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Boroda
2nd Mar 2010, 17:50
Is it baroreferenced callout or RAreferenced?

Spasibo

kijangnim
2nd Mar 2010, 18:22
Greetings
Baro reference

FLEXPWR
2nd Mar 2010, 18:29
ICAO DOC 8168 Part 9:

"...flights shall be stabilised.....by no lower than 300m (1000ft) above threshold in IMC."

That would be baro. Or you'd need a very flat surface at least 3 MN before touchdown to use RadAlt! (Salt Lake? :} )

Flex

Nubboy
2nd Mar 2010, 18:40
Come on guys n gals:ugh:

Think it through. It's there as a standard SOP for many companies to ensure you have enough time to be stable at the threshold.

Just think how much time you'd have before impact if it was a 1000' rad alt going into EGNM, Leeds Bradford. For a UK airport it's at the exotic elevation of 700 odd feet amsl. Just prior to the threshold of runway 32 you have quite a steep escarpment. Not as steep as the other end I grant you, but very close to the threshold. Certainly not the 3 and a bit nm that 1000' baro gives you. Similar tale at runway 09 for EGJJ, Jersey with 300 foot of cliff just before the threshold lights.

Our company manuals infact define the stable approach criteria as being 1000 feet above the threshold elevation. Your steam driven barometric altimeter is the one to use (not forgetting to make corrections for ISA deviations in cold weather etc etc etc etc etc before the true techies get their piece in:ok:)

In fact for lazy pragmatists you could replace it with a dme distance (say 3 and a bit) instead of a height. It's all about having enough distance, hence time, to sort out any minor deviations from your required flightpath.

Founder
2nd Mar 2010, 18:47
Baro for:
CAT 1 & NP

RA for:
CAT 2 & 3

tonker
2nd Mar 2010, 18:51
Leeds is a good example of where you should not use the RADALT calls on landing when new. In short on my 3rd flight all i got was"50....10..smash"

Nubboy
2nd Mar 2010, 18:55
Founder, please read what question Baroda very politely asked. Your answers are of course correct for calling decision heights. But not the correct answer to his very specific question.

He's asking about the call out point, and refernce source for the 1000 foot above stable appraoch call out. This shoud be usoing the barometric altimeter, NEVER the radalt, due to possiblity of undulating terrain, steep escarpments, sea cliffs, deep ravines and canyons, non reflective surfaces or anything else I can't think of:ok:.

toby320
2nd Mar 2010, 22:46
hi, defenitly this call out is with baro reference and is used in imc to be stabilized or close to be and 500 baro as well in vmc.

:ok: toby.

Microburst2002
3rd Mar 2010, 08:28
Yes

But for CAT II III, there is a 1,000 call out, which is RA.

By the way, the 1,000 stabilized call out... is it in the FCOM?

PENKO
3rd Mar 2010, 09:19
It all depends on your individual company SOP.

Boroda
3rd Mar 2010, 17:00
Spasibo for your replies.

I agree that it baro and understand the case when I fly on QFE - baroaltitude reads height from threshold. Imagine you are approaching on QNH at airport with 1456 feet elevation - do you have calculate respective altitude before(2456) and wait for it in approach to call out?

Nubboy
3rd Mar 2010, 18:35
Absolutely, Baroda.
In the UK QFE is mainly for light aircraft use.

All the airlines I've flown with ,. even the tiny regional inter island hopping services,use QNH.

And thank you for acknowledging the repiles.

Good luck and safe landings:ok: