At 13:13 21 October 2016, Bruce Hoult wrote:
On Friday, October 21, 2016 at 11:26:02 AM UTC+3, Tango Whisky wrote:
Assuming they simply started this construction technique at some
point
in time, and didn't start-stop-start it, you don't have to open EVERY
wing.

If the wing of SN #N is opened for any reason and found to be ok,
then
you can assume that all lower SNs are ok too. Conversely, if it's not ok,
then you can assume that all higher SNs are bad too.

No, you can't. If for some reason (end of shift, lunch break,...)there
was more time between the epoxy filling and the lay-up of the spar cap,
there wouldn't be any ondulations.
The only valid assumption is that all S/N's are affected.

Even given what you say, if you find a bad one then all later ones are at
least suspect.


I would agree with the manufacturer's findings saying that ALL DG-300's are
suspect, regardless of s/n. That is why the TN applies to all aircraft.

I know of three DG300 that have had the wings opened up (a costly affair).
Two of them were found to have issues that needed rectification. The OK one
had a higher s/n than the ones which needed work.