As investigators seek answers to why a British Airways Boeing 777-200ER crash landed at London Heathrow in January, it has emerged that an engine on an identical American Airlines twinjet briefly failed to respond to throttle commands last week.
American is investigating the 28 February incident which involved its flight AA299 from Miami to Los Angeles and occurred during the approach at a height of around 2,000ft (610m).
In an information statement to members, the Allied Pilots Association - which represents American Airlines cockpit crew - says the aircraft experienced a "hang-up" of its left-hand engine.
"The auto-throttles were on and the left engine hung at approach idle as the right engine accelerated normally," says APA.
"It is believed that the left engine would not respond to throttle inputs for 10-15s before finally responding and accelerating to the commanded thrust."
American's entire 777-200ER fleet is Rolls-Royce Trent 800 powered. Maintenance personnel have downloaded the flight-data recorder information and will examine the fuel tanks and engine fuel filters for possible contamination. The electronic engine control will also be tested.
American says the 777 "made a normal landing after one engine was slow to respond to the autothrottle at 2,000ft" and that the aircraft has been taken out of service. Neither the US Federal Aviation Administration nor the National Transportation Safety Board has given any further information on the incident.
The UK investigation continues into why both Trent 800s on the BA 777-200ER failed to respond to throttle-increase commands during final approach, resulting in the crash landing.