greg_mp wrote:
In case of a RNP AR approach, which means between high mountains
High mountains are not the only reason for strict and/or unusual track guidance on approaches.. The RNP AR approaches around here (Stockholm/Arlanda) are intended for noise abatement and have curved finals. No obstacle issues whatsoever.
Likelihood is the word indeed. In case of a RNP AR approach, which means between high mountains, any MCAS failure occurence followed by a pitch down – even if it may only happen once with the fixed implementation, may finish in a cfit.
The failure of an AoA sensor may well effect the autopilot as well as increasing the crew workload.
I think this restriction is based on the ability of the aircraft to stay inside the mathematical chances of system failure criteria rather than the likelihood of any likelihood of the aircraft straying outside approach limits if flown by a well trained and vigilant crew.The aircraft can fly again but EASA and the UK CAA has specified that no RNP-AR approaches can be flown.
SafetyDirective2021001_pdf
20210127ADG20210001_pdf
This is rather weird! Why would the avionics disable guidance on an RNP-AR procedure upon the failure of one AoA sensor?
Sounds like it’s what’s wrong with Rolls-Royce Trent 1000s, rather than the 787.
arj1 wrote:
What was wrong with 787?
From the news item LeSving linked to: “Norwegian’s Rolls-Royce Trent 1000-powered 787 aircraft have suffered from long-running reliability issues that have affected reliability and resulted in premature and unplanned maintenance”
LeSving wrote:
The 787 has been a disaster, they had to use long range 737 instead.
What was wrong with 787?
