AD 2020-23-04 Prompted By A Report Of Misassembled Impellers Onto The Shaft Of The Fuel Boost Pump

The FAA is adopting a new airworthiness directive (AD) for certain Gulfstream Aerospace Corporation (Gulfstream) Model GVII-G500 and Model GVII-G600 airplanes.

This AD requires revising your existing airplane flight manual (AFM) and airplane maintenance manual (AMM) to include information pertaining to the fuel boost pump. This AD was prompted by a report of misassembled impellers onto the shaft of the fuel boost pump during production. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective November 24, 2020.

Supplementary Information: The FAA was notified by Gulfstream of the possibility of misassembled impellers onto the shaft of fuel boost pumps used in the production of GVII-G500 and GVII-G600 airplanes. The supplier of fuel boost pumps discovered two misassembled fuel boost pumps on two different make/models of non-Gulfstream aircraft. The Gulfstream GVII-G500 and GVII-G600 fuel boost pumps are very similar in design and are manufactured in the same facility using the same manufacturing processes, so the same condition could exist on the Gulfstream fuel boost pumps.

A misassembled fuel boost pump could result in a woodruff key becoming dislodged and causing friction between static and rotating components internal to the fuel boost pump. This friction could generate heat or sparks inside the fuel tank, which, if the pump were to run dry, could result in a fuel tank fire or fuel tank explosion.

The unsafe condition, if not addressed, could result in a potential source of ignition in the fuel tank and may lead to fire or explosion.

FMI: www.regulations.gov