Brighton, MI, USA
N82383
AERONCA 7AC
Witnesses observed the airplane make a normal engine run-up before takeoff followed by a normal takeoff from the runway. Shortly after takeoff, the engine did not sound like it was developing full power, and the airplane was struggling to climb. Subsequently, the airplane made a 180-degree turn and then descended toward terrain in a nose-down attitude. Postaccident examination of the airplane revealed no evidence of any preimpact mechanical failures or anomalies that would have precluded normal operation. Although the weather conditions at the time of takeoff were conducive to the formation of carburetor ice at glide and cruise power, it could not be determined whether carburetor ice was a factor in the loss of engine power. It is likely that the pilot failed to maintain airspeed during the turn back to the airport, which resulted in a stall. Postaccident examination of the airframe revealed that the pilot's shoulder harness failed during the accident. Material examination of the shoulder harness webbing and stitching showed that they failed due to an overload event. The occupants' injuries suggest that both occupants were using the four-point shoulder harnesses at the time of the accident and were exposed to strong deceleration forces. If the pilot's shoulder harness had not failed, he likely would not have suffered the brain injury he received, which caused permanent disability. However, it is possible that an intact shoulder harness could have led to more severe chest, abdominal, or cervical injuries. The investigation could not determine whether the pilot would have died or sustained a permanent disability from some other injury if the shoulder harness had remained intact.
HISTORY OF FLIGHTOn September 1, 2012, approximately 0830 eastern daylight time, an Aeronca 7AC single-engine airplane, N82383, sustained substantial damage when it impacted terrain following a loss of control during initial takeoff climb from the Brighton Airport (45G), Brighton, Michigan. The private pilot sustained serious injuries, and the passenger sustained fatal injuries. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed and a flight plan was not filed. The local flight was originating at the time of the accident. According to local authorities who spoke to witnesses, the pilot was taking the passenger for a local flight. Witnesses observed a normal engine run-up prior to takeoff, and a normal takeoff from runway 22. Shortly after takeoff, the engine did not sound like it was developing full power and the airplane was struggling to climb. Subsequently, witnesses observed the airplane make a 180-degree turn and then descend toward the terrain in a nose down attitude. PERSONNEL INFORMATIONThe pilot, age 79, held a private pilot certificate with ratings for airplane single-engine land, airplane multi-engine land, and instrument airplanes. The pilot held a valid driver's license for operation of light-sport aircraft. The pilot's most recent third class medical certificate was issued on August 10, 2005. The Aeronca 7AC is defined by Federal Aviation Administration (FAA) as a light sport aircraft (LSA). Pilots flying LSAs are only required to possess a valid driver's license and comply with 14 Code of Federal Regulations 61.53(b), which states that no person may act "as pilot in command, or in any other capacity as a required pilot flight crewmember, while that person knows or has reason to know of any medical condition that would make the person unable to operate the aircraft in a safe manner." A review of the pilot's logbook showed the pilot had accumulated 2,686.5 flight hours, and 7.8 hours in the last 60 days. The pilot's most recent flight review was completed on August 4, 2012. AIRCRAFT INFORMATIONThe Aeronca 7AC, serial number 7AC-1016, was manufactured in 1946, and registered to the owner on June 10, 2008. The airplane was a two place, tandem, high wing monoplane. Basic construction consisted of welded tubes, and a fabric covered fuselage. The airplane was powered by a Continental A-65-8, 65-horsepower reciprocating engine and a fixed pitch wood propeller. The pilot's operating handbook listed a clean stall speed of 38 miles per hour (mph). Review of the maintenance records showed that the most recent annual inspection was completed on November 22, 2011, at a total time of 2,391.5 hours. At the time of the accident, the airplane had accumulated 27.2 hours since the annual inspection. Although the airplane held a standard airworthiness certificate, it met the