Summary
We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:
One Fokker 100 (F28 Mark 0100) operator reported that during maintenance in the APU (auxiliary power unit) compartment, a disconnected nut was discovered on one of the shuttle valves in the deployment lines of the engine fire-extinguishing system. An additional check by the operator revealed that on more aircraft in its fleet, the nuts of the shuttle valves were incorrectly tightened. This condition, if not corrected, could result in failure or deteriorated functioning of the engine fire-extinguishing system in case of an engine fire.
The proposed AD would require actions that are intended to address the unsafe condition described in theMCAI.