Question: How is it safe to have an aircraft pull onto the runway and then take off as another aircraft is seconds from touchdown on the same active runway? I see this frequently in Fort Lauderdale, yet in Philadelphia, the landing aircraft has to touch down before the departing can power up and they use different runways.

— submitted by reader Chris, Parkland, Fla.

Answer: There are separation requirements that exist for takeoff, in flight, and during landing. An airplane may line up on a runway just after a landing, but must wait until the landing airplane is clear of the runway before beginning takeoff.

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An incoming airplane must not land on a runway that has another airplane on it. This can cause a go-around when an airplane is slow to clear the runway after landing.

In some airports where the runways are close together, the separation must be maintained on both runways. Therefore a landing airplane must touch down before another airplane can take off on the parallel runway. Philadelphia is an example of this configuration.

Q: Is there a set speed limit planes must observe on airport taxiways? I believe I have seen several planes from one airline travelling faster than the same type of aircraft from other airlines on taxiways. I know airlines have aggressive schedules to meet, but is it safe to travel faster on taxiways in order to make up a couple of minutes?

— Kevin, Austin

A: Many airlines have a maximum taxi speed listed in their operating limitations and some airports limit the taxi speed of larger aircraft. Otherwise there is no posted limit. However, when incidents do occur, the FAA has taken enforcement action against a pilot for "careless and reckless" operation because of their taxi speed.

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I would agree that taxiing at excessive speed can create an unsafe situation.

Q: Regarding your column about the captain having to taxi at airports, Southwest's company policy also requires the captain to do the take off out of John Wayne Orange County Airport (SNA) due to the noise abatement climb.

— Lori, Anaheim Calif.

A: The noise abatement climb is a maximum performance climb followed by a significant power reduction. I did not know that Southwest limited the maneuver to captains only, but there are other airlines that have this restriction in place.

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