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AIM 

12/2/21 

RAIM outages for the aircraft’s predicted flight path 
and times; 

5. 

Operators may use the receiver’s installed 

RAIM prediction capability (for TSO

C129a/Class 

A1/B1/C1 equipment) to provide non

precision 

approach RAIM, accounting for the latest GPS 
constellation status (for example, NOTAMs or 
NANUs). Receiver non

precision approach RAIM 

should be checked at airports spaced at intervals not 
to exceed 60 NM along the RNAV 1 procedure’s 
flight track. “Terminal” or “Approach” RAIM must 
be available at the ETA over each airport checked; or, 

6. 

Operators not using model

specific software 

or FAA/VOLPE RAIM data will need FAA 
operational approval. 

NOTE

 

If TSO

C145/C146 equipment is used to satisfy the RNAV 

and RNP requirement, the pilot/operator need not perform 
the prediction if WAAS coverage is confirmed to be 
available along the entire route of flight. Outside the U.S. 
or in areas where WAAS coverage is not available, 
operators using TSO

C145/C146 receivers are required to 

check GPS RAIM availability. 

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17.  Cold Temperature Operations 

a. 

Pilots should begin planning for cold tempera-

ture operations during the preflight planning phase. 
Cold temperatures produce barometric altimetry 
errors, which affect instrument flight procedures. 
Currently there are two temperature limitations that 
may be published in the notes box of the middle 
briefing strip on an instrument approach procedure 
(IAP). The two published temperature limitations 
are: 

1. 

A temperature range limitation associated 

with the use of baro

VNAV that may be published on 

an United States PBN IAP titled RNAV (GPS) or 
RNAV (RNP); and/or 

2. 

A Cold Temperature Airport (CTA) limita-

tion designated by a snowflake ICON and 
temperature in Celsius (C) that is published on every 
IAP for the airfield. 

b. 

Pilots should request the lowest forecast 

temperature +/

 1 hour for arrival and departure 

operations. If the temperature is forecast to be outside 
of the baro

VNAV or at or below the CTA 

temperature limitation, consider the following: 

1. 

When using baro

VNAV with an aircraft that 

does not have an automated temperature compensat-
ing function, pilots should plan to use the appropriate 
minima and/or IAP. 

(a) 

The LNAV/VNAV line of minima on an 

RNAV (GPS) may not be used without an approved 
automated temperature compensating function if the 
temperature is outside of the baro

VNAV tempera-

ture range limitation. The LNAV minima may be 
used. 

(b) 

The RNAV (RNP) procedure may not be 

accomplished without an approved automated 
temperature compensating function if the tempera-
ture is outside of the baro

VNAV temperature range 

limitation. 

2. 

If the temperature is forecast to be at or below 

the published CTA temperature, pilots should 
calculate a correction for the appropriate segment/s or 
a correction for all the segments if using the “All 
Segments Method.” 

Pilots should review the operating procedures for the 
aircraft’s temperature compensating system when 
planning to use the system for any cold temperature 
corrections. Any planned altitude correction for the 
intermediate and/or missed approach holding seg-
ments must be coordinated with ATC.  Pilots do not 
have to advise ATC of a correction in the final 
segment. 

NOTE

 

The charted baro

VNAV temperature range limitation 

does not apply to pilots operating aircraft with an 
airworthiness approval to conduct an RNAV (GPS) 
approach to LNAV/VNAV minimums with the use of SBAS 
vertical guidance. 

REFERENCE

 

AIM, Chapter 7, Section 3, Cold Temperature Barometric Altimeter 
Errors, Setting Procedures, and Cold Temperature Airports (CTA). 

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Preflight