Originally Posted by
pineteam
I would keep it simple by just setting the FPA showed on the chart and adjust accordingly (0.1 degree per 10 feet deviation) when checking the altitude every nautical mile. Never been a problem so far.
I think you’re missing the point here.
Indeed (ballpark)
delta 1.0 fpa = delta 100 ft/nm
hence
delta 0.1 fpa = delta 10ft/nm (the correction you’re talking about)
However these are corrections RELATIVE to your ‘base’ FPA. ISA deviation affects the ‘base’ FPA,
ISA deviation has to be taken into account before starting the approach.
The reactive correction on FPA caters for small errors but does not address a systematic error such as a large ISA deviation.