Azimuth Guidance for Nose-in Stands - AGNIS
Visual Docking Guidance Systems (VDGS), sometimes referred to as Nose-in Docking Guidance Systems or Stand Entry Guidance Systems (SEG), provide guidance where accurate aircraft parking is required.
This is usually the case where Jetways /airbridges are used. The AGNIS VDGS currently in use in many major airports in the world include Azimuth Guidance for Nose-in Stands (AGNIS), supported by Parallax Aircraft Parking Aid (PAPA).
Azimuth Guidance for Nose-in Stands (AGNIS)
AGNIS provides Stand centreline alignment guidance and is normally used in conjunction with PAPA, marker boards, lines or mirrors, which provide stopping guidance separately. The system is designed for use from the left pilot position only and the unit displays two closely spaced vertical light bars mounted in a box, as illustrated above, at about flight deck height ahead of the pilot. The light bars display one of the following signals:
- One red bar and one green bar indicating that the pilot should steer away from the red towards the green bar or
- Two green bars, indicating correct alignment
Airport Visual Docking Guidance System - PAPA
The Parallax Aircraft Parking Aid is frequently combined with an AGNIS system, informing flight crews when to stop. The device features no electronics or moving parts; it consists simply of a large grey box (usually with one or more sides missing) with a large rectangular slot cut in to the front.
Inside the box, towards the rear, is a white stick or fluorescent tube, which appears to move from one side of the slot to the other as the viewer moves closer, although it is in fact fixed and the effect is merely due to perspective. Above and/or below this slot will be markings in white or yellow, indicating where different types of plane should stop.
As this system relies on the position of the viewer, it will not give accurate distance information to aircraft which have deviated significantly from the stand centreline.
In some cases, mirrors may be provided to permit a pilot to view the position of the nosewheel of the aircraft relative to the stopping position.
At major Airports, Advanced Visual Docking Guidance Systems (AVDGS) are installed that provide electronically displayed information, such as the azimuth position of the aircraft and stopping distance.
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