exiting a hold; question

[ferris]

With the upcoming airspace changes and traffic increases, traffic into Dubai is going to be holding a lot more. With that in mind, trying to sharpen the accuracy of spacing aircraft out of the hold, I have a question for drivers of both Boeing and Airbus.

I notice that when you are cleared out of the hold, you are usually on the outbound leg. If you get the instruction to "track direct to .....", the time taken to execute the instruction varies greatly. If you continue outbound for a minute, thats 4 miles too far then 4 miles back again, so we end up with 8 miles too many (we account for the time in the turn). We cannot account for you to continue outbound for 1 minute, as sometimes you turn in straight away, and then there is not enough spacing. An old trick I was taught as a youngster when vectoring was to give a heading instruction approximately in the direction of the waypoint, then once you were turning, give the instruction "track direct to .....". My question is: If you are in the holding pattern, get instruction "cancel hold, turn left heading 130" then "track direct to [the holding fix], resume the arrival", is that going to cause you problems?

[ironbutt57]

Can't see a problem from the boeing side of things...:)

[Captain Over]

I HATE to agree with a "Boeing-Butt"... :D :D ....but that'll be a ditto to the "no problem, we can do that!" for the Airbus crowd...IMHO, of course.

:p

[CaptSnails]

Ferris from what I gather you must be a controller in the UAE, is that approach DXB or AUH?
To answere your question what is happening is the following. When an Airbus is in the hold outbound and you issue a clearance "go direct to the VOR, cleared for the full approach" for example the pilot has to intervene and do either a direct to function or what we call an "immediate exit". In this case the aircraft will turn direct to the point requested. What I suspect happens sometimes is that if you clear an aircraft which is outbound for the approach, then the guys just let it stay in the hold until it turns inbound, then presses the immediate exit. There is no problem at all if while in the hold you issue a radar heading followed by a direct to a point either.
Hope that helps, take care and keep us safe.
Snails

[druckmefunk]

On Boeings (777'), if you have already passed abeam the fix on the outbound leg and then execute the exit hold function, it will continue to fly the remainder of the pattern until it reaches the fix again before it will exit the hold, this may be where some of the problems are occuring. Giving a heading should present no problem whatsoever, many other approach controls do just that.

[scanscanscan]

IMHO...ATC should be aware that a clearence containing only "go direct" when executed by the pilots will cause the aircraft to turn the shortest possible way to the new fix.
Computer logic.
The turn left or right may not be the turn atc expect or want for various reasons.
It is wise to preceed the go direct with the required direction of the turn you require or as you said a turn left or right as you require to a heading pointing at the fix or very nearly so then the direct.
This atc awareness of the computer logic to go direct by the shortest possible turn is also relevent to departure aircraft go directs.
I recall CDG departure on 27R with a go direct clearence at 700ft caused the aircraft to turn left when what the the french atc chap wanted was a right turn out as per the sid then a direct, but he did not say so.
Such was ATC surprise as the aircraft climbed out left over the other runways it is said atc spoke in English for a full five minutes after the incident.
Being pissed off and french they then filed a violation against the captain which was defeated. But the conclusion was ATC CDG expected all turns to be right out of 27R.
CDG had another trick of clearing an aircraft for an Ils and switching the ils to the other runway when the aircraft was around 100 feet agl.
This caused pilots on a practice auto land to awake in a hurray as the aircraft lost the ils signal.
In this case the crew had not told the ATC they were doing a practice auto land, next time they did several times and atc also advised before they would swich over the ils.
IMHO...Out of hours direct communication between pilots and atc is one of the best safety features pprune and the internet provides.
They chances of everyone seeing eye to eye in the common market is....?? :)

[ferris]

scanscanscan- any ATC who does not specify a direction of turn, or says "track direct" without specifying the turn, if there is any chance of ambiguity, is a dill.

druckmefunk- this info is what I had suspected, and why we need to alter the instruction to get more precision (if we are running 10nm in trail, continuing out like that burns a slot- see my earlier).

I just wanted to make sure we weren't stuffing something up if we gave you heading instructions whilst you were in a hold.

Thanks for the input everyone. Happy holding:p ;)

[Flat-Spot]

Thanks Ferris but the happy holding and the 'twisty' vectoring are gonna be real interesting when there's a bit wx around Desdi and Dubai. :D

F-S