Cold Temperature Altitude Correction Calculator
Enter the airport temperature, airport elevation, and published approach altitudes to estimate the FAA cold-temperature corrections for each segment. The result shows the corrected MDA or DA, missed-hold altitude, and which correction applies where.
Corrected MDA or DA4,662
- IAF through FAF correction
- 300
- Final-segment correction
- 142
- Missed-approach correction
- 600
- Corrected missed holding altitude
- 12,600
- Correction schedule
- Use the FAF-derived correction from the FAF outward through the IAF, the MDA or DA correction inside the FAF, and the missed-hold correction at the final missed-approach holding altitude.
Segment correction details
| Segment | Reference altitude | Height above airport | Table height | Interpolated table value | Applied correction | Corrected altitude | Note |
|---|---|---|---|---|---|---|---|
| IAF through FAF | 6,200 | 2,994 | 2,994 | 315.4 | 300 | 6,500 | Within published table height range. |
| Final segment | 4,520 | 1,314 | 1,314 | 141.91 | 142 | 4,662 | Within published table height range. |
| Missed approach | 12,000 | 8,794 | 5,000 | 534 | 600 | 12,600 | Above 5,000 ft; 5,000 ft table value used and correction not rounded down. |
FAA standard rounding uses the nearest 100 ft for ordinary segments; MDA or DA uses the interpolated correction rounded up to the next foot.
This calculator does not alter the aircraft altimeter setting or determine whether a procedure currently requires correction.
One or more heights exceeded 5,000 ft, so the 5,000 ft table column was used without rounding the applied correction down.
How to use this calculator
- Choose whether the approach uses the FAA all-segments method or individual segment corrections.
- Enter the reported airport temperature and the airport elevation used as the height reference.
- Enter the published IF, FAF or PFAF, MDA or DA, and missed-approach holding altitudes.
- Select the rounding rule required by your procedure, then read the segment schedule and corrected altitudes.
How the correction is calculated
Cold air makes a pressure altimeter overread: the indicated altitude can be higher than the aircraft's true height above terrain. FAA AIM Table 7-3-1 gives a correction in feet from two inputs, the airport temperature and the height of the published altitude above the airport elevation.
For each altitude, the calculator first computes:
H = published altitude - airport elevation
The table lookup height is limited to the published range:
H_table = min(max(H, 200), 5000)
It then interpolates between the surrounding temperature rows and height columns in the FAA table. The corrected altitude is:
corrected altitude = published altitude + applied correction
Rounding and segment use
Under FAA-standard rounding, ordinary segment corrections are rounded to the nearest 100 ft. The MDA or DA correction is treated differently: it is kept as an interpolated value rounded up to the next foot, so the operational correction is not rounded downward. If the height above airport is more than 5,000 ft, this calculator uses the 5,000 ft table column and rounds upward rather than down.
In all-segments mode, the FAF-derived correction applies from the FAF outward through the IAF. The MDA or DA correction applies inside the FAF, including the final segment and final step-down fixes when those fixes are designated for correction. The missed-approach holding-altitude correction is calculated separately.
In individual-segments mode, the IF altitude sets the initial-segment correction, the FAF or PFAF altitude sets the intermediate-segment correction, the MDA or DA sets the final-segment correction, and the missed holding altitude sets the missed-segment correction.
What moves the answer
Temperature and height above airport drive the result. Colder temperatures increase the correction. Higher published altitudes above the airport usually increase it as well, until the 5,000 ft table limit is reached. Airport elevation matters because the FAA table uses height above the reporting airport, not altitude MSL by itself.
What this calculator leaves out
This tool does not decide whether a specific airport, approach, or segment currently requires correction. It does not evaluate aircraft flight manual limits, operator procedures, NOTAMs, ATC reporting requirements, prohibited corrections, visibility minima, or any approval needed for methods outside the FAA table. It also does not change the aircraft altimeter setting.
Worked example
Suppose the reported airport temperature is -12 degrees C, the airport elevation is 3,206 ft MSL, the FAF altitude is 6,200 ft, the MDA is 4,520 ft, and the missed-approach holding altitude is 12,000 ft. The FAF height above airport is 2,994 ft, so interpolation gives a table value of about 315 ft and FAA-standard rounding applies a 300 ft correction from the FAF outward through the IAF.
The MDA height above airport is 1,314 ft. Interpolation gives 141.9 ft, which becomes a 142 ft final-segment correction because MDA or DA is not rounded downward. The corrected MDA is therefore 4,662 ft. The missed-hold height is above 5,000 ft, so the calculator uses the 5,000 ft column; at -12 degrees C the interpolated value is 534 ft and the applied correction is 600 ft, giving a corrected missed holding altitude of 12,600 ft.
Common questions
Why does cold weather make true altitude lower than indicated altitude?
A pressure altimeter assumes a standard temperature profile. In colder-than-standard air, pressure levels are packed closer together, so an indicated altitude can place the aircraft lower above terrain than expected. The correction adds altitude to compensate for that error.
What is the difference between all-segments and individual-segments correction?
The all-segments method uses the FAF-derived correction from the FAF outward through the IAF, then uses the MDA or DA correction inside the FAF. The individual-segments method calculates the initial, intermediate, final, and missed segments separately from their own reference altitudes. Use the method required by the chart, FAA cold temperature airport information, or your operator.
Should the cold-temperature correction be rounded up?
FAA-standard rounding rounds ordinary segment corrections to the nearest 100 ft, but the MDA or DA correction must not be rounded down. This calculator also avoids rounding down when the height above airport exceeds the 5,000 ft table column. The always-up option rounds every applied correction up to the next 100 ft.
What happens when the height above the airport exceeds 5,000 ft?
The FAA table stops at 5,000 ft. This calculator uses the 5,000 ft column by default and flags that limit in the result table. Any different approved method must come from the applicable procedure or operator guidance, not from this tool.
Do I report a corrected altitude to ATC?
Reporting requirements depend on the procedure, the correction being applied, and current ATC guidance. This calculator only does the arithmetic; it does not determine clearance, reporting, or approval requirements.
Does cold-temperature correction change visibility minimums?
No. This calculation adjusts altitude values used for the applicable approach segments. It does not change published visibility requirements, altimeter settings, aircraft performance limits, or whether the procedure is authorized.