background image

AIM 

6/17/21 

picture, visual cues, etc., especially for high

altitude 

or terrain

challenged locations and during low

visi-

bility conditions. 

REFERENCE

 

AIM Paragraph 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 uncom-
pensated 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

°

(

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 tempera-

tures 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

4 a. thru 7

3

e. 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 publica-
tion (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. 

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 

7

3

Cold Temperature Barometric Altimeter Errors, Setting Procedures and Cold Temperature 

Airports (CTA)