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Or the ball pressure dump value between high & low lines is
leaking.
Gary
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Original Message -----
Sent:
Thursday, August 7, 2014 4:07 PM
Subject:
[LML] LNC2 Gear Pump
Hey guys, I have attached an excel spreadsheet showing the
hydraulic pressure data for nine flights from March 5, 2013 through August 6,
2014. The data for the first 6 flights seem fairly typical, and I would
expect minor changes due to altitude/temperature differences. The flight on
July 11th for example had the gear coming up at 7:21:12am with the pump
shutting off at 1440psi. and slowly dropping to 1080psi at 7500ft where
Bill Harrelson aka Wineaux and I conducted a first GAMI lean exercise. Not
sure why some residual pressure seems to remain on the low side. Perhaps
one of you can shed light on this. The first indication of any irregularity
occurred on the 7/31 flight at 9:49:09am when the pressure had dropped to 850
and the pump came on. The on cycles were momentary for the remainder of the
flight but came with greater frequency. For the last flight on 8/6, the
gear came up with the pump shutting off at 1470psi and I climbed to 2500ft,
pressure immediately began to drop and the pump cycled again at 860psi and
the recycle events came with greater frequency.
So at this point, there
is no evidence of any external fluid leaks. I’m thinking there may an internal
leak in one of the six actuators, an issue with the pump itself, or
possibly…. a failing high pressure limit switch.
Any comments and
advice from all you hydraulic wizards is gratefully
appreciated.
Thanks,
Angier Ames N4ZQlml
This file
only contains the last three flights due to the size of the original not being
accepted on LML. The complete file is posted to
Lancairtalk.net.
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