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
°
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 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
−
5
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
−
2
Cold Temperature Barometric Altimeter Errors, Setting Procedures and Cold Temperature
Airports (CTA)