Aviation Accident Summaries

Aviation Accident Summary IAD00FA023

PLYMOUTH, MA, USA

Aircraft #1

N64RG

Aerotechnik L-13 SEH VIVAT

Analysis

Prior to departure, the flight instructor told the pilot who was receiving his biennial flight review that it was windy and 'they should fly conservatively.' The flight instructor and pilot departed, and soared the motor glider 'in strong lift conditions' in the vicinity of the airport in the power-off configuration. Upon returning to the airport, the flight instructor decided to land in the power off configuration. The pilot delayed the turn to base. Upon turning base, the pilot was uncomfortable with the approach and released control of the motor glider to the flight instructor. The flight instructor then turned the motor glider directly toward the airport and 'very heavy sinking air' was encountered. The flight instructor prepared to land short of the asphalt runway on the grass, but was unable to maintain enough lift to clear the trees bordering the airport. The motor glider descended through the trees, sheared off a large section of the right wing, and came to rest on the right side partially inverted. The speed brake handle was found in the fully extended position. The right speed brake was extended, and the left speed brake was found retracted. The landing runway was 24, and the winds were from 220 degrees at 16 gusting to 23 knots. Examination of the motor glider revealed no mechanical deficiencies.

Factual Information

HISTORY OF FLIGHT On February 23, 2000, at 1442 Eastern Standard Time, an Aerotechnik L-13 SEH Vivat motor glider, was destroyed when it collided with trees during an approach to Runway 24 at the Plymouth Municipal Airport (PYM), Plymouth, Massachusetts. The certificated flight instructor was fatally injured and the certificated private pilot sustained minor injuries. The flight originated at PYM, approximately 1400, for the local instructional flight conducted under 14 CFR part 91. Visual meteorological conditions prevailed. The purpose of flight was for the private pilot to receive a biennial flight review. In a written statement, the pilot said: "I had gone to Plymouth to fly with [the flight instructor] in order to complete my Biennial Flight Review in the same make and model of motor glider that I own, a Aerotechnik Vivat. After a normal take-off and flight about 45 minutes in the vicinity of the Plymouth Airport that included both power-on and power-off periods of time, we were soaring in strong lift conditions near the airport. We decided to land in the power-off mode. I was flying the glider on downwind. [The flight Instructor] had instructed me to fly the approach at 75 miles per hour in order to have plenty of energy for the approach. As we got near the point to turn base, the propeller, which was feathered, began to turn, not wind-milling, but turning very slowly. This distracted me and delayed the turn to base by a few seconds. As we turned from downwind to base, I said to [the flight instructor] that I was not comfortable with how this approach was going and he took over the controls of the glider." "From where we were, [the Flight Instructor] turned directly to the runway, and in very heavy sinking air, we tried to get to the runway. At one point, [the Flight Instructor] said we would have to land on the grass. We hit some trees just short of the airport boundary and crashed heavily." A Federal Aviation Administration (FAA) inspector interviewed the pilot in the hospital. According to the FAA inspector's record of conversation, the pilot said: "Before the flight, [the Flight Instructor] said it was windy and that they should fly conservatively. [The flight instructor] sat in the right seat and he was in the left seat. After departure, they had been 'thermaling' over runway 24 and 33 between 2,000 and 3,000 feet for sometime. He was flying the glider until they were on downwind for landing. He was not comfortable with the approach, because he is used to landing with power. He turned the airplane over to [the flight instructor] who normally lands without power. He thought the base turn was going to be tight and [the flight instructor] was 'carving' the turn toward the runway. The whole event happened in a matter of seconds and he noted the airspeed to be around 70 knots. He thought [the flight instructor] was going to try and balloon over the trees. The glider hit a 'sink' and was being pushed downward into the trees. [The flight instructor] stated he was not going to make the runway and would head for the grass instead. The glider started coming down through the trees, when it caught the right wing on a tree and came to rest on the right side." A witness was in his office located on the airport around 1445, when he learned that the glider had crashed and responded to the crash site. According to his written statement, he said: "I drove to the area and climbed the fence to get to the glider. The glider was on a heading of about 300 degrees and was inverted with a small part of the cockpit/canopy visible (the left side). I could see a person moving in the airplane, and I lifted the now inverted left wing over my head to open the hole between the fuselage and the ground so he could crawl out. I then assisted him to his feet and walked him to a log where he sat waiting for EMTs. I tried to feel for a pulse on the other occupant, but was unable to find one. The passenger told me his name and was coherent and talking well." The accident occurred during the hours of daylight at approximately 41 degrees, 54 minutes north latitude, and 70 degrees, 43 minutes west longitude. PERSONNEL INFORMATION The flight instructor held a commercial pilot certificate and a flight instructor certificate for gliders, and a private pilot certificate for single-engine land airplanes. His logbook(s) were