Prescott Flyer
Member
I had to put in a replacement GSU 73 and have completed the AHRS alignment and Magnetometer Interference tests. But the Magnetometer Calibration test repeatedly fails. I believe this is for two reasons. Either the area I'm attempting to perform the test is not free from magnetic interference, or I am doing something wrong during the test. Here's a rundown of what I've done so far.
Aircraft: RV-9A
Equipment: G3X (GSU 73, GMU 44, GDU 370 (2), GDU 375)
Attempt #1 (last week)
Attempt #2 (last week)
Attempt #3 (last night)
We plan to repeat the test with the engine off again but over the Compass Rose this evening to rule out magnetic interference that could be causing the failure on the ramp.
Any advice on things to check or do differently next time is appreciated!
Thanks!
Aircraft: RV-9A
Equipment: G3X (GSU 73, GMU 44, GDU 370 (2), GDU 375)
Attempt #1 (last week)
- Location: On my ramp (tarmac) about 30 feet away from a row of Port-a-Port hangars, and about 20-25 feet away from a couple of tied-down Cessnas
- Wind: Breezy, occasionally gusting over 15mph
- Engine running
- Started the test pointed North.
- Immediate failure was reported due to the aircraft not being still
- I waited a few moments then restarted the test
- Test procedure would not progress beyond the initial instruction to hold position
Attempt #2 (last week)
- Location: Compass Rose
- Wind: Breezy, occasionally gusting over 15mph
- Engine running
- Started the test pointed North
- The test procedure would not progress beyond the initial instruction to hold position. I waited for 5 minutes, but I never got the instruction to turn the aircraft.
Attempt #3 (last night)
- Location: On my ramp (tarmac) about 30 feet away from a row of Port-a-Port hangars, and about 20-25 feet away from a couple of tied-down Cessnas
- Wind: calm
- Engine OFF
- With the help of an assistant in the cockpit, we started the test and it proceeded as expected, alternating between holding and turning the aircraft, roughly every 30 degrees.
- Test calibration repeatedly failed over many (6+) attempts with "Calibration Error".
- Often where we were instructed to hold it didn't align closely with the next expected 30-degree position (usually we'd be past the expected magnetic heading)
- We tried to slow the rate of turn as the dots "counted down" to the next expected hold position. But if I slowed the turn down too much, the dots would reset and start the countdown over. It makes me think I'm doing something wrong with how I'm turning the aircraft.
We plan to repeat the test with the engine off again but over the Compass Rose this evening to rule out magnetic interference that could be causing the failure on the ramp.
Any advice on things to check or do differently next time is appreciated!
Thanks!