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AIM 

4/20/23

 

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Preflight

4.

Operators may use a third party interface, incorporating FAA/VOLPE RAIM prediction data without

altering performance values, to predict 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 temperature 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) limitation 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 compensating

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 temperature

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 temperature 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 segments 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).