not made available for review. However, a representative of the insurance company stated that the flight instructor reported a total of 1,436 flight hours in gliders and 200 in make and model on November 30, 1999. His most recent Federal Aviation Administration (FAA) third class medical certificate was issued on August 30, 1991. The pilot held a private pilot certificate for gliders and single-engine land airplanes. He was owner of another L-13 SEH Vivat motor glider, and reported a total of 1,450 hours; 200 hours in make and model. His most recent FAA third class medical certificate was issued on September 13, 1985. AIRCRAFT INFORMATION The glider was a 1993 Aerotechnik L-13 SEH Vivat motor glider, registered to a private owner. The motor glider was registered in the standard airworthiness category. The glider was on an annual inspection program with the most recent inspection completed on August 30, 1999. The glider had accrued 74 hours since that inspection and had a total of 789 hours at the time of the accident. METEOROLOGICAL INFORMATION Weather at Plymouth Municipal Airport, at 1452, was wind from 220 degrees at 16 knots gusting to 23 knots, few clouds at 8,500 feet, and visibility 10 statute miles. AIRPORT INFORMATION Plymouth Municipal Airport is an uncontrolled field with two intersecting asphalt runways with paralleling grass runways. The runways are aligned 15/33 and 06/24. The grass runways are primarily used by tow airplanes and gliders. WRECKAGE AND IMPACT INFORMATION The airplane wreckage was examined at the scene on February 24, 2000. The airplane was 1/4 mile east of Runway 24 on a heading of about 270 degrees. The length of the wreckage path was approximately 105 feet. The wreckage path was measured from the first point of contact with pine trees and the final resting place of the fuselage. At the beginning of the wreckage path, an 8-foot top section of a pine tree was found laying at the base of the tree. Approximately 24-feet beyond the initial impact point was another 8-foot long pine tree tip. Seventy-five feet beyond the initial impact point, fresh impact marks were noted on the trunk of a pine tree. At the base of the pine tree was a 19-foot section of the glider's right wing. Ground scars extended for approximately 31 feet from where the wreckage was located. The sheared section of right hand wing had two 3-inch diameter impact marks along the leading edge. The diameter of the two sheared top sections of pine trees were measured to be 3 inches. The remaining inboard section of the right hand wing was pushed against the right hand side of the fuselage. The tail section was intact, twisted to the right, but remained attached to the fuselage by control cables. The lower section of the vertical stabilizer exhibited impact damage and the empennage was bent to the right. The left wing was intact and pulled from the wing root at the rear attachment point. An indentation was noted on the outboard section of the leading edge. The engine remained securely attached to the airplane. The composite/wood propeller remained attached to the engine and was feathered. The tip of one blade was broken off, which resulted in broom straw fractures. The other blade exhibited no impact damage. The right hand side of the spinner was flattened. Engine continuity from the front of the engine to the accessory case was established by manual rotation of the propeller. The landing gear was extended. The spoiler for the left wing was found in the retracted position. The right wing spoiler, which was part of the detached section of the right wing, was found extended. The left flap was found retracted and the right flap remained partially attached by one track to the wing and a position could not be determined. Control cable continuity was established for all flight control surfaces. The left seat was intact and the four point seat belt assembly was found unbuckled. The control stick was intact. The right seat was intact and the four point seat belt assembly had been cut by rescue personnel. The control stick was broken in the forward direction. The right hand side of the forward fuselage was pushed inward into the cockpit area. The canopy was separated from the fuselage. The flap handle was found in the zero degree detent. The spoiler handle was found in the full extended position, and there was no impact damage to the detent gate. The elevator trim handle was found in the full nose down direction. The landing gear handle was found in the gear down position. The pilot stated that during the downwind segment of the flight, he moved the spoiler handle out of the gate and partially deployed the spoilers. He did not recall them being moved after that. He stated it is normal to take the handle out of the gate in preparation for landing, so the pilot can adjust the spoilers as required to establish the proper glide path. An estimated 2 gallons of fuel was visibly observed in the center fuel tank. No mechanical deficiencies were noted with the airframe or engine. MEDICAL/PATHOLOGICAL INFORMATION An autopsy of the flight instructor was performed by the Office of the Chief Medical Examiner's office, Boston, Massachusetts, on February 24, 2000. A toxicology examination of the flight instructor was performed at the FAA's Toxicology Accident Research Laboratory in Oklahoma City, Oklahoma, on March 30, 2000. ADDITIONAL INFORMATION The airplane wreckage was released on February 24, 2000, to Jim Cobb of Ryan Insurance, Co. who represented the owner's insurance company.

Probable Cause and Findings

the flight instructor's inadequate compensation for the wind conditions. A factor was the flight instructor's improper use of speed brakes and the strong gusty winds with downdrafts.

 

Source: NTSB Aviation Accident Database

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