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Which is the maximum speed that an airliner is limited to while taxiing?
I know that during 90 degree turns it is 10 knots, but what about long, straight taxiways? 20 knots? 25? 30?

More broadly, where I can find this information?
Would it be in company SOPs? Manufacturer's FCOM?

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    $\begingroup$ Urban legend: According to Southwest's SOP, "anything below Vr" $\endgroup$ – Philippe Leybaert Dec 27 '13 at 2:55
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    $\begingroup$ @PhilippeLeybaert: would that not be V1? ;) $\endgroup$ – Qantas 94 Heavy Dec 27 '13 at 3:13
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    $\begingroup$ @Qantas94Heavy not if the next part of that sentence is "...in a Cessna 150". :-D $\endgroup$ – voretaq7 Dec 27 '13 at 3:26
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A "Safety Alert for Operators" (SAFO 09004) from 2/11/09 says "Slow the aircraft to a fast walking speed on the centerline of the landing runway prior to attempting to exit the runway. Taxi at a fast walking speed until parked at the ramp or until aligned with the centerline of the runway for takeoff."

Which, of course, isn't a regulation, in this example is specifically talking about winter conditions.

Source: http://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/safo/all_safos/media/2009/SAFO09004.pdf

Riverside County in Southern California has an ordinance (regulation) that states: Section 12.08.100 Taxi speed. No person shall taxi any aircraft on the airport unless there will be no danger of collision with any person or object. All aircraft shall be taxied at a safe and reasonable speed commensurate with safe operation in relation to existing conditions and with due regard for other aircraft, persons and property. (Ord. 5661 § 1, 1988; prior code § 5.11 (part)) Source: http://www.riversideca.gov/municode/pdf/12/12-08.pdf

So whatever a "safe and reasonable speed" is. I've heard it called a "brisk walking pace."

I had an airline pilot as a ground school instructor once, and she said that ground control was giving them a hassle one day, so everyone decided to taxi at a "brisk walking pace" around LAX. Got ground whipped into shape real quick!

The FAA's website, under "Best Practices" says to "Maintain an appropriate taxi speed." http://www.faa.gov/airports/runway_safety/pilots/best_practices/

Since it's not clearly defined by the FAA, I assume that most airlines limit taxi speeds via their SOPs, also due to the variety of equipment, it might be unfeasible for the FAA to mandate a specific speed.

Roughly:

  • Max 30 kts: straight line with no close obstacles (for example: back-tracking on the runway)
  • Max 20 kts: straight line with obstacles (for example: on the taxiway, or close to other aircraft/stands/ground vehicles)
  • Max 10 kts: turns and entry onto ramp area
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    $\begingroup$ I can't speak for airliners, but for light aircraft "a brisk walking pace" (ok, maybe more like "a light jog") is probably the upper limit (and what's prescribed in my POH). If your airspeed indicator moves you are almost certainly taxiing too fast. (mumble mumblestupid downhill taxiway deltamumble mumblewreck my breaksmumble mumble) $\endgroup$ – voretaq7 Dec 27 '13 at 3:28
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    $\begingroup$ If the runway/taxi way is icy, then I can see the "fast walking speed", however a "brisk walk" is about a 20 minute mile, which would be 3 mph. Keeping in mind that a runway at a large airport can easily be 10,000 feet (almost 2 miles), that would be a 40 minute taxi just to taxi the length of the runway. Nobody does that out there in the real world. $\endgroup$ – Lnafziger Dec 27 '13 at 3:34
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    $\begingroup$ @lnafziger nobody does it in GA aircraft either (I have a mile-long taxi at my home field on some days and you can bet your bonnet I'm not doing that distance at "walking speed" unless conditions are lousy). My point was more that "appropriate" taxi speeds are an aircraft-dependent thing: you wouldn't catch me taxiing my Piper at 30 knots even if I was at JFK ('cuz a stiff breeze and I'd be airborne!), but an A380 taking a 3-mile taxi with nobody in front of them might be at 30+ knots for a good part of the trip and be perfectly safe doing so :-) $\endgroup$ – voretaq7 Dec 27 '13 at 4:07
  • $\begingroup$ Only 30kts on the back taxi? I think I've hit 75 before trying to get off the active with an approaching aircraft. I'd say its all operator/ aircraft specific. $\endgroup$ – Rhino Driver Dec 17 '14 at 0:11
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    $\begingroup$ Yeah, that 'brisk walk' thing doesn't actually happen, except maybe in cases of extreme icing on the taxiway. Unless we're talking about a 'brisk walk' for a cheetah. For me, a normal semi-brisk walk is right around 4 mph. Land on runway 10 at KATL and that gets you an hour to taxi to the terminal. Not going to happen (though it may feel like it sometimes.) I think whoever came up with the 'brisk walking pace' thing greatly overestimated the actual walking pace of a human (or they weren't referring to a human.) $\endgroup$ – reirab Dec 23 '14 at 7:29
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And here, a Reference from Boeing's 737 FCTM (pdf). Ch2 for ground operations.

enter image description here

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Both of the 747 operators I flew for in the 1990s observed a max taxi speed of 25 knows on a straight taxiway. We were told in ground school that Boeing recommended 20 knots.

Concerning a previous answer of 10 knots in a turn, while that may be a good general answer, it would be subject to conditions. I remember once almost leaving the taxiway in a turn at Jeddah even though I was a little less than 10 knots. It was over 110F, which made the asphalt a little slippery. After than experience, I slowed my 90 degree turns to around 6-7 knots if there was any question concerning the conditions.

Another consideration concerning taxi speed is how heavy you are and how far you have to taxi. The problem is tire heating. I seem to remember being told the 747 had a max taxi distance of 30,000 feet at max weight. I don't know whether that was really true, but I do know that at Honolulu a taxi to the reef runway from some parking areas is at or a little over that.

Since I've been retired for 15 years, please take anything I say with due consideration to my aging-failing brain.

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  • $\begingroup$ Any kind of information is welcome! Many thanks for your answer Terry! $\endgroup$ – Ygor Montenegro Jan 12 '14 at 12:57
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There is no official FAA guidance on taxi speed. There is an urban legend around that the speed limit is "no faster than a man can walk" and although every airplane exceeds that pace today, the origin of that "no faster than a man can walk" goes back to the early days of aviation. The very early planes had no brakes and no steerable wheels! They required wing walkers to stop the planes and to guide them around corners. Yes it was possible for the pilot to raise the tailskid off the ground and rudder his way around a corner, but in close quarters this would add too much speed so that wing walkers were the solution. Why the rule of "no faster than..." Don't leave your steering gear (the wing walkers) behind!

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  • $\begingroup$ This explains why when I measured, got values more like "no faster than a sprinter can run" $\endgroup$ – h22 Jan 6 '18 at 18:31

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