Missed Approach Point
The missed approach point (engl. Missed point approach , MAPt or MAP) is the point (place) during a landing approach to instrument flight rules , to which the pilot the prescribed missed approach procedures ( Durchstarten ) initiate must , if the runway is not in sight, or it decides that the landing approach cannot be continued in order not (unconsciously) to fall below the Obstacle Clearance Altitude ( OCA ). However, a missed approach procedure can also be initiated before the missed approach point is reached.
Missed approach point for approaches with vertical guidance
For precision approaches ( PA ) and other approaches with vertical guidance ( APV , see approach procedure ), the missed approach point is defined as the intersection of the electronic glide path with the decision height ( DH or DA ). Since the latter is calculated from the OCA and aircraft-specific properties, it is not generally applicable and can therefore not be published in the approach charts .
Missed approach point for non-precision approaches
In the case of non-precision approaches, the missed approach point is determined by a navigation device, a fix or a specified distance to the final approach fix ( FAF ) and published in the approach charts. If the runway is not in sight when the minimum descent altitude ( MDH or MDA ) is reached, the pilot can initially continue to approach this altitude. Only when he reaches the missed approach point does he have to initiate the missed approach procedure - provided the airfield is still not in sight.
Special case USA / military: Visual descent point
The only in the United States common or military airfields Visual descent point ( VDP , dtsch uncommon. View sink-point ) is integrated by its function in the missed approach procedure. There is a point in the minimum descent ( minimum descent altitude MDA) in the descent profile of a non-precision approach as appropriate. From the VDP, the aircraft can descend 3 ° (standard glide path) to reach the runway threshold.
The concept of the VDP was developed by the FAA in order to enable pilots to make a decision about initiating the missed approach procedure before reaching the MAPt. If the runway cannot be seen from the VDP, then it can no longer be reached with a normal descent (3 ° glide angle). Or to put it another way: If the runway is visible from the VDP, then the pilot can perform the standard descent to the runway.
The VDP is always further from the runway threshold than the MAPt.
The FAA has defined the VDP as follows: A defined point on the final approach course of a direct (straight-in) non-precision approach, from which the MDA can continue the approach to the touchdown point of the runway with a normal descent. The prerequisite is that the runway threshold or the approach lights or other markings clearly belonging to the approach end of the runway are clearly visible to the pilot.
Criticism of the concept of the VDP
The VDP does not appear in the terminology of the ICAO and is also not defined in the PANS-OPS, but is an in-house creation of the FAA without observing the relevant ICAO regulations.
Since with a non-precision approach there is no DA or DH as with an ILS approach ( Precision Approach ), but only the MDA, it is up to each pilot himself when to initiate the further descent (below the MDA).
Web links
- FAA's FAA definition of the VDP (English; PDF file)
literature
- Procedures for Air Navigation Services - Aircraft Operations . Doc 8168 OPS / 611 ("PANS OPS"). In: ICAO (Ed.): International Standards and Recommended Practices . 5th edition. Volume I: Flight Procedures, 2006 ( available online (PDF, 1.6 MB) ).
- Ashford, Norman; HP Martin Stanton; Clifton A. Moore - Airport Operations , McGraw-Hill (1997). ISBN 0-07-003077-4
- Bachmann, Faber, Senftleben - Danger manual for pilots , Motorbuch Verlag Stuttgart 1981 ISBN 3-87943-656-8
- Lufthansa Flight Training, Pilot School, BRE OS1 / A - International Air Traffic Regulations and Procedures , 2003