Monday, May 29, 2017

North Wing Apache Sport, N51311: Fatal accident occurred June 18, 2015 near Taos Regional Airport (KSKX), New Mexico

Herbert "Buzz" Waterhouse

The National Transportation Safety Board traveled to the scene of this accident.

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Albuquerque, New Mexico

Aviation Accident Factual Report - National Transportation Safety Board:

Investigation Docket - National Transportation Safety Board:

NTSB Identification: CEN15FA277
14 CFR Part 103: Ultralight
Accident occurred Thursday, June 18, 2015 in Taos, NM
Aircraft: NORTHWING DESIGN APACHE SPORT, registration: N51311
Injuries: 1 Fatal.

NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.


On June 18, 2015, about 0738 mountain standard time, a North Wing Apache Sport powered-lift aircraft, N51311, impacted terrain following a loss of control during initial climb after takeoff from Taos Regional Airport (SKX), Taos, New Mexico. The sport pilot sustained fatal injuries, and the aircraft sustained substantial damage. The aircraft was registered to the pilot/owner and was being operated as a 14 Code of Regulations (CFR) Part 103 personal flight. Day visual meteorological conditions existed at the time of the accident near the accident site, and a flight plan had not been filed for the local flight, which departed about 0736. 

Several witnesses who were working on the departure end of runway 22 reported seeing the aircraft take off from the runway, climb to about 500 ft, and then enter a right turn. The witnesses stated that the aircraft seemed to "fall out of the sky" and stall before it collided with terrain adjacent to and right of the departure end of the runway. One witness stated that he heard the engine revving before impact. See figure 1 for an overhead image of SKX and the accident location.


The 69-year old pilot held a sport pilot certificate for powered-lift aircraft. A review of the pilot's logbook revealed that he had 540 total flight hours, all of which were in powered-lift aircraft and 300 hours of which were in the accident aircraft. According to logbook entries, the last time that the pilot had flown the accident aircraft was August 9, 2014. The most recent entry in the pilot's logbook was dated September 8, 2014, in which he flew another aircraft of the same make and model. Interviews with a family member and a friend of the pilot confirmed that this was pilot's last flight before the accident flight. The family member stated that the pilot kept meticulous records. According to an entry on the last page of his logbook, the pilot had successfully completed a flight review in accordance with 14 CFR Section 61.56(a) on November 22, 2014. The entry was signed by a flight instructor, but the number of flight hours for that flight were not recorded. 


The two-seat, powered-lift aircraft, serial number 4608087, was manufactured and owned by the pilot since 2003. The aircraft had a special airworthiness certificate classifying its operation in the experimental light sport aircraft category. 

The aircraft was powered by a rear-mounted engine, Rotax model 582 UL. According to a friend of the pilot, the aircraft was in good condition, was well maintained by the pilot, and had been stored in an airport hangar since it was new.


SKX is a public airport located about 8 miles northwest of Taos at an elevation of 7,094 ft mean sea level. SKX's principal runway is 4/22, which is 4,083 ft long and 75 ft wide and surfaced with asphalt. A postaccident examination of the runway revealed no abnormalities, and no aircraft parts were found along the takeoff path.


At 0713, the routine aviation weather report for SKX was calm wind, no ceiling, clear skies, visibility 10 statute miles, temperature 18°C, dew point 8°C, and an altimeter setting of 30.35 inches of mercury.


On-site examination of the aircraft, including the flight controls, structure and engine, revealed no evidence of any mechanical anomalies. Grounds scars and the orientation of the wreckage were consistent with the aircraft impacting the ground in a nose-low attitude. No manufacturing anomalies were noted with the aircraft. The wooden propeller assembly was shattered and exhibited signatures consistent with the engine producing power at the time of impact. See figure 2 for a photograph of the accident site and wreckage. 



The University of New Mexico Health Sciences Center, Office of the Medical Investigator, performed an autopsy on the pilot. The cause of death was reported to be "multiple blunt force injuries," and the manner of death was reported to be "accident."

The autopsy identified significant coronary artery disease with 80% stenosis of the proximal left anterior descending coronary artery, as well as increased interstitial fibrosis (scarring) of the wall of the heart. The thickness of the right ventricular wall was significantly increased at 0.7 cm (average thickness is 0.3 cm). In addition, there was evidence of arteriosclerosis in the kidneys and extensive emphysema in the lungs. 


The Federal Aviation Administration's (FAA) Bioaeronautical Research Laboratory performed toxicology testing of specimens from the pilot. The testing detected sildenafil, its metabolite desmethylsildenafil, and zolpidem in the urine and blood (0.003 ug/ml of zolpidem in blood). In addition, 0.0036 ug/ml of tetrahydrocannabinol (THC) and 0.0105 ug/ml tetrahydrocannabinol carboxylic acid (THC-COOH) were identified in the cavity blood. THC-COOH was also identified in the liver (0.0219 ug/ml) and brain (0.0012 ug/ml).

Sildenafil is a prostaglandin inhibitor used to treat erectile dysfunction or pulmonary hypertension and is not impairing. Zolpidem is a short-acting prescription sleep aid and is a Schedule IV controlled substance that carries the warning, "May impair mental and/or physical ability required for the performance of potentially hazardous tasks (e.g., driving, operating heavy machinery)." Therapeutic levels of zolpidem are typically between 0.0250 and 0.3000 ug/ml.

THC is the psychoactive compound found in marijuana, and THC-COOH is its inactive metabolite. THC concentrations typically peak while smoking, whereas THC-COOH concentrations typically peak about 9 to 23 minutes after the start of smoking. Significant performance impairments are usually observed for at least 1 to 2 hours after using marijuana, and residual effects have been reported up to 24 hours.

Medical History

Attempts were made to locate the pilot's primary physician and obtain his personal medical records, but according to the pilot's wife, the physician had recently retired and left town. Therefore, no personal medical records were made available for review. The pilot's wife reported that he had shortness of breath and often used an inhaler to treat it.


The wreckage was released to the owner's representative.

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