency to return to equilibrium that the aircraft displays after being disturbed from its trimmed condition. Occasionally, the initial tendency is different or opposite from the overall tendency, so a distinction must be made between the two. Dynamic stability refers to the aircraft response over time when disturbed from a given AOA, slip, or bank. This type of stability also has three subtypes: [Figure 4-19]

 

• Positive dynamic stability—over time, the motion of the displaced object decreases in amplitude and, because it is positive, the object displaced returns toward the equilibrium state.
• Neutral dynamic stability—once displaced, the displaced object neither decreases nor increases in amplitude. A worn automobile shock absorber exhibits this tendency.
• Negative dynamic stability—over time, the motion of the displaced object increases and becomes more divergent.
• Stability in an aircraft affects two areas significantly:
• Maneuverability—the quality of an aircraft that permits it to be maneuvered easily and to withstand the stresses imposed by maneuvers. It is governed by the aircraft’s weight, inertia, size and location of flight controls, structural strength, and powerplant. It too is an aircraft design characteristic.
• Controllability—the capability of an aircraft to respond to the pilot’s control, especially with regard to flightpath and attitude. It is the quality of the aircraft’s response to the pilot’s control application when maneuvering the aircraft, regardless of its stability characteristics.

Jat’s year to recover in 2010?

Yesterday at the Belgrade Media Centre, Jat’s CEO Srdjan Radovanović announced big changes for the airline in 2010 and a new business plan.

2010 will, by all accounts, be a revolutionary year in Serbian aviation. Not only will the country liberate its sky but Serbian citizens ill be able to travel without visas to the European Union from January 1 and low cost airlines are announcing their arrival. All of this could hurt Jat, but the airline’s CEO is more than optimistic about the upcoming year.

Jat’s fleet plans are of most interest to readers. The airline will have all 16 of its aircraft in operation by the end of 2010. Jat will fix the current handful of grounded aircraft while those leased to Air Ivoire of the Ivory Coast will all be returned by the summer season. In March, Jat will finally lease a Boeing B737-700 which will be used on services to the Middle East and will cut the stop over on route to Abu Dhabi (which is operated via Larnaca). The aircraft will make its debut in Jat’s 2010 summer season timetable. The airline will also lease another Boeing B737-400 which will be used on services to London, Paris, Moscow and summer charter destinations. Jat currently has 4 Boeing B737-300s with the new look economy class seats and the economy class upgrades will continue throughout 2010. No new aircraft will be purchased in 2010 because Jat does not have the finances. The long term lease of the B737-700 will be financed thanks to the government’s 40 million Euro cash injection.

Jat has confirmed that it will launch its Macedonian subsidiary, Aeromak, by March 2010. All plans are in place for promotional flights to be conducted early next year. Jat is waiting for MAT to officially declare bankruptcy. Radovanović also said that in the latter half of 2010 the airline will focus on Banja Luka in Bosnia and Herzegovina, as it is a potential focus city for Jat as plans to launch a Banja Luka based airline, Sky Srpska, has been put on definite hold.

Passengers have also been given some good news. Starting January 1, 2010 all passengers flying with Jat from Belgrade in any cabin class will have the opportunity to use the airline’s complimentary taxi service, which will drive passengers to the airport. For all Serbian citizens travelling to any destination within the European Union, Jat will provide free travel insurance, granted they have a return ticket with Jat. The airline will also reduce its prices so that the average ticket price amounts to 100 Euros, starting from the 2010 summer season.

During 2010 Jat is expected to introduce new destinations. In return for Croatia Airlines’ new service from Zagreb to Belgrade (which you can read more about on Sunday), Jat will receive an all year round permit for flights to Pula and Dubrovnik. The airline plans to introduce a new destination in the Middle East and is holding talks with Portorož Airport management about a possible seasonal summer relaunch.

The airline will join one of the world’s 3 major alliances by the end of 2011. Skyteam is the front runner with recent negotiations held with its main member Air France. Lufthansa has been less than happy with Jat CEO’s recent announcements about joining Skyteam, so Star Alliance and One World are still on the table.

A new advertising campaign will be launched in late December this year within Serbia. Jat has no plans on changing its name or logo. On Wednesday, Radovanović named a new management team, replacing the old squad led by former CEO Saša Vlaisavljević who has lost his job at Jat after he was dumped from the airline’s board of directors. Most of the new positions have been filled by long time Jat employees.

Srdjan Radovanović suggests that all of these plans are already in preparation. He expects a major shift in the attitude towards Jat from April 2010. He also said that on board customer service will be greatly improved while Serbian citizens will be greatly disappointed when they realise that low cost airlines are not all that dreamy as the Serbian media has painted them.

In a bid for cash the airline will sell its agricultural aviation secotr and medicinal aviation secotor. Jat also hopes to create a new technical division although talks will be held with the government regarding this proposal.

