EEngr:
This brings up some interesting philosophical points in handling development
and certification testing. The 777 was developed with an "iron bird". A mockup
of all the aircraft systems where compatibility issues could be researched.
But that was expensive.
I would think that they at least had a fully instrumented test rig in house
for the battery subsystem, including expected worst case load profiles such
as apu starting and fast charging. If they didn't, I would see that as a
serious deficiency.
There's no reason why they shouldn't use a production a/c to do this,
much as a/c such as the Concorde prototypes had strain gauges everywhere and
instrumentation racks right down the isle. It probably costs orders
of magnitude more to do design in production, rather than during development,
but with subsystem parts coming from so many suppliers, how do project
management maintain full visibility ?. For software, it's easy to show that
a single module works as expected, but very difficult once hundreds
of modules are linked together for the application. It's the same for any
complex project. Managing complexity probably has dozens of books written
about it, but do management actually read them ?.
Attention to detail and due diligence are everything. Much harder to argue
for in this world of bean counters, cost centres and hr departments, who
are often more interested in whether you ever inhaled, rather than your
passion and ability to get the job done...