N337LJCessna P337H

On June 24, 2013, at 1255 Pacific daylight time, a Cessna P337H, N337LJ, collided with a power distribution line, building, and delivery truck following takeoff from San Luis Obispo County Regional Airport, San Luis Obispo, California. The airplane was registered to CSC Solutions LLC, and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91. The private pilot/owner sustained fatal injuries; the airplane was destroyed by impact forces and a post impact fire. The cross-country personal flight departed San Luis Obispo at 1254, with a planned destination of Palo Alto Airport of Santa Clara County, Palo Alto, California. Visual meteorological conditions prevailed and no flight plan had been filed.

According to a friend of the pilot, during the month leading up to the accident, the rear engine was "stuttering" as the throttle was advanced from idle to full power. The pilot reported that he was able to forestall the problem by advancing the throttle slowly. The friend had not experienced this problem, having flown with him on a number of occasions; however, the pilot stated to him that it had been getting worse during the 2-week period leading up to the accident.

PCF Aviation, at the pilot's home base of San Luis Obispo, began troubleshooting steps on the rear engine about 1 week prior to the accident. Although they could reproduce the problem, they could not definitively determine its cause, and the pilot asked them to discontinue the diagnosis.

Another mechanic at a maintenance facility (Advantage Aviation) located at Palo Alto Airport, stated that the airplane was brought to him about 2 weeks prior, and that he had attempted to diagnose the same problem. He briefed the pilot on the most likely cause, and was subsequently approached again by the pilot, who agreed to fly the airplane back to his facility on the day of the accident for further diagnosis.

The pilot had also made plans to depart on an international commercial flight from San Francisco International Airport (20 miles from Palo Alto by automobile) at 1925 later that evening. According to his wife, the reason for the flight was so that he could attend a time sensitive business meeting in Europe.

According to the pilot's friend, the pilot planned to fly the airplane in the traffic pattern, and if all was well, continue the flight to the maintenance facility in Palo Alto.

The airplane departed uneventfully and flew a single circuit in the traffic pattern. The pilot requested a touch-and-go landing, and while on the final approach leg for runway 29, an air traffic controller issued landing clearances to the pilot on three different transmissions. The pilot responded to the last transmission, accepting the clearance for the touch-and-go.

A series of security cameras were located at various positions along the length of runway 29. They captured video of various segments of the flight sequences. The recordings revealed that during the touch-and-go, the airplane appeared to utilize almost the full runway length for the ground roll. As it reached the runway overrun, it climbed to about 70 feet above ground level (agl) with the landing gear retracted. The climb progressed to about 150 feet agl and a short time later, the pilot transmitted, "Mayday Mayday". The tower controller responded, and a broken transmission of, "uh" was then received.

A camera located at a tire service center, about 1 mile west-northwest of the departure end of runway 29 recorded the airplane's departure path. The camera was facing northeast, and recorded the airplane flying on a northwest track at an altitude of about 150 feet agl. The airplane remained level and then began to descend out of view, and 4 seconds later, power to the camera was lost. About 20 seconds later power was restored, and a plume of smoke was seen in the vicinity of the airplane's descent path. The airplane collided with a power distribution line during the descent, temporarily shutting off power to multiple local businesses.

Multiple witnesses located at various locations within the airport perimeter recounted observations similar to the video recordings. They recalled that their attention was initially drawn to the airplane because it was producing an unusual sound during the departure roll of the touch-and-go. An air traffic controller reported that she heard the sound of a "bang," and looked below towards the airplane as it passed the control tower at midfield. Another witness described the airplane as making a "popping" sound, with another stating the sound was similar to a radial engine. A witness located at an FBO at midfield, stated that he looked up when he heard the sound of "propellers out of sync" and when he did so, he observed the airplane traveling northwest along the runway.

A witness who was in an airplane holding short of runway 29 was cleared to "line up and wait" by air traffic control personnel just after the accident airplane passed him on the runway after landing. The witness stated that as he looked up he perceived that the airplane was continuing on the runway for a long time. It finally rotated as it approached the runway end, and continued at a low altitude, flying in what he described as ground effect. It eventually transitioned to a shallow climb, with a steep angle of attack such that he could see the entire upper wing surface. The airplane then began to "mush" back down, remaining in the nose-high attitude, and rocking from side to side. It then began a rapid descent, followed a short time later by a flash.

The 44-year-old pilot was originally issued a private pilot certificate with ratings for airplane single-engine land in 1998. In May 2013, about a month before the accident, he was issued an additional rating for multiengine land. At that time he reported his total flight experience in airplanes was 82 hours, of which 23 hours he acted in the capacity of pilot-in-command, primarily in a Cessna 152. He also reported 29 hours of rotorcraft experience, with 1.1 hours as pilot-in-command.

