Holding / Reversal

28.10.2004

Submission:

Two Questions concerning holdings and reversal procedures.

Firstly I have a very high obstacle near the outer primary boundary of OAS on initial approach segment (racetrack). It is located on the boundary almost. I have tried to change some procedure elements but there is no way to eliminate this obstacle. Is it possible to determine a sector with restraining bearings? For example, assign a sector "160 deg to ARP - 245 deg to ARP" and therefore eliminating this obstacle. It seems to be strange and I doubt about this possibility but may be someone has developed such a procedure...

Secondly, what is the meaning of the second wind spiral (it is symmetrical with primary wind spiral and I have marked it in red) which is depicted on the template?


Irina Gorbunova
Procedure designer of North-Western Regional AIS, RUSSIAN FEDERATION

Answer or Commentary:

(I.W.

1. I don't think that such a sector restriction is a possibility. However you might try a base turn reversal instead of a race track for the initial segment. That is outbound on a track or radial from the holding aid to a certain distance or time, then a turn and a track or radial to intercept the localiser. This will eliminate a lot of area and you may be able to adjust the radials to put the obstacle outside the areas or at least into the secondary area. One could also limit the speed in the turn to further reduce the area required. You would have to re-align the holding pattern though, to enable aircraft to smoothly enter the tear drop.

2. The extra turn spiral on the race track template is used in the construction of sector 1 entries into the holding pattern. As this sector requires turns in the opposite direction to the holding pattern one would have to turn the template over to be able to trace over the primary wind spiral. So I think that is why this wind spiral you refer to was put on the template, to avoid this turning over of the hard copy template. If you don't allow sector 1 entries into the holding pattern and these are a bit complicated to construct, you don't need to use the wind spiral you refer to.)