Aviation Accident Summaries

Aviation Accident Summary WPR09LA016

Parowan, UT, USA

Aircraft #1

N151HT

Heisler Lancair Legacy

Analysis

During departure, witnesses in the area reported that the airplane appeared unusually low and then entered a left turn. As the airplane entered the turn, items from the cockpit fell from the airplane. The airplane continued in the left turn until it impacted the ground. Examination of the wreckage revealed no evidence of preimpact mechanical malfunction. The airplane, by design, does not have a cockpit indication for the security of the canopy. Structural documentation of the canopy latching mechanism did not reveal any damage to the latching mechanism, which is indicative of it not being latched when the airplane impacted the ground. Based on post-mortem toxicology results, the pilot had likely recently used two different prescription painkillers that commonly result in impairment, and that may increase risk of seizure, particularly when used together. Based on his height and weight, poorly controlled blood pressure in spite of the use of at least two different medications to lower it, and the presence on autopsy of right-sided heart enlargement, he likely had obstructive sleep apnea, a condition associated with fatigue and cognitive impairment. His response to a real or perceived emergency may have been impaired by the medications themselves, by a seizure induced by the medications, or by the effects of possible obstructive sleep apnea. The pilot did have a single blocked small coronary artery, but the condition had been present and evaluated just over two years prior to the accident, with evidence of good blood flow in spite of the blockage. It is unlikely that the blockage was related to the accident. The pilot had not indicated high blood pressure, use of medications to treat high blood pressure, or use of prescription painkillers on his most recent application for airman medical certificate just over 16 months prior to the accident.

