Matawan, NJ, USA
N69GC
Yakovlev YAK 52
The pilot reported that there were no discrepancies during the taxi, run-up, and takeoff roll. The airplane initially climbed approximately 20 degrees nose-up, and began to bank left. About 200 feet above the ground, the pilot and passenger heard a "bang," and the airplane continued to roll left. The airplane then spun to the right, and impacted a wooded area in a nose-down attitude. Examination of the wreckage revealed that a portion of the wooden propeller was almost entirely embedded in an approximate 3-inch diameter tree branch. The number nine front spark plug was found ejected from the engine. A burned torch mark was present on the underside of the cowling, in the vicinity of the number nine cylinder. Additionally, three other spark plugs were found loose in their cylinders. Review of maintenance records revealed that an annual inspection was performed on the airplane about 1 month prior to the accident. During the inspection, the spark plugs were cleaned, gapped, and rotated. Since the inspection, the airplane had flown approximately 30 minutes. The emergency procedures checklist, for the same make and model as accident airplane, included setting a descent attitude following an engine failure. Review of FAA publications regarding accelerated maneuver stalls, revealed that an airplane will stall at a higher indicated airspeed when excessive maneuvering loads are imposed by steep turns, pullups, or other abrupt changes in flightpath.
HISTORY OF FLIGHT On July 13, 2002, about 1710 eastern daylight time, a Yakovlev YAK 52 experimental airplane, N69GC, was substantially damaged during takeoff from Marlboro Airport (2N8), Matawan, New Jersey. The certificated commercial pilot and passenger sustained serious injuries. Visual meteorological conditions prevailed and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91. According to the pilot's written statement, he arrived at the airport about 1630. He performed a preflight inspection of the airplane, started the engine, and taxied to runway 27. The pilot then performed a run-up, and the airplane seemed "normal." He then initiated a takeoff, and noted that the airplane accelerated normally during the takeoff roll. Due to injuries sustained in the impact, the pilot could not recall any events after liftoff. After the accident, a Federal Aviation Administration (FAA) inspector visited the pilot in the hospital. The pilot was able to report that he heard a "bang" during takeoff. The inspector also spoke to the passenger in the hospital. The passenger reported that during the initial climb, about 200 feet agl, the airplane began to bank left per the noise abatement procedures. The passenger then heard a "bang," and the airplane continued to bank left. The airplane then spun to the right and impacted a wooded area. According to the passenger's written statement, the preflight inspection and run-up seemed normal. He noted that the engine was developing full power during the takeoff roll. During the initial climb, the passenger heard a "thump/bang, pop." One witness stated that he saw the accident takeoff through a window of the flight school based at the airport. The accident airplane tookoff, climbed at an approximate 20-degree angle, and began to bank left about 10 degrees. At that point, the witness stopped looking through the window, and did not see the accident. Another witness stated that she was flying over the airport. She saw the accident airplane takeoff, and it appeared to do a "hammerhead." Specifically, the airplane climbed at a steep angle, continued to roll left, and then "went straight down." The accident occurred during the hours of daylight; located approximately 40 degrees, 21.97 minutes north latitude, and 74 degrees, 15.26 minutes west longitude. PERSONNEL INFORMATION The pilot held a commercial pilot certificate; with ratings for airplane single engine land, airplane multiengine land, and instrument airplane. The pilot's most recent FAA second class medical certificate was issued on July 29, 2001. The pilot reported that at the time of the accident, he had a total flight experience of approximately 4,550 hours; of which, about 118 hours were in the same make and model as the accident airplane. Within the preceding 90 days, he had accumulated about 104 total hours; of which, about 1.5 hours were in the accident airplane. AIRCRAFT INFORMATION The airplane was equipped with a Vedeneyev M-14P, 9-cylinder, 360-horsepower, radial engine. Unlike most reciprocating airplane engines manufactured in the United States, the M-14P rotated counter clockwise when viewed from the cockpit. The pilot reported that the airplane engine was originally manufactured in 1985, and had accumulated about 700 hours of operation. He based the airplane at 2N8, but had some maintenance performed at Linden Airport, Linden, New