Two NPRMs Could Affect As Many As 1,600 Airplanes

The FAA published two proposed Airworthiness Directives in the Federal Register Monday that could affect as many as 1,600 Embraer and Boeing airplanes of U.S. registry.

One AD would affect all Embraer S.A. Model ERJ 170 airplanes; and all Embraer S.A. Model ERJ 190-100 STD, -100 LR, -100 IGW, -200 STD, -200 LR, and -200 IGW airplanes. This proposed AD was prompted by reports of cracks in certain engine low-stage bleed check valves.

This proposed AD would require replacing the air management system (AMS) controller operation program of the AMS controller processor boards, and replacement of the current low-stage bleed check valve and associated seals. The FAA is proposing this AD to prevent failure of the low-stage bleed check valve, which could result in dual engine in-flight shutdown. The FAA estimates that there are 197 airplanes affected by the proposed AD, and that the cost of compliance would be $987 per aircraft.

The other proposed AD is for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. The FAA says that 1,397 aircraft would be affected. This proposed AD was prompted by reports of a manufacturing oversight, in which a supplier omitted the required protective finish on certain bushings installed in the rear spar upper chord on horizontal stabilizers, which could lead to galvanic corrosion and consequent cracking of the rear spar upper chord.

This proposed AD would require an inspection or records check to determine if affected horizontal stabilizers are installed, related investigative actions, and for affected horizontal stabilizers, repetitive inspections for any crack of the horizontal stabilizer rear spar upper chord, and corrective action if necessary.

The FAA has proposed this AD to detect and correct cracking of the rear spar upper chord, which can result in the failure of the upper chord and consequent departure of the horizontal stabilizer from the airplane, which can lead to loss of continued safe flight and landing.

The cost inspecting airplanes as mandated by the AD is estimated to be $118,745 across the fleet, according to the FAA. The agency says it has not received any data to indicate what the full cost of compliance for repairs would be.

Both proposed ADs have public comment periods open through January 14, 2016.

(Images from file)

FMI: www.federalregister.gov/articles/2015/11/30