N1870V

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 continue...