LAX07LA209

The student pilot experienced a partial loss of engine power while cruising at 5,500 feet mean sea level. The engine's rpm surged, became "very erratic," and partial power was lost. Despite application of carburetor heat and troubleshooting for causative factors, the pilot was unable to restore engine power. He made a precautionary landing at a nearby airport. With a faster than normal approach speed, the airplane touched down hard and bounced, and the student pilot lost directional control. Thereafter, the airplane veered off the runway and nosed over in a tomato field about 50 yards beyond the side of the runway. The operator maintained the airplane on a program of annual and 100-hour inspections. The last 100-inspection was performed about 35 hours prior to the accident flight. The post accident examination of the airplane's logbooks revealed record keeping deficiencies, and an examination of the engine revealed inadequate maintenance. For example, recording errors relating to the airplane's operating time were noted in the logbooks, and compliance entries for airworthiness directives were omitted. An examination of the engine revealed one spark plug was only finger tight, a cylinder had signs of excessive oil on its spark plugs, and it appeared not to be firing. All four bottom plugs had excessive carbon buildup and were fouled, and the intake air filter was dirty and partially plugged. No sole cause for the loss of engine power was ascertained.

History of flight

On July 8, 2007, about 1410 Pacific daylight time, a Cessna 152, N95038, experienced a partial loss of engine power during cruise flight. In response to the emergency, the student pilot made a precautionary landing at the New Jerusalem (uncontrolled) Airport, Tracy, California. The airplane touched down hard and bounced, and the student pilot lost directional control. Thereafter, the airplane veered off the runway and nosed over in an adjacent tomato field, about 50 yards beyond the left side of runway 12. The airplane's wings, vertical stabilizer, and firewall were bent, and the airplane was substantially damaged. The pilot sustained a minor injury. The airplane was operated by California Airways, Hayward, California. Visual meteorological conditions prevailed at the time of the solo instructional flight, and a visual flight rules flight plan had been filed. The flight was performed under the provisions of 14 Code of Federal Regulations Part 91, and it originated from Hayward about 1315.

According to the student pilot's flight instructor, while the student was cruising en route about 5,500 feet mean sea level on his long cross-country flight, the engine's rpm began to surge. The student applied carburetor heat, but this action did not restore engine power or remedy the "very erratic" engine rpm experience. The pilot continued to troubleshoot the situation while preparing for a landing at an airport he had observed.

The student reported to the National Transportation Safety Board investigator that he fully retarded the engine's throttle on final approach, and he lowered the wing flaps. The airplane's approach speed was faster than normal, and the runway's surface felt rough. The pilot stated he did not know why he lost control during landing rollout.

Personnel information

The student pilot had a total of 107.1 hours of flight time, of which 59.2 hours were received during the preceding 90 days. The pilot had received solo flight and solo cross-country endorsements on June 8, 2007, and July 3, 2007, respectively.

Meteorological information

Stockton Metropolitan Airport is located about 15 miles from the accident site. At 1355, Stockton reported, in part, the following weather: Sky clear; wind variable at 6 knots; and temperature/dew point of 33/15 degrees, Celsius.

Airplane records and examination

The airplane was recovered from the accident site and examined by the Federal Aviation Administration (FAA) coordinator, under the direction of the Safety Board investigator. The Safety Board investigator reviewed extracts from the airplane and engine logbooks, as provided by the FAA coordinator. The review indicated that the airplane had been maintained following an annual and 100-hour maintenance program.

Recording errors relating to the airplane's time were noted in the logbooks. The Safety Board investigator's reconstruction of the recorded operating times indicated that, at the time of the accident, the airplane's total time was about 7,168.75 hours. The engine's time since receiving its last major overhaul was about 2,693.61 hours. The airplane had been operated 34.87 hours since receiving its last 100-hour inspection on June 16, 2007.

The FAA coordinator examined the airplane wreckage and, in summary, provided the following statement of findings:

According to the oil filter label, the last oil change was performed on June 15, 2007, at a tachometer time of 4,563.1 hours. All spark plugs were removed and examined. The bottom number 3 plug was NOT tight and was removed using fingers. Cylinder number 2 had signs of excessive oil on the plugs and appeared not to be firing. All four bottom plugs exhibited excessive carbon buildup and fouling. It appeared from the spark plugs on cylinders number 1 and 3 that they were operational at the time of the accident. The engine appeared to be running cooler than normal, with intermittent missing (gulping). The air filter appeared dirty and partially plugged. A bracket air filter was installed, pursuant to a supplemental type certificate. This filter requires an inspection to be performed at every preflight. The air filter appeared to be over 90 percent dirty. Operational requirements limit the dirt to not more than 50 percent. As evidenced by the oil level on the dipstick, the oil sump contained 5 quarts of oil. Fuel drained out of the fuel strainer. A flexible fuel line fitting was found loose and could be removed using only fingers. The carburetor finger screen was clean. Neither of the screws that held the finger screen on the carburetor plunger were safety wired, and one of the screws had a stripped head. The crankshaft was rotated by hand, and no evidence of internal mechanical damage was noted. Both magnetos produced spark.

The maintenance record review revealed that neither airworthiness directive (AD) number 87-20-03 (Seat Rail inspection) nor AD 76-07-12 (Bendix ignition switch inspection) were signed off during the last 100-hour inspection.