Do you mean rather than the NTSB or FAA?
@YRP
You are right, my bad.
NTSB, not Boeing visited securaplane.
BTW, just found this:
Securaplane said it makes two battery charging units used on the 787, one for the APU battery in an aft bay, and one for the main ship battery used in a forward bay, which provides backup power for flight critical controls.
U.S. NTSB reviewing whistleblower claims in 787 case - chicagotribune.com
So, the chargers are not identical.