Airbus A320 Questions: What length runway is it certified for? Does InOp Thrust Reverser require (cont'd)

Question

longer runway for landing? (I mean is it spelled out in the Pilot's Operating Handbook) What about Airbus's limitations for landing on wet runways? Anyone know the answers to these?

efarrell01: Sure, 4800 feet wouldn't do you much good if you touched down at 2400 would it?
If 4800 dry is required and if you had to add say 10% for wet and some other number for T/R inop, and then compound the problem with poor drainage and big downpour, I can easily see 6300 feet disappearing REAL soon.

Answer 1

You're exactly right about touching down way down the runway. We always say that the three most useless things to a pilot are the runway behind you, the altitude above you and the fuel you left in the truck. As far as the reverser being inop goes, when the airplane was certified, all of the landing performance data was based on no reverse thrust. They cannot be guaranteed to work every time and there's no way to check them in flight so every landing is planned assuming one or both won'd deploy. You wouldn't have one with an engine shut down anyway.

Answer 2

Reversers are generally said to be either "deployed" or "stowed" - Be aware that in case of emergency, reversers can be operated FULL thrust until the airplane is stopped - In practice (Boeing airplanes) reversers are used down to 60 KIAS, with full trust as precaution to prevent accidental ingestion of debris into the inlet of the engine. When the indicated airspeed in reduced below 60 KIAS, reverse thrust is reduced progressively to idle thrust at about taxi speed (20 knots) then reversers are finally stowed - One thing, is to always reduce the thrust slowly and not "slam" reversers stowed from full reverse, because you could get a burst of "forward thrust" suddenly pushing the airplane forward again - In the 747 and other airplanes with 4 engines, there is a slight variation of the technique used for thrust reduction and stowing of thrust reversers - The inboard engines (nº 2 and 3) are forward of the ouboard engines (nº 1 and 4) - With these airplanes, pilots will use full reverse thrust down to 60 KIAS, then reduce the INBOARD reversers first, because they could blast debris into the inlet of the OUTBOARD engines which are located further AFT - So by 20 knots or so, you might see the outboards still at idle reverse, while the inboards have been stowed a few seconds earlier - Note also that with the 747, using reversers does retract and stows some of the leading edge flaps near the engines, to prevent debris to be blown under the leading edge flaps - .

Answer 3

http://www.san.org/documents/planning/assp/tier_one/Appendix%20B_Aircraft%20Runway%20Length%20Requirements.pdf

A320 requires only 4800 feet of dry runway to land . If wet a certain percentage is added.
In order to stop on some runways, you must land before the touchdown zone markers, at just exactly the right speed, or you will run out of runway before you run out of speed.