definition of a Light Sport Aircraft as contained in 14 Code of Federal Regulations Part 1.1. According to friends of the pilot, the pilot routinely fueled the airplane with automotive gasoline. The airplane records did not show the supplemental type certificate (STC) for the use of automotive gasoline. According to an Experimental Aircraft Association flight manual supplement, "When using unleaded automotive gasoline, the onset of carburetor ice may occur earlier under the same atmospheric conditions then when using 80/87 minimum grade aviation gasoline. There is no change in the techniques for recognizing and correcting for carburetor ice." According to weight and balance information contained in the airplane's maintenance records, the airplane had an empty weight of 765.5 pounds (lbs), and a maximum allowable gross weight of 1,220 lbs. Medical records indicated the pilot/owner's weight was 176 lbs, and the autopsy report listed the passenger's weight as 127 lbs. The total fuel on-board at the time of the accident was unknown. Based on the occupant weights, the remaining useful load without fuel was 151 lbs. The total fuel capacity for the airplane was 13 gallons (or 78 lbs). On November 10, 2010, Aero Fabricators shoulder harness and seat belt assemblies were installed in the front and rear seats per STC number SA1768GL, and Aero Fabricators Installation Instructions AF-41. Aero Fabricators was issued STC SA1768GL for shoulder harness and seat belt assembly on July 1, 1992. According to an individual who owned a hangar near the pilot's hangar, during the most recent annual inspection, the pilot prepped the airplane for the inspection, which included the removal of the seats and lap restraints. Upon completion of the annual inspection, the seats and lap restraints were reinstalled by the pilot. METEOROLOGICAL INFORMATIONAt 0815, the Livingston County Airport (OZW), Howell, Michigan, automated weather observing system, located 9 miles west of the accident site, reported calm wind, visibility 10 miles, clear sky, temperature 19 degrees Celsius, dew point 13 degrees Celsius, and an altimeter setting of 30.15 inches of Mercury. The FAA icing probability chart indicated there was potential for serious carburetor icing at glide power at the time of the accident. AIRPORT INFORMATIONThe Aeronca 7AC, serial number 7AC-1016, was manufactured in 1946, and registered to the owner on June 10, 2008. The airplane was a two place, tandem, high wing monoplane. Basic construction consisted of welded tubes, and a fabric covered fuselage. The airplane was powered by a Continental A-65-8, 65-horsepower reciprocating engine and a fixed pitch wood propeller. The pilot's operating handbook listed a clean stall speed of 38 miles per hour (mph). Review of the maintenance records showed that the most recent annual inspection was completed on November 22, 2011, at a total time of 2,391.5 hours. At the time of the accident, the airplane had accumulated 27.2 hours since the annual inspection. Although the airplane held a standard airworthiness certificate, it met the definition of a Light Sport Aircraft as contained in 14 Code of Federal Regulations Part 1.1. According to friends of the pilot, the pilot routinely fueled the airplane with automotive gasoline. The airplane records did not show the supplemental type certificate (STC) for the use of automotive gasoline. According to an Experimental Aircraft Association flight manual supplement, "When using unleaded automotive gasoline, the onset of carburetor ice may occur earlier under the same atmospheric conditions then when using 80/87 minimum grade aviation gasoline. There is no change in the techniques for recognizing and correcting for carburetor ice." According to weight and balance information contained in the airplane's maintenance records, the airplane had an empty weight of 765.5 pounds (lbs), and a maximum allowable gross weight of 1,220 lbs. Medical records indicated the pilot/owner's weight was 176 lbs, and the autopsy report listed the passenger's weight as 127 lbs. The total fuel on-board at the time of the accident was unknown. Based on the occupant weights, the remaining useful load without fuel was 151 lbs. The total fuel capacity for the airplane was 13 gallons (or 78 lbs). On November 10, 2010, Aero Fabricators shoulder harness and seat belt assemblies were installed in the front and rear seats per STC number SA1768GL, and Aero Fabricators Installation Instructions AF-41. Aero Fabricators was issued STC SA1768GL for shoulder harness and seat belt