Amadeus
Well Known Member
My RV-12iS has the dual G3X VFR package that has had the GPS20A removed and replaced with the GPS175 in March 2023. Last fall, shortly after a take off in VFR conditions, the G3X map screen and PFD background displayed in the color red and the audio alert of "terrain, terrain, pull up, pull up" began repeating itself. Having flown from that airport multiple times and also being able to see clearly on a CAVU day I knew there was nothing in my path at my altitude and continued my flight. Once at cruising altitude my pilot/passenger and I began to assess why this may have occurred and came up with a WAG (wild assumption guess). We were attending a fly-in event that had many aircraft departing once festivities were over. I had just started up and the GPS175 was still in TERR TEST mode when the marshaller began directing me to pull into the line of traffic moving toward the runway. My temperatures were in the green so I began movement. We both figured that moving the airplane while the TERR TEST was still being conducted confused the navigator as to actual location so I made mental note to always wait for the test to complete before beginning to taxi.
Waiting for TERR TEST to complete before movement seemed to do the trick for quite a few months. Then in March of this year I was departing another familiar airport on a VFR day when the same "terrain, terrain, pull up, pull up" event again occurred despite waiting. I wrote it off as a one time thing before it once again occurred leaving an unfamiliar airport (but in a very flat farmland area on the Illinois/Indiana state line) in the path of totality for the April 8 eclipse. Because this was once again taking off from an event when everyone else was I wondered if the close proximity to other navigators could have an input to the problem; after all, two of the three data points are leaving crowded events. However it happened again just last weekend at a small uncrowded airport.
Fortunately all these occurrences were in VFR conditions. Until I figure it out I will not be taking off into IFR conditions. Has anyone else experienced this navigator behavior? I'm stumped on where to begin my research.
Waiting for TERR TEST to complete before movement seemed to do the trick for quite a few months. Then in March of this year I was departing another familiar airport on a VFR day when the same "terrain, terrain, pull up, pull up" event again occurred despite waiting. I wrote it off as a one time thing before it once again occurred leaving an unfamiliar airport (but in a very flat farmland area on the Illinois/Indiana state line) in the path of totality for the April 8 eclipse. Because this was once again taking off from an event when everyone else was I wondered if the close proximity to other navigators could have an input to the problem; after all, two of the three data points are leaving crowded events. However it happened again just last weekend at a small uncrowded airport.
Fortunately all these occurrences were in VFR conditions. Until I figure it out I will not be taking off into IFR conditions. Has anyone else experienced this navigator behavior? I'm stumped on where to begin my research.