PDA

View Full Version : " High Speed Turnoffs"


shon7
18th Apr 2002, 19:33
I have heard the argument that at some of the more modern airports the runways and taxi-ways have been developed in a way that they allow "high speed turnoffs." Two airports most often quoted in this regard are Atlanta and Zurich.

However, reading the max. taxi speed on a 747 thread - a "high speed turnoff" seems to be contradictory?

So I have two question;

1. Is there such a thing as a "high speed turnoff"

2. If there is how is this accomplished and under what circumstances.

Rabbit
18th Apr 2002, 20:12
shon7

Obviously not a pilot, Just for your information almost all instrumented runways in the world have at least one "high speed turnoff". The reason is quite simple - to allow clearence of the runway at a slightly higher than normal taxi speed so as to free the runway for the following traffic. Exit speed is allowed is normally controlled by Company procedures.

Have a nice day

Ford Airlane
19th Apr 2002, 03:43
60 knots groundspeed is the usual maximum speed for a high speed exit.

At busy airports, as an example landing LAX 25L, they prefer you to turn off the high speed taxiway as it gets you off the runway quicker so the guy behind you doesn't have to go around. The time taken to slow to 10 knots for a turn onto a normal taxiway and the cross the hold short line can be significant in the case of a heavy like a 747.
:)

G.Khan
19th Apr 2002, 10:41
Oh, the luxury of being able to land on 25L! We were always given 24R, even when a heavy 744 freighter going to the ICC, (threshold 25L), despite our requests, made as early as possible!

Off topic, back to thread, we used 45kts as our company ideal max speed for a fast turn-off on a B744, as mentioned, often hard to stop at the hold short line if parallel runways in use.

OzExpat
19th Apr 2002, 13:35
Ooops, sorry, thought this might've been a thread about blonde's in sports cars...:(

FlyingForFun
19th Apr 2002, 13:44
If you find blondes in sports cars a turn-off, OzEx, just send them my way :D

FFF
--------

OzExpat
20th Apr 2002, 09:47
Some people have NO shame... :D

Fr O'Blivien
20th Apr 2002, 10:31
60 Kts??? Good luck...

ICAO recommended exit speeds are 35Kts for a 30 degree exit and 50 Kts for a 20 degree turnoff.

ICAO Annex 14, Aerodromes, 3.8.18

dv8
22nd Apr 2002, 18:21
It was this months TEC test in 'The Log'
See page 19

Self Loading Freight
23rd Apr 2002, 12:09
And there's no truth in the rumour that they're going to put a camber in the turnoffs at Dub to cater for the Ryanair all-Ireland turbotaxi championship challenge.

R

OzExpat
23rd Apr 2002, 12:42
Okay, s'pose I better make a serious post here...

I happened to be browsing thru Annex 14 today and can confirm the basics of the post by Fr O'Blivien. The design standard calls for a minimum turn angle of 25 degrees, a maximum angle of 45 degrees and an optimum angle of 30 degrees. All of this is only intended to provide flexibility in the design of these things, if needed.

There are maximum speeds quoted which accord pretty much with what Fr O'Blivien posted as well. But remember that these are simply design standards - aircraft speed can always be lower than that, without any problem. Again, it's all intended to provide design flexibility to cater for most situations.