There have been a number of accidents where the AAIB has highlighted engineer fatigue as a contributing factor.
The AAIB report into the 2010 Olympic DHC8, which suffered engine oil loss, necessitating a shutdown and precautionary diversion (this following a maintenance input at FlyBe). The report highlighted fatigue amongst maintenance staff. One engineer had worked an average of 15.7 hrs a day over a ten day period!!
In 2011 they (the AAIB) recommended that EASA expand guidance/advisory material in EASA Part 145 regulation, “on how approved maintenance organisations should manage and monitor the risk of maintenance engineer fatigue as part of their requirement to take human performance limitations into account.”
Pretty weak & the EASA response, even weaker! The elephant in the room is that ‘effectively’ maintenance engineer’s hours are uncontrolled. The reason is cost, EASA don’t have the balls to grasp the nettle of regulating engineer duty hours/fatigue.