Aviation Accident Summaries

Aviation Accident Summary WPR12FA091

Show Low, AZ, USA

Aircraft #1

N445GH

CESSNA T206H

Analysis

The private pilot departed before dawn in the single-engine airplane with three passengers. One passenger reported that after an uneventful departure, the airplane made an unexpected right turn, with no comment from the pilot. A ground witness observed the airplane in an unusual attitude shortly after takeoff. The airplane then flew out of her view, and a few seconds later, she observed an explosion beyond the runway. The debris field and associated ground scars were adjacent and perpendicular to the runway. The airplane damage and debris distribution were consistent with a high-speed, right-wing-low descent into the ground. All sections of the airplane were located at the accident site, and no anomalies were noted with the airframe or engine that would have precluded normal operation. The damage to the propeller and turbocharger was consistent with the engine producing power at the time of impact. The airport's automated weather observation system was reporting 8-mile visibility, but with low broken cloud ceilings about the time the pilot would have been performing his preflight inspection. A rapid degradation in weather conditions occurred over the 10-minute-period following the accident, including freezing dense fog and low overcast cloud ceilings. The airport was located on the outskirts of a town, and the route of flight following the initial turn was toward a sparsely populated area. The moon was below the horizon at the time of the accident. The pilot did not possess an instrument rating, which coupled with the lighting and weather conditions, could have made him vulnerable to spatial disorientation. The airplane's impact trajectory was consistent with the pilot experiencing this phenomenon. Additionally, an instrument-rated pilot departed from the same runway shortly after the accident unaware that it had occurred. He reported that before departure, he could see haze beginning to form close to the ground but could still see clear skies in his direction of travel and presumed that visual meteorological conditions existed. However, during the initial climb, he inadvertently entered a fog layer, and became disoriented. The pilot had been taking prescription medication for anxiety, the use of which he did not report in any application for a Federal Aviation Administration medical certificate. Although use of such medication may impair the mental and/or physical ability required for flight, it was not possible to conclusively determine what role, if any, the medication played in the accident.

