mm wrote:
This reminds me of the time I was on an airplane about to take off,
and I saw a guy on the wing doing something. In a few seconds he was
putting the cover panel on, and after a bit, he turned the screwdriver
upside down and was hammering on the screw with its handle. A couple
minutes later he left. I think a lot of the passengers would have
been bothered if they had seen this, but it didn't bother me.
Mechical stuff is not perfect.

As long as the screw on the access panel wasn't stripped there shouldn't
be any problem. Of course, if the hammering with the end of the
screwdriver resulted in the screw being stripped then shortly after
takeoff the access cover might have popped off, reducing the airfoil
surface, impeding the airflow over the wing and causing turbulence over
the area of the access panel. If it was a small panel and the aircraft
was properly loaded and operated and in perfect weather conditions then
it shouldn't be a problem. Of course there is always the possibility
that there would be ice on the wings, that the aircraft would be
operated outside its weight and balance envelope, or that you could have
an engine failure just after rotation.

In which case you wouldn't necessarily be here to be so flippant about
"mechical (sic) stuff not being perfect".