CHI01LA175

The tailwheel airplane was substantially damaged while landing following a ground loop in the direction of the prevailing crosswind. Federal Aviation Administration advisory circular information describes the increased ground loop tendencies of a tailwheel airplane to pilots.

On June 16, 2001, at 1815 central daylight time, a Piper Tri-Pacer, PA-22-150, N3526Z, piloted by a private pilot, sustained substantial damage during landing on runway 36 (4,000 feet by 75 feet, asphalt) at the Morris Municipal Airport, Morris, Illinois. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 personal flight was not operating on a flight plan. The pilot and one passenger did not sustain any injuries. The flight departed Wausau, Wisconsin, at 1545, en route to Morris, Illinois.

The pilot reported in a written statement, "Departed Wausau, WI 3:45 pm for Morris, IL topped fuel at Wausau. Arrived Morris [approximately] 6:15 pm landing on [runway] 36 at Morris, IL after cross country [visual flight rules] trip from Wausau, WI. Weather conditions excellent. Visibility excellent. Wind 280 reported 10 kts. Flew standard pattern and normal final approach left wing down and right rudder to track runway centerline. Touched down left wheel [and] tail at about 55 mph tracking straight. Right wheel touched and slow drift to left began as rolling out. Compensated with more right rudder and brake. Full right rudder and maximum right brake would not arrest the drift. I pushed full throttle to attempt go around. As soon as I throttle the plane whipped left and skidded sideways with right gear folding under fuselage and shearing off. [Propeller] hit dirt and right wing tip dropped to ground as we slid to a stop in the grass at the edge of the runway. This was not a challenging crosswind situation. I've landed many time with this kind of cross wind without problems. Perhaps it's a natural thing to want to blame a mechanical failure for what may well have been pilot error, but the more I think about what happened the more I come to believe there was something more involved. There was no fish tailing after setting down leading to loss of control. It was just drifting to the left that couldn't be corrected by full right rudder and braking. 'P'-factor when I pushed throttle would add left turning tendency when I had no more right rudder available to counteract it. The reported crosswind didn't exceed the crosswind capability of the airplane. The wind sock confirmed direction and [approximate] speed of wind. After exiting the plane, wind wasn't gusting noticeably."

According to the Advisory Circular 61-21A, Flight Training Handbook, "After-Landing Roll", The landing process must never be considered complete until the airplane decelerates to the normal taxi speed during the landing roll or has been brought to a complete stop when clear of the landing area. Many accidents have occurred as a result of pilots abandoning their vigilance and positive control after getting the airplane on the ground. The pilot must be alert for directional control difficulties immediately upon and after touchdown due to the ground friction on the wheels. The friction creates a pivot point on which a moment arm can act. This is especially true in tailwheel-type airplanes because unlike nosewheel-type airplanes, the center of gravity (CG) is behind the main wheels (Fig. 9-10). Any difference between the direction the tailwheel-type airplane is traveling and the direction it is headed will produce a moment about the pivot point of the wheels and the airplane will tend to swerve. Nosewheel-type airplanes make the task of directional control much easier because the center of gravity, being ahead of the main landing wheels, presents a moment arm which tends to straighten the airplane's path during the touchdown and after landing roll, However, this should not lull the pilot into a false sense of security. Loss of directional control may lead to an aggravated, uncontrolled, tight turn on the ground, or a 'ground loop.' The combination of centrifugal force acting on the CG and ground friction on the main wheels resisting it during the ground loop may cause the airplane to tip or lean enough for the outside wingtip to contact the ground, and maneuvering impose a sideward force which could collapse the landing gear. Tailwheel-type airplanes are most susceptible to ground loops late in the after-landing roll because rudder effectiveness decreases with the decreasing flow of air along the rudder surface as the airplane slows."