Palmer, AK, USA
N6353E
CESSNA 172
The student pilot was flying the airplane over a remote river valley as his friends and relatives were driving their all-terrain vehicles in the valley. The pilot executed a touch-and-go landing on a gravel bar, and, just after takeoff, the airplane entered a steep climb and turned to the left. During the left turn, the wings of the airplane rolled perpendicular to the ground, and it descended in a near-vertical, nose-down attitude to ground impact. A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions that would have precluded normal operation. The flight profile was consistent with the pilot exceeding the airplane's critical angle of attack, which resulted in an aerodynamic stall and loss of control at an altitude too low to allow for recovery.
HISTORY OF FLIGHTOn October 29, 2016, about 1445 Alaska daylight time, a Cessna 172 airplane, N6353E, sustained substantial damage when it impacted terrain following a loss of control during takeoff initial climb from a remote, gravel-covered bar adjacent to the Knik River, about 12 miles southeast of Palmer, Alaska. The student pilot sustained fatal injuries. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed for the personal flight, which originated from the Wasilla Airport, Wasilla, Alaska, at an unknown time. According to friends and relatives of the pilot, the pilot was flying for recreational purposes as they were driving their all-terrain vehicles (ATVs) in the Knik River valley area for recreational purposes. A friend of the pilot reported that, at 1444, the pilot executed a touch-and-go landing to the southeast on a gravel bar adjacent to the Knik River, near Friday Creek, and about 8.5 miles northwest of the Knik Glacier. The airplane then climbed to about 100 ft above ground level (agl) and turned left (north) toward Friday Creek. According to the witness, by the time the airplane got to the tree line, it had descended to about 75 feet agl. The airplane was "banked pretty hard" as it continued to turn and lose altitude. The witness observed that, as the airplane continued to turn toward a southeast heading, it "dropped" and then impacted terrain. The witness reported that he did not hear any abnormal engine sounds or any sounds of the engine "revving up" before the impact. He further reported that the pilot had been flying around the group of ATVs during the afternoon, and he did not hear any abnormal sounds emitting from the airplane. The witness estimated that, at time of the accident, the wind was coming from the upper Knik River valley, blowing "steady in a northwest direction," at an estimated speed of 20 to 25 mph with higher gusts. Two friends of the pilot, who submitted a joint witness statement, reported that, after the pilot executed the touch-and-go landing, the airplane "flew over directly in front of us" between 100 to 200 feet agl with an estimated headwind of 10 to 15 knots. They stated that the airplane was at "full throttle" and that it climbed to 300 feet agl and then turned left. They reported that they believed a gust of wind occurred at that moment and that the wings were then "perpendicular to the ground." The airplane "quickly fell" and "spun" 360° with a nose-down attitude and impacted the terrain nose first. The pilot's brother reported that, after the pilot executed the touch-and-go landing, the airplane was climbing, and it appeared the wind "hit him with a hard gust" and tried "pushing the plane around." He stated that the pilot attempted to correct the situation with rudder, but the wind was "too strong," and it "pushed" the airplane into the ground nose first. Video footage of the accident was downloaded from a GoPro camera that was recovered from the wreckage. The video showed the airplane configured with full flaps and descending toward the gravel bar. The airplane touched down on the gravel bar, and the pilot quickly retracted the flaps to about 10°. At no point during the airplane's ground roll did the nose wheel touch the gravel bar. The airplane then resumed flight and appeared to enter a steep climb shortly thereafter. As the airplane continued to climb, the pilot appeared to be looking toward the ground below and to the left of the airplane. Then, the pilot glanced forward toward the windscreen and instrument panel area before looking downward and to the left toward the ground again. The airplane was still in a steep climb, and the wings appeared to be level with the horizon in the roll axis. During the steep climb, as the pilot was looking downward and to the left, the airplane began to yaw to the left. As the airplane yawed, the pilot once again looked toward the front of the airplane; at the same moment, the pilot made a left roll control input on the airplane's yoke. The portion of the left aileron that was captured in the camera's view showed the aileron moving in a manner corresponding to the left roll command. Within 2 seconds of the yaw onset and 1 second after the pilot's left roll control