Jeppesen approach chart temperature correction

[Airtw777]

Hello guys/gals,

:ugh: I am having difficulties on finding the related articles and/or regulations on stating....if jeppesen approach chart "noted" minimum temperature -xx Celsius, then cold temp. Altitude correction will not be needed for OAT which is higher than what noted. Vice versa. Ex. EGLL RNAV27L. Wish to have something from icao publications...><

[justanotherflyer]

Try PANS-OPS (Doc 8168). Vol. 1 Part III Sec. 1 Ch. 4:

4.3 TEMPERATURE CORRECTION

4.3.1 Requirement for temperature correction

The calculated minimum safe altitudes/heights must be adjusted when the ambient temperature on the surface is much lower than that predicted by the standard atmosphere. In such conditions, an approximate correction is 4 per cent height increase for every 10°C below standard temperature as measured at the altimeter setting source. This is safe for all altimeter setting source altitudes for temperatures above –15°C.

4.3.2 Tabulated corrections
For colder temperatures, a more accurate correction should be obtained from Tables III-1-4-1 a) and III-1-4-1 b).

etc.... etc.....

However,

note this discussion paper (http://www.caa.co.uk/docs/2261/20120203ColdTemperatureCorrectionsConsultationDocument.pdf) for issues surrounding this question, and also

Eurocontrol RNAV design guidance (http://www.ecacnav.com/downloads/iss3_0.pdf) 10.7.3.2 from which the minimum promulgated temperature on the 27L chart is derived - it is based upon the mean low temperature, at aerodrome elevation, for the coldest month of the year, collated over a period of at least 5 years.

Altitude correction will not be needed for OAT which is higher than what noted.

Be careful here: that is a temperature below which the procedure is NOT available... It is not a temperature below which you have to make corrections!



.

[Airtw777]

Thank you for the interesting article; however, it had deepen my confusion...
I understand the subject of the article is about UK not correcting ATC given altitude when temperature is colder than ISA. BUT IS IT A FACT OR A SINGLE CASE? Do i need to make a concern of ATC rv altitude next time when i go there in cold days?
from the eurocontrol document, it seems like we still have to apply correction ("these values should be add to the minimum safe altitude as appropriate"). Correct me if I am wrong...
Colder than ISA day.....
"Baro-Vnav NA BELOW -15C"
Therefore when
it is -10C.....LNAV/VNAV minimum can be use without any correction
And
It is -20C.....LNAV minimum but must apply altitude correction

I understand it is two different scenarios with EGLL "minimum temperature....." Without further explanation....
Or it could be me that is lack of the ability to understand. Tahnks

[Airtw777]

Cold Temperature Altitude Corrections
In the design of RNP AR procedures, the allowable temperature range is normally specified and the procedure design accounts for operations and obstacle clearance for any temperature within the specified range. If the actual temperature is within the specified temperature range, the pilot can fly the RNP AR procedure and there are no temperature corrections needed (or allowed). If the actual temperature is outside the specified temperature range, then the crew cannot fly the RNP AR procedure.

[justanotherflyer]

I think you have your answer!









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