AIM Text
- Pilot.
- Be aware that the controller issues clearance for approach based only on known traffic.
- Follows the procedure as shown on the IAP, including all restrictive notations, such as:
- Procedure not authorized at night;
- Approach not authorized when local area altimeter not available;
- Procedure not authorized when control tower not in operation;
- Procedure not authorized when glide slope not used;
- Straight‐in minimums not authorized at night; etc.
- Radar required; or
- The circling minimums published on the instrument approach chart provide adequate obstruction clearance and pilots should not descend below the circling altitude until the aircraft is in a position to make final descent for landing. Sound judgment and knowledge of the pilot's and the aircraft's capabilities are the criteria for determining the exact maneuver in each instance since airport design and the aircraft position, altitude and airspeed must all be considered.
- Upon receipt of an approach clearance while on an unpublished route or being radar vectored:
- Complies with the minimum altitude for IFR; and
- Maintains the last assigned altitude until established on a segment of a published route or IAP, at which time published altitudes apply.
- There are currently 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:
- A temperature range limitation associated with the use of baro-VNAV that may be published on a United States PBN IAP titled RNAV (GPS) or RNAV (RNP); and/or
- 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.
- 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.
- Controller.
- Issues an approach clearance based on known traffic.
- Issues an IFR approach clearance only after the aircraft is established on a segment of published route or IAP, or assigns an appropriate altitude for the aircraft to maintain until so established.
Source: FAA Aeronautical Information Manual · current edition · paragraph 5-5-4.
The short answer
This advisory AIM section covers the instrument approach phase. Controllers issue an approach clearance based only on known traffic; pilots follow the IAP and all restrictive notations, hold the last assigned altitude until established on a published segment, and apply published temperature limitations. It supports IFR approach procedures under 14 CFR 91.175.
Research Notes
Common Questions
What altitude do I hold after getting an approach clearance on a vector?
On an unpublished route or while being radar vectored, the AIM advises complying with the minimum altitude for IFR and maintaining the last assigned altitude until established on a segment of a published route or IAP, at which time published altitudes apply.
What temperature limitations appear on an instrument approach chart?
Two may be published in the notes box: a temperature-range limitation associated with baro-VNAV on a PBN RNAV (GPS) or RNAV (RNP) IAP, and a Cold Temperature Airport (CTA) limitation marked by a snowflake ICON and temperature in Celsius, published on every IAP for the airfield.
May I descend below circling minimums once cleared to circle?
No. The circling minimums provide adequate obstruction clearance, and the AIM advises pilots not to descend below the circling altitude until the aircraft is in a position to make a final descent for landing.