NTSB Factual Report

HISTORY OF FLIGHT

On October 13, 2011, at 1911 eastern daylight time, a Cessna 150F, N3086X, was substantially damaged when it impacted trees and terrain at Berkeley County Airport (MKS), Moncks Corner, South Carolina. The private pilot was fatally injured. Twilight visual meteorological conditions prevailed. No flight plan had been filed for the personal flight, which was conducted under the provisions of 14 Code of Federal Regulations Part 91.

According to a flight instructor, the pilot’s intent was to practice for an upcoming flight review.

There were no witnesses to the accident; however, there was a witness to the pilot's activities prior to starting the airplane. That witness stated that he saw the pilot park his car near the hangar that housed the airplane, untie it, and pull it out of the hangar. Then, as the witness was leaving the airport, he saw the pilot get into the airplane. The witness also noted that the sun had gone down, but it was not quite dark when he left.

Radar, just after the timeframe that the witness had seen the pilot, included a target transmitting a 1200 transponder code. At 1851, the target was first observed at 100 feet, departing runway 23. The target then made a left turn, followed by a right turn, and proceeded to the northwest. It subsequently completed a turn back toward the airport and entered a left downwind leg at 800 feet. After the left downwind, the target completed a left descending turn to a final approach to runway 23, with the final radar contact of the approach occurring at 1902.

At 1907, another target was observed at 100 feet, departing runway 23. The target entered a left downwind and subsequently completed the traffic pattern, with last contact approaching runway 23 at 1911. There was no further radar contact.

The pilot was reported missing on October 24, 2011, and he and the airplane were found on October 27, 2011.

PERSONNEL INFORMATION

According to Federal Aviation Administration (FAA) records, the pilot, age 64, held a private pilot certificate with an airplane single-engine land rating. His most recent FAA third class medical certificate was issued April 15, 2011, and at the time, the pilot reported 1,060 total hours of flight experience. According to the pilot's logbooks, his most recent flight review occurred on June 15, 2002, and his most recent recorded flight occurred on May 8, 2011, at 1,062.6 hours of flight time.

AIRCRAFT INFORMATION

According to FAA records, the airplane was manufactured in 1966 and registered to the owner on August 10, 1992. It was powered by a Continental Motors O-200 series, 100-horsepower engine. The airplane's most recent annual inspection was completed on July 10, 2011. At the time of the inspection, the reported total time was 3,600.2 hours in service with a tachometer time of 1,688.0 hours.

METEOROLOGICAL INFORMATION

Weather, recorded at the airport at 1855, included calm wind, visibility 10 statute miles, clear skies, temperature 22 degrees C, dew point 18 degrees C, and an altimeter setting of 29.65 inches Hg.

According to United States Naval Observatory data, sunset occurred at 1849. The end of civil twilight occurred at 1914, and moonrise was not until 1933, with the moon then having a 98 percent visible disk.

AIRPORT INFORMATION

Runway 23 was 4,351 feet long and 75 feet wide, and was constructed of concrete. The airport did not have an air traffic control tower. Communications utilized a common traffic advisory frequency and were not recorded.

WRECKAGE AND IMPACT INFORMATION

The wreckage was located in a level, wooded area about 60 feet outside the northwest airport perimeter fence, about 1,900 feet from the approach end of runway 23. The airplane came to rest in the vicinity of 33 degrees 11.24 minutes north latitude, 080 degrees 02.25 minutes west longitude. Initial tree cuts were consistent with an approximately 45-degree right-wing-down turn, 45-degree angle of descent, on a 330-degree magnetic heading.

The airplane came to rest wedged between several trees, with the wings, left wing up, right wing down, nearly vertical. About 8 feet from the right wing tip, where the wing was first in contact with the ground, it was bent about 90 degrees toward, and under the fuselage. The fuselage came to rest approximately parallel to, and about 5 feet above the ground.

All components of the airplane were located at the accident site, and flight control continuity was confirmed to all flight control surfaces. The flaps were confirmed extended to about 15 degrees by measurement of the flap actuator drive screw.

