machlimter99
18th Apr 2006, 07:02
Can anyone please answer these more finer points about holding.
Why is the entry to a hold heading dependant???
How does the 30 degree gate alter with the wind???
How does the abeam position alter with the wind?? Is there any kind of rule??
thanks
GusHoneybun
18th Apr 2006, 16:22
I don't claim to be an expert on holds, but I do have to use them in anger quite often. First and only thing I am sure of is that hold are not an exact science. Especially if you are using an NDB at a coastal airfield. As long as you are above MSA you can make a complete arse of the hold and still be safe. Anyhoo,
1) Entry to a hold is really designed so that at some point, you end up passing over the beacon. Whether it's a direct, parallel or offset really depends on the angle you are coming in wrt the inbound heading of the hold. Whichever is the easiest and requires the least amount of handling to get you to pass over the beacon generally heading in the right direction.
Personally I find that sometimes it is easier to enter the hold if you offset heading directly for the beacon in the last 2-3 miles. For example, a hold is 090 inbound and is a right hand hold. You have a tailwind and you're heading 020. This indicates a direct join. However, if you fly direct to the beacon before you turn you will get blown through the overhead and it's a real ballache to sort out. As you are above MSA and with ATC in cahoots, offset your approach to the beacon by 30 degrees (ie, heading about 350) initally and when the beacon is approaching your 1 o clock, turn to fly direct to the beacon. This means that you approach the overhead with a smaller angle between your heading and inbound track, and means that the entry to the hold is a little easier.
2) The gate is a guide that you are roughly in the correct area at the correct time. It doesn't get changed by the wind. If you reach the gate to early, then chances are you haven't assessed the wind correctly and best to fly along the gate until your 1 minute (or whatever wind corrected timing you are using) has elasped. It means that your hold is not wide enough and you need to assess your outbound heading next time around the hold. Obviously the opposite is true if you don't reach the gate during the hold. Remember that it is only a rough guide.
3) When I was taught holds, I was taught that you start the stopwatch when either abeam the beacon or wings level, whichever is the latter. Seems to work OK for me.
As I said before, holds are not an exact science. However, when you roll out bang on the inbound heading it does feel satisfying. How sad am I :(