Air Operations

Well thought, thanks, Tapani.

I wrote this article for Air Rescue Mag, in 2013, about the means of protection for helicopter pilots. The full magazine can be ordered here: https://www.rettungsdienst-shop.de/produkt/airrescue-magazine-safety/

@ Steve Roesli
i think using constant FPA doing NPA apch is not the more easy way to conduct 2D APCH....as nobody compute the true FPA otherwise you have to change FPA every NM to adjust your gradient.

Does AIRBUS correct delta isa Temp on FPA ? ...ATR does not.

On NPA 2D ,delta temperature can be a big penalty or trigger EGPWS on finale.

If you use a constant FPA to perform a NPA , difference of altitude between true altitude and indicated altitude will be maintain til MDA , while out of ISA conditions.

EXAMPLE (for ATR pilots)
if your temperature delta ISA temperature is +30 like some hot countries (india, saudia etc.. ) at 3000" FAF/FAP your true altitude is 3360"

At FAF/FAP if you descend using constant FPA 3° :
- you'll arrive at your normal DA point ( CDFA ) at 610" too bad if your ceiling is 500".
- If you continue to descend to 250" you will be almost at threshold.

In this case to descent from your FAF to MDA correcting delta temp you need to increase your FPA by 0.3° FPA should be set at 3.3°
Now you can imagine what will happen if temperature delta isa is -30° like most of polar countries ....maybe you'll do your descent below your OCH.

that is why LNAV/VNAV APCH have low temperature limit and sometimes a high temperature limit.

It reminds to me when i was flying in Indonesia , most of my trainees asked to me why we have at FAF 3 whites on PAPI ... and 2 whites close to MDA