fluctuating fuel flow indication C404
hey gents !
i freelance on a 404 and have experienced a fluactuating fuel flow indication in cruise and descend.
with engines leaned and set for cruise power after some time the right fuel flow starts to jump up and down , occasionally even up to redline fuel flow . then its ok again and restarts after a couple of minutes. i strongly believe it can be only an indication fault since the engine does not make any symptoms that the fuel flow really fluctuates that much - it runs smoothly regardless of the needle jumping .
on the other hand i have read there was an AD with the big bore continentals due to fuel pump seal failures where a fluctuating fuel flow was the first indication .
i talked with the maintanance about it and we looked at the mechanical fuel pump. its bone dry so there does not seem to be any leak. they cannot see anything and have no idea what the problem could be.
maybe i have luck and meet some technicians here who are familiar with maintanace and troubleshooting on this aircraft/engine and can give some hints what it could be so it can be sorted out.
engine is a continental GTSIO-520-M
thanks very much for any useful hints !