Operators of Rolls-Royce Trent 800-powered Boeing 777s face mandatory fuel pump removals to correct an issue linked to thrust-loss incidents, a European Union Aviation Safety Agency (EASA) directive said.
The airworthiness directive, published Nov. 21, gives affected Boeing 777 operators 250 flight cycles, or until early February 2024—14 months after the mandate’s Dec. 5, 2022, effective date—to remove certain fuel pumps from service. The pumps, made by Eaton, run the risk of corrosion on internal parts. Denison Vane Pump Parts
“Investigation results determined that certain engines had been exposed to unacceptable levels of water contamination, which caused corrosion developing on the fuel pump internal components, leading to debris release and filter blockages in variable stator vane actuator control units, which finally resulted in the variable stator vane system to fail in the closed position,” the EASA directive said.
The issue has caused multiple loss-of-thrust occurrences, the agency added, without providing details.
The problem is not new. A November 2021 directive required operators to ensure no aircraft had two engines with pumps flagged as being at risk, and prohibited installation of affected pumps. The newest directive’s added requirement calls for pulling all affected pumps still in service “for in-shop refurbishment, overhaul or repair to allow return to service.”
Affected pumps carry specific part number and serial number combinations and are listed in service bulletins issued by Eaton and Rolls-Royce. The directive does not say how many pumps are in the affected pool. Queries to both companies were not immediately answered.
Aviation Week Network’s Fleet Discovery shows about 100 Trent 800-powered 777s in service—most of them with American Airlines and British Airways. Another 68 are in storage, including 14 operated by Cathay Pacific.
Parker F1 Pump Senior Air Transport & Safety Editor Sean Broderick covers aviation safety, MRO, and the airline business from Aviation Week Network's Washington, D.C. office.