Aviation Accident Summaries

Aviation Accident Summary WPR12FA044

Pomona, CA, USA

Aircraft #1

N741SB

MOONEY M20M

Analysis

After the pilot reported to the airport air traffic controller that the airplane was inbound, he was cleared to land. The controller informed the pilot of departing traffic from the runway, but the pilot did not respond. Another controller noted that the airplane was low and on the base leg of the traffic pattern at that time. The controller who was in contact with the pilot noted that the airplane was low and that it then turned "wing up" and crashed. The airplane collided with a 75-foot-tall stanchion, which was in a fairground about 3/4 mile southeast of the airport. The pilot made no mayday calls during the approach or accident sequence. Witnesses observed the airplane at a lower-than-normal altitude for landing. The traffic pattern altitude for the airport is 2,013 feet. At the time of the accident, an overcast layer was reported at 2,000 feet. It is likely that the pilot was maintaining a lower altitude to remain below the overcast layer in visual conditions and failed to maintain sufficient altitude to clear the obstruction while on the base leg of the traffic pattern. A postaccident examination of the airframe and engine revealed no mechanical anomalies that would have precluded normal operation. The pilot did not possess a medical certificate because he had not responded to a request by the Federal Aviation Administration for additional details regarding his diabetes diagnosis. However, review of the pilot's autopsy and toxicology testing revealed no evidence of sudden incapacitation. Although postaccident testing revealed the presence of diphenhydramine, it could not be determined if it was impairing at the time of the accident.

