Originally Posted by
flyinfool1
The AMA rule does not use the word valve. It just says you must have 2 ways to shut of fuel flow.
The fuel pump does meet the requirements of the AMA rule. It is remotely operated, it is operated by the ECU, Loss of power will shut down flow since we are using positive displacement pumps. I still have, and will continue to have a fuel solenoid in all of my jets. But as the rule is written, if you do not need the solenoid valve for startup, I don't know that it is required per the rule.
I did not think of it that way. When I read it, the phrase "closes with loss of power" implies a normally closed solenoid valve - a fuel pump does not "close" in the normal sense one thinks of "opening" and "closing".
You are right though in that the wording is ambiguous. I don't know what the intent was when the rule was originally written, but my guess is that, since most production turbine engines have (or have had, RAMs not withstanding), a fuel solenoid, that it was intended to require them, along with a manual valve.
For my part, I have never had a failure of a fuel solenoid, but in spite of myself, I quite often forget to check the manual shutoff before fueling, and I don't think that just a stopped fuel pump is enough to keep from flooding the engine during fueling - what with the high speed fueling pumps most of us use...
Bob