Passengers stable- finances trembling

Croatia Airlines has seen its losses soar. On Wednesday the airline reported that it ended the first 9 months of the year with a net loss of 94.2 million Kunas or 12.88 million Euros. During the same period last year, the airline reported losses of 22.2 million Kunas or 3 million Euros. Croatia Airlines’ operating earnings also fell by 18%. This is despite Croatia Airlines’ cost cutting measures, which were introduced earlier in the year. The Croatian national carrier has, unlike most European carriers, managed to keep its passenger numbers stable in spite of the global financial crisis. However, this did little to save the airline’s finances.

The other 2 main airlines in the region, Adria and Jat also reported losses with the latters amounting to 11 million Euros for the first 9 months while Adria has reported some improvement with its figures.

Despite the grim news, Croatia Airlines has announced that it will prolong its seasonal Split to London service until the end of November. After the winter break, the service will recommence in March.

Overloading also affects stability. An aircraft that is stable and controllable when loaded normally may have very different flight characteristics when overloaded. Although the distribution of weight has the most direct effect on this, an increase in the aircraft’s gross weight may be expected to have an adverse effect on stability, regardless of location of the CG. The stability of many certificated aircraft is completely unsatisfactory if the gross weight is exceeded.

The effect of additional weight on the wing structure of an aircraft is not readily apparent. Airworthiness requirements prescribe that the structure of an aircraft certificated in the normal category (in which acrobatics are prohibited) must be strong enough to withstand a load factor of 3.8 Gs to take care of dynamic loads caused by maneuvering and gusts. This means that the primary structure of the aircraft can withstand a load of 3.8 times the approved gross weight of the aircraft without structural failure occurring. If this is accepted as indicative of the load factors that may be imposed during operations for which the aircraft is intended, a 100-pound overload imposes a potential structural overload of 380 pounds. The same consideration is even more impressive in the case of utility and acrobatic category aircraft, which have load factor requirements of 4.4 and 6.0, respectively.

Structural failures which result from overloading may be dramatic and catastrophic, but more often they affect structural components progressively in a manner that is difficult to detect and expensive to repair. Habitual overloading tends to cause cumulative stress and damage that may not be detected during preflight inspections and result in structural failure later during completely normal operations. The additional stress placed on structural parts by overloading is believed to accelerate the occurrence of metallic fatigue failures.

Knowledge of load factors imposed by flight maneuvers and gusts emphasizes the consequences of an increase in the gross weight of an aircraft. The structure of an aircraft about to undergo a load factor of 3 Gs, as in recovery from a steep dive, must be prepared to withstand an added load of 300 pounds for each 100-pound increase in weight. It should be noted that this would be imposed by the addition of about 16 gallons of unneeded fuel in a particular aircraft. FAA-certificated civil aircraft have been analyzed structurally and tested for flight at the maximum gross weight authorized and within the speeds posted for the type of flights to be performed. Flights at weights in excess of this amount are quite possible and often are well within the performance capabilities of an aircraft. This fact should not mislead the pilot, as the pilot may not realize that loads for which the aircraft was not designed are being imposed on all or some part of the structure.

In loading an aircraft with either passengers or cargo, the structure must be considered. Seats, baggage compartments, and cabin floors are designed for a certain load or concentration of load and no more. For example, a light plane baggage compartment may be placarded for 20 pounds because of the limited strength of its supporting structure even though the aircraft may not be overloaded or out of CG limits with more weight at that location.

The takeoff/climb and landing performance of an aircraft are determined on the basis of its maximum allowable takeoff and landing weights. A heavier gross weight results in a longer takeoff run and shallower climb, and a faster touchdown speed and longer landing roll. Even a minor overload may make it impossible for the aircraft to clear an obstacle that normally would not be a problem during takeoff under more favorable conditions.

The detrimental effects of overloading on performance are not limited to the immediate hazards involved with takeoffs and landings. Overloading has an adverse effect on all climb and cruise performance which leads to overheating during climbs, added wear on engine parts, increased fuel consumption, slower cruising speeds, and reduced range.

