The approach to Ushuaia International Airport in Argentina, near the southern tip of South America, is known for being windy. Last week, an Airbus A340-300 made a beautiful cross-wind landing there, kicking the crab out with a little cross control to keep the wings level and the aircraft from drifting off centerline.
Notice how low the wings are situated on the A340’s fuselage, and how much lower the bottom of the engine nacelles are. This requires the pilot to keep the wings as level as possible so nothing strikes the ground right before landing. On smaller or high wing planes, a wing down into the wind approach can be used instead of a crab, this is called a side-slip. Side-slip approaches can end with only one side of the aircraft’s gear touching down first, and its wing still drooped into the wind. As the aircraft slows, the wing can be raised and the landing gear on the other side of the aircraft can touch down safely.
With the jet’s nose into the wind to counteract its drift, once again a maneuver known as a crab, the pilots applies the rudder right before touchdown. This must be done carefully, however, because the plane will yaw and could lose its ground track, causing the wing to dip. Applying the cross elevator with the rudder keeps the plane flat, it so it touches down as close as possible on the centerline. If the aircraft just landed while still cocked sideways into the wind, it would put extreme lateral stress loads on the landing gear. Thus the idea is to “kick-out the crab” right before and during touchdown to bring the aircraft’s landing gear on the same heading as the runway. In the B-52, the gear actually swivel on the runway heading so that the giant bomber can land crabbed, as can be seen in the post below.
The next video shows the cockpit’s perspective from a McDonnell Douglas MD-80 making the same approach to Ushuaia in 2007, albeit under much colder conditions.
This destination deserves special attention. In case you needed a refresher in South American geography, there isn’t a whole lot of hard ground below Ushuaia, in Argentina’s Tierra del Fuego Province, until you get to Antarctica.
Even if the last few seconds of the trip to Ushuaia are spent flying sideways, the breathtaking scenery at the end of the world is totally worth it.
Photo credit: Topshot gif via embedded Youtube, crosswind diagram via Wikicommons, map via Google Earth
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