Originally Posted by
Flap 80
.....totally impracticable on a walkround for flight crew to lie under the engine to confirm latch closure especially if cowling weight gives impression of totally closed and if latches have been secured closed when cowling was open...
So it's entirely possible, probable even, the pilot performing the walkround checked the cowl doors & believed them to be properly latched.
Would it be worth pilots feeling the difference between a secure and insecure cowl door side-by-side? Not my aircraft, but I'd have thought there'd be some telltale sign that could be easily verified on walkround, even without that banned screwdriver, providing you knew exactly what to look for.