assembly on July 1, 1992. According to an individual who owned a hangar near the pilot's hangar, during the most recent annual inspection, the pilot prepped the airplane for the inspection, which included the removal of the seats and lap restraints. Upon completion of the annual inspection, the seats and lap restraints were reinstalled by the pilot. WRECKAGE AND IMPACT INFORMATIONThe airplane came to rest upright in swampy terrain approximately 1,000 feet from the departure end of runway 22. The engine was found buried within the terrain and displaced aft into the firewall. The fuselage was crushed upward and aft. The empennage was partially separated and displaced to the right. Examination of the airplane showed that flight control continuity was established from all flight control surfaces to the cockpit area. The wooden propeller remained attached to the engine and displayed leading edge gouges and splintering. The crankshaft was rotated by hand and continuity was confirmed from the propeller to the rear accessory gears and to the valve train. The carburetor remained partially attached to the engine, but was impact damaged. The carburetor float bowl contained fuel and water. The carburetor float was undamaged, and the fuel intake screen was clear. The carburetor heat control at the engine was found in the OFF position. ADDITIONAL INFORMATIONExcerpt of Pilot's Operating Handbook According to the pilot's operating handbook, Emergency Procedures, Engine Runs Rough, it states: "Pull Carburetor full ON. If the roughness is caused by carburetor ice, roughness will probably increase momentarily, then the engine should begin to run smoothly. If applying carburetor heat does not smooth the engine, check mags. It is possible a fouled plug, worn plug wire, or faulty mag is causing the roughness, in which cases switching to the good mag, while resulting in a slight loss of power, will smooth the engine. Land as soon as practical." Other Accident Involving Failed Aero Fabricators Shoulder Harness On March 3, 2013, about 1558 mountain standard time, a Cessna 172M airplane, N5129R, impacted trees and snow covered mountainous terrain 11 nautical miles east northeast of Saratoga, Wyoming . The pilot was fatally injured and the airplane sustained substantial damage. During the on-scene wreckage documentation, the NTSB observed that the pilot's shoulder harness had failed during the accident, similar to the Aeronca failure with a separation of the threading at the "Y" junction. The pilot restraint was manufactured by Aero Fabricators (model number H-702-300) and installed on the accident airplane on February 9, 2003. The date of manufacturing stamp on the shoulder harness restraint was smeared and was illegible. The shoulder harness label stated the restraint system was an FAA-PMA part with a "rated strength of assembly [of] 1,500 pounds." MEDICAL AND PATHOLOGICAL INFORMATIONPilot Injuries Accident site photographs, medical records, as well as autopsy, and toxicological reports were reviewed by the National Transportation Safety Board (NTSB) Chief Medical Officer, in an effort to determine the extent and severity of the pilot's injuries. According to medical records released to the NTSB by the pilot's family, the pilot was found with a decreased level of consciousness, responding only to painful stimulation. On arrival to the hospital, the following injuries were identified: a posterior dislocation of his left hip prosthesis with a fracture of the hip socket (acetabulum), a fracture of his left elbow (olecranon), bruising of the soft tissue around his right eye with a fracture of the floor of the orbit, compartment syndrome in his right forearm, and "bruising over bilateral shoulders, right greater than left with associated right sided bruising over lateral chest, abdomen, hip"; the physician notes remarked "seatbelt sign". According to Computerized Tomography (CT) scan of his head, he had bleeding around and swelling within his brain. Passenger Injuries An autopsy was performed on the passenger by the Sparrow Forensic Pathology facility, Lansing, Michigan. According to the autopsy report, the cause of death was "multiple injuries." SURVIVAL ASPECTSPilot Seat The pilot seat was found with its four seat posts attached to the aircraft floor, and the seat frame was bent down, forward, and to the right. Pilot Restraint The pilot restraint was manufactured by Aero Fabricators (model number H-702-300) and installed on the accident airplane on November 11, 2010. The restraint was manufactured on May 27, 