input, the airplane was in a near-vertical, nose-down attitude. The terrain visible in the background of the image suggested that the airplane began spinning to the left rapidly as the nose pointed vertically toward the ground. The video file then showed an area of corrupted video that lasted a few seconds. When the recording resumed, it showed the airplane spinning to the left in a steep nose-down attitude, which continued to ground impact. The pilot appeared to be conscious and alert as the airplane impacted the ground. The video file did not record audio. For further information about the video footage, refer to the Vehicle Recorder Laboratory Factual Report in the public docket for this investigation. WRECKAGE AND IMPACT INFORMATIONThe NTSB investigator-in-charge (IIC) and a Federal Aviation Administration (FAA) Anchorage Flight Standards District Office (FSDO) aviation safety inspector (ASI) traveled to the accident scene on October 30, 2016, via helicopter. The accident site was in an area of flat, gravel-covered terrain north of the Knik River with heavy vegetation to the north. The area was surrounded by steep, mountainous terrain. The airplane was resting in a nose-down attitude on about a 100° magnetic heading. Scattered forward (east) of the airplane were small portions of broken windscreen, various pieces of hardware, and two sections of the fractured propeller. All the airplane's main components were found at the wreckage site. The airplane's cabin was heavily crushed and compressed aft, and both wings were partially separated at the wing root areas. The metal cockpit "v-brace" behind the windscreen area was found bent outwards. The fuselage was slightly angled to the left, and the empennage was elevated about a 45° angle off the ground. The cockpit was severely damaged with extensive deformation. The windscreen was segmented and separated with all windscreen material shattered or missing. The right and left yokes were found bent downward. The throttle, mixture, primer, and carburetor heat controls were found in the full forward positions. The magneto switch was found in the both position. The cabin aft of the cockpit contained various airplane maintenance items (such as bottles of oil, cargo straps, and paper towels) along with an airplane environmental cover. Both cockpit doors were found separated. The nose landing gear was found separated, and the left and right main landing gears were intact. Both wings displayed impact crushing and bending with both lift struts bent. Both fuel cells exhibited minor leaking, and both fuel cells were tested for the presence of water with negative results. The engine compartment was heavily crushed, and the engine cowling was heavily fractured. Oil leakage from the engine case was present. The spinner for the two-blade metal propeller was deformed. The propeller remained attached to the crankshaft flange. One propeller blade was intact and partially buried in the gravel. The other propeller blade was fractured into three pieces. The wreckage was recovered and transported via helicopter external load to a secure facility in Wasilla. On November 29, 2016, a wreckage examination and layout were done under the direction of the NTSB IIC. Also present were an ASI from the FAA Anchorage FSDO and air safety investigators from Textron Aviation and Continental Motors. During the examination, no evidence of preimpact mechanical malfunctions or failures with the airframe and engine were noted. ADDITIONAL INFORMATIONThe FAA's Airplane Flying Handbook, FAA-H-8083-3A, states the following about stall awareness. The key to stall awareness is the pilot's ability to visualize the wing's angle of attack in any particular circumstance, and thereby be able to estimate his/her margin of safety above stall. This is a learned skill that must be acquired early in flight training and carried through the pilot's entire flying career. The pilot must understand and appreciate factors such as airspeed, pitch attitude, load factor, relative wind, power setting, and airplane configuration in order to develop a reasonably accurate mental picture of the wing's angle of attack at any particular time. It is essential to flight safety that a pilot take into consideration this visualization of the wing's angle of attack prior to entering any flight maneuver. MEDICAL AND PATHOLOGICAL INFORMATIONThe Alaska State Medical Examiner, Anchorage, Alaska, conducted an autopsy of the pilot. The cause of the death for the pilot was attributed to multiple, blunt force injuries. The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicology tests on specimens from the pilot that were negative for carbon monoxide, ethanol, and drugs.
The student pilot's exceedance of the airplane's critical angle of attack during a steep climbing turn following a touch-and-go landing, which resulted in an aerodynamic stall at too low of an altitude to recover.
Source: NTSB Aviation Accident Database
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