On Saturday, December 7, 2019 at 9:27:51 AM UTC-8, Dave Nadler wrote:
I've been persuaded to give an OSTIV talk about motorglider safety issues,
in particular propulsion system failures. I'm going to discuss
common failures, the systemic reasons this stuff has happened and
WILL CONTINUE to happen, and some ideas for systemic improvements.

I'm looking for pictures and/or documentation of failures, for example:
- failed position switches (ie limit switches, prop position sensor)
- failed fuel systems (improper hoses, routing, leak sources, etc)
- failed structural components (cracked exhaust, mounts, pylons, etc)
- failed drive belts
- failed electrical connectors
- failed motor controller
- failed electronics
and anything else you might happen to have.

Ideally a good photo, make and model, approximate date, brief description..
Please email to me offline.

Thanks in advance for the help!
Best Regards, Dave

PS: Probably time to redo this study, but situation isn't that much changed:
http://www.nadler.com/public/DeRese_...ilplanes.p df

If this talk is to be about safety issues, it shouldn't be concerned with maintenance issues. Safety issues are things that affect the outcome of a flight - if a maintenance issue occurs that prevents the flight from occurring, there is no safety issue.

An in-flight fire is definitely a safety issue; a dead battery that keeps you from starting your engine is not. I have experienced both; examples include:

Maintenance:
Hydrolocking due to unknown contamination in the fuel system.
Flywheel screws that jam engine operation because of insufficient locking adhesive.
Drive belt that fails during engine starting.
Engine controller failure due to unknown causes.

Flight safety:
Mast mounting bolt failure due to unknown causes resulting in loss of all power (propulsion failure followed by uneventful landing).
Fuel system fire due to unknown causes (propulsion failure followed by uneventful landing).
Decompression valve plug working out due to missing washer (propulsion failure followed by uneventful landing).

The truth is that very few true flight safety issues have occurred, perhaps on a par with towplane engine failures. The more likely issue is engine failure to start with a bad outlanding outcome. And, I suspect these are dwarfed by all of the fatal stall/spins trying to do a low save (one occurred recently).

Tom