High Speed Turnoff Defintion

[CaptainMongo]

Each airplane has recommended speeds at which to exit the runway via a high speed turnoff.

What is the defintion of a high speed turnoff? Is there a specific length the turnoff must be to be considered high speed?

How can I identify on a JEPP plate whether a turn off is officially considered a high speed one?

[Goldenrivett]

What is the definition of a high speed turnoff?

In the old days we called them Rapid Exit Taxiway (RET).
"Rapid Exit Taxiway — A taxiway connected to a
runway at an acute angle and designed to allow
landing aeroplanes to turn off at higher speeds
than are achieved on other exit taxi-ways and
thereby minimizing runway occupancy times."
Page 21 http://ww1.jeppesen.com/documents/av...ry-legends.pdf

See http://www.gcmap.com/diagrams/pdf/EGLL.pdf
"HOLD N4W/RAPID EXIT TAXIWAY (RET) REDESIGNATED AS UNDER CONSTRUCTION." as an example of what one looks like.

See page 166 http://ww1.jeppesen.com/documents/av...port-signs.pdf

Lots of information on radius of turn / maximum speed etc here :icao_doc_9157_aerodrome design manual-part2.pdf

[DaveReidUK]

Originally Posted by CaptainMongo

What is the defintion of a high speed turnoff? Is there a specific length the turnoff must be to be considered high speed?

ICAO Annex 14 defines a RET as one that departs the runway at an angle of between 25° and 45° (ideally 30°) and is able to accommodate Code 3 or 4 aircraft exiting at a speed of up to 93 kph in wet conditions.

As for the length, Annex 14 simply states that "A rapid exit taxiway should include a straight distance after the turn-off curve sufficuent for an exiting aircraft to come to a full stop clear of any intersecting taxiway."

[lederhosen]

Is kph kilometres or knots?

[topgas]

A knot is a unit of speed, so knots per hour is actually an acceleration, like meters per second per second, so not a likely unit in this context.

[DIBO]

km/h

Code:

to enable exit speeds under wet conditions of:
— 93 km/h where the code number is 3 or 4; and
— 65 km/h where the code number is 1 or 2.

[framer]

Don't try it at 93kts

[PilotJames]

That's runway code rather than aircraft code

[RAT 5]

No idea why, but the grey cells seem to have an idea, from centuries ago, that 45 degrees & 45kts have some relevance.

[DaveReidUK]

Originally Posted by PilotJames

That's runway code rather than aircraft code

Well yes and no. It describes the aerodrome, but in terms of the aircraft it's intended for. From Annex 14:

"The code is composed of two elements which are related to the aeroplane performance characteristics and dimensions. Element 1 is a number based on the aeroplane reference field length and Element 2 is a letter based on the aeroplane wingspan and the outer main gear wheel span".

[pfvspnf]

My OMA states max 50kts for turn off , best to do it even slower, many at times it's a rapid and then a 90 degree turn after. Keep it slow.

[DaveReidUK]

Which of course is the same as the 93 km/h quoted by metricated ICAO.