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Re: [LML] P-STATc?
Hi Ross,
P-static is a meteorological phenomenon that requires specific weather
conditions. I don't know about your typical weather in South Africa, but I
wouldn't expect you'd have P-static issues on nearly every flight, beginning on
takeoff. Particularly on an airplane not known to have significant
P-static problems. If it were me, I'd look to other things before
electrically bonding airframe parts.
Have you tried swapping out the GPS antenna and the antenna cable?
Anybody near you with the same unit you could swap out for a test?
If it's only the GPS part of the component, and only one GPS receiver, I'd
look to the antenna and the coax.
You might post this question on Bob Nuckolls' AeroElectric newsgroup
at:
Someone there will likely give you a logical troubleshooting sequence that
will minimize replacement of good parts while you're closing in on the
problem.
Dennis
Dennis
The loss of the GPS signal is as regular
as clockwork. Sometimes as the aircraft lifts off the ground it’s gone.
Initially I thought it was the gear pump but sometimes it goes well after gear
up. I have considered that I use a 28v system but MGL assures me that its
equipment can take the voltage. Nonetheless I tried a voltage converter to 14v
and still the GPS signal was lost. Then I smoothed out the input voltage using
a capacitor in an attempt to eliminate voltage spikes. Still lost the signal.
Nothing else seems to be affected within the EFIS or the other
avionics, which only adds to the mystery.
Thus, I am led to the idea of
P-STAT. Is there perhaps a momentary electrical discharge into the system that
disrupts the GPS. If so why only the one GPS and why none of the other
equipment? The Tru Trak AP is rock solid using the secondary GPS; the comms
are rock solid; as is the transponder.
BTW in answer to another list
member, all ground connections have been checked and are good.
All very
frustrating.
Ross
On 2010/12/30 4:21 AM, "Dennis Johnson"
<pinetownd@volcano.net>
wrote:
Hi
Ross,
There are many, many Legacies flying without P-static
problems disabling their avionics. Before I went to a lot of trouble
electrically bonding parts of the airframe, I'd try to determine how your
Legacy is different from the others. And I'd make sure all the
electrical grounds are solidly connected.
Do you have
any indication that P-static is a frequent problem in your airplane?
Is anything except the GPS function of your MGL Voyager affected?
I once picked up enough static charge that what little hair I have on
my head stood straight up, towards the charged canopy. It didn't cause
a problem with any of the avionics,
though.
Dennis
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