Introduction
On February 1, 2008, at 0830 Pacific standard time, a single-engine Cessna 152 (registration N49811) operated by West Valley Flying Club experienced a loss of engine power during takeoff and subsequently landed hard on runway 13 at Palo Alto Airport of Santa Clara County (PAO), Palo Alto, California. The positioning flight was conducted under 14 Code of Federal Regulations Part 91. The commercial pilot, the sole occupant, was not injured. The airplane sustained structural damage to the firewall and fuselage. Visual meteorological conditions prevailed for the local flight, which was originally destined for San Carlos Airport (SQL), San Carlos, California. No flight plan had been filed.
Sequence of Events
According to the pilot’s written statement, the previous day, maintenance work had involved finding a piece of baffling in the throat of the carburetor venturi. The carburetor was removed, cleaned, inspected, and reinstalled. On the morning of the accident, the pilot performed a post-maintenance run-up inspection and intended to return the airplane to SQL. After start-up, she performed a run-up with all indications normal. She then taxied to runway 31, where she conducted another run-up with no issues detected.
During the takeoff roll, the engine developed 2,300 rpm and all gauges were in the green. On climb-out, the pilot reported a 600-foot-per-minute climb at 70 knots. She lowered the nose to reduce the climb rate but left the throttle and mixture in the full forward position. At about 500 feet mean sea level (msl), the engine experienced a hesitation. The pilot decided she could not complete the pattern to land on runway 31 and instead made a 180-degree turn back to runway 13, informing the controller of her intent to land. With the runway in front of her, she reduced airspeed to just above a stall and performed several S-turns and a slip.
The pilot stated that the airplane was still high and she was concerned about overshooting the runway. About halfway down the runway, in an attempt to lose altitude, she reduced airspeed as much as possible, causing the sink rate to increase. She lowered the nose to slow the sink rate, then raised the nose again to flare prior to landing. However, the sink rate was too high, and she was unable to raise the nose before the aircraft struck the runway.
Inspection Findings
Rossi Aircraft, Inc., Palo Alto, California, performed an engine inspection. The inspection revealed that the bottom number 1 cylinder spark plug was excessively fouled with carbon deposits. The other spark plugs exhibited normal operating signatures. A compression check of all cylinders showed that cylinders 2, 3, and 4 had normal compression, while the number 1 cylinder had zero compression. Maintenance personnel reported blow-by past the piston rings and exhaust valve of the number 1 cylinder. The carburetor heat box was inspected with no damage noted that would have restricted airflow; however, the seals were missing. The carburetor was removed and inspected with no mechanical discrepancies noted; about 2 ounces of water were found in the fuel bowl.