Have you ever had a Shuler error manifest in the IRS, what caused it?

[Fingermouse]

Have you ever had a Shuler error manifest in the IRS, what caused it?
How did you deal with it?

[BOAC]

How would I know?

[Fingermouse]

A bounded or unbounded error in position and/or speed reporting of various magnitude could be one symptom. Do you hold an ATPL or CPL boac?

[main_dog]

Incautious student pilot vs. grizzled old line veterans ;) (crunch, crunch)

PS meanwhile, I had to go back to the books to discover that I once did have a vague idea of what a Schuler error was :}

PPS And by the way, not that I'm any authority, but it does appear to be Schuler :ok:

[SNS3Guppy]

http://www.pprune.org/tech-log/119072-ins-irs-schuler-effect.html

[Ex Cargo Clown]

Firstly, I wouldn't be having a go at BOAC's credentials !! :eek:

Secondly, the only thing I know about Schuler errors are that they occur due to pendulous forces. I really don't think any pilot other than a NASA one really needs to understand them.

[FullWings]

Yes, tricky problem. I re-routed power from engineering through the main deflector dish which corrected the tachyon imbalance.

Next?

P.S. I think it is a question only really asked by examining boards - you'd have to go a long way back to find equipment that you could actually see an error of this kind develop...

[BOAC]

Actually, FM, I used to lecture on IRS systems (probably before you were born), but I don't reckon I'd know a Schuler loop error in flight from a big black dog. Which light is going to come on on my MS flight sim screen? Ah yes - The Schuler loop error light, of course, assuming the big black dog light did not light first. I've probably seen more tachyon imbalance, on reflection.

"A bounded or unbounded error in position and/or speed reporting of various magnitude could be one symptom." - ah well, yes, I've had quite a few of those (mostly fortunately bounded) but not caused by the IRS.

[wiggy]

Could have.

A while back on a very long haul flight we had one of the three IRSs on a 747-400 exhibit G/S errors (vs. other aids) and displacement from the mean position of the other two IRSs and the FMC position. Being a bit of a geek I timed the IRS's behaviour and funnily enough the errors had a period of around 90 minutes and were cyclical.

No idea if this was a Shuler error ( what does the team think?) and no idea what caused it.

[STBYRUD]

Hmm, I'm sure its there, I'm sure the period is correctly 84.4 minutes, but I dont really care as long as my clever FMS uses DME, VOR and GPS updating to compensate for such long-term drift ;) Call me ignorant, I call it realistic :)

[eckhard]

Apparently if one bored a hole vertically down right through the earth and dropped a penny down it, it would appear at the antipodes 84.4 minutes later (ignoring air resistance).

[STBYRUD]

Or a pendulum with length r = radius of the earth will swing with a period of 84.4 minutes.

[BOAC]

and dropped a penny down it - (sorry JT) - could the Aussies wait that long for the penny to drop?:)

[Feather #3]

Hey, lay off! We're waiting longer than that for a wicket to fall!;)

Hopefully not today, though!!

G'day ;)

Oh, yes, the topic. Well, over the course of 32 years flying the B747 in its various marques, had a few Carousel IV's fall over and lost the odd FMC, but Schuler never raised his ugly head.

[renard]

A guy I flew with said that in bombing contests, US vs UK in F4's witht he same kit, the British always came out on top. He reckoned it was because their time on target was the time of minimum schuler error.