Index   517 -- Page 518 -- 519

AIM                                                                                                                    12/10/15


                                                           TBL 7-2-3
                                              ICAO Cold Temperature Error Table
                                                  Height Above Airport in Feet

                          200   300   400   500   600   700     800     900    1000    1500     2000    3000    4000    5000

                    +10   10    10    10    10    20     20     20       20      20      30      40      60      80      90

                     0    20    20    30    30    40     40     50       50      60      90     120     170     230      280

                    -10   20    30    40    50    60     70     80       90     100     150     200     290     390      490
 Reported Temp C




                    -20   30    50    60    70    90    100     120     130     140     210     280     420     570      710

                    -30   40    60    80    100   120   140     150     170     190     280     380     570     760      950

                    -40   50    80    100   120   150   170     190     220     240     360     480     720     970     1210

                    -50   60    90    120   150   180   210     240     270     300     450     590     890     1190    1500


EXAMPLE-
Temperature-10 degrees Celsius, and the aircraft altitude is 1,000 feet above the airport elevation. The chart shows that
the reported current altimeter setting may place the aircraft as much as 100 feet below the altitude indicated by the altimeter.


7-2-4. High Barometric Pressure                                         2. Departures. Advise pilots to set 31.00 inch-
                                                                   es prior to reaching any mandatory/crossing altitude
   a. Cold, dry air masses may produce barometric
                                                                   or 1,500 feet, whichever is lower.
pressures in excess of 31.00 inches of Mercury, and
many altimeters do not have an accurate means of                     c. The altimeter error caused by the high pressure
being adjusted for settings of these levels. When the              will be in the opposite direction to the error caused by
altimeter cannot be set to the higher pressure setting,            the cold temperature.
the aircraft actual altitude will be higher than the
altimeter indicates.                                               7-2-5. Low Barometric Pressure
REFERENCE-
AIM, Paragraph 7-2-3 , Altimeter Errors.                           When abnormally low barometric pressure condi-
                                                                   tions occur (below 28.00), flight operations by
  b. When the barometric pressure exceeds
                                                                   aircraft unable to set the actual altimeter setting are
31.00 inches, air traffic controllers will issue the
                                                                   not recommended.
actual altimeter setting, and:
                                                                   NOTE-
     1. En Route/Arrivals. Advise pilots to remain                 The true altitude of the aircraft is lower than the indicated
set on 31.00 inches until reaching the final approach              altitude if the pilot is unable to set the actual altimeter
segment.                                                           setting.




7-2-4                                                                                           Altimeter Setting Procedures