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When can you log instrument approaches? Read this 3-page PDF to learn more.
Types of Approaches
A Contact Approach is an approach available to aircraft operating on an IFR flight plan, where the pilot may deviate from the published instrument approach procedure (IAP) and proceed to the destination airport by visual reference to the surface. The pilot must request this type of approach from ATC and may only be issued if there is at least 1 SM visibility and the aircraft can remain clear of clouds.
A Visual Approach is an approach to a runway at an airport conducted under IFR but where the pilot proceeds by visual reference and clear of clouds to the airport. The pilot must at all times have either the airport or the preceding aircraft in sight. ATC may assign a visual approach.
A PAR (precision approach radar) approach is a type of radar guided approach designed to provide lateral and vertical guidance to an aircraft pilot for landing, until the landing threshold is reached. After the aircraft reaches the decision height (DH) or decision altitude (DA), guidance is advisory only.
Precision Runway Monitoring (PRM) is a RADAR system for monitoring approaches involving closely spaced parallel runways.
For all straight-in instrument approaches, to include contact approaches in IFR weather conditions, the approach must be stabilized before descending below 1,000 feet above the airport or TDZE.
For visual approaches and straight-in instrument approaches in VFR weather conditions, the approach must be stabilized before descending below 500 feet above the airport elevation.
Descents During Approach
If, during an approach with vertical guidance (glide slope or glide path), the glide slope and localizer are centered, but the airspeed is too fast, the pilot's first action should be to reduce power.
The rate of descent on the glide slope depends upon ground speed. The rate of descent required to stay on the ILS glide slope must be decreased if the ground speed is decreased. Likewise, if ground speed increases, rate of descent must increase.
For a stabilized approach, the aircraft must be in an approved configuration for landing with a descent rate of less than 1,000 fpm when below DA or MDA and using bank angles of less than 15° below 500 feet AGL.
Operational experience and research have shown that a descent rate of greater than approximately 1,000 fpm is unacceptable during the final stages of an approach (below 1,000 feet AGL). This is due to a human perceptual limitation that is independent of the type of airplane or helicopter. Therefore, the operational practices and techniques must ensure that descent rates greater than 1,000 fpm are not permitted in either the instrument or visual portions of an approach and landing operation.
(source: Instrument Procedures Handbook, Chapter 4)
Circle to Land
For the final segment of a circling approach maneuver, the approach must be stabilized 500 feet above the airport elevation or at the MDA, whichever is lower.
If the pilot loses visual reference while circling to land from an instrument approach and ATC radar service is not available, the missed approach action should be to make a climbing turn toward the landing runway and continue the turn until established on the missed approach course.
A visual maneuver accomplished by a pilot at the completion of an instrument approach to permit a straight-in landing on a parallel runway not more than 1,200 feet to either side of the runway to which the instrument approach was conducted. When cleared to execute a published sidestep maneuver for a specific approach and landing on the parallel runway, the pilot is expected to commence the maneuver as soon as possible after the runway or runway environment is in sight.
A No-Gyro approach is available to a pilot under radar control who experiences loss of the directional gyro (heading indicator) or other stabilized compass. The pilot should advise ATC and request a No-Gyro vector or approach. The pilot should make all turns at standard rate and should execute the turns immediately upon receipt of instructions.
When a surveillance or precision approach is made, the pilot will be advised after the aircraft has been turned onto final approach to make turns at half standard rate.
If forecast weather at the destination airport during a period 1 hour before ETA through 1 hour after ETA predicts ceilings lower than 2000 feet and/or visibility less than 3 SM, an alternate airport is required for the IFR flight.
Standard alternate minimums for selection of an alternate airport is based on forecast weather at the alternate airport during a period from one hour before ETA through one hour after ETA. If the alternate airport has an acceptable precision approach, the forecast ceiling must be 600 feet or higher with a visibility of 2 SM or greater. If the only acceptable approach is non-precision, the forecast ceiling must be 800 feet or higher with a visibility of 2 SM or greater. (See §91.169).
Note that these minimums only apply to the selection of an alternate. If an approach is flown at an alternate airport the published minimums apply.
Glidepath Qualification Surface
The Glidepath Qualification Surface (GQS) extends from the runway threshold along the runway centerline extended to the decision altitude (DA) point. It limits the height of obstructions between DA and runway threshold (RWT). When obstructions exceed the height of the GQS, an approach procedure with positive vertical guidance (an ILS, or WAAS GPS) is not authorized.