Originally Posted by
wrench1
Okay, to verify. Per the diagram below when you ground ran the aircraft for the system check, both the unmetered fuel PSI/flow and the metered fuel PSI/flow had unstable (fluctuating) indications on the test gauges?
Was the indicated unmetered/metered fuel PSI within the required limits per the manual aside from the fluctuations?
And after you replaced the engine-driven fuel pump on the 13th, there was no change in the unmetered fuel PSI/flow?
When you checked the airframe fuel supply system, did you inspect the internal passages of the fuel lines/hoses from the electric fuel pump to the engine driven fuel pump?
Did you check the airframe fuel bladder venting system was properly working?
Yes both indicators have fluctuations.
Sometimes showing good pressure and FF (within the limits), but sometimes we face a sudden decrease in pressure and FF without any change in power settings or mixture. 99% of the time without any power loss (except yesterday, while performing a ground check at full power, FF decreased rapidly from 27 GPH to 12 GPH, with a sudden and noticable loss of power).
After remplacing the engine driven fuel pump nothing has changed (I mean that sometimes FF and pressure are good, sometimes fluctuating, and sometimes we encounter a sudden loss). It is an eratic and unpreductable behavior.
And we also tried to adjust many times the
engine driven fuel pump as per TCM OVH manual X30607 chap 73-00-00. But after few minutes of engine running we start to get (again) FF and pressure fluctuations and sudden decrease.
We did not inspect the internal passages of the fuel lines/hoses from the electric fuel pump to the engine driven fuel pump yet. We plan to do it next week as everything else has been done.
The airframe fuel bladder venting system is properly working