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noblues
19th Apr 2006, 23:59
Has anyone any suggestions what the best procedure would be with a total loss of Nav in the Polar Regions ... ie. all IRS and GPS fail ....

The variation is so great the use of the standy compass would be near useless?

Sky Wave
20th Apr 2006, 00:13
I have no experience of such operations, however I would think declare Mayday, Speak to other aircraft and tell them what's going on. ask if any punters have a handheld GPS, If not get a rough track from Sun/Moon (other aircraft could tell you the relative position of the sun/moon for the correct track). use wx radar ground mapping and keep a steady heading until you can positively identify somewhere.

Only my thoughts, be interested to hear what the experts say.

noblues
20th Apr 2006, 01:29
I've been at >75deg N on pitch black nights with no moon, I often ponder the consequences of a total nav failure.

WX Radar ground mapping is not a bad idea, assuming the ATT info hasn't dropped off with the IRS's which might confuse the WX Radar tilt system and disable it. (probabaly on an airbus, Boeing would no doubt go to 'raw tilt mode').

Most hand held GPS units dont work inside airliners ..... otherwise I would carry one!

The answer to this I am sure relies on last known position and earths rotation to calculate heading changes, the problem of True and Magnetic and huge variation changes is what is going to cause problems .....

Rim Pointer
20th Apr 2006, 03:14
When you say total nav loss, I assume you mean traditional nav aids as well. I routinely navigate in Canada's high arctic. With total nav failure by day if you had the capability to convert your instruments to true, point the aircraft at the sun, then 15 x GMT-west long will give you your true heading. Arctic radio will then have you on radar and I'm sure would be able to provide vectors to a suitable airport for nav repair. I hope this makes sense, I do fly a pressurized aircraft, but am not a high flyer so hopefully I was able to help. We also always carry an astro-compass.

Sky Wave
20th Apr 2006, 10:34
Most hand held GPS units dont work inside airliners ..... otherwise I would carry one!

Fairly certain they do work to some degree. I know of SLF who always takes his when flying to track the route and I've also seen discussion elsewhere on pprune regarding them.

SW

Charles Darwin
20th Apr 2006, 11:42
Fairly certain they do work to some degree. I know of SLF who always takes his when flying to track the route and I've also seen discussion elsewhere on pprune regarding them.
SW

Garmin 60CSX is the only GPS that has perfect reception inside the flightdeck of a B-757/767. I´ve tried many, but to my surprise the 60CSX received excellent signal through all front windows. Most others were totally left in the dark.

I have no connection with Garmin Inc. whatsoever! :ok:

javelin
20th Apr 2006, 16:56
Well I gues if you are very near the pole, everyway is south..................

It's a start ;)

noblues
20th Apr 2006, 19:05
point the aircraft at the sun, then 15 x GMT-west long will give you your true heading

I've not heard of that one before ... useful ... will have to think how that works.

Well I gues if you are very near the pole, everyway is south..................

Yeah .. but say over northern Greenland that could be either Russia or the Atlantic ... it would be easy to go 'over the pole' by mistake ...

Re. Hand held GPS units .. interesting some do work, I have heard of passengers esp with bluetooth units on the window works ... Trouble at the pointy bit the glass has heated elements and blocks the signal ...

con-pilot
20th Apr 2006, 19:51
A few years ago we bought a 727-200 with no long range nav, later LRNs were installed. In the period of our operating this aircraft before the LRNS were installed one of the other pilots brought his Marine style (for boats) GPS off of his boat, proped it up on the windscreen and we used it with no problems.

Now, we never, repeat never told ATC that we had LRN style equiptment on board nor did we ever (at least I didn't) use the boat GPS for anything but judging progress on long legs.

It was amusing however to read the upper winds as current. "Current 320 degrees at 110 knots.":p

lowandfast
20th Apr 2006, 20:54
I have a garmin gps-72 and it realy works great in the cockpit of the 707.

Even if we have 3 INS on board I use the gps for position reports over the north atlantic.

laf

Regis Potter
20th Apr 2006, 21:16
noblues,

I suppose you could always wake up the skipper & ask him what to do? :}

Cheers :ok:

mono
20th Apr 2006, 21:54
I would suggest you were having a VERY bad day if you had a total nav failure on todays multi redundant a/c. All IRS and GPS fail is unlikely in the extreme. Probably the only thing that would cause this would be a TOTAL electrical failure and even this would still leave basic nav info available via the stby buss. If total electrical failure occured navigating would not be your major concern IMHO.

vapilot2004
20th Apr 2006, 22:50
What you need in this case is an old-timer that is familiar with a flight deck position called the Navigator.

Hopefully the man brought along his sextant. :)

Jinkster
20th Apr 2006, 22:58
I have as PAX had a handheld Garmin GPS40 working in an airliner - just keep it next to a window and it did work ok.

Although if your over the south pole and have a total failure - surely wouldnt you just head south :=

noblues
20th Apr 2006, 23:54
I suppose you could always wake up the skipper & ask him what to do?


We had an FO who a few years back mid atlantic in a empty 747-200 heard a company a/c divert into Gander ... without waking the skipper (who was in the bunks) he spoke to ops told them they were within range and promtly did a 180 ...

Needless to say the bleary eyed Capt. went 'ape' when he saw they were heading east ... the fact he had adinner engagement that evening also had a bearing on his reaction!

noblues
21st Apr 2006, 00:02
I would suggest you were having a VERY bad day if you had a total nav failure on todays multi redundant a/c. All IRS and GPS fail is unlikely in the extreme.

What made me start this topic was a few weeks ago I was operating back from San Fran in a rare non GPS 747-400, at about 75N over Northern Canada me and the other FO at the controls got an 'unable RMP' message (Rnav Accuracy Monitoring), it started drifting rapidly to about 8 miles ... checked the IRS, of which one seemed 'rouge' but eventually settled down when we briefly picked up a VOR near Baffin (Iqaluit) .... So we were nearly down to 'just' two IRS's ... still no big deal .. but getting uncomfortable ... it would be sods law we would then loose a electrical bus .... I always assume 'if it can happen - it will!'

My company has specific guidlines on what equipment is serviceable to operated into the very Northern latitudes ... but once you are 'there' and it fails .... ???

Yeah ... old style Navigators ... Bring em back!