Moderators: richierich, ua900, PanAm_DC10, hOMSaR

 
Fly2HMO
Topic Author
Posts: 7184
Joined: Sat Jan 24, 2004 12:14 pm

Explain This Garmin G1000 Glitch

Sat Jun 20, 2009 6:02 pm

So last Wednesday I was flying practice approaches for my CFII course. We were doing this approach into PRC: http://204.108.4.16/d-tpp/0906/00546R21L.PDF I set it up so my instructor (playing a retarded student) held at DUKIW, which means you activate the APP but set the HSI to OBS mode so you can hold and so it won't cycle to the next waypoint. We have WAAS in our planes so we would use the LPV minima. Now, when you do the LPV approach, the G1000 automatically gives you electronic glideslope information once you're inbound on the final approach course, after PEVYU in this case.

So I turn PEVYU outbound, don't get the glideslope or "vertical track" announcement yet, and don't think much of it. But then we get to within less than 1nm of RUBIW, and still no glideslope. Interestingly the HSI has the magenta "GPS LPV" annunciation on, but still no glideslope showing up next to the altimeter once we passed RUBIW. Me and my instructor look at each other and we both got the WTF? face going on. He continues flying the approach while I go to the AUX pages and check GPS status. Everything checks out ok. WAAS is working. Basically there's no indication that there's anything wrong with the GPS or rest of the G1000. We decide to continue the APP but to change to LNAV minima.

I read through the G1000 users guide and found nothing mentioning anything like this. The requirements for getting an LPV glidepath indication is that you have to have less than full CDI deflection, be in a position prior to the FAF, and have WAAS available. We had all of the above.

Anybody experienced this before?

[Edited 2009-06-20 11:04:07]
 
DescendVia
Posts: 141
Joined: Sun Jan 18, 2009 4:26 am

RE: Explain This Garmin G1000 Glitch

Sat Jun 20, 2009 6:42 pm

Quoting FLY2HMO (Thread starter):

Anybody experienced this before?

I have had "something" similar.

I activated VTF prior to takeoff and would then get vectors for the approach. About 20 minutes later I got an advisory message saying use LNAV MDA (LPV published and where I'm at we always have at least 9-10 in view 95% of the time). I can't remember if we got LPV on the HSI or not b/c approach screwed me over and made me intercept inside/right over the FAF and didn't clear me for the approach till I questioned him about 3.5 from the runway after he told me to contact tower.

I got a feeling it might have to do with us messing with the OBS early (e.g. you playing with the OBS when the TAA is actually to used and my activation of VTF prior to takeoff) so that is what I can think of.

[Edited 2009-06-20 11:48:41]
 
Fly2HMO
Topic Author
Posts: 7184
Joined: Sat Jan 24, 2004 12:14 pm

RE: Explain This Garmin G1000 Glitch

Sun Jun 21, 2009 1:33 am



Quoting DescendVia (Reply 1):
so that is what I can think of.

yeah I was thinking that had something to do with it as well. I've been considering recreating the situation in the G1000 PC trainer, I'll see what happens.

Who is online

Users browsing this forum: VMCA787 and 20 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos