CESSNA 172

Full Narrative

HISTORY OF FLIGHTOn October 28, 2021, at 1311, a Cessna 172M, N1870V, was substantially damaged when it was involved in an accident in Ukiah, California. The student pilot, the sole occupant, was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight.
 
The pilot was making a solo cross-country flight as part of his requirements in pursuit of a private pilot's license and had planned for a full stop landing at Ukiah Municipal Airport. According to FAA automatic dependent surveillance–broadcast (ADS-B) data, the airplane departed Napa County Airport at 1219 and flew a direct course to Ukiah, arriving in the traffic pattern from the southeast at 1308.

About that time, a witness, who was located near the north end of Runway 15 on the west side of the airport, noticed the airplane “porpoising” at the approach (north) end of Runway 15. He watched as the pilot initiated a go-around, and the airplane climbed with the flaps deployed. He did not think much more of it and looked away.

A security camera located about midfield on the west side of the runway captured the airplane during the initial climb phase of the go-around. The video revealed that the airplane climbed to about 60 ft agl and then assumed a level attitude, while still tracking over the runway. After reaching midfield, the airplane pitched down and descended toward the runway. The airplane’s nose struck the ground, separating the nosewheel, and the airplane continued to travel along the runway, until it passed out of the camera’s field of view behind a building. The engine could be heard operating throughout, and the airplane was not trailing smoke or vapors at any time during the video (figure 1).

Figure 1 - Composite image of flight path from security video – Runway 15, left to right
A witness located on the east side of the airport did not initially see the airplane but saw a cloud of dust appear at the end of Runway 15. He then watched as the tail of the airplane lifted up into view as it pitched down on its nose and rolled over onto its roof. PERSONNEL INFORMATIONThe pilot started his flight training in July 2021, about 3 months before the accident. He had accrued a total of 31.3 flight hours, all of which were in the same make and model as the accident airplane. The accident flight was the pilot’s fifth solo flight and his second solo cross-country flight. AIRCRAFT INFORMATIONThe airplane was owned and operated by Mike Smith Aviation, a Part 61 flight school. The owner of the flight school performed most of the airplane’s maintenance, including the annual and 100-hour inspections. AIRPORT INFORMATIONThe airplane was owned and operated by Mike Smith Aviation, a Part 61 flight school. The owner of the flight school performed most of the airplane’s maintenance, including the annual and 100-hour inspections. WRECKAGE AND IMPACT INFORMATIONThe airplane came to rest inverted on a grass verge adjacent to a diagonal taxiway on the right side of runway 15. Damage to the airframe was limited to the vertical stabilizer, rudder, leading edge tip of the left wing, and the windshield, which had shattered. The propeller exhibited evidence of runway contact including tip curl and multi-directional gouges and scratches.

Examination of the runway surface revealed a tire skid mark and gouge on the centerline about two thirds of the way down the 4,423-ft-long runway. The gouge matched the shape of the nose wheel rim and fork, which had detached and was recovered 350 ft downrange from the gouge. From the initial gouge, a scrape mark, along with 20 slash marks that matched the propeller blade tips continued 700 ft, progressively moving to the right of the runway centerline, and ending at the main wreckage (figure 2).


Figure 2 - Airplane flight track (red), ground track (blue). Runway damage, and airplane at accident location.
Following the accident, 1 ounce of water was drained from the gascolator, and 3 ounces of water were drained from the fuel tank drain in the left wing. The complete contents of both fuel tanks were then drained, and an additional 3 ounces of water were found in the left tank.

The flaps were in the retracted position: the elevator trim was set for takeoff: and the carburetor heat control and corresponding air door were in the off positions.

Examination of the airframe and engine revealed a series of maintenance discrepancies. These included seat rails worn beyond serviceable limits; an inoperative throttle friction lock; engine camshaft-lobe wear with accompanying metallic debris in the engine oil screen; and degraded and worn spark plug ignition cables and P-lead wires.

Fuel Tanks

Examination of the left tank revealed a leak had developed around the left fuel tank filler neck adapter assembly. The outboard tank strap had snapped, and there was extensive brown staining trailing aft of the fuel filler cap. The gasket that sealed the filler neck adapter to the tank had degraded and was no longer providing a seal. Silicon sealant was present in multiple areas inside the top wing skin consistent with an attempted leak repair.

The forward tank support pads had worn away, such that the lower wing skin stringer rivets were in direct contact with the tank. This contact had resulted in fretting damage to the underside of the tank.