Factual Information

HISTORY OF FLIGHT On November 18, 2011, about 1415 Pacific standard time, a Mooney M20M, N741SB, impacted a horse-racing track at the Pomona Fairplex, Pomona, California, while maneuvering for landing at Brackett Field (POC), La Verne, California. The pilot/owner operated the airplane under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. The pilot, the sole occupant, was fatally injured; the airplane was substantially damaged. Visual meteorological conditions prevailed for the local flight that departed El Monte Airport (EMT), El Monte, California, about 1400. No flight plan had been filed. A witness reported seeing the airplane out of his window, flying low over his neighbor's house, about two houses over from his. He stated that the speed seemed slow compared to what he has seen in the past; his house is located on the regular flight path for the airport. The witness rushed to the other side of the house, and saw the airplane between his house and the race track. The airplane was on a north-northeast heading and then banked to the left. He thought that the airplane was going to make an off-airport landing, and was relieved when the airplane banked to the left. The witness reported that he thought the airplane was going "to make it." The witness reported that the airplane, all of a sudden, spun clockwise and dove toward the ground. He lost sight of the airplane, but heard a "crash pop like sound," and immediately called 911. The witness also reported that there were overcast conditions at the time of the accident. Written statements provided by the Federal Aviation Administration (FAA) control tower personnel located at Brackett Field control tower reported that the pilot called inbound and the controller cleared the pilot to land on runway 26 left. The pilot subsequently requested and was approved to land on runway 26R. At this time the controller informed the pilot of a sheriff helicopter that was departing runway 26 left, however, there was no response from the pilot. The controller then noted that the airplane, while on left base, was low. The airplane then turned wing up and went down in the fairground area southeast of the airport. There were no mayday calls made by the pilot prior to the accident. PERSONNEL INFORMATIONThe pilot, age 65, held a commercial pilot certificate with ratings for airplane multiengine land and instrument airplane. He also held a private pilot certificate with a rating for airplane single engine land. His certificate held the limitation that he must wear corrective lenses for near and distant vision. According to the pilot's airmen medical records, he had been denied a medical certificate on May 25, 2010. In the pilot's possession was his third-class medical issued on May 1, 2008. At the time of the pilot's most recent medical application, May 25, 2010, he reported a total time 1,600 flight hours, with 100 flight hours accrued in the past 6 months. At that time, his medical application was denied, and he was asked to provide additional details. The FAA sent a letter to the pilot on June 8, 2010, and on July 7, 2010, requesting that he forward additional medical information for evaluation. On August 2, 2010, the FAA sent a third letter indicating that the pilot had not sent in additional medical information, and his request for an airman medical certificate was denied. The National Transportation Safety Board investigator-in-charge (NTSB IIC) reviewed the pilot's logbook, and estimated a total time of 1,759.4 hours, with approximately 419.7 total hours in the accident airplane, 36.8 hours in the last 90 days and 16 hours in the last 30 days. The pilot passed his commercial flight proficiency test on May 22, 2009, and had an instrument proficiency check on January 31, 2010. AIRCRAFT INFORMATION The four-seat, low-wing retractable gear airplane, N741SB, model M20M, serial number 27-0285, and was manufactured in 2000. It was powered by a Textron Lycoming TIO-540-AF1B, serial number L-10386-61A, 270-hp engine. The airframe logbook indicated that the last annual inspection was on December 29, 2010. The preceding annual inspection had been completed on October 2, 2009. According to the pilot's personal logbook, a new engine was placed on the accident airplane on November 26, 2010, at a Hobbs hour meter time of 1,417.3. METEOROLOGICAL INFORMATION The nearest weather reporting facility from the airport is located 9 nautical miles east at Ontario International Airport, Ontario, California. At 1353, the sky was clear with a 2,000-foot ceiling, visibility was 5 statute miles, temperature was 12 degrees C, dew point was 8 degrees C, and the wind was from 290 degrees at 4 knots. The altimeter setting was 29.94 inHg. AIRPORT INFORMATION The airplane was approaching Brackett Field Airport (POC), La Verne, California, for landing. The airport elevation was 1,013.9 feet, and had a control tower. The pattern altitude was identified as 2,013.9 feet mean sea level (msl). Runway 26R had a 3,661-foot by 75-foot asphalt runway, with a 0.9 percent gradient. It was a right-hand traffic runway. Obstructions noted were a 15-foot road, 540 feet from the runway and 159 feet left of runway centerline. It had a 22:1 slope to clear the road. No other obstructions were identified. WRECKAGE AND IMPACT INFORMATION Investigators from the National Transportation Safety Board and an inspector from the Federal Aviation Administration (FAA) responded to the accident site, and reported that the entire airplane was located at the accident site, and fuel was leaking from the airplane. The accident site was about 3/4 mile southeast of the airport, and had come to rest inverted on the Pomona County Fair Grounds race track. The first identified point of impact was a damaged light stanchion about 100 feet east of the main wreckage. The light stanchion was about 75 feet tall, and was located in the infield on the northeast portion of the race track. The light stanchion to the main wreckage was approximately 40 feet, with the left elevator and left elevator counterweight identified in the debris field. The pilot remained belted to his seat via the airplane's restraint system. MEDICAL AND PATHOLOGICAL INFORMATION A postmortem examination of the pilot was conducted by the County of Los Angeles, Department of the Coroner. The cause of death was reported as blunt force injuries. The toxicology results were positive for Diltiazem (less than 0.10 ug/mL), Diphenhydramine (less than 0.50 ug/mL), and less than 10 percent saturation level of Carbon Monoxide. The pilot had a medical history of diabetes, mellitus, hypertension, and sleep apnea. The FAA's Forensic Toxicology Research Team, Civil Aerospace Medical Institute (CAMI), performed toxicology on specimens from the pilot. The results were negative for carbon monoxide, cyanide and volatiles. Positive results were identified for the following tested drugs: Dextromethorphan detected in Urine Dextromethorphan NOT detected in blood (cavity) 0.047 (ug/ml, ug/g) detected in urine Diphenhydramine detected in urine Ephedrine detected in urine Glipizide detected in urine Glipizide detected in blood (cavity) Pseudoephedrine detected in urine TEST AND RESEARCH Flight control continuity was established throughout the airplane. The three-bladed propeller assembly remained attached to the engine. For the purposes of the examination, the propeller blades were randomly identified as blade 1, blade 2, and blade 3. Blade 1 was bent forward at the hub, with leading edge polishing, and trailing edge gouge marks. Blade 2 had Q-tip bending, and chordwise scratch marks at the tip of the blade. Blade 3 had S-bending and chordwise scratch marks approximately half the length of the blade from the tip inboard. The vacuum pump was disassembled with no discrepancies noted to the internal mechanism. The left magneto remained secured at its mounting pad, but had sustained impact damage and could not be tested. The right magneto remained undamaged and secured at its mounting pad. The impulse coupler drive was intact. When the drive was manually rotated it functioned normally with spark produced at the six leads. The top spark plugs were removed, according to the Champion Aviation Check-A-Plug chart AV-27, the spark plugs exhibited normal wear. All 6 fuel injectors were removed and were clear of debris. The fuel flow divider diaphragm had fractured in an outward direction; it was removed and shipped to the NTSB Materials Laboratory for further examination. There was no evidence of any pre impact mechanical malfunctions observed during the engine examination that would have precluded normal operation (reports are attached to the public docket for this accident). According to the NTSB materials laboratory chemist, the glass-fiber reinforced-silicone rubber diaphragm had an approximately 0.6-inch fracture located near the central spindle. The examination revealed that the fracture surface was consistent with overstress in soft polymers such as silicone rubber. The fractured glass-fibers also exhibited features consistent with overstress. (Detailed report attached to the public docket for this accident).

Probable Cause and Findings

The pilot’s failure to maintain sufficient altitude to clear obstructions while maneuvering on the base leg of the traffic pattern for landing.

 

Source: NTSB Aviation Accident Database

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