Factual Information

HISTORY OF FLIGHT On October 18, 2008, about 1400 mountain daylight time, N151HT, a Heisler Lancair Legacy collided with terrain shortly after takeoff from the Parowan Airport, Parowan, Utah. The airplane was registered to a private company and the pilot was operating it under the provisions of 14 Code of Federal Regulations Part 91. The airline transport pilot was killed and the passenger sustained serious injuries. The airplane was substantially damaged. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight. According to local law enforcement personnel, the pilot owned a cabin in the Parowan area and rented a hangar at the Parowan Airport. At the time of the accident, he was returning to North Las Vegas Airport, Las Vegas, Nevada, where the airplane was based. Witnesses were driving in a car, northeast of the airport about 5 miles, driving towards Parowan. They reported that the airplane departed from runway 04 and climbed to an estimated 400 to 500 feet above ground level. The witnesses said that initially they thought that the airplane was a cropduster because it remained at such a low altitude. The airplane then entered a left turn and witnesses saw objects fall, “...off of or out of the airplane.” The airplane continued in a left turn and lost altitude until the left wing tip impacted the ground and the witnesses saw a cloud of dust at the area of impact. Law enforcement personnel that initially responded to the accident site went to the area specified by the witnesses as the location where the objects departed the airplane. At this location, personal effects including clothing were identified. According to a family member of the passenger, the passenger could not recall any details related to the accident. PERSONNEL INFORMATION The pilot, age 59, held an airline transport certificate for single-engine airplanes. He also held a commercial pilot certificate for multi-engine airplanes, rotorcraft, gliders, and lighter than air free balloon. The pilot held a second-class medical certificate that was issued on May 1, 2007, and held the restriction that the pilot must wear corrective lenses. The pilot reported 5,000 flight hours on his last medical application. A review of a copy of the pilot’s logbook showed that he had about 4,469 flight hours, with 150 hours in the accident airplane. AIRCRAFT INFORMATION The two-seat, low-wing, retractable gear airplane, serial number (SN) L2K-267, was issued its airworthiness certificate in 2006. It was powered by a Teledyne Continental IO-550-C engine and equipped with an Aerocomposites propeller. Review of copies of the maintenance logbook records showed that the last condition inspection was on June 11, 2008, at a total time of 69.6 hours. On September 25, 2008, the oil was changed at a total time of 89.6 hours. METEOROLOGICAL INFORMATION At 1353, an aviation routine weather report (METAR) at Cedar City Regional Airport, Cedar City, Utah, located approximately 17 nautical miles southwest of the accident site, was reporting, in part: wind, 170 degrees at 10 knots and gusting to 21 knots; visibility, 10 statute miles; sky condition clear; temperature, 73 degrees Fahrenheit; dew point, 19 degrees Fahrenheit; altimeter, 30.21 inHg. According to initial responders, the wind conditions reported at Cedar City were consistent with winds in the Parowan area at the time of the accident. WRECKAGE AND IMPACT INFORMATION An inspector from the Salt Lake City, Utah, Federal Aviation Administration Flight Standards District Office responded to the accident scene. The inspector reported that the debris field was approximately 200 feet in length on flat, grassy terrain. The first identified point of impact contained green lens fragments and the main wreckage came to rest facing northeast. One propeller blade had separated from the propeller assembly and was identified in the debris field. MEDICAL AND PATHOLOGICAL INFORMATION The State of Utah, Office for the Medical Examiner, completed an autopsy on the pilot. The manner of death was classified as an accident due to blunt force injuries. The report noted “other significant conditions” of atherosclerotic coronary artery disease, cardiomegaly, and acute mixed drug intoxication. The FAA Bioaeronautical Research Laboratory completed toxicology testing. The tests were negative for carbon monoxide, cyanide, and volatiles. The test was positive for the following tested drugs: 10.01 (ug/ml, ug/g) acetaminophen, 0.055 (ug/ml, ug/g) diazepam, 0.031 (ug/mL, ug/g) dihydrocodeine, doxazosin, 0.152 (ug/ml, ug/g) hydrocodone, and 0.094 (ug/ml, ug/g) nordiazepam, detected in blood; 0.46 (ug/mL, ug/g) dihydrocodeine, doxazosin, 1.755 (ug/ml, ug/g) hydrocodone, 0.54 (ug/mL, ug/g) hydromorphone, and nordiazepam, were detected in urine. The pilot’s most recent application for airman medical certificate in May 2007 noted the use of medications including only allopurinol, atorvastatin, and aspirin. The application also noted a “precautionary” coronary angiogram in 2006 which “showed no blockage.” Blood pressure on the exam conducted in conjunction with that application was noted as 134/83. There was no additional information regarding the angiogram in the FAA medical records. Records obtained from the pilot’s cardiologist regarding the angiogram (performed September 25, 2006) noted a “totally occluded” small left anterior descending coronary artery with “good collaterals” and otherwise normal coronary arteries. The cardiologist’s records also noted that the pilot indicated a history of high blood pressure for which he had been discharged from the Army, and a “ruptured disc,” neither of which were noted on the pilot’s most recent application for airman medical certificate. Medications noted on the cardiologist’s records included ramipril, dutasteride, and propanolol, none of which were noted on the pilot’s most recent application for airman medical certificate, and atorvastatin, fish oil, vitamins, and aspirin. No other medications were noted either in the cardiologist’s records or on any applications for airman medical certificate. At autopsy, the pilot was noted to have “near total stenosis of the proximal left anterior descending coronary artery with no evidence of acute thrombosis” and “mild right ventricular dilatation,” and his height and weight were noted as 182 cm and 112 kg, respectively. TESTS AND RESEARCH The wreckage was examined by investigators following its recovery from the accident site. The airplane was extensively damaged by impact forces. The inboard edges of both wings remained attached at the fuselage structure. The empennage section broke free from the remainder of the fuselage. The rudder and elevator control surfaces also separated but were identified in the wreckage debris. The canopy system was documented. The canopy was controlled through a manually actuated lever and spring system. The airplane had been modified to include access stairs on each side that were interconnected through the canopy. If the canopy was latched, the stairs retracted. If the canopy was unlatched, the stairs were extended. The latching pins on the canopy frame were undamaged. The canopy had two forward hinges, which were twisted forward and to the left. According to the Lancair representative, there is no cockpit indication to indicate whether or not the canopy is securely latched. All control surfaces were identified. The control tubes to the ailerons and elevators were traced. The control cables were traced from the area of the rudder pedals, aft to the rudder bellcrank. According to the Lancair representative, the aileron and elevator trim actuators were in a position consistent with neutral trim. According to the Lancair representative, the rudder actuator showed slightly left trim. The landing gear was retracted and the landing gear lever in the cockpit was in the up position. The flap actuator position was consistent with the flaps in the retracted position. The airplane was equipped with 5-point seatbelt harnesses. All belts had been cut by initial responders. The restraint system was mounted on the rear bulkhead. According to the Lancair representative, the restraint system should be mounted higher so that the occupant loads are distributed properly. The Lancair representative indicated that usually they are mounted on the structural portion of the cabin ceiling. The engine was documented and internally examined with a borescope. Thumb compression was obtained on all cylinders and all valves produced similar amounts of lift. The left and right magneto drive shafts were rotated by hand. The right magneto sparked at all leads. The left magneto sparked at all leads except for the number 2 cylinder on the top. The magneto lead sparked when rotated to a different terminal at the distributor. The magneto was disassembled; no anomalies were noted. The magneto was reassembled and spark was produced at all leads. The fuel manifold valve was disassembled and fuel was evident. It was consistent in color and smell to 100 low lead. The spark plugs were removed and documented. They had normal wear signatures in accordance with the Champion AV-27 chart. The spark plugs for cylinders 1, 3, and 5 were oil soaked. The spark plugs for cylinders 2 and 6 had light carbon deposits and 4 had slightly more carbon deposits. The Aerocomposites propeller was documented. Blade 1 had separated at the blade butt. The steel pin was pulled aft. The blade retained its general shape but was cracked in several places. Blades 2 and 3 remained with the hub, but were pulled slightly out from the hub. Blade 2 showed leading edge marks going aft from the hub, outboard to mid-blade. Blade 3 did not show any leading edge damage. Blades 2 and 3 showed chordwise striations on their convex sides at the tips. Examination of the wreckage revealed no evidence of preimpact mechanical malfunction.

Probable Cause and Findings

The pilot failed to secure the canopy prior to takeoff, resulting in his inability to control the aircraft during the takeoff. Contributing to the accident was the pilot’s impairment from prescription medications and possible obstructive sleep apnea.

 

Source: NTSB Aviation Accident Database

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