Seven months after Koito Industries made the stunning revelation that it falsified test data on some 150,000 aircraft seats in the world fleet, EASA and the FAA have each issued proposed airworthiness directives (ADs), although the European agency appears to be taking a harder line than its US counterpart.

EASA's proposal covers virtually all models of the following aircraft types if equipped with passenger seats manufactured by the Japanese manufacturer: the Airbus A300, A310, A318, A319, A320, A321, A330 and A340, and the Boeing 717, 737, 747, 757, 767, 777, plus the McDonnell Douglas MD-11, DC-9, MD-88 and MD-90.

"The Japanese airworthiness authority JCAB has informed EASA that a review of the safety of passenger seats manufactured by Koito industries has disclosed discrepancies which include falsification of static, dynamic and flammability testing, as well as uncontrolled changes to production data (material and dimensional)," says EASA in its proposed AD.

"In addition JCAB confirmed that Koito records, showing evidence of falsification, could not be deemed complete. Examples include: fictitious dynamic test pulse plots inserted into test reports following failure to meet required certification requirements; flammability test coupons not representative of production parts, for instance by use of alternative adhesive not specified on the approved drawing; and fictitious deformation values entered in test reports when values exceeded the maximum allowed."

Armed with this information, the JCAB and EASA concluded that all data - both design and manufacturing - generated by Koito "must be treated as suspect".

A programme of confidence testing was initiated using seats returned from service. "Results from tests performed by Koito with the supervision of JCAB confirmed a high proportion of seat models failed the requirements for structural, flammability and occupant injury criteria," says EASA, noting, however, that the exact level of airworthiness risk for each seat model can only be determined through further dynamic or static testing and flammability testing.

The agency's proposed AD requires affected seats to be replaced no later than two years after the effective date of the directive if no testing is performed. However, it says, "completion of testing in accordance with the requirements of this AD may allow the seats to remain in service for a longer duration". Any certification programme plan instigated by an airline must be presented to EASA for agreement. The agency also sees the removal of all Koito seats within ten years.

EASA's proposed AD will be closed for consultation on 17 November.

Thee FAA's proposal appears less stringent than that of EASA. While it would require airlines to determine if affected seats and seating systems and their components are compliant with certain FAA regulations - and removal of those seats if shown to be unsafe - the US agency has set different compliance times and will not require full compliance with every applicable regulation.

"Because this proposed AD will not require full compliance with every applicable regulation, seats on which the requirements of this proposed AD are completed successfully and are permitted to remain in service are limited in how they can be used. That is, unless they are shown to fully comply with the regulatory requirements, this proposed AD would restrict the installation of such seats and would require specific marking. These seats can be used as a direct spare for the same part number seat. However, any other use of such seats would be considered a new installation approval and would be required to comply with all regulations. Thus, seats not meeting all regulations could not be installed except as noted above, and if removed from an approved arrangement, would have to be destroyed or rendered unusable in some other manner acceptable to the FAA," says the agency in its proposed AD.

Asked if the FAA is concerned that unfavourable comparisons will be made about the FAA's AD versus EASA's AD, an FAA spokesman says: "Clearly the FAA doesn't operate in a vacuum, but that said what we have to do is look at the safety impact and the safety issue and the proposed solution based on our environment, not the environment that exists in Europe."

Koito seats are no longer offerable on Airbus and Boeing aircraft. However, a far larger percentage of Boeing aircraft in the world fleet are impacted by the Koito debacle. Some 278 US aircraft operated by Continental Airlines are affected, says the FAA spokesman, noting, however, that the carrier has "already upgraded some of their seats".

Source: Air Transport Intelligence news