Instrument Approaches (Part One)

Compliance With Published Standard Instrument Approach Procedures

Compliance with the approach procedures shown on the approach charts provides necessary navigation guidance information for alignment with the final approach courses, as well as obstruction clearance. Under certain conditions, a course reversal maneuver or procedure turn may be necessary. However, this procedure is not authorized when:

  1. The symbol “NoPT” appears on the approach course on the plan view of the approach chart.
  2. Radar vectoring is provided to the final approach course.
  3. A holding pattern is published in lieu of a procedure turn.
  4. Executing a timed approach from a holding fix.
  5. Otherwise directed by ATC.

Instrument Approaches to Civil Airports

Unless otherwise authorized, when an instrument letdown to an airport is necessary, the pilot should use a standard IAP prescribed for that airport. IAPs are depicted on IAP charts and are found in the TPP.

ATC approach procedures depend upon the facilities available at the terminal area, the type of instrument approach executed, and the existing weather conditions. The ATC facilities, NAVAIDs, and associated frequencies appropriate to each standard instrument approach are given on the approach chart. Individual charts are published for standard approach procedures associated with the following types of facilities:

  1. Nondirectional beacon (NDB)
  2. Very-high frequency omnirange (VOR)
  3. Very-high frequency omnirange with distance measuring equipment (VORTAC or VOR/DME)
  4. Localizer (LOC)
  5. Instrument landing system (ILS)
  6. Localizer-type directional aid (LDA)
  7. Simplified directional facility (SDF)
  8. Area navigation (RNAV)
  9. Global positioning system (GPS)

An IAP can be flown in one of two ways: as a full approach or with the assistance of radar vectors. When the IAP is flown as a full approach, pilots conduct their own navigation using the routes and altitudes depicted on the instrument approach chart. A full approach allows the pilot to transition from the en route phase, to the instrument approach, and then to a landing with minimal assistance from ATC. This type of procedure may be requested by the pilot but is most often used in areas without radar coverage. A full approach also provides the pilot with a means of completing an instrument approach in the event of a communications failure.

When an approach is flown with the assistance of radar vectors, ATC provides guidance in the form of headings and altitudes, which position the aircraft to intercept the final approach. From this point, the pilot resumes navigation, intercepts the final approach course, and completes the approach using the IAP chart. This is often a more expedient method of flying the approach, as opposed to the full approach, and allows ATC to sequence arriving traffic. A pilot operating in radar contact can generally expect the assistance of radar vectors to the final approach course.


Approach to Airport Without an Operating Control Tower

Figure 10-8 shows an approach procedure at an airport without an operating control tower. When approaching such a facility, the pilot should monitor the AWOS/ASOS if available for the latest weather conditions. When direct communication between the pilot and controller is no longer required, the ARTCC or approach controller issues a clearance for an instrument approach and advises “change to advisory frequency approved.” When the aircraft arrives on a “cruise” clearance, ATC does not issue further clearance for approach and landing.

Figure 10-8. Monroeville, Alabama (MVC) VOR or GPS Rwy 3 Approach: An approach procedure at an airport without an operating control tower.

Figure 10-8. Monroeville, Alabama (MVC) VOR or GPS Rwy 3 Approach: An approach procedure at an airport without an operating control tower. [click image to enlarge]

If an approach clearance is required, ATC authorizes the pilots to execute his or her choice of standard instrument approach (if more than one is published for the airport) with the phrase “Cleared for the approach” and the communications frequency change required, if any. From this point on, there is no contact with ATC. The pilot is responsible for closing the IFR flight plan before landing, if in VFR conditions, or by telephone after landing.

Unless otherwise authorized by ATC, a pilot is expected to execute the complete IAP shown on the chart.


Approach to Airport With an Operating Tower, With No Approach Control

When an aircraft approaches an airport with an operating control tower, but no approach control, ATC issues a clearance to an approach/outer fix with the appropriate information and instructions as follows:

  1. Name of the fix
  2. Altitude to be maintained
  3. Holding information and expected approach clearance time, if appropriate
  4. Instructions regarding further communications, including:
    1. facility to be contacted
    2. time and place of contact
    3. frequency/ies to be used

If ATIS is available, a pilot should monitor that frequency for information such as ceiling, visibility, wind direction and velocity, altimeter setting, instrument approach, and runways in use prior to initial radio contact with the tower. If ATIS is not available, ATC provides weather information from the nearest reporting station.

Approach to an Airport With an Operating Tower, With an Approach Control

Where radar is approved for approach control service, it is used to provide vectors in conjunction with published IAPs. Radar vectors can provide course guidance and expedite traffic to the final approach course of any established IAP. Figure 10-9 shows an IAP chart with maximum ATC facilities available.

Figure 10-9. Gulfport, Mississippi (GPT) ILS or LOC Rwy 14 Approach: An instrument procedure chart with maximum ATC facilities available.

Figure 10-9. Gulfport, Mississippi (GPT) ILS or LOC Rwy 14 Approach: An instrument procedure chart with maximum ATC facilities available. [click image to enlarge]

Approach control facilities that provide this radar service operate in the following manner:

  1. Arriving aircraft are either cleared to an outer fix most appropriate to the route being flown with vertical separation and, if required, given holding information; or,
  2. When radar hand-offs are effected between ARTCC and approach control, or between two approach control facilities, aircraft are cleared to the airport or to a fix so located that the hand-off is completed prior to the time the aircraft reaches the fix.
    1. When the radar hand-offs are utilized, successive arriving flights may be handed off to approach control with radar separation in lieu of vertical separation.
    2. After hand-off to approach control, an aircraft is vectored to the appropriate final approach course.
  3. Radar vectors and altitude/flight levels are issued as required for spacing and separating aircraft; do not deviate from the headings issued by approach control.
  4. Aircraft are normally informed when it becomes necessary to be vectored across the final approach course for spacing or other reasons. If approach course crossing is imminent and the pilot has not been informed that the aircraft will be vectored across the final approach course, the pilot should query the controller. The pilot is not expected to turn inbound on the final approach course unless an approach clearance has been issued. This clearance is normally issued with the final vector for interception of the final approach course, and the vector enables the pilot to establish the aircraft on the final approach course prior to reaching the final approach fix.
  5. Once the aircraft is established inbound on the final approach course, radar separation is maintained with other aircraft, and the pilot is expected to complete the approach using the NAVAID designated in the clearance (ILS, VOR, NDB, GPS, etc.) as the primary means of navigation.
  6. After passing the final approach fix inbound, the pilot is expected to proceed direct to the airport and complete the approach or to execute the published missed approach procedure.
  7. Radar service is automatically terminated when the landing is completed or when the pilot is instructed to change to advisory frequency at uncontrolled airports, whichever occurs first.

Flight Literacy Recommends

William Kershner's Instrument Flight Manual - Everything you need to know to obtain an FAA instrument rating, or a great refresher for existing instrument pilots. Covered subjects include airplane performance and basic instrument flying, navigation and communications, clearances, planning IFR flight, and carrying out the instrument flight itself from preflight, takeoff and departure, en route, through to the approach and landing phases.