There was a buckle in the lower tank skin that had resulted in a 3/16-inch-deep, 2 1/2-inch-long, and 3-inch-wide raised area just forward of the fuel supply screen (figure 3). The buckled area inside the tank had a pronounced fold that was discolored in a manner consistent with corrosion. A fuel level dipstick was found moving free within the left tank, and a fuel cap chain was found in the right tank.


Figure 3 – Inboard side of left fuel tank.
Cessna Single Engine Service Bulletin SEB 92-26, revision 1, provided a modification for installing additional fuel drains in the wing fuel tanks. The modification was designed to assist in the detection and removal of water or other contaminants in the wing fuel tanks. Although Cessna stated that compliance was mandatory, FAA regulations do not require adherence to service bulletins for Part 91 operations, and the bulletin had not been applied to the accident airplane. ADDITIONAL INFORMATIONThe San Francisco Bay and surrounding areas had received significant rainfall during the week leading up to the accident. The events broke multiple daily precipitation records, with Santa Rosa and Napa receiving 7.83 and 5.35 inches of rain, respectively, 4 days before the accident. The airplane was stored outside at Napa County Airport during those rain showers.

A flight instructor who had performed the logbook endorsement for the accident flight stated that he flew the airplane earlier in the morning. During the preflight inspection, he found a small quantity of water in the gascolator. He was surprised because although he had often seen water contamination in other airplanes, this was the first time he had seen it in the accident airplane. The airplane and engine performed without issue on that flight.

On the accident flight, just before departure, the accident pilot requested the airplane be fueled to capacity. The line technician who serviced the airplane stated that he added 7 gallons of 100 low-lead aviation gasoline, and as he was reeling the fuel line back into the fueling truck, he noticed the pilot checking the fuel quantity at the filler caps, and then collecting a fuel sample at the wing tank drains. A photo recovered from the pilot’s phone taken at 1158, 21 minutes before departure while on the airport ramp, showed a “fuel-check” sumping tool, held by the pilot. It contained clear light-blue fluid that looked like aviation gasoline. Below the blue fluid there was a small clear globule that appeared to be water.

The manager of the fixed base operator that supplied the fuel stated that no pilots of other aircraft supplied from the same fuel truck came forward to report any issues with the fuel. Additionally, fueling logs did not indicate the presence of water or contaminants present in the fuel tank farm or truck. Visual examination of a sample recovered from the drain of the fuel truck indicated that it was clear and bright, with no evidence of either entrained water or water slugs. FLIGHT RECORDERSThe pilot had installed a GoPro HERO digital camera to a suction mount on the left side of the windshield. The unit was connected to the airplane’s intercom and the pilot’s headset, such that it recorded the microphone audio as well as radio traffic communication. It recorded the preflight checks, takeoff and enroute segments, along with the landing approach.

The video was reviewed by a specialist from the National Transportation Safety Board Vehicle Recorders Division. It showed that after reaching the runup area, the pilot recited the before take-off checklist, which included a confirmation that the seatbelts were buckled. Before takeoff he exclaimed irritation that he had lost his pencil, and after takeoff he became animated, stating that he had lost and then found his pen. He continued to talk throughout the flight, citing reporting points and airplane parameters, and about 12 minutes after takeoff he turned the camera off.

The camera began recording again as the airplane approached Ukiah. Two airplanes were already in the traffic pattern, and the pilot reported his location while communicating with them. During the downwind landing leg, the pilot of the airplane ahead reported that he was extending the downwind leg to accommodate landing traffic. As the accident pilot began to recite the before landing checklist, and after reaching the carburetor heat and flaps section, he was interrupted and briefly alarmed as the airplane flew close to a bird. He then stopped talking, and the completion of the checklist items, which included confirmation that the seatbelts were buckled, was not heard.

As the airplane continued the left downwind leg for runway 15, a helicopter pilot reported that they were departing. The accident pilot transmitted that he had the traffic in sight and that he would extend his downwind leg. About 35 seconds later, he transmitted that he was turning left base. During the final approach leg, he stated, “alright, flap’s in, carb heat’s out, lights on, seventy.”

The landing approach to runway 15 was nominal, and the airplane appeared to flare just over the runway numbers. After reaching the 1000-ft runway markings, the camera captured a stroboscopic effect of the propeller, consistent with an increase in engine speed, and the pilot transmitted, “Cessna 172 going around.”

