History of Flight
On June 7, 2014, about 0700 mountain daylight time, an experimental light sport North Wing Apache Sport weight-shift-control trike, registration N2804P, collided with terrain following takeoff from Polson Airport, Polson, Montana. The private pilot, the sole occupant, sustained fatal injuries. The aircraft was destroyed. The local flight departed Polson about 0658. Visual meteorological conditions prevailed; no flight plan was filed.
The trike's owner stated it was originally equipped with a Mustang III 19-meter wing, which he determined was larger than needed. He ordered a 15-meter wing scheduled to arrive in eight weeks. The accident pilot owned a similarly equipped trike with floats and asked to use the 19-meter wing, offering his 16-meter wing in the interim. The owner agreed. The day before the accident, the pilot flew the trike for about 20 to 30 minutes with the original 19-meter wing installed.
Later that night, after dinner, both spent the evening assembling and attaching the 16-meter wing, completing installation by 2300. They reviewed the installation, and the pilot stated he would test fly the trike in the morning, cautiously take off, fly low over the runway to ascertain handling characteristics, and if controllable, continue climb and perform practice maneuvers.
The owner observed the takeoff. He reported the trike rotated from runway 36, climbed in a controlled manner, turned left, then left again onto a left downwind leg. At midfield, it turned left crossing the runway heading east over the fairgrounds. The owner felt the trike performed as expected and appeared under control.
Shortly thereafter, it began a steep 360-degree turn. The owner was initially unconcerned because the pilot habitually performed tight descending turns. The turn continued into a "corkscrew" descent. Concerned, the owner hoped to see the ballistic recovery parachute deploy but it did not; the aircraft disappeared from view. He estimated the aircraft made between six and eight revolutions during the descent.
Another witness in a recreational vehicle park east of the airport observed an "ultralight" aircraft from the airport direction at an appropriate altitude. He initially thought it was his friend flying and waved. He observed the pilot's arm moving and assumed a wave back. The aircraft then initiated a steep, rapid banking turn that quickly progressed into a spin, continuing spiraling until descending out of view. A witness in a boatyard east of the runway reported the initial turn was so aggressive he could see the complete profile; he estimated the bank angle between 45 and 60 degrees, and the engine was operating at high power throughout. The turn transitioned into a spiraling descent with the engine still operating. It passed behind a trailer, and he heard a thud. None of the witnesses observed the ballistic recovery parachute deploying.
The aircraft came to rest in the northwest corner of a recreational vehicle park, about 1,800 feet east of the runway midfield position. The debris field was about 30 feet long. The first point of impact was a 1-foot-wide excavation in the grass, followed 15 feet downrange by a 4-foot-wide by 10-foot-long soil excavation. Fragmented fuselage components and the nose wheel assembly were distributed to the main wreckage. The trike came to rest inverted, partially covered by the wing, which was upright. The pilot was ejected from the wreckage and located adjacent to the wing. His Lynx Avionics Micro helmet was found intact and unbuckled just beyond the main debris field.
Aircraft Information
Construction of the trike, serial number JENSEN761944, was completed in September 2005. In January 2008, it was issued a special airworthiness certificate as an experimental operating light-sport weight-shift-control aircraft. The basis was for an existing aircraft without an airworthiness certificate that did not meet Federal Aviation Regulations Part 103.1 criteria. At application, the owner reported total airframe flight time of 72 hours.
It originally had a Rotax 503 UL DCDI, 50-horsepower, 2-cylinder, 2-stroke engine. Five months and 6.25 flight hours after certificate issuance, the engine was removed and replaced with a Rotax 912 UL, 80-horsepower, 4-cylinder, 4-stroke engine, serial number 4407754. The logbook indicated a series of Phase 1 flight tests totaling 5.8 hours, documenting a new gross weight of 1,097 pounds, empty weight of 512 pounds, and use of a North Wing MP 17 wing.
On April 26, 2012, a North Wing GT5 wing was installed. On October 4, 2013, a North Wing Mustang III 19-meter wing was installed at the time of the last annual inspection. The wing was replaced by a North Wing GT5 wing on November 15, 2013, after which the trike underwent Phase 1 flight tests totaling 5.1 hours. As of the annual inspection, total flight time since airworthiness certificate issuance was about 90 hours.
