Minden, NV, USA
N2856Q
Cessna TU-206F
While attempting a full-stop landing, the pilot allowed the aircraft to drop onto the runway surface with enough force that it bounced back into the air. The pilot then continued the landing sequence, and the aircraft hit hard enough on the second touchdown that it once again bounced back into the air. On its third touchdown it hit nose wheel first, damaging the airframe, and bouncing back into the air a third time. On the fourth touchdown, it contacted the terrain off the side of the runway, and eventually came to a stop. After the first and second touchdowns, the pilot did not add power to cushion the next contact as called for in FAA Advisory Circular (AC) 61-21A, nor, as called for in the same AC, did he make the decision to execute a go-around when it became obvious that his attempt to salvage the landing was not meeting success. An improperly serviced nose wheel strut may have contributed to the severity of the damage.
On July 25, 2001, approximately 2000 Pacific daylight time, a Cessna TU-206F, N2856Q, was damaged during a hard landing at Minden-Tahoe Airport, Minden, Nevada. The private pilot and his passenger were not injured, but the aircraft, which is owned and operated by the pilot, sustained substantial damage. The 14 CFR Part 91 personal pleasure flight, which departed Watsonville, California, about 90 minutes earlier, was being operated in visual meteorological conditions. No fight plan had been filed. There was no report of an ELT activation. According to the pilot, who was landing just after sunset, he set the flaps on the Robertson STOL kit-equipped aircraft to 30 degrees, and set the elevator trim so that it was "...adjusted back a bit." He then made a "final power reduction," and leveled off at what he thought was about two feet above the runway surface. As the aircraft slowed he "...held the control wheel where I had pulled it back to initially, waiting for the aircraft to settle." Then according to the pilot, "The plane dropped abruptly to the runway without changing attitude and bounced back into the air and the yoke, which was in my left hand, pulled forward with significant force." The plane contacted the runway a second time, hitting first on the main wheels and followed immediately by the nose gear, and then bounced back into the air a second time. On the third touchdown, which according to the pilot was the hardest, the nose wheel hit first, followed by the main wheels and a third bounce into the air. The fourth and final touchdown occurred just off the right side of the runway. During this sequence, the pilot did not change the power setting nor initiate a go-around. After the accident, the pilot said that the aircraft's elevator had been stiff since he bought it, that it was "missing" its elevator down spring, that the Roberston STOL elevator assist spring was not functioning properly, that the elevator and elevator trim tab travel limits were set incorrectly, and that a mechanic at Big Sky Aviation advised him the nose gear strut was low on hydraulic fluid. He also stated that he felt the forces needed to pull the control yoke back while the aircraft was sitting in a static condition on the ground were excessive. The FAA's post-accident inspection of the aircraft, which had been purchased by the pilot about 40 days prior to the accident, revealed that it was equipped with the appropriate late-model (after aircraft 20602579) bellcrank-attached dual elevator down springs (Part #1260479-2), which run down and aft from the elevator bellcrank. The link assembly-attached single-downspring system present in Cessna 206's prior to number 20602580 (Part #1260449-1), which runs forward in the tailcone, is not applicable to this specific aircraft. The dual downsprings, which increase elevator down forces, are a result of the static stability certification requirements for this model aircraft. The flaps-up/elevator-down static elevator forces created by the combination of downspring resistance, elevator moment, and friction within the system were determined by two maintenance shops to be 30 pounds (Paradise Valley Flying Service) and 33 pounds (Big Sky Aviation) respectively. According to engineers at Cessna Aircraft, these measurements are within both the Civil Aviation Regulations (CAR) Part 3 strength of pilots temporary application limitations (certification basis for this aircraft), and the expected range for the Cessna model TU206F. In addition, as part of a Sierra (formerly Robertson) Supplemental Type Certificate SA1513WE short takeoff and landing (STOL) kit installation, the aircraft was equipped with a graduated-assist elevator upspring assembly. The assembly, which was installed in this aircraft by the STC holder (Robertson Aircraft) in November of 1975, is interconnected with the flap system through a channel box assembly and a spring arm assembly, and helps to compensate for the increased elevator loads created during flap extension. An FAA inspector observed the spring's function at each of the four primary flap setting, and no malfunctions or anomalies that would have impeded its functions were observed. In addition, the static yoke pull force measurements made by Big Sky Aviation, at the request of the owner, and the measurements made by the FAA, confirmed that with the flaps down the assist spring significantly reduced the required yoke pull force in both positive and negative elevator positions. Photographs of the positioning of the spring activation mechanism during each flap setting were sent to Sierra Industries, Inc. (current holder of the subject STC), and they reported that the details of the installation appeared satisfactory, with no unsafe conditions being observed. Although the elevator up travel limit and the elevator trim tab down travel limit (up elevator assist) were beyond those specified by Cessna, the pilot was able to set the trim he desired for the approach and flare, and he did not attempt to reset the trim during the series of bounced touchdowns. Through the FAA's and NTSB's post-accident discussion with the pilot, it was determined that during the sequence of bounced contacts with the runway surface, the pilot did not add power to cushion the subsequent touchdown as called for in FAA's Flight Training Handbook (AC 61-21A), nor did he execute a go-around as called for under these conditions in the same publication.
The pilot's inadequate recovery from a bounced landing, and his improper remedial action after it became clear that he was not successfully salvaging the landing attempt. Factors include an improperly serviced nose gear strut.
Source: NTSB Aviation Accident Database
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