Turbulent Times

On Sunday morning, there wasn't a cloud in the sky. The wind socks and flags at the airport were barely moving, seemingly confirming the morning's good report from the FAA weather briefer and everything I had seen on the computer. My friend and I piled into a trusty Piper Cherokee 180, expecting a ride well-suited to casual sightseeing and taking aerial snapshots. We weren't more than 300 feet into the initial climb when the turbulence started. It was moderate turbulence for a Cherokee 180, with a few severe jolts thrown in for good measure. It took another 2,200 feet to get through the worst of what Mother Nature had cooked up. There was a band of not-too-bumpy air between 2,500 feet and 4,000 feet. Above that, the turbulence started again.

By the time we were ready to return to the airport, the wind situation on the ground had changed. The three wind socks were fully inflated and pointing in different directions. It took a lot of work during the approach and landing to combat the fickle winds and even more work to be nonchalant. The touchdown resulted in only one bounce of a couple of feet, followed by minor maneuvering to nudge the plane to the runway centerline.

With winds on my mind, I perused the NTSB's files for recently completed investigations of accidents that were related to wind conditions while landing. Although the airplanes got banged up, the occupants generally escaped injury.

Piper PA-28-180
On October 2, 2004, a Piper PA-28-180 was landing at Marion, Iowa, after a flight from Moline, Ill. Day-VFR conditions prevailed. On his first approach to runway 17 at the Marion Airport, the pilot encountered what he later described as "choppy" turbulence and decided to go around. During the second approach, the airplane again encountered the turbulence, and the pilot requested and initiated another go-around.

The pilot told investigators, "Immediately, it felt like a gust of wind went under my right wing and belly, and just started pushing me over to the left. I immediately applied right rudder and aileron as hard as I could and tried to push the nose down, but there was no response."

The pilot said he "didn't have a chance to put flaps back up or try to cut power." He also said that the airplane went "up and over" and hit an airport hangar. The pilot theorized that it's possible that the passenger inadvertently stomped on the rudder pedals during the go-around. The pilot and passenger received minor injuries, and the airplane was substantially damaged. Shortly after the accident, the recorded observation showed the wind from 200 degrees at 15 knots gusting to 19 knots. The NTSB determined that the probable cause of the accident was the pilot's inadequate compensation for the gusting wind conditions and his failure to maintain aircraft control. Factors in the accident were the encountered turbulence, the gusting wind and the airport hangar.

Cessna 185F
On October 1, 2004, a Cessna 185F was performing touch-and-go landings on runway 20 at the Santa Fe Municipal Airport in Santa Fe, N.M. The pilot told investigators that during one of the landing rolls, he encountered a wind gust from the left, which "weather-cocked the plane to about 15 degrees left of centerline." He applied power and full right rudder, but was unable to straighten the airplane. He reduced engine power and applied brakes. The airplane groundlooped to the left, followed by the right wing and elevator impacting the runway surface. The right wing spar and aileron were bent, and the right elevator was crushed. The pilot was uninjured. The weather observation taken about two minutes after the accident recorded the wind as being from 150 degrees at seven knots with gusts to 15 knots. The calculated crosswind component would have been from seven to 12 knots. The NTSB determined that the probable cause of the accident was the pilot's failure to maintain aircraft control during the landing roll, resulting in a groundloop. Contributing to the accident was the crosswind.

Cessna 172N
The pilot was a flight instructor, held a commercial certificate for single-engine land airplanes and was instrument-rated. He had logged 740 flight hours. He went on a day-VFR local flight in the Hillsboro, N.D., area, using a Cessna 172N rented from a flying club. During landing on runway 16, the airplane veered off the runway and nosed over. Although the airplane was substantially damaged, the pilot was uninjured. A weather observation recorded at Grand Forks, N.D., about 28 nm north of the accident site, showed winds from 130 degrees at 16 knots gusting to 21 knots. The Safety Board's report quoted the Cessna 172N's Information Manual as placing the maximum demonstrated crosswind velocity for takeoff or landing the airplane at 15 knots. The NTSB didn't have a record of winds at the accident location. The NTSB determined that the probable cause of the accident was directional control not obtained and maintained by the pilot during the landing roll.

Mooney M20K
The single-engine Mooney was arriving at Jackson Hole Airport in Wyoming after a day-VFR flight from Riverton, Wyo. The pilot told an investigator that he had attempted to land on runway 19, but performed a go-around because of wind shear at approximately 15 to 20 feet AGL. During the second landing attempt, he increased his airspeed to compensate for the wind. The pilot reported that as he was executing the flare for touchdown, "the bottom dropped out." He added power for another go-around, but the airplane continued to sink. He reported that the airplane drifted to the left and struck a runway light. The landing gear collapsed, both wings were bent, and the fuselage was wrinkled. Although the airport's automated weather observation system reported that the winds were from 210 degrees at nine knots, the pilot said that they appeared to be from 250 degrees at 10 to 15 knots. The NTSB determined that the probable cause of the accident was the pilot's failure to maintain aircraft control, resulting in a stall and mush. Contributing factors included the wind shear, the crosswind as well as the runway light.

Beechcraft 18
The airplane was landing at the Airlake Airport in Lakeville, Minn., on August 29, 2004. Runway 12 was in use, which was 4,098 feet long by 75 feet wide. The day-VFR flight had departed a private airstrip near Spooner, Wis. The pilot told investigators that the crosswinds on final were quite strong and that he needed to crab into the wind to maintain runway alignment. He reported that after the initial touchdown, the airplane bounced about three to four feet into the air. He said that the "wind got under the right wing" and the airplane went off the left side of the runway. He said that the airplane then groundlooped, and the left wing hit the ground. The airplane then struck a number of light boxes while continuing in a left turn. The right main landing gear separated, and the airplane went into a ditch. One passenger received minor injuries, while the other two and the pilot were uninjured. Winds recorded at the airport at the time of the accident were from 150 degrees at nine knots, gusting to 14 knots. The probable cause was the pilot's inadequate flare, the improper recovery from a bounced landing, the loss of directional control and the inadequate compensation for the crosswind. The crosswind was a factor.

Peter Katz is editor and publisher of NTSB Reporter, an independent monthly update on aircraft accident investigations and other news concerning the National Transportation Safety Board. To subscribe, write to: NTSB Reporter, Subscription Dept., P.O. Box 831, White Plains, NY 10602-0831.