Jersey. The airplane's most recent annual inspection was performed on June 10, 2002. During the inspection, the spark plugs were cleaned, gapped, and rotated. After the inspection, the airplane was flown approximately 30 minutes back to 2N8, where it sat until the accident flight. The mechanic, who endorsed the annual inspection, stated that he had previously owned the accident airplane. Additionally, he had provided the accident pilot flight instruction in the airplane. METEOROLOGICAL INFORMATION The reported winds at an airport approximately 15 miles north of the accident site, at 1651, were from 150 degrees at 11 knots. The reported winds at an airport approximately 10 miles southeast of the accident site, at 1655, were from 190 degrees at 8 knots, gusting to 14 knots. WRECKAGE AND IMPACT INFORMATION The wreckage was located in a wooded area, near the departure end of runway 27. Examination of the accident site by a Federal Aviation Administration (FAA) inspector revealed that a strong odor of fuel was present, and nearby vegetation was discolored. Additionally, the inspector noted that a portion of the wooden propeller was almost entirely embedded in an approximate 3-inch diameter tree branch. Further examination of the wreckage by an FAA inspector revealed that the fuel tanks had ruptured. Fuel was present in the carburetor and the fuel line to the carburetor. The carburetor fuel screen was absent of debris. The inspector established flight control continuity from all control surfaces to the cockpit area. The inspector added that he was able to rotate the propeller by hand, and attain thumb compression on all cylinders. He verified crankshaft and valve train continuity, and did not find any internal discrepancies with the engine. The inspector further stated that the number nine cylinder front spark plug was found ejected from the cylinder. The bottom threaded portion of the spark plug had separated, and reminded inside the threaded area of the cylinder. The other spark plugs had remained in their respective cylinders; however, three of the spark plugs were found to be "loose." The inspector also noted a burn "torching" spot on the underside of the engine cowling, in the vicinity of the number nine cylinder. The wreckage was subsequently examined by an FAA inspector and Safety Board investigator. The examination revealed that when the engine cowling was re-aligned over the engine, the burned area of the cowling aligned with the vicinity of the number nine front spark plug. It was also noted that the right side of the airplane had sustained more impact damage than the left, consistent with the passenger's statement of a right spin. TESTS AND RESEARCH The number nine front spark plug, and threaded piece from the inside of the cylinder, were forwarded to the Safety Board's Materials Laboratory for further examination. According to a Safety Board Metallurgist, the fracture of the two spark plug pieces was consistent with overstress, and no evidence of fatigue cracking or preexisting defects were noted. ADDITIONAL INFORMATION Review of publication FAA-H-8083-3, Airplane Flying Handbook, revealed: "Emergency Operation Partial Power Loss When experiencing a partial power loss in flight, consider maintaining an airspeed that will provide the best airplane performance available. This airspeed will be approximately best glide speed." Review of a YAK 52 flight handbook revealed that the initial climb speed was 160 kmph (86 knots), and the recommended climbing speed was 170 kmph (92 knots). Review of a YAK-52 checklist revealed: "Emergency Procedures Engine failure after takeoff 1. set descent attitude (170 kph)" Review of publication FAA AC 61-21A Flight Training Handbook (1980 Revision) revealed: "Torque effect is the force which causes the airplane to have a tendency to swerve (yaw) to the left, and is created by the engine and propeller." However, the left turning tendency was based on an engine that rotated clockwise when viewed from the cockpit, whereas the accident engine rotated counter clockwise. Further review of the Flight Training Handbook revealed: "The airplane will, however, stall at a higher indicated airspeed when excessive maneuvering loads are imposed by steep turns, pullups, or other abrupt changes in its flightpath. Stalls entered from such flight situations are called accelerated maneuver stalls…" Wreckage Release: The wreckage was released to a representative of the owner's insurance company on July 17, 2002.
The pilot's excessive maneuvering and failure to maintain aircraft control, following a partial power loss during the initial climb, which resulted in an inadvertent stall/spin. A factor in the accident was an inadequate annual condition inspection performed by the certificated mechanic.
Source: NTSB Aviation Accident Database
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