Do you think 2010 will be Jat’s year of recovery? Send a comment with your thoughts.

Static stability refers to the initial tendency, or direction of movement, back to equilibrium. In aviation, it refers to the aircraft’s initial response when disturbed from a given AOA, slip, or bank.

• Positive static stability—the initial tendency of the aircraft to return to the original state of equilibrium after being disturbed [Figure 4-18]

• Neutral static stability—the initial tendency of the aircraft to remain in a new condition after its equilibrium has been disturbed [Figure 4-18]

• Negative static stability—the initial tendency of the aircraft to continue away from the original state of equilibrium after being disturbed [Figure 4-18]

Helicopters ruled the roost today, namely BK117's and EC130's.

Of most interest was Kawasaki BK117 ZK-HKZ at Airwork. This machine has been undergoing a massive amount of work since first noted some months ago, and at last this prolonged testing has unveiled special markings to indicate it is powered by a new power plant. Follow this link for more:

http://www.shephard.co.uk/news/1798/heli-expo-2009-honeywell-announces-lts101-850b-2-engine-upgrade-for-eurocopter-bk117/

Also in attendance at Airwork's facility were BK117's ZK-HEN and ZK-HPD, the latter wearing a different style of registration from the last time I saw it when it had the "ZK" prefix added.

Outside Hawker Pacific was a number of the Advanced Flight Eurocopter EC130 fleet, and in this photo is ZK-HJV, HKX and HXW while yet another of the example was tucked in the hanger.

North Shore based Cessna 182S ZK-JCV/3, nee ZK-MGO, was carrying out circuits.

Stability is the inherent quality of an aircraft to correct for conditions that may disturb its equilibrium, and to return to or to continue on the original flightpath. It is primarily an aircraft design characteristic.
The flightpaths and attitudes an aircraft flies are limited by the aerodynamic characteristics of the aircraft, its propulsion system, and its structural strength. These limitations indicate the maximum performance and maneuverability of the aircraft. If the aircraft is to provide maximum utility, it must be safely controllable to the full extent of these limits without exceeding the pilot’s strength or requiring exceptional flying ability. If an aircraft is to fly straight and steady along any arbitrary flightpath, the forces acting on it must be in static equilibrium. The reaction of any body when its equilibrium is disturbed is referred to as stability. The two types of stability are static and dynamic.

New arrivals this winter

This winter foreign carriers will be making many modifications when it comes to the former Yugoslav region. The arrival of low cost airlines in Zagreb, Belgrade and Sarajevo are expected to mark the 2009/10 winter season.

At Ljubljana’s Jože Pučnik Airport, there will be minimal changes when it comes to foreign airline operations. Malev, which has suspended services to the United States, has lost a large number of transit passengers from neighbouring countries heading towards North America . As a result flights to Ljubljana will be terminated.

At Zagreb’s Pleso Airport the Portuguese national carrier TAP will introduce a stopover on its Lisbon to Zagreb service and will thus connect Zagreb with Bologna in Italy. It remains to be seen wether low cost airlines will answer the call of the airport’s CEO to begin flights to Croatia’s capital. Norwegian Air Shuttle is scheduled to make its debut in Zagreb during the next summer season.

Belgrade will see one of the biggest winter increases when foreign airlines are in question. From December 7, TAROM Romanian Airlines will connect Bucharest and Belgrade. The low cost Nikki will introduce 6 weekly flights from Vienna to Belgrade starting February 1. Olympic will increase services from Athens. As a result the two cities will be connected with 2 daily flights starting January 1. Meanwhile, Lufthansa will introduce a third daily flight from Munich.

Sarajevo will see the resumption of flights to Stockholm from April 3. Flights will be operated by the low cost Norwegian Air Shuttle. Skopje, which is no longer a main base for any airline, will be hoping that new local carriers will start up flights. The low cost Germanwings will suspend flights from Skopje to Cologne. Air Berlin will make Priština its mini base with flights to Zurich, Munich, Geneva, Hannover and Dusseldorf starting October 25.

Visit the blog this Saturday for Adria Airways’ 2009/10 winter modifications.

LATEST NEWS

Croatia Airlines will be launching flights between Zagreb and Belgrade on May Day (May 1) next year. You can read more about the new service on Sunday. Until then, check out the new route launches section for flight details.

Each aircraft handles somewhat differently because each resists or responds to control pressures in its own way. For example, a training aircraft is quick to respond to control applications, while a transport aircraft feels heavy on the controls and responds to control pressures more slowly. These features can be designed into an aircraft to facilitate the particular purpose of the aircraft by considering certain stability and maneuvering requirements. The following discussion summarizes the more important aspects of an aircraft’s stability, maneuverability and controllability qualities; how they are analyzed; and their relationship to various flight conditions.