When is a door not a door?
JohnFTEng asked yesterday -
'On most consumer appliances there is an interlock that prevents operation when casing is open. On a highly automated machine like an Airbus why is there nothing similar - Fan cowl unlocked > start-up inhibited?'
The answer seems to be that fan cowls are not doors, but structure (according to EASA). As long as they do not break under 150% of expected flight loads (bending is acceptable), 'the theoretical probability of failure is zero and does not need to be considered further.' (Report 1.18.1, page 81).
So, as the fan cowl is not a door, it can never be ajar - as every schoolboy knows