Originally Posted by
hotelmode
I might be making this up, but I think I read somewhere if the pressure is higher than 31.00 you aren't supposed to fly because altimeters aren't calibrated for it. I would think it would only affect instrument flights though.
"Cold dry air masses can produce barometric pressures in excess of 31.00 inches of mercury. Because barometric readings of 31.00 inches of mercury or higher rarely occur, most standard altimeters do not permit the setting of barometric pressures above that level and are not calibrated to indicate accurate aircraft altitude above 31.00 inches of mercury. As a result, most altimeters cannot be set to provide accurate altitude readouts to the pilot in these situations."
Yeah... In May 94' they added that rule to the FARs stating that a TFR is to be where the barometric conditions of 31.00 inches or higher exist... can't find the exact part 91 paragraph though... I'm guessing it's not too uncommon in Alaska and Canada... any Alaska guys out there who can testify to this?