WASHINGTON (Reuters) – A United Airlines plane with a Pratt & Whitney engine that failed on Saturday flew less than half of the flights allowed by U.S. regulators between fan inspections, two sources said with knowledge .
The Boeing Co 777 aircraft flew nearly 3,000 cycles, equivalent to one takeoff and landing, comparable to the checks every 6,500 cycles assigned to a separate United engine incident in 2018, the sources said.
They sought anonymity as they were not authorized to speak in public. United declined to comment.
Pratt, the manufacturer of the PW4000 engines, advised airlines on Monday to increase the checks after every 1,000 cycles, in a bulletin that Reuters sees. It did not immediately respond to a request for comment.
The U.S. Federal Aviation Administration said Tuesday that it immediately inspects 777 aircraft with PW4000 engines before flying again, and goes further than Pratt.
The engines are used in 128 older versions of the aircraft, accounting for less than 10% of the more than 1,600,777 delivered, and only a handful of airlines in the United States, South Korea and Japan have recently operated them.
Japan and South Korea also grounded the aircraft for blowing fans.
On Monday, the FAA acknowledged that after a Japan Airlines (JAL) PW4000 engine incident in December, it was considering setting up blade inspections using acoustic imaging to find signs of metal fatigue.
One of the sources held a risk assessment meeting last week to discuss the issue before the United engine failed, confirming an earlier report by CNN. No decision was imminent before the United incident, the source added.
A spokesman for Pratt, which is owned by Raytheon Technologies, said Wednesday that fan blades should be sent to the repair station in East Hartford, Connecticut, for the latest inspections, including those from Japan and South Korea.
Each engine has 22 blades that must be removed separately and it will take eight hours to inspect it, FAA administrator Steve Dickson told Bloomberg TV on Wednesday.
This equates to 352 hours of work per aircraft, as each 777 has two engines. Boeing said 69 of the planes were in active service before Saturday’s incident, while 59 were grounded during the pandemic amid low demand.
Pratt did not respond to questions about how many engines he could inspect per month. United did not comment on how long it expects the inspections to last, while JAL and ANA Holdings said the timing was unclear.
(This story is corrected to remove foreign word ‘and’ in paragraph 11)
Reporting by David Shepardson in Washington; additional reporting by Tim Kelly in Tokyo, written by Jamie Freed. Edited by Gerry Doyle