Traffic messages while parked

[RVDan]

Why am I getting traffic alerts when parked in the tiedown? ADSB 472 is the in device?

 

[jakej]

While the system is powered up & with 'coverage' you will get that, I 'see' traffic with the hangar doors open.

 

[DBRV10]

Traffic is traffic.

Jake is correct

 

[swatson999]

Yes, seeing traffic is one thing. He said he's getting *alerts*, which he should not be if his transponder (which model?) is in Ground or Standby mode, right?

I never get traffic alerts while on the ground, and I see traffic just fine while taxiing, etc.

 

[XPRSAV8R]

I also see traffic nearby and sometimes overhead while hangared with the doors open, 472 on and transponder in "auto", but I've never heard an alert. Also, I've taxied near the runway and held short of the runway, and I've never heard an alert (albeit it'd be a useful warning of aircrafts on base or final before taking the runway at an uncontrolled field, especially at dusk or night).

 

[RVDan]

I’m not talking about seeing traffic, that of course happens, but rather a traffic alert and call out while parked. Typically traffic alerts are suppressed unless flying. I was getting traffic alerts from departing airplanes over the runway.

 

[jakej]

I’m not talking about seeing traffic, that of course happens, but rather a traffic alert and call out while parked. Typically traffic alerts are suppressed unless flying. I was getting traffic alerts from departing airplanes over the runway.

Then it appears you may have the transponder in Flight mode rather than Ground mode? I always set the system up in Auto so that the ‘alerts’ will not happen on the ground.

 

[XPRSAV8R]

I’m not talking about seeing traffic, that of course happens, but rather a traffic alert and call out while parked. Typically traffic alerts are suppressed unless flying. I was getting traffic alerts from departing airplanes over the runway.

Is it possible that pressure altitude fluctuated (or something in your system) enough triggering the transition from Ground to Flight mode?

 

[RVDan]

I believe the ground/ flat condition is based on airspeed.

 

[jakej]

RVDan, to help eliminate probable causes re airspeed why not do a 'zero airspeed calibration' ? - however that should not be necessary if there is no airspeed indicated while stationary but will eliminate one data point.

 

[RVDan]

No airspeed indicated when this happened.

 

[jakej]

Today I had the same alert while taxiing down the runway while landing, transponder did not show in ground mode until I went below 30 knots, increase speed above 30 kts & goes into flight mode. There’s the clue - did you check your settings ? Or maybe there were strong surface winds gusts ? I’d be interested to hear what you find.

 

[swatson999]

Today I had the same alert while taxiing down the runway while landing, transponder did not show in ground mode until I went below 30 knots, increase speed above 30 kts & goes into flight mode. There’s the clue - did you check your settings ? Or maybe there were strong surface winds gusts ? I’d be interested to hear what you find.

OP said he was parked...and doesn't the stdby/gnd/flight determination involve more than just airspeed? I thought it folded the ADAHRS and maybe GPS info into the computations...

 

[jakej]

OP said he was parked...and doesn't the stdby/gnd/flight determination involve more than just airspeed? I thought it folded the ADAHRS and maybe GPS info into the computations...

I understand & did not disregard that - what I was trying to get as was to determine the surface wind while he was stationary as an explanation as to the ‘trigger’ event to turn the system on to think it was in flight mode. In my case it appeared to me that the main factor was indicated speed ( & maybe GPS) turning off/on Txpdr Gnd/ Flight mode.