The standard trick for in-flight recording of a reasonable sound track with a camcorder is to get a small external mike, and tuck it inside the headset.
I have done this with various camcorders, and the #1 thing is to get a mike that is small enough to fit inside the earcup (obviously) and has a thin enough cable so you don't get noise coming in through the gap created (same issue as with glasses actually).
The setup I currently use, which works very well, is a miniature mike from
http://www.soundprofessionals.com/cg...egory/140/mics
model SP-LAV-1 (if I recall correctl).
I also bought the SP-LAV-3 which is amazingly sensitive but not needed for this application. This model also has a much lower limit on the maximum supply voltage, though I have not found this on their website today so perhaps they have changed the design.
The mike needs to be purchased specified (wired) for "dual mono".
I then use a pre-amp SP-PREAMP
http://www.soundprofessionals.com/cg...item/SP-PREAMP
but mine came without all the accessories shown in the above URL. This is set to 0db gain (it has a three-position gain switch as well as the rotary knob). Practically the whole reason for this preamp is to get a manual sound level adjustment; experimentation shows that setting the switch to 0db and the knob to 75% of max is just perfect, with my Sony HC1 high-def cam.
The Sony HC1 cam has a great feature which is manual sound level control. It isn't really accessible during use but it disables the AGC (automatic gain control) feature which all consumer cams have by default and which is a total pain in this application.
I hope the above helps somebody. The result is really excellent - as good as the best professionally produced sound track I have seen on TV when recording on GA flights.
The proper way, which avoids all the wires, would be a connection into the aircraft intercom. I have the PS Engineering PS7000 which is a top-end unit but even that doesn't have a spare output (well not according to my installation manual, or the illiterate ape who works on their American customer service). One could however take a signal off the cockpit speaker cable (attenuating suitably, using 2 resistors) and almost every plane will have one of those, and the connection (to the actual speaker terminals) would be trivial since the speaker itself can usually be easily extracted from its mounting. You just need to fly with the speaker switched ON on the intercom. If you then fix a tiny jack socket somewhere, it's unlikely anybody will find it and query whether it has the right paperwork
