Clarifications in the 25 August 2011 Update to the AIM

FAA has published the 25 August 2011 update to the Aeronautical Information Manual (AIM). This set of changes includes a couple of clarifications worth calling out for IFR pilots:

  • 1-2-3. Use of Suitable Area Navigation (RNAV) Systems on Conventional Procedures and Routes
  • 5-4-6. Approach Clearance

The change in section 1-2-3 reflects the content of a new advisory circular, AC 90-108 Use of Suitable Area Navigation (RNAV) Systems on Conventional Routes and Procedures (PDF), published on 3 March 2011. This AC describes in detail how you can use an IFR-approved GPS (subject to any limitations in the supplements to your AFM) as a substitute for courses and fixes defined by VOR, DME, LOM, and NDB navaids. It also describes limitations on using both basic and WAAS GPS equipment, in particular when flying the final approach course on an instrument approach.

The update to 5-4-6 clarifies ATC approach clearances, in particular:

e. The following applies to aircraft on radar vectors and/or cleared “direct to” in conjunction with an approach clearance:
1. Maintain the last altitude assigned by ATC until the aircraft is established on a published segment of a transition route, or approach procedure segment, or other published route, for which a lower altitude is published on the chart. If already on an established route, or approach or arrival segment, you may descend to whatever minimum altitude is listed for that route or segment.
2. Continue on the vector heading until intercepting the next published ground track applicable to the approach clearance.
3. Once reaching the final approach fix via the published segments, the pilot may continue on approach to a landing.
4. If proceeding to an IAF with a published course reversal (procedure turn or hold-in-lieu of PT pattern), except when cleared for a straight in approach by ATC, the pilot must execute the procedure turn/hold-in-lieu of PT, and complete the approach.
5. If cleared to an IAF/IF via a NoPT route, or no procedure turn/hold-in-lieu of PT is published, continue with the published approach.
6. In addition to the above, RNAV aircraft may be issued a clearance direct to an Intermediate Fix followed by a straight-in approach clearance.