Factual Information

HISTORY OF FLIGHT On February 4, 2012, about 0630 mountain standard time, a Cessna T206H, N445GH, collided with level terrain shortly after takeoff from Show Low Regional Airport, Show Low, Arizona. The pilot was operating the airplane under the provisions of Title 14 Code of Federal Regulations Part 91. The private pilot and one passenger were fatally injured, and two passengers sustained serious injuries. The airplane sustained substantial damage during the accident sequence, and was partially consumed by post impact fire. The personal flight departed Show Low about 1 minute prior to the accident, with a planned destination of Boulder City Municipal Airport, Boulder City, Nevada. Night instrument meteorological conditions prevailed at the time of the accident, and no flight plan had been filed. The pilot and passengers were traveling to attend a convention in the Las Vegas area, which was due to start at 1030 Pacific standard time. A witness who was traveling in her automobile northbound on route 77, about 1,000 feet southwest of the departure end of runway 24, observed an airplane in the sky to her right. It appeared to be descending steeply, and traveling at a high rate of speed. She stated that she was familiar with operations at the airport, and initially thought the airplane was landing. She was concerned that it was flying much higher and faster than appropriate, and that it may overshoot the runway. The witness slowed down, concerned that the airplane may collide with her automobile, and it subsequently passed out of her view behind the elevated runway. She assumed it had landed; however, a few seconds later, she observed an explosion beyond the runway. She immediately reported the accident to her husband, who was a Battalion Chief based at a local fire station. She stated that she could clearly see the airplane prior to the accident, and observed the flashing strobe lights on both wings, as well as a white light. She did not see any smoke, fire, or vapors trailing from the airplane at any time. She reported that about 7 minutes after the accident, the area became enveloped in fog, such that she could no longer see the fire. An instrument rated pilot departed his house for the airport at 0610. He stated that the weather conditions en route to the airport were clear, and that he could see stars in the sky. Airport security records revealed that he opened the airport gate at 0615. After removing his airplane from the hangar, he noticed haze forming around the street lamps. Concerned that the area may soon become enveloped in fog, he expedited his preflight checks and started the airplane's engine. He began to taxi to runway 24, and as he reached the intersection of runway 21 and the taxiway, the lights for runway 24 turned off. He turned them back on, and lined up the airplane for departure. He could see the runway lights clearly, and observed clear skies directly ahead. He began the takeoff roll, and took off. Once he reached an altitude of between 100 and 200 feet, he entered a cloud layer and lost ground reference. He realized he was inadvertently beginning a left turn, and became slightly disoriented. He began to fly the airplane by reference to the instruments, and just as he was about to turn on the autopilot, the airplane broke out into clear skies. He continued the flight, reporting that the sky was completely clear once he was about 1 mile west of the airport. He was unaware that there had just been an accident, and while he did not see fire on the ground, he stated that his focus was primarily with monitoring the airplane's flight instruments. The airplane did not accumulate any ice during takeoff and initial climb. Only one of the surviving passengers recalled the accident sequence. She was located in an aft seat, and recalled that the pilot performed an uneventful preflight inspection, engine start, and taxi. The airplane then began the takeoff roll, and shortly after rotation, she felt it turn to the right. She was surprised that the airplane turned so soon, because she did not think they had gained enough altitude. She did not hear anyone talk during takeoff, and the pilot did not voice any concerns. Her next recollection was of waking up on the ground. MEDICAL AND PATHOLOGICAL INFORMATION A postmortem examination was conducted on the pilot by the Coconino County Health Department, Office of The Medical Examiner. The cause of death was reported as the effect of multiple blunt force injuries. Toxicological tests on specimens from the pilot were performed by the Federal Aviation Administration (FAA) Civil Aerospace Medical Institute (CAMI). The results were negative for carbon monoxide and ingested ethanol, and the specimens were unsuitable for Cyanide analysis. The report contained the following findings for tested drugs: >>Diclofenac detected in Urine >>0.993 (ug/mL, ug/g) Lorazepam detected in Urine >>0.011 (ug/mL, ug/g) Lorazepam detected in Blood Refer to the toxicology report included in the public docket for specific test parameters and results. The pilot held a third-class medical certificate issued in March 2010, with the limitations that he must have available glasses for near vision. He reported on his most recent application for a medical certificate the use of prescription medications for the treatment of Gastro Esophageal Reflux Disease (GERD) and hypothyroidism. Based on the thyroid condition, he was issued a 6-year authorization for special issuance of a medical certificate. As such, he was required to provide the FAA with a status of the condition prepared by his treating physician every 24 months. In September 2010, he provided a letter from a Doctor of Naturopathic Medicine, rather than his regular healthcare provider, stating that the thyroid condition was stable. Review of his personal medical records revealed that he had been regularly prescribed Lorazepam since 2007 for the treatment of “anxiety and agitation.” He did not report the use of Lorazepam on any of his previous medical certificate applications. According to CAMI, Lorazepam is a prescription benzodiazepine used for the management of anxiety disorders and for insomnia, with warnings that it may impair mental and/or physical ability required for the performance of potentially hazardous tasks. The therapeutic low and high blood levels are 0.1600 ug/mL, and 0.2700 ug/mL, respectively. PERSONNEL INFORMATION A review of FAA airman records revealed that the 66-year-old pilot held a private pilot certificate with a rating for airplane single-engine land issued in July 2003. No personal flight records were located, however, at the time of his last medical application, he reported a total flight time of 1,150 hours, with 60 hours in the previous 6 months. Family members reported that he flew the airplane regularly for business, and often early in the morning. AIRCRAFT INFORMATION The high-wing, fixed landing gear airplane was manufactured in 2008, and equipped with a turbocharged, six-cylinder Lycoming engine, and a McCauley three-blade constant speed propeller. The airplane was equipped with a Honeywell KC140 dual axis autopilot, and a Garmin G1000 Integrated Flight Deck, which included a primary and multifunction flight display. A conventional airspeed indicator, attitude indicator, and altimeter were provided as standby instruments. According to maintenance records, the airplane had undergone its most recent 100-hour/annual inspection on July 14, 2011. At that time, the engine, airframe, and propeller had accumulated 319 hours since manufacture. The most recent maintenance entry was for an engine oil and filter change, and occurred on January 24 2012, at a tachometer time of 354 hours. Damage to the airplane's instruments precluded an accurate assessment of the total flight hours at the time of the accident. Fueling records established that the airplane was last serviced on January 28, 2012, with the addition of 46.6 gallons of 100 low lead aviation fuel at Show Low Airport. METEOROLOGICAL INFORMATION Show Low Airport was equipped with an Automated Weather Observing System (AWOS), located north of the airport, adjacent to the threshold of runway 24, and 