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backofthedrag
5th Feb 2006, 15:51
I've had a couple of instances recently of potential confliction between aircraft exiting at a high speed turn off , from the runway, having just landed, and aircraft taxi-ing out for departure in the opposite direction along the parallel taxi-way. At LGW in particular, departures taxi-ing out for 08R via R and 26R can be head on to high speed exiting traffic and quite close. Instructions such as 'can you expedite round the corner' are used. I would have thought that exiting at 45 knots would be quite reasonable and then switching to ground when clear of the runway. If we have to be prepared to remain clear of the parallel taxiway, this would require heavy braking on the turn-off. Normally aircraft would expect to vacate at the exit best suiting their deceleration and this is not always predictable.
Cancun is another example- a/c using the full length of runway 12 to land and taxi-ing in back along A can interfere with following a/c exiting at the high-speed. Instructions such as ' not there, exit at B' are used at the last minute.
Is there not a more formal ATC procedure or should we always be prepared to exit at high speed, clear the runway expeditiously, and then stop clear of the parallel. Not always a lot of room.

GlueBall
6th Feb 2006, 05:36
backofthedrag: "Is there not a more formal ATC procedure..."

Assuredly, ATC cannot predict your exact end of the landing roll, nor read your mind as to where you might turn off the runway.

Needles to say, you must use your own discretion and exercise common sense and preclude the high speed turn-off if you see another airplane on the taxiway that may pose a traffic conflict. :ooh:

BOAC
6th Feb 2006, 07:49
I cannot see the issue here. To my simple mind the HSTO forms part of your 'landing roll' and as such you have 'approval' to use it, whereas a taxyway does not. Therefore you MUST plan to be able to come to a halt on the HSTO. Whether you do or not will depend on getting permission to use said taxyway in time (except, possibly for 'FR' on 26L at LGW). The Mark I eyeball is a valuable asset in determining the future.

facsimile
6th Feb 2006, 08:27
No such thing as a "high speed turnoff" I think you mean"rapid exit turnoff". Therein lies the problem, rapid exit allows you a 45 degree (or less) turnoff instead of 90 hence the rapid exit, the "high speed turnoff" brigade frighten the s**t out of me especially the BA shuttle to LGW who seem to have abandoned the use of reverse thrust and depart the runway still under heavy braking. 25 to 30 kts with the speed under control is the only way to leave using the RET.

BOAC
6th Feb 2006, 08:51
Not so, facs - I was involved in the discussion group on the use of RETILS and a higher speed was agreed to be acceptable and helpful.

Terminology agreed, BTW, but trying to keep it simple.

facsimile
6th Feb 2006, 08:57
The 25 to 30 is just my preference, getting a bit old now but never been in favour of pointing my 767/757 away from active runway at excessive speeds.

FlapsOne
6th Feb 2006, 09:43
A bigger problem is when a rapid exit suddenly has a 90' turn in it after only the first few metres (LGW C?).

It makes it a bit of a nonsense to have a rapid exit only to then have to slam on the anchors to prevent driving on the grass!

Gonzo
6th Feb 2006, 10:39
I'd be interested in any LHR regulars commenting on the new 27L turn off at N6. That seems to me to be a very shallow turn off the runway, and then a very sharp turn to make a 90 degree intersection with taxiway A.

BOAC
6th Feb 2006, 10:40
Facs - I should have added that the 'higher speed' was agreed for RET FR primarily. Otherwise I concur:)

skiesfull
6th Feb 2006, 13:48
From Jeppesen:- rapid exit turn-offs, max. speed 60 kts. I wouldn't consider it safe at more than 20 kts in a B747.

RMC
10th Feb 2006, 20:21
Thought it was 50 knots....this is groundspeed so HWC allows more...if dry etc.

BYMONEK
13th Feb 2006, 15:19
It is 60 kts and it is groundspeed. Based on DRY runway. Would work for a 73 but pushing it for a 77.