The Federal Aviation Administration is due to issue three safety directives that, once carried out, may lead to some grounded Boeing 777 aircraft returning to service. The affected jets are outfitted with Pratt & Whitney 4000 engines that have been out of service since February 2021 when FAA ordered immediate inspections of 777s with those particular engines, following an incident in which a United Airlines 777 suffered engine failure soon after taking off from Denver International Airport, with debris from broken fan blades scattering across the ground below.
The Boeing 777 is a long-range, wide-body aircraft and the world’s largest twin-engine commercial jet. Other than the Pratt & Whitney engine, operators may choose the GE Aviation GE90 or Rolls-Royce Trent 800 turbofan engines to power the aircraft.
Reportedly, there have been two other similar incidents involving the 777 and the PW4000 engines.
United Airlines is the only U.S. operator of 777s with the PW4000 engine. It has 52 such aircraft, and it as said many of the affected engines already have undergone FAA’s proposed modifications.
The FAA directives were proposed in December 2021 and will be effective in April.
One directive calls for adding debris shields to the engines’ thrust reverser inner walls; inspecting fan cowl doors for moisture ingression; and ongoing inspecting the engines’ hydraulic pump shutoff valves.
A second FAA directive calls for the engine inlet to be modified, so that it may withstand fan-blade
The last directive requires specific corrective actions following various results of the inspections.
After the directives are issued by FAA, Boeing will be expected to deliver a service bulletin to the customers operating the affected aircraft, defining how the requirements must be fulfilled. If FAA endorses the Boeing bulletin, and the aircraft are properly inspected and reconditioned, the grounded aircraft will be cleared to resume service.
Other airlines operating the 777 with PW4000 engines include Japan’s All-Nippon Airways, Korean Air Lines, Asiana Airlines, and Jin Air. Japan Airlines, which also reported PW4000 engine failure aboard one of its 777s, retired all 13 of those aircraft following the February 2021 grounding.