Summary
The Federal Aviation Administration (FAA) proposes to adopt a new airworthiness directive (AD) that is applicable to Turbomeca S.A. Arriel models 2 S1, 2 B, and 2 C turboshaft engines. This proposal would require initial and repetitive visual inspections for fuel leaks, and replacement of fuel pumps that are found leaking fuel. In addition, this proposal would require removal from service fuel pumps that are found with pump wall thickness below minimum. This proposal is prompted by a manufacturing investigation of pump bodies found to have below minimum material thickness, which could cause fuel leakage through thin, porous walls, reducing fuel pump fire resistance. The actions specified by the proposed AD are intended to prevent fuel leakage, which may cause engine fires that could lead to an in-flight engine shutdown, damage to the helicopter, and forced landing.