AIM
4/20/23
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Cold Temperature Barometric Altimeter Errors, Setting Procedures and Cold Temperature
Airports (CTA)
c.
A current list of CTAs is located at: https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/
dtpp/search/. Airports are listed by ICAO code, Airport Name, Temperature in Celsius, and affected segment(s).
d.
Airport Criteria. The CTA risk analysis is performed on airports that have at least one runway of 2500 ft.
Pilots operating into an airport with a runway length less than 2500 ft may make a cold temperature altitude
correction in cold temperature conditions, if desired. Comply with operating and reporting procedures for CTAs.
e.
ATC Reporting Requirements. Pilots must advise ATC with the corrected altitude when applying an altitude
correction on any approach segment with the exception of the final segment.
f.
Methods to apply correction: The FAA recommends operators/pilots use either the All Segments Method
or the Individual Segments Method when making corrections at CTAs.
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5. Cold Temperature Airport Procedures
a.
PILOTS MUST NOT MAKE AN ALTIMETER CHANGE to accomplish an altitude correction. Pilots
must ensure that the altimeter is set to the current altimeter setting provided by ATC in accordance with 14 CFR
§91.121.
b.
Actions on when and where to make corrections: Pilots will make an altitude correction to the published,
“at”, “at or above”, and “at or below” altitudes on all designated segment(s) to all runways for all published
instrument approach procedures when the reported airport temperature is at or below the published CTA
temperature on the approach plate. A pilot may request an altitude correction (if desired) on any approach at any
United States airport when extreme cold temperature is encountered. Pilots making a correction must comply
with ATC reporting requirements.
c.
Correctable altitudes: ATC does not apply a cold temperature correction to their Minimum Vectoring
Altitude (MVA) or Minimum IFR Altitude (MIA) charts. Pilots must request approval from ATC to apply a cold
temperature correction to any ATC assigned altitude. Pilots must not correct altitudes published on Standard
Instrument Departures (SIDs), Obstacle Departure Procedures (ODPs), and Standard Terminal Arrivals
(STARs).
d.
Use of corrected MDA/DA: Pilots will use the corrected MDA or DA as the minimum altitude for an
approach. Pilots must meet the requirements in 14 CFR Part 91.175 in order to operate below the corrected MDA
or DA. Pilots must see and avoid obstacles when descending below the minimum altitude on the approach.
NOTE
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The corrected DA or MDA does not affect the visibility minima published for the approach. With the application of a cold
temperature correction to the DA or MDA, the airplane should be in a position on the glideslope/glidepath or at the published
missed approach point to identify the runway environment.
e.
Acceptable use of the table for manual CTA altitude correction (see TBL 7
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1): Pilots may calculate a
correction with a visual interpolation of the chart when using reported temperature and height above airport. This
calculated altitude correction may then be rounded to the nearest whole hundred or rounded up. For example,
a correction of 130 ft from the chart may be rounded to 100 ft or 200 ft. A correction of 280 ft will be rounded
up to 300 ft. This rounded correction will be added to the appropriate altitudes for the “Individual” or “All”
segment method. The correction calculated from the table for the MDA or DA may be used as is or rounded up,
but never rounded down. This number will be added to the MDA, DA, and all step-down fix altitudes inside of
the FAF/PFAF.
1.
No extrapolation above the 5000 ft column is required. Pilots may use the 5000 ft “height above airport
in feet” column for calculating corrections when the calculated altitude is greater than 5000 ft above reporting
station elevation. Pilots must add the correction(s) from the table to the affected segment altitude(s) and fly at
the new corrected altitude. Do not round down when using the 5000 ft column for calculated height above airport
values greater than 5000 ft. Pilots may extrapolate above the 5000 ft column to apply a correction if desired.
2.
These techniques have been adopted to minimize pilot distraction by limiting the number of entries into
the table when making corrections. Although not all altitudes on the approach will be corrected back to standard
10/5/23
AIM