The airplane began to climb until 5 seconds later the stroboscopic effect of the propeller changed, and the airplane stopped climbing. The nose of the airplane then pitched down slightly, and the pilot stated, “whoa, whoa, whoa.” The recording then ended. MEDICAL AND PATHOLOGICAL INFORMATIONBennet Omalu Pathology performed the pilot’s autopsy at the request of the Mendocino County Sheriff-Coroner. The cause of death was head and face injury. According to the autopsy report, the pilot had heart disease and identified plaque causing a 90-95% narrowing of the proximal portion of the left anterior descending coronary artery. No other significant natural disease was identified.

Central Valley Toxicology, Inc., performed toxicological testing of blood and vitreous specimens from the pilot at the request of Bennet Omalu Pathology. No tested-for substances were detected.

The FAA Forensic Sciences Laboratory also performed toxicological testing of specimens from the pilot, detecting codeine in urine at 47 ng/mL and morphine in urine at 90 ng/mL. Neither codeine nor morphine was detected in heart blood.

Codeine and morphine are opioid substances that may be medicinal, illicit, or associated with poppy seed consumption. Morphine is a metabolite of codeine. Both codeine and morphine have potential to cause cognitive and psychomotor impairment. Medicinally, codeine and morphine are available by prescription to treat pain, cough, and diarrhea. An open prescription for codeine or morphine is generally disqualifying for FAA medical certification, although certification may be granted by FAA decision in certain cases of infrequent use for acceptable medical conditions. Regardless, the FAA states that a pilot should not fly after using either medication until adequate time has elapsed for it to be eliminated from the pilot’s system. Both codeine and morphine may be used illicitly, and both are metabolites of the illicit opioid drug heroin. Also, because codeine and morphine occur naturally in the poppy plant, both might be detected in the urine of a person who has consumed poppy seeds.

The pilot’s wife stated that she was not aware of her husband ever using prescription pain medication and that he had eaten a bagel with poppy seeds during the days leading up to the accident. SURVIVAL ASPECTSThe airplane came to rest inverted, and the pilot, who had been seated in the left seat, was partially ejected through the upper section of the windshield.

The pilot’s seat was found locked in place about the midrange position on the seat rails; its locking pins were intact and unbent; and the roller assemblies were within tolerance. The seat did not show any evidence of preimpact movement.

The pilot’s seat was equipped with a 3-point harness. Although the shoulder harness was attached to the center lap buckle, the lap buckle was found unlatched, and its strap was in the fully extended position.

Examination of the seat belt and buckle did not reveal any indications of damage or failure. The tongue could be latched into the buckle assembly with a positive click and released at a repeatable latch angle, and there was no evidence that the belt had stretched, bunched, or frayed.

Damage within the cabin was limited to the lower section of the left instrument panel, which included the circuit breaker panel, ignition and master switches, and fuel primer, all of which had sustained forward bending damage. The overhead speaker assembly in the forward cabin roof had sustained crush damage, and its plastic cover was broken on the left side.

A series of tests was performed to determine if the damage could be attributed to contact with the pilot during the accident sequence. The tests revealed that if the pilot had been securely buckled into his seat, he would not have been able to move forward and contact the damaged areas.

The pilot’s flight instructor stated that in addition to adherence to the standard pre-landing and pre-takeoff checks, his students are taught the “GUMPS” pre-landing flow, specifically:

“Gas (quantity checked and fuel selector on both), Undercarriage - confirmed down, Mixture - rich, Propeller - set for downwind leg/or high RPMs on final for constant speed propellers as appropriate, Seatbelts - seatbelts and shoulder harnesses on and secure, Switches - lights on.”

He stated that the pilot always wore his seatbelt and flying without it was not an option. The pilot’s wife also stated that he always used his seatbelt when driving and was insistent that others wore them too. TESTS AND RESEARCHVideo Study

The security camera video was analyzed by a specialist from the NTSB Vehicle Performance Division. The results indicated that by the time the airplane had reached midfield it was traveling at a ground speed of 52 kts and maneuvering about 50 ft above the runway. Over the next 7 seconds, the airplane accelerated to about 60 knots and climbed to 68 ft. With about 2,000 ft of runway remaining, it then began a 1,350 ft per minute descent, striking the ground about 1,670 ft from the runway end while traveling at a speed of 77 kts.

The airplane continued to travel along the ground over the runway and out of view for a further 20 seconds until the sound of the engine stopped.

Audio analysis indicated that the engine and propeller speed during the flight segment varied between 2,415 and 2,505 rpm, and after the ground collision, the engine continued to operate at a speed of about 2,150 rpm.