The Random thought thread

[old man emu]

1 hour ago, facthunter said:

 IF any Place is close to sea level, A  baro above 1013.2   by much will push it to below AMSL  pressure height. Nev

I agree with that. 

 

What caused me to pose the question was how would a pilot know how high the aircraft actually was aove ground if the DA gave a calculated location that was below ground level.

 

[rgmwa]

By setting 1040HPa on the altimeter assuming ground is effectively sea level (and temp =15 deg).

[facthunter]

You always need to know Ground Height and your actual height to determine Height above ground. Putting in the Local area QNH, OR setting your altimeter to read the Aerodrome Height when you are on the ground will achieve that, and separate you from other traffic referencing the same Info. Nev.