BAY MINETTE, AL, USA
N3874H
Mooney M20J
About 23 miles from the destination airport, the pilot reported to approach control that the engine had lost power. He declared an emergency, and the controller issued radar vectors toward the Bay Minette Municipal Airport. However, the pilot was forced to make an off-airport landing at night. During the landing, the airplane collided with a grove of trees about 1.75 from the airport. Wreckage examination revealed that the alternate air door was out of its normally installed position, and had blocked airflow to the engine induction ram air inlet. On 5/10/92, the manufacturer had issued a service bulletin (SB), SB-M20-253, which provided for repair of the alternate air door. Recent maintenance had been performed on the induction air box assembly, but there was no record of SB compliance. After the accident, on 12/22/95, the FAA issued a priority airworthiness directive (AD), which addressed this problem.
HISTORY OF FLIGHT On December 13, 1995, at 1915 central standard time, a Mooney M20J, N3874H, collided with trees while attempting an emergency landing to the Bay Minette Municipal Airport in Bay Minette, Alabama. The business flight operated under the provisions of Title 14 CFR Part 91 with a flight plan filed. Visual weather conditions prevailed at the time of the accident. The airplane received substantial damage; the pilot and passenger were fatally injured. The flight departed Sparta, Tennessee, at 1620 hours. At 1610, the pilot of N3874H telephoned Nashville Automated Flight Service Station and requested a preflight briefing from Sparta, Tennessee to Fairhope, Alabama. After the preflight briefing, the pilot filed an instrument flight plan to Fairhope. At 1622, the pilot reported off of Sparta, and established radio contact with Memphis Center. A review of air traffic data disclosed that the flight had received routine handling until the flight was about 23 miles northeast of Fairhope, at 6000 feet. At 1914, the pilot reported to Mobile Approach Control that he had an engine problem, and declared an emergency. After the pilot declared an emergency, the approach controller instructed the pilot to turn right to a 265 degree magnetic heading for vectors to Bay Minette Municipal Airport. While maneuvering for the emergency landing, the airplane collided with a stand of trees approximately 1.75 miles east of the airport. PERSONNEL INFORMATION Information on the pilot is included in this report on page 3 of the factual report under the data field labeled "First Pilot Information". AIRCRAFT INFORMATION Information on the aircraft is contained in this report on page 2 of the factual report under the data field labeled "Aircraft Information". METEOROLOGICAL INFORMATION Visual weather conditions prevailed at the time of the accident. Weather information is contained in this report on page 3 of the factual report under the data field labeled "Weather Information". WRECKAGE AND IMPACT INFORMATION Examination of the accident site disclosed that the tops of several trees were damaged and the aircraft came to rest on the ground in a nose low attitude. Debris from the airplane was scattered over an area 125 feet long and 45 feet wide; the wreckage was oriented on a 320 degree magnetic heading. The accident site examination also disclosed that the outboard wing panels were torn from the airframe, and they were located southeast of the main wreckage. All airframe components were recovered from the accident site, and the examination of these components failed to disclose a mechanical malfunction or failure. The engine and propeller assemblies remained attached to the airframe. The engine assembly was removed from the airframe and mounted on a test stand. An examination of the engine assembly failed to disclose an obvious mechanical problem. During the final phase of the functional test preparation, it was discovered that the induction air box alternate air door was out of it's normally installed position. The alternate air door was positioned over the ram air induction opening. None of the hardware used to secure the alternate air door to the induction assembly was recovered for examination. During the initial engine run, the induction air box assembly was left in the post impact position; subsequently, the engine only developed partial power. Once the induction assembly was removed from the engine, the engine developed full power. MEDICAL AND PATHOLOGICAL INFORMATION On December 14, 1995, the postmortem examination on the pilot was conducted by Dr. James C.U. Downs at the Alabama Department Of Forensic Science in Mobile, Alabama. During the toxicological examinations 28.200 (ug/ml, ug/g) of acetaminophen (Tylenol) was detected in the urine sample. ADDITIONAL INFORMATION A search of service difficulty reports, service warranty, airworthiness directives, and service bulletins on the M20J induction system, revealed several occurrences which attributed the loss of engine power to the failure of the induction air box. The historical search also discovered that Mooney had issued a Service Bulletin (SB) SB-M20-253, dated 5/10/92 which provided a repair for the alternate air door. According to Mooney, the SB was issued after a report of an alternate air door lodged in the induction air duct, and restricted induction airflow to the engine. The SB changed the alternate air door plate and bolt configuration, thus reducing wear caused by engine vibration. A review of the aircraft maintenance log disclosed that recent maintenance had been performed on the induction air box assembly, but there was no record of SB compliance (see attached copy of extract from engine log). Subsequent to the findings developed during this investigation, the Federal Aviation Administration issued Priority Letter Airworthiness Directive, 95-26-16, dated December 22, 1995. The aircraft wreckage was released to Mark Andrews, President of Sea Air Inc., in Orange Beach, Alabama.
failure of the alternate air door, which resulted in blockage of air through the induction system. A factor relating to the accident was: failure to comply with Safety Bulletin SB-M20-253.
Source: NTSB Aviation Accident Database
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