AIM
4/20/23
7
−
3
−
6
Cold Temperature Barometric Altimeter Errors, Setting Procedures and Cold Temperature
Airports (CTA)
(a)
On initial check
−
in with ATC providing approach clearance: Missoula, MT (example below).
S
Vectors to final approach course: Outside of IAFs: “
Request 9700 ft for cold temperature
operations.”
S
Vectors to final approach course: Inside of ODIRE:
“Request 7300 ft for cold temperature
operations.
”
S
Missed Approach segment: “
Require final holding altitude, 12500 ft on missed approach for cold
temperature operations.
”
(b)
Pilots cleared by ATC for an instrument approach procedure; “Cleared the RNAV (GPS) Y RWY 12
approach (from any IAF)”. Missoula, MT (example below).
S
IAF: “
Request 9700 ft for cold temperature operations at LANNY, CHARL, or ODIRE.
”
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
−
12
°
C: RNAV (GPS) Y RWY 12.
1.
All Segments Method: All segments corrected from IAF through MA holding altitude.
(a)
Manual Calculation:
(1)
Cold Temperature Restricted Airport Temperature Limit:
−
12
°
C.
(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 Temperature Error Table, a height above airport of 2994 ft and
−
12
°
C.
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
−
12
°
C is approximately 150ft. Use 150 ft or round up to 200 ft.
(10)
Add corrections to altitudes up to but not including the FAF:
[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)
TBL 7
−
3
−
1: 8794 ft at
−
12
°
C. Enter table at
−
12
°
C and intersect the 5000 ft height above airport
column. The approximate value is 500 ft.
(13)
Add correction to holding fix final altitude:
3/15/07
7110.65R CHG 2
AIM
10/5/23