History of Flight
On June 24, 2013, at 1255 Pacific daylight time, a Cessna P337H, registration N337LJ, collided with a power distribution line, a building, and a delivery truck following a touch-and-go landing at San Luis Obispo County Regional Airport, San Luis Obispo, California. The airplane was operated by the pilot under 14 CFR Part 91 as a personal cross-country flight with a planned destination of Palo Alto Airport, California. Visual meteorological conditions prevailed, and no flight plan was filed.
The pilot had reported to a friend that the rear engine was "stuttering" during throttle advancement in the month prior, a problem that worsened over the two weeks before the accident. Maintenance at PCF Aviation in San Luis Obispo attempted diagnosis about one week prior but could not determine the cause; the pilot asked them to stop. Another mechanic at Advantage Aviation in Palo Alto had also attempted diagnosis about two weeks prior and recommended the governor control be overhauled. The pilot planned to fly the traffic pattern and, if all was well, continue to Palo Alto for further maintenance.
The departure was uneventful. After one circuit, the pilot requested a touch-and-go on runway 29. Video recordings showed the airplane used nearly the full runway for the ground roll, climbed to about 70 feet agl with gear retracted, then to about 150 feet agl. The pilot transmitted "Mayday Mayday" followed by a broken transmission. The airplane then descended, colliding with power lines, a building, and a truck. Witnesses reported unusual engine sounds.
Personnel Information
The 44-year-old pilot held a private pilot certificate with single-engine land rating issued in 1998 and a multiengine land rating added in May 2013. At that time he reported 82 total hours in airplanes (23 as PIC, primarily in a Cessna 152) and 29 hours in rotorcraft. His logbook showed 22 hours of multiengine training in a Piper PA-44 and 14 hours of dual instruction in the accident airplane. His last logbook entry on June 3, 2013, indicated 118 total hours, including 2.8 hours as PIC in the accident airplane. He held a third-class medical certificate issued in March 2013 with no limitations.
Aircraft Information
The 1978-model Cessna P337H was a pressurized, high-wing, centerline-thrust multiengine airplane powered by two Continental TSIO-360 turbocharged engines with McCauley two-blade constant-speed propellers. The pilot purchased it two months prior. The last maintenance entry was a 100-hour/annual inspection on March 22, 2013, at 2,096.2 total airframe hours. Front and rear engines had 1,110 and 616 hours since factory rebuild, respectively.
A work order dated one week before the accident documented rear engine stuttering at 2,000 rpm; maintenance could duplicate but not resolve the problem. The order noted adjusting the aft idle mixture, swapping fuel components, and finding excessive play in prop governor linkage. The pilot declined further troubleshooting.
Wreckage and Impact Information
The main wreckage came to rest against a building and a truck about 1 mile west-northwest of the departure end of runway 29. Initial impact was with three power distribution lines; two lines were separated from insulator supports on a 35-foot pole. Two pine trees were topped at 35 feet, and a second tree showed a 40-foot-wide swath of cut branches. The building's east wall had paint transfer marks. The cabin was consumed by fire. The flap actuator indicated 10-degree flap deployment. Landing gear was stowed. Engine controls were full forward except the rear mixture control, which was about 10 degrees short of full forward. Both propellers showed damage consistent with a flat pitch (power) setting.
Tests and Research
Both engines were examined at Continental Motors. The rear engine had thermal damage; due to fire, a test run could not be performed, but disassembly revealed no pre-impact anomalies. The front engine had the right magneto timed at 1 degree after TDC instead of the nominal 20 degrees before TDC. A test run with the magneto in that position achieved only 1,850 rpm at full throttle versus the expected 2,400 rpm. After correcting the timing, the engine ran normally and achieved maximum rpm. The original left magneto functioned normally on a test stand.
Additional Information
The airplane's POH included emergency procedures for single-engine operation after takeoff, specifying feathering the inoperative propeller, retracting flaps and gear, and maintaining 89 KIAS (80 KIAS with obstacles). A single-engine climb rate of 440 ft/min was possible under specified conditions. The sea level landing distance using short field technique was about 810 feet.