The manufacturers of modern aircraft furnish weight and balance data with each aircraft produced. Generally, this information may be found in the FAA-approved AFM/POH and easy-to-read charts for determining weight and balance data are now provided. Increased performance and load-carrying capability of these aircraft require strict adherence to the operating limitations prescribed by the manufacturer. Deviations from the recommendations can result in structural damage or complete failure of the aircraft’s structure. Even if an aircraft is loaded well within the maximum weight limitations, it is imperative that weight distribution be within the limits of CG location. The preceding brief study of aerodynamics and load factors points out the reasons for this precaution. The following discussion is background information into some of the reasons why weight and balance conditions are important to the safe flight of an aircraft.

In some aircraft, it is not possible to .ll all seats, baggage compartments, and fuel tanks, and still remains within approved weight or balance limits. For example, in several popular four-place aircraft, the fuel tanks may not be .lled to capacity when four occupants and their baggage are carried. In a certain two-place aircraft, no baggage may be carried in the compartment aft of the seats when spins are to be practiced. It is important for a pilot to be aware of the weight and balance limitations of the aircraft being flown and the reasons for these limitations.

As in climbs, the forces which act on the aircraft go through definite changes when a descent is entered from straight-and-level flight. For the following example, the aircraft is descending at the same power as used in straight-and-level flight.

As forward pressure is applied to the control yoke to initiate the descent, the AOA is decreased momentarily. Initially, the momentum of the aircraft causes the aircraft to briefly continue along the same flightpath. For this instant, the AOA decreases causing the total lift to decrease. With weight now being greater than lift, the aircraft begins to descend. At the same time, the flightpath goes from level to a descending flightpath. Do not confuse a reduction in lift with the inability to generate sufficient lift to maintain level flight. The flightpath is being manipulated with available thrust in reserve and with the elevator.

To descend at the same airspeed as used in straight-and-level flight, the power must be reduced as the descent is entered. The component of weight acting forward along the flightpath increases as the angle of rate of descent increases and, conversely, decreases as the angle of rate of descent decreases. The component of weight acting forward along the flightpath increases as the angle of rate of descent increases and, conversely, decreases as the angle of rate of descent decreases.

A forlorn sight at Hamilton Airport on 7 November was nearly the whole fleet of the CTC Aviation Alpha R 2160's parked up. They are still registered to CTC Aviation Training (NZ) Ltd but are presumably trapped in the voluntary liquidation of Alpha Aviation which occurred on 23 January 2008. There were 10 CTC aircraft present - ZK-CTQ,R,S,T,V,Xand Y (in the white with blue and yellow trim scheme) as well as Robin R2160's ZK-TZD and ZK-TZM (in the blue and white trim scheme). There were 3 aircraft on one side of the open fronted hangar...

...and 6 on the other side.

Out front was the 10th CTC Alpha, ZK-FXY in a white and green scheme looking as though it is active. This was the original aircraft built by Alpha Aviation and it first flew on 12 April 2006. There were also 3 other Alpha R 2160's on the field - ZK-WCD, ZK-WJH and ZK-WKF owned by the Waikato Aero Club.

On 23 June 2009 Alpha Aviation was sold to Hong Kong based company IXL Ltd who intend to re-start manufacturing planes at the Alpha Aviation factory at Hamilton Airport.

5 million Euros for taxi shuttle

Jat’s latest initiative to win back passengers involves offering a free taxi service within Belgrade for all of those passengers that have a return ticket with Jat. While the airline’s management believes the move will lure passengers away from increasing competition, local media are speculating whether the move is financially viable.

The entire project will set Jat back some 5 million Euros in 2010. The airline recently called upon all taxi companies interested to take part through a public tender. Jat is requesting for 250 taxi vehicles to be available to the airline on a daily basis. The current projection is that 1.600 taxi commutes would be carried out to the airport as a result of this measure. This number could rise if the number of passengers increases, as projected by Jat’s management.

The Serbian national carrier did not wish to estimate the cost of the project. They say that the taxi service is being introduced as a new commodity for its passengers and that they expect “only positive effects from this measure which will mean more passengers and a greater profit for Jat”.

Under the tender rules, several taxi companies can bid jointly in order to win the job. However, the 250 vehicles that will be used on a daily basis must be equipped with a GPS system, receipt printer and the cars must be of a higher standard. Do you think Jat’s new service is a waste of money or a good way to appeal to passengers? Send a comment.