Airbus has modified the thrust-reverser actuation system of production A350-900s after a failure of a locking mechanism on an in-service aircraft.

The locking actuator was removed from the jet after several failure messages, and investigators found that it failed a primary lock integrity test, says the European Aviation Safety Agency.

EASA states that the component can be affected by internal contamination from carbon dust, and that this can affect the retention capability of the actuator.

A350 thrust reversers use a translating-sleeve design and the sleeve uses three retention mechanisms.

EASA says two of these can potentially be affected by the problem, which would leave only the third system – a lock employing a different design – for retention.

It notes that there is a theoretical risk of in-flight deployment of a reverser translating sleeve, should the third lock fail, and the master minimum equipment list for the type has been amended to declare any thrust-reverser lock failure as a ‘no go’ item – preventing dispatch of the aircraft.

Airbus has introduced a new thrust-reverser actuation system standard into A350 production, after the component's manufacturer corrected the problem. EASA has ordered in-service A350s to be modified to the same standard, within 750 cycles since first flight.

Source: Cirium Dashboard