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mole_man

Rc thinks altitude is wrong

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Hi

 

Just recently, last few days, RC has started to think I am at the wrong altitude on descent. If the instruction is to descend to 11000, I do so and sit there. RC tells me my assigned altitude is 11,000 and to stick to it. Just leaves me there giving me constant warnings. I have checked the baro is correct, using ASE and also hitting the B button.

 

I have tried this in several aircraft with the same effect. Different flights, mostly to London or Dublin at present.

 

Any ideas?

 

Graeme

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There's no such altitude as 11,000ft in London or Dublin Graeme. The transition altitude / level in Europe varies by country and also within a country.

 

You should still be on standard pressure when you reach FL110. And don't hit the B button when the TA is not 18,000ft. It doesn't work the same as in the US.

 

If you repeat that flight you will notice you were cleared down to "flight level one one zero". Not "eleven thousand feet". The difference is quite significant.

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Hi Ray

 

Isn't one one zero 11,000ft? I get down to one one zero, but they keep telling me to maintain one one zero. Used RC for years and not had this issue before.

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Sorry got it. FL110 rather than 11,000 means RC still knows I am above transition level for that region. Still learning after 10 years here.

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Sorry got it. FL110 rather than 11,000 means RC still knows I am above transition level for that region. Still learning after 10 years here.

 

That's it Graeme. Whenever you're cleared to a flight level you must be on standard pressure. When you're cleared to an altitude you should be on QNH. :smile:

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Sorry got it. FL110 rather than 11,000 means RC still knows I am above transition level for that region. Still learning after 10 years here.

 

 

You should have started flying in Europe earlier!   :biggrin:

 

(Sorry, couldn't resist.  :ph34r:  )

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I have been having the same problem intermittently and hit it again today after not seeing it for awhile. I used to think it was a problem only when I used the Maddog MD80 and experienced extremely high pressures. Today, when flying the PMDG 737, it happened again over Europe. I didn't hit 'b' as per the instructions and set QNH to 994 as per RC4. It kept barking I was busting altitude even though I had leveled off at the altitude RC4 requested. I've been told numerous times this is a pilot problem, not an RC4 problem, but there's no way to recover once this happens and you'll get vectored all over the place until you reach the expected altitude (might as well kill off RC4 when that happens as you won't get RC4 to correct itself). This ONLY seems to happen to me when I have pressures in the extremes (I've noticed it when I had pressures in excess of 30.35 and now during lower pressures over Europe (994 today). Not sure what the deal here is, but it makes for a crappy experience when you spent the last 3 hours on a flight only to find RC4 won't accept your altitude settings.

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RC4 has been tested thoroughly so any problems with altitude have to be down to the user - sorry.

 

Please give more details including your plan and where the problems started. If you set QNH to 994 then presumably you were cleared to an altitude. What was it?

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Hi,

 

I have flown today using RC in Europe with some low pressure and have not found a problem.

 

If you can provide the information which Ray has requested  a solution to your problem will be found.

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It happens occasionally that RC clears you to a (still) flight level - still standard pressure - but advises you of the QNH - any chance this might be the cause?

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Hi.

 

http://forum.avsim.net/topic/287747-creating-a-log/

 

Three years on it still happens to me on occasion, and I still think it's either a ghost (though after 3 years I'd expect that to have been overwritten) or an FS glitch where it's doing something like failing to report correctly the user plane altitude or flight level.

 

I work around it by moving up (or down) a couple of hundred feet. That leaves me nominally within the +- 300' envelope but fits also with what RC thinks FS thinks I'm doing.

 

Next time you're told off, try flying a bit higher (or lower) and see what effect that has.

 

Cheers,

D

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Another thing to check are the deviation settings. From memory I think it's in General. Make sure the altitude value isn't too small. If in doubt set them back to the default values in the manual.

 

And referring back to part of the complaint... I've been told numerous times this is a pilot problem, not an RC4 problem, but there's no way to recover once this happens and you'll get vectored all over the place until you reach the expected altitude (might as well kill off RC4 when that happens as you won't get RC4 to correct itself).

 

The only time you'll get vectored is if you've missed a waypoint or have not reached the correct FL or altitude when 40 miles from arrival. That is mandatory. The situation is certainly recoverable and there is no need to shut down RC. Until I have more details of your plan I cannot help you.

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Don't increase the deviations in the general tab much more or less than the default values. It will play havoc with RC monitoring.

 

As far as altitude transition levels, you'll hear an RC prompt "altimeter check" when you need to switch between standard pressure and local QNH. The PMDG 737NG series has adjacent to the MCP as part of the baro switch a convenient way to select standard or your entered setting. On the PFD both settings are shown and the one I think in yellow is active. When I cruise above the transition altitude into the flight levels, I set this switch to standard but dial in the expected local pressure based on the arrival METAR from the preflight weather report (from Active Sky in my case) so no need to make much of a change in dialing in the delivered pressure saving time in its setting. Offhand I don't recall how to switch between millibars and inches.

 

Also be sure that there is no outstanding communication acknowledgement when near a waypoint or crossing altitude  as that can cause RC to miss its monitoring of your aircraft in that immediate area and you will not get credit. When not near one of those conditions and RC issues a command regarding altitude or heading, wait if you can to ack it until the aircraft starts to perform its change. In some cases I've had an immediate temporary change upon activation opposite to the intended performance which will trigger RC warnings.

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