Aviation Accident Summaries

Aviation Accident Summary ATL97LA059

HUNTSVILLE, AL, USA

Aircraft #1

N3761Y

Cessna 210D

Analysis

After departing from Redstone Army Airfield, the pilot attempted to level off at 3000 feet. When he did, he experienced difficulties pushing the nose over, which was lessened when nose down trim was applied and power was reduced. As the airplane accelerated, a severe vibration was noted, which was lessened when power was reduced. After trying to pinpoint the problem, the pilot noticed visible damage to the right elevator. A precautionary landing was then executed at the departure airfield. An examination of the elevator revealed a chordwise split and corrosion in the trim tab. There was also a chordwise split in the elevator, that resulted from the oscillation of the trim tab, in flight. Cessna Service Bulletin, SEB92-1, had been issued in January 1992. It recommended that a modification be made to strengthen the trim tab to prevent cracks from forming. The service bulletin recommended that this be accomplished within the next 100 hours of operation or 12 months, whichever occurred first; however, the service bulletin had not been complied with.

Factual Information

On April 14, 1997, about 1615 central daylight time, a Cessna 210D, N3761Y, experienced a severe vibration during takeoff climb from the Redstone Army Airfield, Huntsville, Alabama. The airplane was operated by the pilot under the provisions of Title 14 CFR Part 91, and instrument flight rules. An instrument flight plan was filed for the personal flight, while visual meteorological conditions prevailed. There were no injuries to the commercial pilot nor to the pilot rated passenger. The airplane was substantially damaged. The flight to Decatur, Alabama, was originating at the time. According to the pilot in command (PIC), this flight was to familiarize him with the aircraft, while allowing the aircraft owner, a certified flight instructor (CFI), to stay instrument current. The pilot in command, a commercial pilot training for a CFI certificate, was flying in the right seat. The owner would later take over the controls in order to practice instrument approaches, with the PIC as a safety pilot. The PIC stated he completed a normal preflight and takeoff from Redstone Army Airfield. When he began to level off at the assigned altitude of 3000 feet, the PIC thought there was a "large amount of forward forces with both hands to level the airplane". The owner offered to input nose down trim and reduce power, which the PIC allowed. As the aircraft leveled off and airspeed increased, "the aircraft experienced a very violent, high frequency vibration". The owner then stated he called and reported a possible engine failure to approach control. When power was reduced, both pilots reported the vibration lessened significantly. The PIC stated he then scanned the engine instruments and noted no unusual readings, so he reapplied power to the engine, only to experience the same vibration. At this point, the owner reported he called approach control and asked for an immediate return to the departure airfield. The PIC then stated he turned around to examine the airplane and noticed the structural damage to the right elevator. The owner then stated he "realized they had a tail flutter problem and not an engine problem". Fire equipment was brought out on the departure runway, and the owner assumed the controls for the landing because he had "considerable experience in the aircraft". The owner stated he decided to land the aircraft with no flaps down, "so as not to introduce any further turbulence to the tail". An uneventful landing was made on the departure runway. An examination of the airplane by an airworthiness inspector from the Alabama Flight Standards District Office, and a Cessna Aircraft Co. representative revealed the right elevator was torn chordwise at the midpoint, and the trim tab actuator assembly was torn loose from the trim tab. The inspection noted the elevator trim tab was the foam filled type. The trim tab had split chordwise at about the mid-span and was held together with the piano wire hinge pin. There was also evidence of corrosion inside the tab skin. The examination showed that the horn, linkage, and actuator were broken loose but still contained in the structure. The elevator was also split in two chordwise about mid-span. Cessna Aircraft Co. issued a Service Bulletin in January 1992, number SEB92-1, which recommended the modification of the elevator trim tab on eight models of airplane, including the Cessna 210. After discovering the possibility that cracks could develop in the elevator trim tab, Cessna recommended a "doubler installation modification" be used to strengthen the elevator trim tab. They recommended this modification be done "within the next 100 hours of operation or 12 months, whichever occurs first". A review of the aircraft log books revealed the horizontal stabilizer was replaced on August 11, 1989 after a ramp accident. No other service was completed on the horizontal stabilizer. The last annual inspection was completed on February 12, 1997.

Probable Cause and Findings

corrosion and subsequent failure of the elevator trim tab, which resulted in vibration and failure of the elevator. Failure of maintenance personnel to comply with a service bulletin was a related factor.

 

Source: NTSB Aviation Accident Database

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