2010. The shoulder harness label stated the restraint system was a FAA-PMA part with a "rated strength of assembly [of] 1,500 pounds." The lap belt was attached to the seat at the back seat posts. The lap belt fitting was pinned between the installation bolt and the seat frame, which prevented the lap belt from swiveling forward and aft. The lap belt webbing was pinned between the lap belt fitting and the seat frame, which prevented the seat belt from being able to be adjusted for proper fitting. The left side lap belt had been cut by rescue personnel, and the tongue end of the lap belt was missing from the wreckage. The shoulder harness had been removed from the airplane by FAA inspectors. The shoulder harness was separated at the stitched "Y" junction that connected the two shoulder straps and the fuselage attach strap behind the occupants head. Passenger Seat The passenger seat was found with its four seat posts attached to the aircraft floor, and the front frame tube was creased down approximately 10 inches from the forward left seat post. Passenger Restraint The passenger restraint was manufactured by Aero Fabricators (model number H-702-300) and installed on the accident airplane on November 11, 2010. The shoulder harness portion of the restraint was manufactured on May 27, 2010, and the lap belt portion was manufactured on August 25, 2010. The shoulder harness label stated the restraint system was a FAA-PMA part with a "rated strength of assembly [of] 1,500 pounds." The lap belt was attached to the seat at the back seat posts. The lap belt fitting was pinned between the installation bolt and the seat frame, which prevented the lap belt from swiveling forward and aft. The lap belt webbing was pinned between the lap belt fitting and the seat frame, which prevented the seat belt from being able to be adjusted for proper fitting. The shoulder harness had been removed from the airplane by FAA inspectors. The shoulder harness was intact. Seat Restraint Installation The NTSB Survival Factors Group inquired to the mechanic who installed the seat belts and shoulder harnesses into the airplane about the pinned lap belts found in the accident airplane. He explained that he installed bushings into the attachment fittings for the lap belts. The bushings would allow the bolt at the attach point to be fully tightened while also allowing the seat belt to be adjusted and swivel forward and aft. The bushings are not provided by Aero Fabricators in the installation kit for a new restraint system or detailed as required parts in the installation instructions. During the examination of the airplane, the bushings were not found in the lap belt attachment fittings, thus pinning the hardware and lap belt webbing in one position. Shoulder Harness Restraint System Testing Webbing Breaking Strength Testing On March 18, 2013, an independent research lab conducted a breaking strength test using an exemplar webbing sample provided by Aero Fabricators. In accordance with the Society of Automotive Engineers Aerospace Standard (SAE AS) 8043B, the breaking strength of the webbing was measured approximately 20.9 kilonewtons (kN), which met the breaking strength requirement for upper torso of 17.8 kN, but did not meet the breaking strength requirement for the pelvic of 22.2 kN. Technical Standard Order (TSO) C22f, dated January 1, 1990, was effective at the time Aero Fabricators applied for the seat belt STC. TSO C22f stated "new models of safety belts that are to be identified with applicable TSO markings and that are manufactured after May 1, 1972, must meet the standards set forth in National Aerospace Standard (NAS) Specification 802 revised May 15, 1950. NAS 802 stated that the rated minimum breaking strength of the complete belt assembly, i.e. 1,500 pounds (lbs). Therefore, the pelvic breaking strength requirement at the time of Aero Fabricators STC application was 2,250 lbs (10kN). Although the breaking strength of the webbing did not meet the TSO pelvic requirements currently effective as detailed in SAE AS 8043B, the webbing breaking strength met TSO C22f standards in effect at the tim
The pilot’s failure to maintain airspeed following a partial loss of engine power for reasons that could not be determined during postaccident examination, which resulted in an aerodynamic stall and loss of airplane control. Contributing to the severity of the pilot’s head injuries was the failure of the shoulder harness assembly.
Source: NTSB Aviation Accident Database
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