Phalconphixer;
This link however demonstrates that with Spanair this was not uncommon. Just one month before the accident a Spanair aircraft was filmed during a routine take off from Glasgow; in this instance the flaps and slats were not deployed until the engines were run-up at the end of the runway prior to take-off; could it be that a sticky nose leg switch had failed to operate the relay that energises the TOWS and that only cleared when the brakes were applied thus compressing the nose leg?
I've seen this video a number of times.
The slats/flaps are extended at 1:23 into the video while the aircraft is in a left turn to line up with the runway. Engine thrust does not increase in the turn, (nor would such increase be necessary for the turn).
The engines are at idle thrust until 2:09 into the video.
So the TOCW would not have sounded regardless of the "nosewheel switch" or compression/extension of the oleo.
A number of explanations are possible:
They forgot then caught their error;
They delayed the pre-takeoff checklist until departing the ramp area;
That is the point at which the crew did their checklist;
I don't know the Spanair checklist SOP or sequence so I don't know if the control check is done at the same time as the slat/flap extension, and whether it is before or after the flight control check. There is no flight control check visible on the video, (I was watching the elevators for a downward movement), so we might assume it was either done as part of the departure from the ramp area or it was forgotten; again, we don't know and cannot draw conclusions.
The key understanding is, we don't know why the slats were extended at this point. But they were, and before the engine thrust was increased to the point where the TOCW system would have sounded.
PJ2