PPRuNe Forums - View Single Post - Cold temperature corrections on LNAV/VNAV minima
Old 14th Dec 2015, 14:26
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Skyjob
 
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sonicbum has the right approach to this situation.

There is a difference to LNAV, LNAV/VNAV and APV altitudes.

LNAV minima, like VOR, LOC, NDB and visuals are to be corrected for Cold Weather.
LNAV/VNAV minima are not, as the procedure is defined up to a minimum temperature for which it is safe to be used. This temperature must be displayed on the chart in order for the approach to be used.

APV minima are a different animal all together.
As the previous minima all apply to Barometric VNAV aircraft, the APV minima ONLY apply to aircraft which benefit from a vertical GPS input (eg not the 737). These minima do not require correcting as they are more accurate then barometric VNAV which relies on the correct QNH input to prevent a Blunder Error.

Ultimately, it is this latter Blunder Error we are trying to avoid, getting too close to terrain, when we are not supposed to be...
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