US cargo carrier Kitty Hawk says the US Federal Aviation Administration has approved its alternative means of compliance on an FAA airworthiness directive (AD).
The directive imposes severe payload limits on Boeing 727s that were converted into freighters by a number of third-party maintenance organisations.
The AD affects conversions undertaken using supplemental type certificates (STCs) held by FedEx Aviation Services, Pemco World Air Services, Miami-based Aeronautical Engineers and Kitty Hawk Aircargo.
The AD affects 30 airlines operating 370 aircraft, including FedEx with 117 and Kitty Hawk with about 30. It requires the operators to reduce payloads from the current 3,632kg (8,000lb) per shipping container to 1,360kg (3,000lb) or adhere to operational limitations that allow higher payloads per container up to 2,180kg (4,800lb).
The AD results from concern that the aircraft flooring conversions were engineered without Boeing's load-path data.
Kitty Hawk says it is the only STC holder to gain an FAA-approved method to fully comply with the floor AD. It believes the modification, which involves side restraints, can be applied to two of the three other STCs, and Kitty Hawk will market its modification package to other affected 727F operators.
Kitty Hawk says the modification costs between $25,000 and $50,000 per aircraft. The FAA estimates that extensive floor strengthening would cost $711,000 per aircraft.
The FAA has ordered inspection of lower skin panel lap joints on Boeing 727-100/200s for fatigue cracks. The airworthiness directive, prompted by discovery of cracks in four 727s, affects 1,500 of the aircraft worldwide.
Operators must perform repetitive visual and eddy current inspections. American Airlines, Federal Express and Kitty Hawk are among the affected airlines.
Source: Flight International
