Joining a hold: when do you start your clock?
 

When joining a hold via the sector 1/parallel or sector 2/offset, when do you start your clock?

I have always taught, and been taught, that it is when 'wings level', and not on passing over the holding facility. Recently, however, a colleague was criticised for waiting ‘til wings level – having been taught to do so at Cranwell; the (OCU) instructor insisted that it was on passing over the facility. I have been looking for a reference, thus far in vain, as to which method is correct. I still maintain it’s wings level, but would graciously accept evidence to the contrary!

Ta, in advance, for any knowledgeable thoughts on this.

The source document for the answer is ICAO Document 8168, Procedures for Air Navigation Services - Aircraft Operations. (known as PANS-OPS).

If you have access to Jeppesen or Aerad flight guides, you will find the ICAO 8168 hold entry and timing requirements copied in them. I'm not sure where you will find it in military documents, but it just may be in the pocket-size regional flight guides.

Sorry not to have the full answer - but I might have got you pointing in the right direction.

Personally I don't it is written down as a 'law' anywhere. From my IR test I seem to recall that all you had to do is establish on the inbound course and reamin within the defined protected area for the hold (ie at the correct speed).

If you go over the fix and then start your rate one turn onto the outbound leg, then I don't see why you have to time that. In my mind the only bit where you need to time is your outbound leg, so start your watch at the start of the outbound leg, which to me is wings level or passing abeam the holding fix (whichever the later).

I suspect the instructor 'just preferred' the method he was advocating. I stand to be corrected though, especially as you seem to be talking military aviation and all I did in the military was run round shooting at things with a rifle.......!

PP

Wings level, or abeam, whichever is later.

PANS-OPS Part 4 Ch1, para 1.2.4:
"Outbound timing begins over or abeam the fix whichever occurs later. If the abeam position cannot be determined, start timing when turn to outbound is completed"

So you only use "wings level" if you can't determine abeam, which happens if you are holding on a fix, rather than a beacon.

On parallel entry consider starting the time as you go over the facility so that you give yourself the opportunity to know when to turn back to the beacon.

Once you're actually in the hold then wait until abeam or wings level (whichever is the later) on the outbound and aim to be going back over the beacon 3 minutes later.

Personally, I found it better to get established on the outbound heading and think to myself "Wings level, stopwatch running" (and double-check that it WAS running).

I might be out of date on this, but DAYNE and MIRSI at Manchester are the two holding fixes which come to mind, where the abeam position cannot be determined. Interestingly, there's an outbound limit at MIRSI - POL 30d - while there isn't one published for DAYNE.

I'm well aware of the "wings level or abeam, whichever is later" rule for a direct/sector 3 join, hence my specification of parallel/sector 1 or offset/sector 2 in the original question.

But thank you for the replies nonetheless.

I don't bother, you tell it how long a leg you want and Airbus does it for you :ok:

Assuming we are following what I hope is conventional wisdom, the timing corrections for joins to the hold are the same as those for outbound leg in the hold i.e. +/- one second for each knot of headwind/tailwind. The question being asked here is when to start the timer.

Regarding sector 2/offset joins, you won't be turning for much more than 10 seconds to intercept the QDR which defines the join. It could therefore be argued that you could add 10s to your calculated outbound time to give yourself a bit more room prior to making the inbound turn after the entry. This will of course tend to put you slightly wide at the end of the join and you are likely to intercept the inbound track from inside the hold. From a test point of view it could be argued that if you fly for the pre-planned amount of time you will have less opportunity to make a cock-up of tracking the QDR, although the flip side is that you will be closer to the beacon when making the inbound turn.

With sector 1/parallel joins, consider the following. if you are joining a right-hand hold with an inbound track of 090 (draw the picture) and the wind is 090/30, you would expect to fly outbound in the join for 30s. If we were joining the hold on a heading of 360 (remember hold entry is based on heading, not QDM as most of my students seem to think!), we would take 30s to turn from 360 onto our join heading of 270. If we were to turn inbound 30s after crossing the beacon, the chances are we would be rather close to the beacon and it would be quite difficult to intercept the inbound track. And yes I know you are allowed to track straight back to the beacon but it does make life easier if you intercept the inbound track in a parallel join so that you are more likely to be in the right place when turning outbound in the subsequent hold. Bearing that in mind, and assuming you've got this far without losing the will to live, it makes sense to restart the timer when wings level on your outbound heading in a parallel join. I think!!!

Looking at your nice diagram of the above scenario, and changing the wind to 140/30 to push us further outside the hold in the join, note that there is every chance that you will end up intercepting the inbound track from the non-holding side, or even turning onto the inbound track as if by magic. That one usually really confuses the troops, even when they've been pre-briefed.

I've been instructing for 8 years and am currently at a southern-based flight school which is suddenly quite a popular topic on pprune. This is the first posting I've made so I hope it at least makes some sense!

Doh! Missed a bit, which is quite unbelievable considering how long the last post was. Start your timer over the beacon in a parallel join, and then re-start it wings level and fly outbound for your wind-corrected time. If you forget to re-start the timer wings level, work out roughly how long your turn took after the beacon (10s for each 30 degrees of turn) and add that to the outbound time.

Doubtless this will elicit zero responses and I've just wasted the last 10 minutes of one's supposedly precious time on the planet. Having said that it's the Superbowl tonight, so it's probably a bit early to go to the pub anyway...