7110.65R
7-3-6. Examples for Calculating Altitude
Corrections on CTAs
All 14 CFR Part 97 IAPs must be corrected at an
airport. The following example provides the steps for
correcting the different segments of an approach and
will be applied to all 14 CFR Part 97 IAPs:
a. Missoula Intl (KMSO). Reported Temperature
-12C: RNAV (GPS) Y RWY 12.
1. All Segments Method: All segments correct
ed from IAF through MA holding altitude.
(a) Manual Calculation:
(1) Cold Temperature Restricted Airport
Temperature Limit: -12C.
(2) Altitude at the Final Approach Fix
(FAF) (SUPPY) = 6200 ft.
(3) Airport elevation = 3206 ft.
(4) Difference: 6200 ft. " 3206 ft. = 2994 ft.
(5) Use TBL 7-3-1, ICAO Cold Tempera
ture Error Table, a height above airport of 2994 ft. and
-12C. Visual interpolation is approximately 300 ft.
Actual interpolation is 300 ft.
(6) Add 300 ft. to the FAF and all procedure
altitudes outside of the FAF up to and including IAF
altitude(s):
[a] LANNY (IAF), CHARL (IAF), and
ODIRE (IAF Holding-in-Lieu): 9400 + 300 = 9700
ft.
[b] CALIP (stepdown fix): 7000 + 300 =
7300 ft.
[c] SUPPY (FAF): 6200 + 300 = 6500 ft.
(7) Correct altitudes within the final
segment altitude based on the minima used. LP MDA
= 4520 ft.
(8) Difference: 4520 ft. " 3206 ft. = 1314 ft.
(9) AIM 7-3-1 Table: 1314 ft. at -12C is
approximately 150ft. Use 150 ft. or round up to 200
ft.
(10) Add corrections to altitudes up to but
not including the FAF:
7-3-6
[a] BEGPE (stepdown fix): 4840 + 150 =
4990 ft.
[b] LNAV MDA: 4520 + 150 = 4670 ft.
(11) Correct JENKI/Missed Approach
Holding Altitude: MA altitude is 12000:
[a] JENKI: 12000 - 3206 = 8794 ft.
(12) Table 7-3-1: 8794 ft. at -12C. Enter
table at -12C and intersect the 5000 ft. height above
airport column. The approximate value is 500 ft.
(13) Add correction to holding fix final
altitude:
[a] JENKI: 12000 + 500 = 12500 ft.
b. Temperature Compensating System: Operators
using a temperature compensating RNAV system to
make altitude corrections will be set to the current
airport temperature (-12C) and activated prior to
passing the IAF. A manual calculation of the cold
temperature altitude correction is required for the
MDA/DA.
1. Individual Segments Method: Missoula
requires correction in the intermediate and final
segments. However, in this example, the missed
approach is also shown.
(a) Manual Calculation: Use the appropriate
steps in the All Segments Method above to apply a
correction to the required segment.
(1) Intermediate. Use steps 7-3-6 a. 1. (a)
(1) thru (6). Do not correct the IAF or IF when using
individual segments method.
(2) Final. Use steps 7-3-6 a. 1. (a) (7) thru
(10).
(3) Missed Approach. Use steps 7-3-6 a, 1.
(a) (11) thru (13).
(b) Temperature Compensating System: Op
erators using a temperature compensating RNAV
system to make altitude corrections will be set to the
current airport temperature (-12C) and activated at
a point needed to correct the altitude for the segment.
A manual calculation of the cold temperature altitude
correction is required for the MDA/DA.
Cold Temperature Barometric Altimeter Errors, Setting Procedures and Cold Temperature
Airports (CTA)