The fan cowls are an un pressurised area , so no warning system is deemed necessary , maybe not from now on
A fairly simple modification to add a warning input from new prox sensors on the cowls
Both engine fan cowls unlatched is the most obvious cause , it must have been done pre flight - many reasons exist for gaining access to both engines , but on a turn round is unusual
A lack of manpower at a previous nightstop , and not enough hours left for a routine inspection often creates turnround/ transit maintenance
Easy to miss latches hanging down if under time pressure , the crew are time limited to make departures, the pushback crew are no longer engineers or mechanics , they used to be , and part of the pushback is to check for loose panels, fuel leaks etc - used to be part of pushback
Too much clock chasing and cost reduction ,this is the result , some operators have duplicate inspections on fan cowls , others do not .
It would be interesting to see the tech log entry for opening the fan cowls .......