A Safety Recommendation of the Australian Transport Safety Bureau in charge of the investigation has led Rolls-Royce, in agreement with the European Aviation Safety Agency (EASA), to launch an additional immediate "once-around-the fleet" inspection. This inspection is a one time focused borescope measurement inspection of the High/Intermediate Turbine bearing support structure oil feed tube for concentricity of the counter-bore and inspection of related components.
This additional inspection is welcome by EASA as a beneficial precautionary measure, and it will enable gather data on potential misalignment of the counter-bore within the inner diameter of the concerned pipe. Non compliant engines will be rejected. EASA will monitor the results of the inspections performed, as well as further analysis from Rolls-Royce, and decide whether revised or additional mandatory action needs to be taken.
The safety of the Trent 900 fleet is currently ensured by the inspection requirements of EASA Airworthiness Directive of November 22 associated to Rolls-Royce Non Modification Service Bulletin of that date. For now there is no change to the requirements of the EASA directive.
In addition, EASA has approved an upgrade of the electronic controller software (FADEC) of the Trent 900 Intermediate Pressure Turbine Overspeed protection. This software is designed to monitor several parameters and lead to engine automatic shutdown whenever necessary.
