Ground speed limits at airports

Both 757 and A340 ops manuals specify max 30 knots groundspeed (displayed on Nav display and generated by Inertial Reference Systems coupled with GPS) when on straights and max 10 knots for sharp turns (without use of differential braking).

I do KNOW for a fact that I´ve never seen any limits on taxyspeed publiced in Jeppesen, on any of the airports in Europe I´ve been to.

Must admit never heard of ‘speed’ limits with regards to taxying, in any case there isn’t always a suitable or available display that shows an accurate groundspeed.

Having looked at the French AIP and CDG charts – I can’t find any mention of ‘speed’ limits on taxiways at CDG.

I can only say that if you look through the specific airport info in an AIP you might find it there .Can’t remember where i read it sorry because it came up when Ryanair called and asked was there a speed limit and that came up as given by the AO.

Another point which i’ve heard in conversation at work is that harsh braking to make early or first turn-offs after landing, fast taxiing and riding the brakes, followed by a short turnaround (esp with LCC’s trying to make up time on late services) would mean that brake temps wouldn’t have sufficiantly cooled for the next departure.

If this was allowed to happen I wouldn’t like to bet the performance figures would be quite so accurate in the case of a RTO.

I’ve never seen or heard of an official taxi speed limit. We try to keep it under 25 knots as that is the speed at which our spoilers pop up on the ground. I’ve heard of crews being given a bit of friendly advice after a flight by an FAA inspector who happened to be riding in the back that they were taxiing a bit too fast and that was noted by the spoilers deploying. Also with a heavier aircraft on a long taxi speeds of 20-25 knots will heat up the brakes quite a bit faster than if we take it slower.

So that is my take on it for US operations, nothing official but about 15 knots or so is a speed that keeps everyone from bunching up. There are situations where higher speeds are needed (ie crossing a runway with landing traffic) but it’s at the captains digression. Now if you work for Southwest your taxi speed is roughly V1. 🙂

Most airports have a speed restiction on taxiways of 15kts .

I know of CDG that has 30kts for there long straight taxiways others may also have them.

Very interesting, could you give the references for those statements please? Do they come from the AIP and are they reproduced on the appropriate Thales/Aerad plates or Jeppesen?

exmpa

Most airports have a speed restiction on taxiways of 15kts .

I know of CDG that has 30kts for there long straight taxiways others may also have them.

I´ve never seen any limitation publiced by airport authorities regarding taxi speed. As mentioned above, the only limit would be that of the aircraft manufacturer. The 737 Flight Crew Training Manual RECOMMANDS taxi speeds of no greater than 20 kts maximum, however on Long Straight Taxiways, speeds up to 30 kts are acceptible. Maximum Speed for a turn of more than about 30° is 10kts. This speeds are not in the Limitation Chapter of the Boeing Manual, and are there for a recommandation only.

Deano, you use the FMC, GPS, IRU displayed Groundspeed . If you haven’t got 2 out of those 3 you’re not going to be there anyway. You wouldn’t satisy BRNav requirements without them.

exmpa

Appreciate that, I did not know whether said equipment would display this info a) on the ground & b) at such low groundspeeds

Let’s just clarify this one a bit:

As I said above, I know of no airport imposed taxy speed limits at any airport I have operated from in Western Europe, Middle East, Far East, Oceania or North America throughout the last 40 or so years. That includes Amsterdam, Schipol which I first visited when it was under construction in 1965.

If anyone “knows” of a specific airport taxy speed limit (as opposed to something like “Speed should be restricted to walking pace in the parking area”) and can produce the reference for it, the I’ll have seen something new. But then, things change all the time.

Deano, you use the FMC, GPS, IRU displayed Groundspeed . If you haven’t got 2 out of those 3 you’re not going to be there anyway. You wouldn’t satisy BRNav requirements without them.

exmpa

They can’t use the ASI for an indication of the speed because this measures Airspeed (Indicated), so obviously a 20kt headwind when going 5kts will give a 25kt reading, conversly a 20kt tailwind means they have to reach a groundspeed of over 20kts for it to register, maybe wysiwyg or Whiskey Delta can answer the question

As speed is displayed in Knots not Kilometres/Hour it would seem a bit unlikely wouldn’t it?

exmpa

Well, it was explained to me in kph. But if knots is the regular speed, then the equivalent to 50kph will probably be mentioned on the charts.

I have once heard that the official speed limit is 50 kph.

As speed is displayed in Knots not Kilometres/Hour it would seem a bit unlikely wouldn’t it?

exmpa

I have once heard that the official speed limit is 50 kph. However, an exception is made for the taxiway to the Polderbaan owing its length. Obviously traffice and weather permitting.

Actually, I have been told that the 737s used by Transavia have uprated engines specifically to make the taxi faster. Since Transavia flies a lot during the calmer periods since they are a charterer. Probably just nonsense, but it was a nice story I once heard nontheless. 😀

I know of no airport imposed taxy speed limits. Taxy speeds are normally defined by structural/fatigue considerations and a typical figure would be 30 Knots. In certain circumstances you might taxy faster, e.g. back tracking to the takeoff position.

Companies may set their own limits for taxy speeds and flag exceedances on the Flight Data Recorder. Should any particular airport appear to be generating a high level of exceedances then the cause would be sought and measures introduced to lower the incidence of these events.

By the “Polderbaan” I assume you mean 18R? – It’s so far away from Amsterdam Ryanair are thinking of using it.

exmpa