* Some components suspected of having corroded
* EASA: Aircraft should not have two affected engines (Adds number of engines involved, airline comments)
FRANKFURT, Dec 22 (Reuters) - The European aviation safety regulator ordered airlines to replace some Rolls-Royce Trent 1000 engines on their aircraft as some components are suspected of having corroded.
The European Aviation Safety Agency (EASA) said, to reduce the risk of both engines shutting down in flight, a new life cycle limit must be applied to 15 engines with specific serial numbers.
In cases where a plane has two affected engines installed, airlines must replace one of them, it said in an Emergency Airworthiness Directive published on its website on Thursday.
Rolls-Royce told investors in August that 400 to 500 Trent 1000 engines were affected by problems with components wearing out earlier than expected, according to a conference call transcript.
The affected engines are primarily installed on Boeing 787 aircraft, according to EASA.
"This directive mandates action we are taking as part of the continual development of our pro-active engine management programme," a Rolls-Royce spokesman said.
Several airlines including Air New Zealand, British Airways, Virgin Atlantic and Japan's ANA Holdings have previously reported problems with Rolls-Royce Trent engines, leading to extra inspection and maintenance and prompting them to cancel or delay some flights.
British Airways, ANA, Air New Zealand and Singapore Airlines' low-cost arm Scoot said they did not have any of the specific engines referred to in the directive in their fleets.
A Boeing spokesman declined immediate comment.
The Trent 1000 powered the first 787-8 to enter service in 2011. The latest version of the engine, the Trent 1000 TEN, entered service in November and will power Boeing 787 Dreamliner aircraft operated by Air New Zealand, Norwegian and Scoot. (Reporting by Victoria Bryan, Maria Sheahan, and Kate Holton; additional reporting by Jamie Freed in Singapore; Editing by Adrian Croft and Himani Sarkar)