4,500 feet east of the accident site. An aviation routine weather report (METAR) was recorded at 0615. It reported calm wind; visibility 10 miles; 300 feet broken cloud ceiling; temperature -6 degrees C; dew point -7 degrees C; altimeter 30.15 inches of mercury. At 0635, the visibility had reduced to 8 miles, with a 200-feet overcast ceiling. Over the next 5 minutes the visibility decreased to 1 1/4 miles, and by 0651 freezing fog enveloped the airport, with 1/4-mile visibility and an overcast ceiling of 100 feet. According to a representative from Lockheed Martin Flight Service, the pilot did not request any weather services. Additionally, there was no record of him obtaining a weather briefing from any Direct User Access Terminal (DUAT) provider. The pilot utilized the AOPA (Aircraft Owners and Pilots Association) Internet Flight Planner to calculate his route the evening prior to the flight, but it could not be determined if he used this service for weather analysis. The flight planner indicated that his intended route of flight was on a northwest heading, direct from Show Low to Boulder City. According to the U.S. Naval Observatory, Astronomical Applications Department, the beginning of civil twilight began at 0649 in Show Low, with sunrise occurring at 0716. Moonset occurred at 0439. AIRPORT INFORMATION The airport was located about 1 mile northeast of the outskirts of Show Low, and was immediately surrounded to the north, east, and south by uninhabited terrain. Airport security records indicated that the pilot entered the airport at 0556. According to airport personnel, the pilot-operated runway lights will illuminate for 20 minutes before automatically switching off. WRECKAGE AND IMPACT INFORMATION The accident site was located about 1,700 feet north of the approach end of runway 6, at an elevation of 6,371 feet mean sea level. The wreckage came to rest in level terrain, adjacent to a water catchment basin. The area was comprised of soft dirt and rocks, lightly interspersed with brush and low trees. The first identified point of impact was characterized by a 10-inch-wide, 40-foot-long swath of excavated dirt. The ground excavation was oriented on a bearing of about 340 degrees magnetic. A section of wing tip rib was located at the initial disruption, and a green wing tip navigation lamp was located an additional 30 feet downrange. A second ground disruption began 25 feet northwest of the first impact point. This disruption was on a bearing of about 360 degrees, was 25 feet in length, and expanded to a width of 6 feet as it intersected the initial ground disruption. The second ground disruption was about 18 inches deep, and contained a segment of the right landing gear leg brake line, and a section of the nose landing gear scissor-assembly and shimmy-damper. Fragmented sections of the right landing gear wheel pant were dispersed around the area. The debris field continued 260 feet further to the main wreckage, and contained fragments of insulation material, the remaining nose landing gear assembly, the upper engine cowling, and the pilot's door. The red wing tip navigation lamp was located in the center of the debris field. The nose wheel was located about 200 feet beyond the primary wreckage. The primary airplane structure came to rest on a heading of 275 degrees. The main cabin had rotated onto its right side against a tree, exposing the inside of the aft cabin. The forward cabin flight instruments were mostly consumed by fire. The engine remained in line with the fuselage, but had separated from the firewall, and came to rest inverted. The right wing was folded underneath the engine, and sustained leading edge crush damage along its entire span, and thermal damage to the fuel tank. The left wing sustained leading edge crush damage to outboard section, starting at the flap/aileron junction, with similar thermal damage in the area of the fuel tank. All major sections of the airframe and engine were accounted for at the accident site. SURVIVAL ASPECTS Both deceased occupants remained buckled into their respective front seats, which had become detached and ejected from the airframe. The first surviving occupant, located in the aft right seat, remained buckled into his seat, which had also broken free from its moorings and come to rest against the aft bulkhead. First response personnel subsequently removed him from the airplane as it continued to burn. The second surviving occupant was positioned in the rear left seat, which remained attached to the airframe. She was able to unbuckle her belt following the accident, and extricate herself from the wreckage. All of the airplane's seats were equipped with a seatbelt airbag system manufactured by AmSafe. Examination revealed that all four airbags had deployed during impact. TESTS AND RESEARCH The following is a summary of the airframe and engine examination. No anomalies were noted that would have precluded normal operation. A complete report is contained within the public docket. Airframe The tail section remained intact, and partially attached to the aft cabin at the bulkhead, which exhibited longitudinal twisting damage to its skin sections. The vertical and horizontal stabilizers sustained minimal damage, with all of their respective control surfaces remaining attached. The elevator trim tab actuator was examined; the distance between the actuator housing, and the eye-bolt corresponded to a 5-degree tab-down (takeoff) position when compared to Cessna documentation. The rudder and elevator control cables were continuous from their flight control horns through to their respective cabin control termination points. The left and right aileron and both flaps remained attached to the wing, with their associated control cables continuous through to the wing root. The flap actuator motor was examined, and displayed actuator thread exposure consistent with a 20-degree flap position, when compared to Cessna documentation. The backup flight instruments were recovered, and sustained extensive thermal damage, which precluded a determination of their operational status at the time of the accident. Engine The engine remained largely intact, and had sustained thermal damage to the oil sump, intake manifold, and all ancillary components. All three blades of the propeller remained attached to the hub, which remained attached to the crankshaft. Two blades exhibited chordwise abrasions, leading edge gouges, and tip twist, with the third blade curled aft at the hub. The throttle, mixture, and propeller governor controls remained attached to their respective engine controls. The top spark plugs for all cylinders were removed. Visual inspection of the combustion chambers was accomplished through the spark plug bores utilizing a borescope; there was no evidence of foreign object damage and all valve heads appeared intact. The engine’s internal mechanical continuity was established through to the accessory case by rotation of the crankshaft by hand. Cylinder compression was attained on all cylinders, and the rockers and valves appeared to move appropriately. The turbochargers exhaust impellor blades appeared free of damage, with the assembly continuous to the intake impeller. The intake impeller’s six blades exhibited leading edge damage and bent and broken tips, with corresponding radial scoring of the intake chamber. The vacuum pump was separated from the engine, and exhibited thermal exposure to its case, mounting pad, and drive coupling. The internal cavity was exposed, and both the rotor and vanes appeared intact. ADDITIONAL INFORMATION No radar coverage was available for the accident site at the airport elevation. Additionally, while the airplane's Integrated Flight Deck was capable of recording flight data, the non-volatile memory card required to store such information was not located, and presumed to have either been consumed by fire, or not installed.

Probable Cause and Findings

The pilot’s encounter with low clouds/low visibility conditions during the initial climb, which resulted in spatial disorientation and loss of airplane control.

 

Source: NTSB Aviation Accident Database

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