"jmk" wrote in message
ups.com...

Mxsmanic wrote:
That assumes it survives the wreck.

Small, solid-state devices can survive some extraordinarily high
accelerations, even if they aren't necessarily built to do so.
There's certainly a good chance that something like a flash memory
device will survive intact.

We designed something similar a few years back (still being evaluated
by the SE FSDO, I believe) although our goal was long-term recording of
stress on the airframe. We designed it to include optional aircraft
data, but your average 30 year old C-172 or Warrior just doesn't have
much in the way of electrical data to record. None of the usual stuff
(control position) is there.

You could instrument everything of course, the the price would be
prohibitive (i.e. no one would pay for it).

While we were most interested in things like pulling so many G's that
the wings came off, the FAA rejected our first design because we could
potentially lose the last 100 ms. or so of data (i.e. the actual crash,
after the wings pulled off). We hadn't considered that important (it's
sort of "after the fact"), but they pointed out that in a lot of
mountain crashes the first sign of a problem is hitting the mountain.
We implemented a ferro-ram buffer (in front of the main storage) - both
non-volatile. Even if the pins got pulled off the IC, the die could
still be read (with difficulty).

Sounds like the FAA is missing the point. If they lose the last 100 ms
before the airplane hits the mountain, big deal. Don't the previous 5 (or
30) minutes tell the story.. Either 1) The airplane was cruising along at 8k
ft and hit a 10k mountain. Or: 2) The airplane stalled and spun down into
the ground. Or: 3) Whatever.

I just don't see how that last 1/10 second is gonna tell anyone much...

KB