Altimeter setting exceeding 31.00 in Hg and raising approach minimums
Asked by: sm9692 5240 views FAA Regulations, Flight Instructor, General Aviation
. In the rare event that the local altimeter setting is over 31.00 in Hg, why is the decision made (by the FAA) to raise the minimums on instrument approaches if aircraft are operating in a region with this high of a setting? Assuming the typical kollsman window maxes out at 31.00 and the local altimeter is 31.05, you will still be flying at an altitude higher than whats indicated on your altimeter(assuming you have 31.00 set in your window). Therefore, regardless of what your approach mins are, you would still be above them, in this case approximately 50 feet. My logic may be wrong here, but I’ve just been having a tough time grasping the concept when the altimeter setting is above this 31.00 range. My only other thought would be that if the altimeter setting was greater than 31.00 in Hg, there is a chance that it could also be extremely cold and therefore the FAA is assuming worst case scenario and adding this buffer due to errors in the altimeter because of non standard temperature.
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