Rolls Royce has decided to speed up the replacement of the 787 Trent-1000 intermediate pressure turbine blades.
The incident that has triggered the need to speed things up is one where a Norwegian 789 was departing Rome in August for LAX and and the left side engine failed, sending parts falling into suburbs of Rome.
The Trent-1000G/01A Package-B engine suffered what’s described as a “progressive failure” of the intermediate pressure turbine fan which led to an overload failure of the trailing blade.
This has now happened on ten different occasions although this is the worst by far, and the cause is being levelled at air pollution – especially sulphur dioxides reacting with high temperatures in the engines. Rolls Royce has admitted the engines recently repaired from Package B & C that has led to lengthy out of service periods for RR equipped Dreamliners, are also affected, but the replacement is relatively straight forward.
In the meantime complicated algorithms have been issued to airlines giving them accelerated time frames for replacement based on where they’ve flown. The blades are supposed to last 1,410 cycles, but have failed between 103 and 200 cycles earlier than designed.
The Italian authorities are also insisting through EASA that Rolls Royce mandate that no aircraft flies with two unmodified engines entering the danger point up to 250 cycles before normal replacement.
Rolls Royce is looking at a $1 billion bill through 2019-20 to fix the 780 in-service engines.