AIM ¶ 7-3-6 — Cold Temperature Altitude Corrections
AIM 7-3-6 walks through cold temperature altitude corrections on CTAs using KMSO RNAV (GPS) Y RWY 12 — All Segments and Individual Segments methods.
In Plain English
AIM 7-3-6 shows how to calculate cold temperature altitude corrections on instrument approaches at Cold Temperature Restricted Airports (CTAs) using Missoula Intl (KMSO), RNAV (GPS) Y RWY 12, at -12°C as a worked example.
Two correction methods are demonstrated:
- All Segments Method: Correct every altitude from the IAF through the missed approach holding altitude.
- Individual Segments Method: Correct only the segment(s) the airport requires (intermediate, final, and/or missed). The IAF/IF are not corrected when using this method.
For each segment you:
- Subtract airport elevation from the segment altitude to get height above airport.
- Enter TBL 7-3-1 (ICAO Cold Temperature Error Table) with that height and the reported temperature, interpolating as needed.
- Add the correction to the published altitude.
Final segment corrections are based on the minima used (LP, LNAV, etc.). For operators with a temperature compensating RNAV system, the system is set to current airport temperature and activated before the IAF (All Segments) or as needed (Individual Segments), but the MDA/DA must still be corrected manually. This protects required obstacle clearance when cold air makes true altitude lower than indicated.
AIM Source Text
FAA AIM ¶ 7-3-67-3-6. 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: Missoula Intl (KMSO). Reported Temperature -12 ° C: RNAV (GPS) Y RWY 12. All Segments Method: All segments corrected from IAF through MA holding altitude. Manual Calculation: Cold Temperature Restricted Airport Temperature Limit: -12 ° C. Altitude at the Final Approach Fix (FAF) (SUPPY) = 6200 ft. Airport elevation = 3206 ft. Difference: 6200 ft – 3206 ft = 2994 ft. 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. Add 300 ft to the FAF and all procedure altitudes outside of the FAF up to and including IAF altitude(s): LANNY (IAF), CHARL (IAF), and ODIRE (IAF Holding-in-Lieu): 9400 + 300 = 9700 ft. CALIP (stepdown fix): 7000 + 300 = 7300 ft. SUPPY (FAF): 6200 + 300 = 6500 ft. Correct altitudes within the final segment altitude based on the minima used. LP MDA = 4520 ft. Difference: 4520 ft – 3206 ft = 1314 ft. AIM 7-3-1 Table: 1314 ft at -12 ° C is approximately 150ft. Use 150 ft or round up to 200 ft. Add corrections to altitudes up to but not including the FAF: BEGPE (stepdown fix): 4840 + 150 = 4990 ft. LNAV MDA: 4520 + 150 = 4670 ft. Correct JENKI/Missed Approach Holding Altitude: MA altitude is 12000: JENKI: 12000 - 3206 = 8794 ft. 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. Add correction to holding fix final altitude: JENKI: 12000 + 500 = 12500 ft. Temperature Compensating System: Operators using a temperature compensating RNAV system to make altitude corrections will be set to the current airport temperature (-12 ° C) and activated prior to passing the IAF. A manual calculation of the cold temperature altitude correction is required for the MDA/DA. Individual Segments Method: Missoula requires correction in the intermediate and final segments. However, in this example, the missed approach is also shown. Manual Calculation: Use the appropriate steps in the All Segments Method above to apply a correction to the required segment. Intermediate. Use steps 7-3-6 a 1 (a) (1) thru (6) . Do not correct the IAF or IF when using individual segments method. Final. Use steps 7-3-6 a 1 (a) (7) thru (10) . Missed Approach. Use steps 7-3-6 a 1 (a) (11) thru (13) . Temperature Compensating System: Operators using a temperature compensating RNAV system to make altitude corrections will be set to the current airport temperature (-12 ° C) 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. FIG 7-3-2 Missoula Intl RNAV (GPS) Y RWY 12 Previous | Top | Next AIM | ATPUBS | FAA | Send your comments regarding this website.
Oral Exam Questions a DPE Might Ask
Q1Using the AIM 7-3-6 KMSO example at -12°C, how do you calculate the correction added to the FAF altitude at SUPPY?
Per AIM 7-3-6, subtract airport elevation (3206 ft) from the FAF altitude (6200 ft) to get a height above airport of 2994 ft. Enter TBL 7-3-1 at -12°C and interpolate, yielding ~300 ft. Add 300 ft to 6200 ft for a corrected SUPPY altitude of 6500 ft.
Q2When using the Individual Segments Method, are the IAF and IF altitudes corrected?
No. Per AIM 7-3-6, when applying the Individual Segments Method, you do not correct the IAF or IF altitudes — only the segments the airport requires (intermediate, final, and/or missed approach) are corrected.
Q3If you have a temperature compensating RNAV system, do you still need to manually calculate any cold temperature corrections?
Yes. Per AIM 7-3-6, even when the RNAV system is set to current airport temperature and activated prior to the IAF (All Segments) or as needed (Individual Segments), a manual calculation of the cold temperature altitude correction is still required for the MDA/DA.
Related Paragraphs in AIM Chapter 7