The tachometer time was 1,688.9 hours.

The engine firewall was deflected upward. The fuselage and empennage remained intact and were wrinkled and dented. Both wings exhibited leading edge, aft crushing. The elevator, horizontal stabilizer, rudder, and vertical stabilizer remained attached at all attachment points. The vertical stabilizer exhibited leading edge impact damage while the leading edges of the horizontal stabilizers were not damaged.

The propeller remained attached to the propeller hub. One blade was missing the propeller tip, and exhibited s-bending and leading edge damage. The other blade exhibited slight aft bending.

The engine remained attached to the fuselage. Crankshaft continuity was confirmed to the accessory section of the engine by hand-turning the propeller. Compression was obtained on three of the four cylinders with the fourth cylinder exhibiting impact damage. Spark was obtained on all towers of the magnetos. The presence of fuel was confirmed in the right fuel tank, fuel lines, and carburetor.

The field examination of the airframe and powerplant revealed no preimpact mechanical anomalies that would have precluded normal airplane operation.

MEDICAL AND PATHOLOGICAL INFORMATION

According to local authorities, the pilot was found about 30 feet from the airplane.

An autopsy was performed on the pilot at the Medical University of South Carolina, Charleston, South Carolina, with the cause of death reported as "probable toxic effects of ethylene glycol."

The autopsy also noted that there were scattered contusions and abrasions on the body up to 1 inch [in length], fractures of the 6th and 7th ribs, and hemorrhagic abdominal wall musculature, but no palpable fractures or dislocations of the extremities.

Microscopic examination of the kidney revealed the presence of numerous fan-shaped, birefringent crystals.

According to the toxicological profile for ethylene glycol prepared by the United States Department of Health and Human Services:

“Information on the health effects of oral exposure in humans is largely limited to case reports of acute accidental or intentional ingestion of ethylene glycol. These case reports have identified three stages of acute oral ethylene glycol toxicity in humans. These stages are well documented and occur within 72 hours after ingestion. The first stage involves central nervous system depression, metabolic changes (hyperosmolality), and gastrointestinal upset, and spans the period from 30 minutes to 12 hours. During the second stage (12–24 hours after ingestion), metabolic acidosis and associated cardio-pulmonary symptoms…become evident. During stage three, which covers the period 24–72 hours after ethylene glycol ingestion, renal involvement becomes evident. The third stage is characterized by flank pain and oliguria/anuria. Histopathological findings show renal tubular necrosis and deposition of calcium oxalate crystals. Often, the cardiopulmonary effects in the second stage are not evident, so the distinguishing symptoms of ethylene glycol intoxication are central nervous system depression, acidosis, and nephrotoxicity.”

The profile also noted that, “Adverse neurological reactions are among the first symptoms to appear in humans after ethylene glycol ingestion.”

Forensic toxicology testing was also performed at the FAA Bioaeronautical Sciences Research Laboratory, in Oklahoma City, Oklahoma. The results included no carbon monoxide or cyanide detected in the blood, no ethanol detected in the urine, Bupropion detected in the urine but not in the blood, and 1.187 (ug/mL, ug/g) Lamotrigine detected in the blood and urine. Ethylene glycol was not noted.

Neither Bupropion nor Lamotrigine were reported on the pilot’s most recent application for a medical certificate, and the investigation was unable to identify treating physicians or obtain further personal medical information.

According to the NTSB Medical Officer Factual Report, “buproprion is an antidepressant used to treat depression and as a smoking cessation aid. Buproprion carries the following FDA warnings: 1) a dose-dependent risk of seizures; 2) may impair mental and/or physical ability required for the performance of potentially hazardous tasks (e.g., driving, operating heavy machinery). Lamotrigine is an atypical anti-seizure medication that is also used to treat bipolar disease.”

An investigation into how or why the pilot may have ingested ethylene glycol is beyond the scope of this investigation.

NTSB Probable Cause

The debilitating effects of ethylene glycol poisoning, which resulted in the pilot’s inability to maintain control of the airplane.