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Landing And Windspeed/direction

Sat Jul 03, 2004 2:52 pm

Some days back our aircraft would not land and kept circling because of low-visibility (<1500m) and finally after circling for over 45 minutes, the pilot elected to return to DEL rather than land at the destination.

One of the runways RWY28 at the destination is configured for landings in low visibility upto 900m, but the crew said that becuase of wind direction RWY10 was our assigned rwy and so we couldnt use RWY28.

I understand landing "into the wind". But how critical is that? Is it that much of a problem landing with the wind? The aircraft was an Airbus A320.

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RE: Landing And Windspeed/direction

Sat Jul 03, 2004 3:22 pm

Most airlines and airliners have a 10 knot maximum tailwind component for takeoffs and landings.
*NO CARRIER* -- A Naval Aviator's worst nightmare!
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RE: Landing And Windspeed/direction

Sat Jul 03, 2004 3:32 pm

Touchdown speed is the largest factor in determining landing distances. Stopping an aircraft (or anything for that matter) requires reducing the object's kinetic energy (KE) to zero. KE = 1/2 * mass * velocity^2. The formula shows that an increase in velocity will result in a large increase in KE (due to the squared factor).

A headwind allows an aircraft to fly slower in relation to the ground and landing distances will reduce significantly.
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RE: Landing And Windspeed/direction

Sat Jul 03, 2004 6:03 pm

As Liamksa said already, landing speed is the main issue involved. Whereas a headwind is desirable because it effectively reduces the aircraft's ground speed while landing, a tailwind does just the opposite. That is, it increases the aircraft's ground speed. From practice we all know that the faster you're driving/biking/skiing/etc, the longer the required stopping distance - the same obviously goes for an airplane, so that a faster landing speed means a longer rollout (the simple equation above, for kintetic energy, proves that fact mathematically). Landing with a tailwind isn't necessarily horrible given enough runway, but it's certainly not a great thing either; many overruns are caused by tailwinds...

10-15 kts is the normal maximum tailwind component allowed for most commercial aircraft, as AAR90 pointed out.


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