Medical and Pathological Information
The 62-year-old male pilot held a private pilot certificate with airplane single-engine land rating issued in 1973, upgraded to multiengine in 1983. He reported 975 total flight hours as of his last medical examination on December 23, 2009. He was 67 inches tall and weighed 191 pounds. A flight logbook was not located; the trike owner stated the pilot had been flying weight-shift aircraft for many years.
Review of prior medical certificate applications revealed a history of high blood pressure, and in 2004 he was diagnosed with coronary artery disease requiring a stent. In 2009, he reported medications including aspirin, enalapril, hydrochlorothiazide, and atorvastatin. His certificate was initially deferred, then issued as a third-class special issuance limited to needing glasses for near vision, marked "Not valid for any class after 12/31/2011." FAA regulations do not require a current medical certificate to operate light sport aircraft as long as the most recent has not been suspended or revoked.
According to FAA medical review, he passed a stress thallium test in 2009 and an exercise stress test in 2010; since he did not renew his medical certificate, no further clinical information regarding his coronary artery disease is available.
An autopsy was performed by the Forensic Science Division, Montana Department of Justice. The cause of death was blunt force injuries; manner of death was accident. The pathologist noted heart abnormalities: the posterior descending coronary artery was supplied by the right coronary artery, a stent was in the proximal right coronary artery, and the remainder of coronary arteries had atherosclerosis producing no greater than 25-50% stenosis. A subendocardial 0.5 cm white fibrous scar was found in the inferior wall of the left ventricle.
Toxicology testing by the FAA's Civil Aerospace Medical Institute identified: atenolol and tamsulosin in muscle and liver; zolpidem in blood and liver; hydrocodone in liver (0.037 ug/g) and blood (0.164 ug/ml) with its metabolite dihydrocodeine in liver; tramadol in vitreous (2.918 ug/ml), brain (7.251 ug/g), blood (14.469 ug/ml), liver (26.948 ug/g), and gastric contents (336.45 ug/ml), with its active metabolite O-desmethyltramadol in blood, gastric contents, and vitreous.
Atenolol is a beta blocker for high blood pressure; tamsulosin treats enlarged prostate; zolpidem is a sedative for insomnia (Schedule IV controlled substance); hydrocodone is an opioid analgesic (Schedule II); tramadol is an opioid analgesic (Schedule IV). Both hydrocodone and tramadol carry warnings about impairment in mental/physical ability for hazardous tasks; tramadol also warns of seizure risk.
Tests and Research
Primary airframe and wing components sustained crush damage with buckling, bending, or fracturing consistent with ground impact. The trike mast remained at a hang point position 54 inches from the keel nose plate, showing no movement indications; this distance appeared appropriate for Mustang III 15-meter wing specifications (54 inches +/- 1.5 inches).
The wing canvas was intact except for a 16-inch-long tear near the center crossbar junction. Leading edge tubes were intact; wing crossbars split midspan. All wing ribs were intact in pockets; cross tubes and kingpost were intact. The control bar was bent about 30 degrees midspan; both control frame vertical struts separated midspan. The keel tube separated into three sections about 2 feet forward and 3 feet aft of the mast. All cables were intact at fittings except the cable connecting the right side of the lower control frame to the aft keel, which separated at the swage on the control bar with "cup and cone" failure signatures consistent with overload (impact) failure.
The wing was marked "North Wing - APEX" with no serial or model number. A North Wing representative stated the wing was a model manufactured under previous ownership, designed for a smaller, single-place trike application with a gross weight limit of about 850 pounds. The representative stated the mast position of 54 inches was appropriate.
The engine remained attached to the airframe with no indications of catastrophic failure. The three-bladed composite propeller remained attached to its hub at the engine gearbox; one blade fractured midspan and remained partially attached; the remaining blades had leading edge nicks. The fuel tank was ruptured; according to the owner, it contained about 12 gallons of fuel at takeoff. The pilot was in the front seat.
The ballistic recovery parachute activation handle had become detached from the airframe, was in the undeployed position, and its lockout safety pin was not present. The activating cable sustained damage to its outer sheeting, presumably during impact; the rocket appeared to have fired from the launch tube, partially extracting the parachute from the canister. The attachment bridles remained tied on airframe structural members. The damage was consistent with parachute deployment during the impact sequence when the activation cable and handle detached from the airframe. A warning on the activation handle stated the engine must be shut off before deploying the parachute.