Folks,
How to fool the system:
Quite a while ago now, in one day at YSSY, three aeroplanes got airborne, the gear would not retract ---- two from one airline, the third, as I recall, anther airline handled by the former.
Same reason in all cases, gear pins not removed by the same departure "engineer".
Another example, one of mine, nose gear pins left in at EGLL, a very tidy minded "engineer" rolled up the red flags and held them with a rubber band "so the greasy flags don't leave greasy streaks on the U/C legs"?? Rather defeats the purpose of having bleeding great long red flags, doesn't it??
Another personal experience, doing the walk-around on a B744 ---- no flag at all on the nose gear pin, at least I was following what I always taught trainees ---- look for the "hole in the hole", not just the absence of the flag --- which is why you need a real torch, not a toy. (Ain't modern LED globes great)
Also on the B744, I have had pitot covers, with no flags, left on, to be discovered by me on the walk around,the post facto claim was that strong winds must have torn them off.
In short, if it can be done, one day, somebody will it.
But, in this case, it is certainly a trail of holes all lining up ---- proving anything is possible. The tec. crew is the last line of defense, on the face of it, looks like they screwed up.
Tootle pip!!