Taxiing an aircraft is harder than it seems
Question: Is there a speed limit for planes while taxiing on the taxiway?
– James Chen, Taiwan
Answer: Some airports have speed limits but more often airplanes will have a limitation in the flight manual for maximum taxi speeds. This is usually around 30 knots.
Q: How are airliners turned by the pilot while on the ground? I never see a steering wheel in the cockpit.
– Robert Allen, Boise, Idaho
A: There is a small nose gear steering wheel on the left side of the captain’s seat, which is used when taxiing.
Q: I’ve been told by pilot friends that taxiing is actually one of the most difficult parts of aviation. What should a pilot do if he/she gets lost or is unclear on taxiing instructions?
– Jim, Youngstown, Ohio
A: Anytime there is an uncertainty about a taxi route or clearance, the pilot will ask the controller to repeat the clearance. This happens occasionally but not often.
Q: How much power – engine-thrust wise – is required while taxiing to take off at maximum takeoff weight?
– No name provided
A: It depends on the slope of the taxiway or the ramp. Once the jet is moving, it doesn’t require much thrust to keep it moving. The captain advances the thrust levers, allowing the engines to spin up until the aircraft begins to move, then reduces them to near-idle.
To answer your question, there is not an exact thrust value.
Q: On a recent trip, when the plane arrived that we were later to board it had smoke coming from underneath the starboard engine. As we prepared to take off and taxied out to the runway, the same smoke appeared. It actually was enough to come up over the wing. It appeared to be smoke and not steam. I pointed it out to the flight attendant and was told not to worry. Fortunately, we arrived in SEA without incident. What might this have been?
– Dean, Layton, Utah
A: It is possible that there was a very slight hydraulic leak where the fluid contacted a hot part of the engine. This would be unusual but not unheard of.
John Cox is a retired airline captain with US Airways and runs his own aviation safety consulting company, Safety Operating Systems.