Performing similar maintenance tasks on redundant systems at the same time, or by the same person during a particular maintenance check, may lead to the repetition of a maintenance error. This creates a risk of simultaneous failure of the redundant systems when the aircraft is back into service.
There are a range of safeguards or best practices that can be applied to prevent repetition of a maintenance error. These include
– Staggered scheduling of the task
– Using different personnel to carry out the task
– Performing an additional cross-check inspection, and requiring a dual signature to verify that the task was correctly carried out and in accordance with the maintenance procedures.
Where possible, and unless otherwise specified, carry out a test of one system or one engine run at a time.
In all cases, it is important to correctly apply the maintenance procedures.
Author – Zinhom Mohmoud – Aviation Training Consultant