FAA listens to users on 400-series Cessna wing spar cracks

August 20, 2004

FAA listens to users on 400-series Cessna wing spar cracks
Will take phased approach to remedy problem

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Thanks to the efforts of AOPA and major Cessna owner organizations, the FAA has agreed to a more reasonable approach to remedy a wing spar cap problem with many 400-series Cessna twin-engine aircraft. Earlier this year the FAA issued, and subsequently withdrew, a proposal that would have required an expensive modification to many of the 400-series twins. Yesterday at a public meeting in Kansas City, Missouri, the FAA said it would issue a notice of proposed rulemaking (NPRM) by the end of the year, with an AD coming out by mid-2005.

"The FAA listened seriously to the input from aircraft owners and the industry, and they mitigated the impact of the AD to some extent," said AOPA Director of Certification and Regulatory Policy Luis Gutierrez, who represented AOPA at the meeting. "The AD will be phased in over about a five-year period. For some of the lower-time owner-flown aircraft, the AD will likely not become applicable for many more years."

The FAA withdrew the original NPRM after AOPA and other organizations challenged the assumptions behind the proposal. That measure would have covered most models in the 400 series of twin-engine Cessnas - nearly 1,500 aircraft - and required an inspection and installation of a wing spar strap kit at a cost of up to $70,000 per aircraft. In some cases, the fix would have exceeded the value of the aircraft.

The FAA agreed to work with AOPA and other groups representing affected owners to develop alternative solutions to address what the agency believes is an unsafe condition.

"The data supports that there is a cracking issue in the 402 and 402A models," said Gutierrez. "For the rest of the fleet, we're still looking at statistical engineering predictions, rather than actual field experience. For that reason, we still need data from owners on time in service, inspection status, and operational profiles."

Owners of 400-series Cessnas are requested to complete the survey sponsored by AOPA, the Cessna Pilots Association, Cessna Twin Spar Corp., Cessna Owners Organization, Twin Cessna Flyers, and Regional Air Cargo Carriers Association.

The FAA indicated that it is willing to consider well-engineered alternate means of compliance (AMOC) to remedy the problem and seemed to be prompting the assembled owners, owner's group representatives, and other interested parties to come up with additional solutions for the upcoming AD. Agency engineers said they would consider both physical and inspection alternatives.

An inspection system that may hold promise is Photon Induced Positron Annihilation (PIPA) technology. At the Kansas City meeting, Positron Systems showed how it uses PIPA to detect defects in wing structures. This technology is used by the military but has never before been used in general aviation applications.

The FAA's outline of the new NPRM for the airworthiness directive departs from the fixed-date compliance times that were part of the first NPRM. The new NPRM will most likely feature a graduated compliance schedule. The compliance change was due mainly to a lack of industry capability to complete the lower main wing spar inspection and doubler installation in the shorter time span. This lack of capability also may slow implementation of the modifications since the new schedule is designed to complete approximately 120 airplanes a year. The spar doubler kits can cost up to $14,600, and installation time is estimated at 385 to 400 hours for shops experienced in the procedure.

The new FAA proposal for tip-tank twins such as the 401, 401A, 401B, 402, 402A, 402B, 411, and 411A models would require installing a wing spar strap kit in aircraft with more than 6,500 hours time in service. Airplanes that have more than 18,000 airframe hours would have to comply with the AD as soon as it is issued. Airplanes with 12,000 to 18,000 airframe hours would have to comply at 200 flight hours after issuance - 10,000 to 11,999-hour airplanes would have 400 hours, and all lower time airplanes would have 800 hours to comply.

For 402C and 414A (late model version) airplanes, the AD would kick in at 15,000 hours. Owners with more than 20,000 hours would have to comply within 500 hours of the issue date of the AD; 18,000 to 19,999-hour airplane owners would have 1,000 hours to comply, and 15,000 to 17,999-hour airplane owners would have 1,500 hours to comply.

For additional information, see AOPA's regulatory brief.

August 20, 2004