Up to 40 Rolls-Royce engines on Airbus A380 superjumbos worldwide will need to be replaced, according to Australian airline Qantas.
Qantas chief executive Alan Joyce was speaking two weeks after a Rolls-Royce Trent 900 engine on an A380 exploded in mid-air, forcing an emergency landing.
Qantas has grounded its six A380s since the incident.
The Trent 900 engines are used on A380s operated by Qantas, Lufthansa and Singapore Airlines.
Between them the three airlines operate 20 A380 planes, each of which has four Rolls-Royce engines.
Mr Joyce told reporters at Sydney airport the airline had already replaced three engines on its planes.
"We've been talking to Airbus and Rolls-Royce and we understand that the number [of engines to be replaced] is around 40," he said.
"We'll have a daily dialogue with Rolls-Royce to determine which engines actually need to be taken off," he said.
Investigators believe an oil leak inside the engines may have caused the fire on the Qantas flight from Singapore to Sydney on 4 November.
Rolls-Royce has said the engine failure "was confined to a specific component" which led to an oil fire and loss of turbine pressure.
The plane was forced to return to Singapore shortly after take-off.
All 459 passengers and crew were unharmed, but analysts said it was the most serious incident in the three-year history of the Airbus plane.
All six of Qantas' A380s have been grounded while safety checks are carried out.
Singapore Airlines, with 11 A380s, said it has replaced three Trent 900s. Lufthansa, with three of the aircraft, said it has replaced one engine, but the reason was unrelated to the Qantas explosion.
Other A380 users Emirates and Air France do not use Rolls' engines.
Last week, Rolls said it had isolated the cause of the fault, and that the issue could have a slight impact on profits growth this year.
Airbus said that problems could delay future deliveries of A380s, but said it was too early to determine the impact.
Rolls had been due to hold a press conference at a Chinese air show on Wednesday, but cancelled without giving a reason.