Heavy Snow and ILSs?

[Wankel7]

I just heard a rather scary account from a pilot who did an ILS in heavy snow. Basicly, the IDent sounded good. However, on the approach the needles were a little jittery. When he broke out they where not where they should be.

Anybody heard of heavy snow distorting ILS signals?

Wankel

 

[minitour]

haven't heard of that one...could it have been a prop RPM thing?

-mini

 

[Donsa320]

Yep, heavy snow can affect the ILS, at least the Glide Slope, which is reflected off of the ground in front of the Glide Slope antenna. That should be well known. But if it was as bad as what was stated, the self monitor should have tripped the transmitters off. It would be very interesting to find out if it were just that one airplane or the ILS system that was at fault.

Other than while departing airplanes are overflying the Localizer antennas, I had never heard of the Localizer being unreliable and staying on the air for any length of time.

I can see how a heavy coating of wet snow on the antennas could cause the problem though, but then not tripping off....that is a different problem.

 

[Swede]

ILS systems are good. 99.99% of the time, you'll either have an accurate system, or you'll get flags. Sometimes, though...

Once long ago I chased an ILS glideslope to a dangerously low altitude with no warning other than my altitude relative to the field. That is why it is important on an ILS to continuously cross-check the aircraft's altitude relative to the distance to touchdown. They should remain very close to the published angle. If not, abandon the approach. Keep track of the markers, too. It's easy, once on glidepath, to blow off the rest of the crosscheck. Don't do it!

 

[Benhuntn]

I have never flown an ILS that didn't have a runway at the end of it except in Hong Kong.

 

[wasp junior]

I've always found it sadly ironic that the more experience you have, the better your situational awareness becomes....as well as getting to fly better equipment, usually with two pilots, more means of cross checking your position, (glass, gps, gpws, radar alt) and the instrument rating is the same one you got issued in a 172... the more you learn, the scarier it is reminiscing and realizing how lucky we've all been. Dont' know what kind of plane this guy was in, or why he was out flying that day, but I hope he had a reckoning...

 

[singlespeed]

I have never flown an ILS that didn't have a runway at the end of it except in Hong Kong.

Then you have never been to Aspen. ERRR sorry thats Localizer on the departure