Physics:Cold temperature airport
In aviation, a cold temperature airport[1] or cold temperature restricted airport[2][3] is an airport at risk of loss of required obstacle clearance during an instrument approach due to cold temperature.
) placed on its instrument approach procedure chart(s).Principle
An aircraft's barometric altimeter is corrected only for the air pressure under International Standard Atmosphere condition.[4]: II-5-5-6 When the ambient (at altitude) temperature is colder than the International Standard Atmosphere condition, the aircraft's true altitude is lower than the indicated barometric altitude, bringing pilots closer to obstacles than where they think they are.[1]: 7-3-1 Consequently, the obstacle clearance actually achieved is less than required obstacle clearance.[4]: II-1-1-2
History
In 1990s, the aviation industry raised the problem that aircraft would fly dangerously close to the terrain under extremely cold temperature. United States Federal Aviation Administration (FAA) partnered with Mitre Corporation in a study to create a systematic approach to identify parts of instrument approach procedures threatened by obstacles in low temperatures for airports with runways of at least 2,500 ft (760 m) in the United States. Several hundred airports were identified in the study, forming a list of Cold Temperature Restricted Airports. In September 2015, The temperature correction procedure became mandatory for all operations[2] except for military airfields.[5]
As of September 2025, the United States has 183 designated civilian cold temperature airports, and 10 military airfields that satisfy the cold temperature airport criteria.[5]
Criteria
To qualify as a cold temperature airport, an airport is first assessed based on its historical temperature data and its required obstacle clearance. If there is more than 1% chance that a pilot may be unable to maintain the required obstacle clearance in an approach segment, the approach segment gets assigned a temperature restriction. These restrictions typically impact airports at higher elevations and extreme cold climates.[2]
Temperature correction
Pilots are responsible for accounting for the impact of extreme cold temperature during the planning stage of the flight. This is achieved by manually adding temperature corrections to published minimum altitudes/heights in instrument approach procedures based on the reported temperature near estimated arrival time and height above the airport.[1]: 7-3-1.b FAA recommends pilots to apply the temperature correction to either individual segments identified for additional temperature restriction or the entire instrument approach procedure,[1]: 7-3-4.f while International Civil Aviation Organization mandates that such correction be applied to "all published minimum altitudes/heights in both conventional and PBN procedures."[4]: II-1-1-2
| Height above airport (ft) | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Reported temperature (°C) | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | 1000 | 1500 | 2000 | 3000 | 4000 | 5000 | |
| +10 | 10 | 10 | 10 | 10 | 20 | 20 | 20 | 20 | 20 | 30 | 40 | 60 | 80 | 90 | |
| 0 | 20 | 20 | 30 | 30 | 40 | 40 | 50 | 50 | 60 | 90 | 120 | 170 | 230 | 280 | |
| -10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | 150 | 200 | 290 | 390 | 490 | |
| -20 | 30 | 50 | 60 | 70 | 90 | 100 | 120 | 130 | 140 | 210 | 280 | 420 | 570 | 710 | |
| -30 | 40 | 60 | 80 | 100 | 120 | 140 | 150 | 170 | 190 | 280 | 380 | 570 | 760 | 950 | |
| -40 | 50 | 80 | 100 | 120 | 150 | 170 | 190 | 220 | 240 | 360 | 480 | 720 | 970 | 1210 | |
| -50 | 60 | 90 | 120 | 150 | 180 | 210 | 240 | 270 | 300 | 450 | 590 | 890 | 1190 | 1500 | |
| To use the table, find the reported temperature in the left column, and read across the top row to locate the height above the airport (subtract the airport elevation from the flight altitude). Find the intersection of the temperature row and height above airport column. This number represents how far the aircraft may be below the indicated altitude due to possible cold temperature induced error.[1]: 7-3-1.b | |||||||||||||||
Some approved flight management systems are capable of automatically apply the temperature correction, in which case the temperature correction does not need to be reapplied.[4]: II-1-1-2, II-5-5-4
For vertical separation purposes, pilots are required to inform air traffic controllers on the temperature correction applied except for the final approach segment and are never allowed to change the altimeter setting for altitude correction.[1]: 7-3-5
Incidents
On February 9, 2020, while on an approach to Usinsk, a Boeing 737-500 operated by Utair flew below its glidepath and struck a pile of snow located 32 m (105 ft) before the runway. Russia's Interstate Aviation Committee determined that the crew member failed to correct for the cold air temperature, which was measured to be −21 °C (−6 °F) at the time of the crash, resulting in the aircraft flying at 280 ft (85 m) below its indicated altitude.[7]
Sources
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 "Cold Temperature Barometric Altimeter Errors, Setting Procedures and Cold Temperature Airports (CTA)" (in en). Federal Aviation Administration. https://www.faa.gov/air_traffic/publications/atpubs/aim_html/chap7_section_3.html.
This article incorporates text from this source, which is in the public domain.
- ↑ 2.0 2.1 2.2 "Cold Temperature Restricted Airports" (in en). Aircraft Owners and Pilots Association. 3 November 2016. https://www.aopa.org/advocacy/advocacy-briefs/air-traffic-services-brief-cold-temperature-restricted-airports.
- ↑ "Cold Temperature Restricted Airports". Oct 31, 2019. https://nbaa.org/aircraft-operations/safety/in-flight-safety/aircraft-icing/cold-temperature-restricted-airports/.
- ↑ 4.0 4.1 4.2 4.3 "Volume I − Flight Procedures". Doc 8168: Procedures for Air Navigation Services - Aircraft Operations (Sixth ed.). International Civil Aviation Organization. 2018. ISBN 978-92-9258-670-6.
- ↑ 5.0 5.1 "COLD TEMPERATURE AIRPORTS, 2 Oct 2025 – 3 Sep 2026". Federal Aviation Administration. https://aeronav.faa.gov/d-tpp/Cold_Temp_Airports.pdf.
- ↑ "Cold Temperature Restricted Airports". Federal Aviation Administration. January 7, 2016. https://www.faasafety.gov/files/events/AL/AL01/2016/AL0166676/Cold_Temp_Restricted_Airport_NOTAM.pdf. This article incorporates text from this source, which is in the public domain.
- ↑ Kaminski-Morrow, David. "Snow-strike 737 crew did not correct altitude for low temperature" (in en). https://www.flightglobal.com/safety/snow-strike-737-crew-did-not-correct-altitude-for-low-temperature/142894.article.
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