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Old 22nd Mar 2020, 10:50
  #25 (permalink)  
compressor stall
 
Join Date: Feb 2000
Location: 500 miles from Chaikhosi, Yogistan
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FLS aside - with the advent of LNAV / VNAV there are fewer occasions where cold weather temp correction is required as these charts have a temperature range.

Nick - it's not that straight forward to get FLT OPS to generate a table that is really accurate as the temp correction changes with the height over ground, not height AAL - so it's different for every runway. And inversions (as are common in extreme cold high pressure systems) play with the math again as the cold temperature formulae rely on a uniform decrease in air temp.

So what guys out there doing on FPA approaches when it comes to corrections to descent angle?
Just dial in a few more tenths depending how cold it is and PM monitors high/low and PF adjusts - like any NPA. You are aiming for a CDFA but it doesn't always work, through chart design or adjusted FPA not quite accurate. I just checked some GoPro footage and I made 4 FPA adjustments between 2500' and minima (340') when it was ISA-40ish.

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