When a Beech Sierra flown by a 4,000-hour commercial pilot, accompanied by his wife and daughter, arrived at the Fulton County Airport at Wauseon, Ohio, the wind was from the west-southwest at 26 to 35 knots, with gusts as high as 43 knots. The VFR flight from Troy, Michigan, a distance of only 76 nm, had taken nearly an hour because of the powerful headwind aloft.
The pilot had briefed himself online. He may or may not have seen the special message from the National Weather Service warning of extremely strong winds and possible "minor property damage" -- a warning intended, to be sure, principally for the owners of awnings and tall vehicles, not airplanes. But he was not unaware of the wind, which was blowing hard at Troy as well. While his airplane was being fueled he had inquired whether other airplanes were flying, and learned that only one had taken off: an MU-2, whose wing loading and speed put it in an entirely different class than the Sierra.
The single east-west runway at Wauseon is 75 feet wide, 3,882 feet long, and was flanked by 80-foot trees 200 feet from the runway on the north side and 550 feet from it on the south. The west-southwest wind was 20 to 30 degrees off the runway heading, and so the crosswind component would be between 35 and 50 percent of the wind speed or, if the wind were blowing at 40 knots when he landed, about 14 to 20 knots. The trees, which were on private property and which the airport commission had been trying for years to have cut, affected the flow of air over the runway when the wind blew strongly across them. The airport manager described them as producing a "terrible, terrible funnel effect ... with lots of rolling wind."
The Sierra never made it to the runway. There were no witnesses to the accident, in which all three occupants of the airplane died, but the wreckage was found 350 feet north of the approach end of Runway 27. The right wing had struck first, 250 feet north of the threshold, and the airplane had slid 100 feet northward before coming to rest pointed west-southwest. The airplane was upright; the cabin area was crushed; the nose gear had separated; the gear switch was in the up position, with the right main retracted and the left main extended, as if the gear had been in the process of retracting when the accident occurred. The flaps were fully extended. There was no post-crash fire, but ample fuel was present in both tanks and nothing was found to suggest that mechanical trouble had played a part in the accident. In fact, although a pilot on the ground had observed the Sierra passing overhead at 1,000 feet and wondered why anybody would be flying on such a day, radar showed the Sierra making a somewhat low but otherwise unremarkable approach to the runway. Its average descent rate was 400 fpm, its groundspeed 68 knots -- approximately a three-degree glideslope, like that of an ILS. The last radar return put it 120 feet above the surface and about 1,000 feet from the runway threshold -- a normal position for final approach.
The NTSB's finding of probable cause confined itself to the evident facts:
The pilot's failure to maintain control during the approach to landing. Factors were the high wind gusts and turbulence, and the pilot's decision to fly in those conditions.
Even though the centennial of powered flight is already well behind us, no single crosswind landing technique is used by all pilots and approved by all instructors. But a couple of general principles are agreed upon. One is to keep speed up and "fly the plane on," because the effects of the crosswind get larger as the airplane gets slower. Controllability is also better at higher speed. Another common practice is to use only partial flaps, or no flaps at all. There are several reasons for this. If a go-around is required, full flap would impede it. Full flap conflicts with the higher-than-normal speeds used during the approach and right through to the touchdown. Full flap lowers the nose of the airplane and, if height control is difficult during the flare, makes a nosewheel strike more likely.
A steady, smooth crosswind presents some challenges for pilots, but the task is made more difficult when the wind is gusty or turbulent, as it often is when buildings or other obstacles beside the runway, like the tall trees at Wauseon, disturb the flow near the surface. You can't see air, but if the runway environment were a river rather than the atmosphere you would see white water.
It is instructive, in fact, to study the behavior of the small plastic kayaks called playboats -- lots of tape and photographs can be found online, since playboating is one of the "look at me" sports -- the point of which is to remain in place, while performing goofy gyrations, rolls, flips and so on, on a fast-moving river. The sport takes advantage of the fact that, even in rapidly moving water, eddies and reverse currents form near obstructions. The first requirement of playboating is to be able to hold position in one of these; a small excursion from the pocket of stillness and the boat is swept rapidly downstream.
The reason playboating in particular, and rivers in general, should be of interest to pilots is that they aid in visualizing the behavior of air. When you have observed how a still pool and a swift current can exist side by side, just a couple of feet apart, you get a better understanding of how turbulent winds can produce sudden changes of airspeed, how currents can suddenly change direction, how a calm can exist in the middle of a rapid flow and vice versa, and how thoroughly unpredictable agitated air can be.
