Menu Sign In Contact FAQ
Banner
Welcome to our forums

Complete loss of GPS position yesterday

When flying to EDMA last night I had an complete GPS position loss on all devices.

I was on a radar vectored ILS approach RWY 25 at Augsburg and cleared to intercept the localiser when the GPS got lost on all devices. It was not an avionics failure, because even on the iPhone and iPad the GPS went away and the aircraft symbol went straight forward like when driving with Google maps in a long tunnel.

Look at the pics:

Taken from Foreflight

Taken from Flightradar24

Are there any explanations for the phenomenon?

EDDS , Germany

Good you were on an ILS not a GPS approach – would be quite a stress situation if you have to reconfigure and switch to ILS when in turn to final.

As there was not predicted outage in the area last night, most probable cause is that some ground based interference – can be anything from a Microwave oven going berserk (GPS is at about half the frequency of microwaves) to someone experimenting with jammers you can buy online.

Good reminder for all of us that it doesnt hurt to tune in the ILS frequency as backup on a GPS-approach (if available) and think about our procedure for GPS outage in case ILS backup is not available.

Germany

How long did the outage last?

CB IR Instruction
LOWG, LOWW

How long did the outage last?

About 1,5-2 minutes.

EDDS , Germany

Did you operate any device or move it’s position in the plane?

I had a gps fail in a sr22 g2 after switching on a delorme inreach.

CB IR Instruction
LOWG, LOWW

eddsPeter wrote:

because even on the iPhone and iPad the GPS went away and the aircraft symbol went straight forward like when driving with Google maps in a long tunnel.

Would 3G/4G/LTE cellular data on iPhone/iPad made a difference to these scenarios?
I guess on low level that keeps more position accuracy than sole GPS?
Also, not sure if SD/FF use that assisted data or just query on GPS?

ESSEX, United Kingdom

aren’t outages mentioned somewhere on a website ? don’t remember which one.

EDLN, Germany

Were any VHF frequencies selected mentioned here i.e. 11th or 13th sub harmonic of 1575MHz? A few secs’ transmission on one of these can wipe out GPS totally, and you won’t necessarily know beforehand if you didn’t use that frequency previously.

I’ve had a total loss of GPS only once, IIRC, flying down the middle of the Adriatic in solid IMC I think it was 2004. Probably jamming, connected with the Yugoslav wars.

I had another curious one on the KLN94 only, never tracked down but probably a “glitch” wiped out the constellation data and it took about an hour to get it back. It was a departure from Padova to the north and I got it back halfway across the Alps. But other GPS devices worked.

Nothing beats ILS

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

Were any VHF frequencies selected mentioned here i.e. 11th or 13th sub harmonic of 1575MHz? A few secs’ transmission on one of these can wipe out GPS totally, and you won’t necessarily know beforehand if you didn’t use that frequency previously.

As you wrote, those frequencies are supposed to be checked during installation of the GPS. See e.g. the IM for the GTN650.

ESKC (Uppsala/Sundbro), Sweden

Indeed, but almost no installer does that

Or the aircraft manufacturer… Socata never tested their installation – as I proved.

There is a nice business in these filters. This is also why the composite antenna (GPS+VHF) manufacturers incorporate a tuned cavity notch filter in the base; a lot of VHF radios radiate all over the place.

Administrator
Shoreham EGKA, United Kingdom
22 Posts
Sign in to add your message

Back to Top