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