Summary
We propose to rescind airworthiness directive (AD) 2009-18-19. This proposed AD results from mandatory continuing airworthiness information (MCAI) issued by EASA, to rescind EASA AD 2010-0083. The MCAI specifies the following:
It has been assessed that multiple NRV [non return valve] failures in combination with certain trapped fuel cases could potentially increase the quantity of unusable fuel on the aeroplane, possibly leading to fuel starvation which could result in engines in-flight shut down and would constitute an unsafe condition. To prevent and detect this condition, EASA issued EASA AD 2010-0083.
Based on in service experience, mainly on the results of the operational test required by EASA AD 2010-0083, Airbus has performed a safety analysis on the NRV to check if the safety objectives are met.
This analysis of the Collector Cell motive flow line NRV, taking into account all failure scenarios, concludes that the previous non compliance can be alleviated. Consequently, no unsafe condition exists any more on the affected NRV.
For the reasons described above, EASA AD 2010-0083 is cancelled. The proposed AD would rescind the parallel FAA AD 2009-18-19.