BY ORDER OF THE SECRETARY OF THE AIR FORCE AIR FORCE ...

140
AFMAN 11-217V1 3 JANUARY 2005
Chapter 8
PLANNING AN INSTRUMENT FLIGHT
8.1. Altimeter Setting Procedures. Accomplish the following procedures at an altimeter
checkpoint if practical: (Altimeter checkpoints are required at all USAF bases if the takeoff
end of the runway varies more than 25 feet from the official field elevation.)
8.1.1. Procedure. Set the reported altimeter setting on the barometric scale. Compare
the indicated altitude to the elevation of a known checkpoint. The maximum allowable
error is 75 feet. If the altimeter error exceeds 75 feet, the instrument is out of tolerance
for flight. No further corrections are necessary if the altimeter is within tolerance.
8.1.2. Off-Scale Altimeter Settings. Figures 8.1 and 8.2 give a sampling of possible
altimeter settings and their resulting correction factors.
8.1.2.1. WARNING: Most altimeters will only accommodate altimeter settings from
28.10 inches to 31.00 inches. Attempting to adjust an altimeter outside this range
may cause internal damage to the instrument. At some higher latitude locations,
extremely high and low pressures occasionally occur outside this range. When this
occurs, a correction may be made to all depicted approach altitudes (DH, MDA, FAF,
intermediate altitudes) using a ratio of 10 feet for every .01-inch difference between
the actual altimeter setting and the lower or upper limit set in the altimeter. If the
actual altimeter setting is greater than 31.00 inches, the correction factor will be
subtracted from all depicted approach altitudes. If the actual altimeter setting is
less than 28.10 inches, the correction factor will be added to all depicted approach
altitudes.
Table 8.1. Altimeter Correction Factor: Actual Altimeter Setting Exceeds Altimeter Upper
Limit.
ACTUAL ALSTG VALUE SET IN ALTIMETER DIFFERENCE
CORRECTION
(- Feet)
31.01 31.00 .01 10
31.02 31.00 .02 20
31.03 31.00 .03 30
31.04 31.00 .04 40
31.05 31.00 .05 50
31.06 31.00 .06 60
31.07 31.00 .07 70
31.08 31.00 .08 80
31.09 31.00 .09 90
31.10 31.00 .10 100
31.20 31.00 .20 200
31.30 31.00 .30 300
31.40 31.00 .40 400
31.50 31.00 .50 500
32.00 31.00 1.00 1,000