AIM 

4/20/23 

consequences of these effects on approach minima, power settings, sight picture, visual cues, etc., especially for 

high

−

altitude or terrain

−

challenged locations and during low

−

visibility conditions. 

REFERENCE

−

 

AIM, Para 5

−

4

−

5, Instrument Approach Procedure (IAP) Charts. 

a. 

Uncompensated Baro

−

VNAV note on 14 CFR Part 97 IAPs. The area navigation (RNAV) global 

positioning system (GPS) and RNAV required navigation performance (RNP) notes, “For uncompensated 

Baro

−

VNAV systems, lateral navigation (LNAV)/VNAV NA below –XX

°

C (

−

XX

°

F) or above XX

°

C (XXX

°

F)” 

and “For uncompensated Baro

−

VNAV systems, procedure NA below –XX

°

C (

−

XX

°

F) or above XX

°

C 

(XXX

°

F)” apply to baro

−

VNAV equipped aircraft. These temperatures and how they are used are independent 

of the temperature and procedures applied for a Cold Temperature Airport. 

1. 

The uncompensated baro

−

VNAV chart note and temperature range on an RNAV (GPS) approach is 

applicable to the LNAV/VNAV line of minima. Baro

−

VNAV equipped aircraft without a temperature 

compensating system may not use the RNAV (GPS) approach LNAV/VNAV line of minima when the actual 

temperature is above or below the charted temperature range. 

2. 

The uncompensated baro

−

VNAV chart note and temperature range on an RNAV (RNP) approach applies 

to the entire procedure. For aircraft without a baro

−

VNAV and temperature compensating system, the RNAV 

(RNP) approach is not authorized when the actual temperature is above or below the charted uncompensated 

baro

−

VNAV temperature range. 

b. 

Baro

−

VNAV temperature range versus CTA temperature: The baro

−

VNAV and CTA temperatures are 

independent and do not follow the same correction or reporting procedures. However, there are times when both 

procedures, each according to its associated temperature, should be accomplished on the approach. 

c. 

Operating and ATC reporting procedures. 

1. 

Do not use the CTA operating or reporting procedure found in this section, 7

−

3

−

4a thru 7

−

3

−

5e when 

complying with the baro

−

VNAV temperature note on an RNAV (GPS) approach. Correction is not required nor 

expected to be applied to procedure altitudes or VNAV paths outside of the final approach segment. 

2. 

Operators must advise ATC when making temperature corrections on RNP authorization required (AR) 

approaches while adhering to baro

−

VNAV temperature note. 

3. 

Reporting altitude corrections is required when complying with CTAs in conjunction with the 

baro

−

VNAV temperature note. The CTA altitude corrections will be reported in this situation. No altitude 

correction reporting is required in the final segment

. 

NOTE

−

 

When executing an approach with vertical guidance at a CTA (i.e., ILS, localizer performance with vertical guidance (LPV), 

LNAV/VNAV), pilots are reminded to intersect the glideslope/glidepath at the corrected intermediate altitude (if applicable) 

and follow the published glideslope/glidepath to the corrected minima. The ILS glideslope and WAAS generated glidepath 

are unaffected by cold temperatures and provide vertical guidance to the corrected DA. Begin descent on the ILS glideslope 

or WAAS generated glidepath when directed by aircraft instrumentation. Temperature affects the precise final approach fix 

(PFAF) true altitude where a baro

−

VNAV generated glidepath begins. The PFAF altitude must be corrected when below the 

CTA temperature restriction for the intermediate segment or outside of the baro

−

VNAV temperature restriction when using 

the LNAV/VNAV line of minima to the corrected DA. 

7

−

3

−

4.  Cold Temperature Airports (CTA) 

a. 

General: The FAA has determined that operating in cold temperatures has placed some 14 CFR Part 97 

instrument approach procedures in the United States National Airspace System at risk for loss of required 

obstacle clearance (ROC). An airport that is determined to be at risk will have an ICON and temperature 

published on the instrument approach procedure (IAP) in the terminal procedures publication (TPP). 

b. 

CTA identification in TPP: A CTA is identified by a “snowflake” icon (

 ) and temperature limit, in 

Celsius, on U.S. Government approach charts. 

7

−

3

−

2 

Cold Temperature Barometric Altimeter Errors, Setting Procedures and Cold Temperature 

Airports (CTA)