Pilot IFR Altitude Deviations
Pilot altitude deviations often occur when flying a published departure or standard arrival procedure. Many procedures have published altitudes that ATC expects the pilot to follow. A thorough understanding of the following ATC phraseology and ILS altitude information will reduce deviations and subsequent danger to pilots and passengers.
“DESCEND AND MAINTAIN”- Instructs the pilot to descend now (at a standard rate) to the newly assigned altitude and maintain that altitude until a new altitude assignment is received. The pilot will disregard all altitudes published on the STAR.
“DESCEND VIA” – Instructs a pilot to vertically navigate on the STAR and comply with published speeds.
“RESUME THE ARRIVAL” – Instructs a pilot to rejoin the lateral confines of the arrival only. Previously issued speeds and altitudes are still required.
“CLIMB AND MAINTAIN” – Instructs the aircraft to climb now (at a standard rate) to the newly assigned altitude and maintain that altitude until a new altitude assignment is received. Pilots will disregard all altitudes published on the SID.
“RESUME NORMAL SPEED” – Instructs a pilot to comply with speeds published on the SID.
“DELETE SPEED RESTRICTIONS” – Instructs the pilot to disregard all previously issued speeds including speeds on upcoming portions of an RNAV SID.
“RESUME THE DEPARTURE” – Instructs a pilot to rejoin the lateral confines of the departure only. Previously issued speeds and altitudes are still required.
A Precision Final Approach Fix (PFAF) and/or a Glideslope Intercept Point defines the final approach segment (the end of the “feather”) as depicted in the Profile View on the approach plate. From the PFAF or Glideslope Intercept Point to the runway, use of the approach mode (APP) is the proper way to navigate the ILS. Without explicit guidance otherwise, there is no provision for capturing the glideslope beyond the PFAF or Glideslope Intercept Point and all altitude constraints must be met. Published altitudes at fixes outside of the Precision Final Approach Fix are part of the initial or intermediate segments of the approach and provide vertical separation from obstructions or other aircraft. An extension of the glideslope may not satisfy the minimum altitudes published outside the PFAF.
A review of Chapter 5 in the Aeronautical Information Manual (AIM) can refresh your understanding of Departure, Enroute, and Arrival procedures. Here is a direct link which you can copy and paste into your browser: http://www.faa.gov/air_traffic/publications/ATpubs/AIM/chap5toc.htm
(This information is provided to all pilots, those with instrument ratings and those without, because the principle of following established procedures applies to all. In addition, just in case you are getting your instrument rating next week, we wanted you to have this information, as well.)