Originally Posted by
Desert185
Fuel makes fire...and fuel at an aircraft carburetor is controlled by...?
Both mixture control, throttle AND PRIMER .
Engine fire was caused (probably) by TOO MUCH PRIMING. Mixture could have been at ICO and it could still have caught fire.
Nothing to do with the mixture control.
You said in your original post that there was repeated cranking during the attempted hot start. You were over 100m away. Could the repeated cranking not be part of the engine fire during startup procedure? The POH says that if the fire doesn't stop while continuing to crank after a few seconds, the aircraft should be abandoned. By the time you had got your extinguisher and travelled more than 100m it will have taken at least 15 seconds, probably much more. Unless the FI says they didn't continue to crank (and they may have been in shock straight afterwards) then how can you know whether they did or not?
They were following the authorised procedures until probably over cranking.
Clearing mags is not part of most training (I only know about it because it happened during my training). Its not in any text book that I've seen. I think you are doing the FI a disservice.
I can't comment on their hot start procedure as there are lots of engine variants around, but this one
http://www.ddac.com.au/documents/aircraft/PA28.pdf suggests not priming at all unless it doesn't start first time, the only difference between hot and cold start is a higher throttle setting for a hot start. If priming was the cause (and their aircraft is similar to this one), then they weren't following the POH...