The pilot's logbooks indicated his multiengine training utilized about 22 hours of flight time, and occurred in a Piper PA-44 during the period from April 6, 2013, through to his check ride on May 16, 2013. Over the following month he received about 14 hours of dual instruction in the accident airplane culminating in his high performance and complex-airplane endorsements. His last logbook entry was dated June 3, 2013, and indicated a total flight experience of 118 hours, of which 2.8 hours was logged as pilot-in-command time in the accident airplane.

A review of Federal Aviation Administration (FAA) airman records revealed that the pilot held a third-class medical certificate issued in March 2013 with no limitations.

The pressurized, high-wing, centerline-thrust multiengine airplane was manufactured in 1978, and purchased by the pilot 2 months prior to the accident. It was powered by two Continental Motors Incorporated TSIO-360 series turbocharged-engines and equipped with McCauley two-blade constant-speed propellers.

The last entry in the airplane's maintenance logbooks was a 100-hour/annual inspection, which was recorded as being completed on March 22, 2013. At that time, the airframe had accrued 2,096.2 total flight hours. The front and rear engines had accumulated 1,110 and 616 hours, respectively, since their factory rebuild.

A work order dated 1 week before the accident was provided by PCF Aviation, which documented the diagnosis of the rear engine. The order indicated that the engine stuttered at 2,000 rpm, and that maintenance personnel could duplicate the problem, but were unable to resolve the discrepancy. The "Action Taken" section of the order specifically stated:

"Adjusted aft idle mixture and check aft engine fuel pressures per Teledyne Continental SID97-3E. Fuel pressures satisfactory. Swapped fuel pump and flow divider from forward to aft engine. No change in aft engine. Returned fuel pumps to original configuration. Inspected aft engine for induction leaks, no discrepancies found. Stopped troubleshooting at owners request.... Found excessive play in prop governor assembly linkage. Notified owner that prop governor needed to be sent out for repair/overhaul."

The owner of PCF Aviation stated that he informed the owner that the airplane had not been repaired. The pilot stated that the problem was, "manageable" and that he would take it to another repair facility. The airplane then remained on the ramp, and was not flown again until the day of the accident.

In a post-accident interview, the mechanics at PCF Aviation who performed the diagnosis stated that the propeller blade pitch angle did not change while the engine was stuttering, and they therefore discounted a governor problem as the cause. They further stated that if the throttle was rapidly advanced the engine speed would reach 1,900 to 2,100 rpm, and then stutter and "oscillate" but not reach full speed.

A mechanic from Advantage Aviation in Palo Alto stated that he had performed troubleshooting steps about 2 weeks prior to the accident for the same problem, and that he recommended the governor control be sent to a repair facility for overhaul. Work orders for that visit indicated that the tachometer for the front engine was providing intermittent readings, and that this discrepancy was resolved by repairing the right-hand magneto ground.

Runway 29 at San Luis Obispo Airport was 6,100 feet long, by 150 feet wide, and comprised of asphalt. A 600-foot-long blast pad/stopway projected beyond the runway's departure end, and the area from the runway to the accident site was comprised of level open fields, transected by a two-lane road.

Following the accident, the runway was examined for remnants of foreign objects or recent propeller strike damage; none were found.

An autopsy of the pilot was conducted by the San Luis County Sheriff-Coroner's Office. The cause of death was reported as the effect of multiple blunt force trauma injuries, with significant contributing conditions including smoke inhalation, and extensive thermal injuries.

Toxicological tests on specimens recovered from the pilot were performed by the FAA Civil Aerospace Medical Institute. The results were negative for all screened drug substances and ingested alcohol. With the following findings for carbon monoxide, and cyanide:

18 (%) CARBON MONOXIDE detected in Blood

0.41 (ug/ml) CYANIDE detected in Blood

Refer to the toxicology report included in the public docket for specific test parameters and results.

The main wreckage came to rest adjacent to a building in a business park, 1 mile beyond, and directly in line with, the departure end of runway 29. The initial point of impact was characterized by damage to a series of three power-distribution lines located on the border of the street, which divided the building and a strawberry field. Two of the lines had become separated from their insulator supports on top of the 35-foot-tall wooden power pole. Two pine trees adjacent to the distribution lines were topped at the 35-foot level. A second tree, 50 feet to the northwest, exhibited a 40-foot-wide swath of cut branches at an angle 45 degrees relative to the ground. The debris field, consisting of tree branches and limbs, continued another 25 feet to the building. The building's east-facing wall was about 30 feet tall and constructed of cement blocks. The right wing was located on the roof of the building, just above a series of diagonal white, blue, and black paint transfer marks on the face of the wall. Additionally, the debris field, consisting of the rear engine's turbocharger inlet wheel and shroud, as well as cowling fragments, continued to the main wreckage, which had come to rest impinged against the front of a truck. The entire cabin area was consumed by fire and a fuel odor was present at the site.

The entire cabin structure and wing center section was consumed by fire, with burnt wire remnants, seating structure, and lower frame components remaining. The flap actuator jack screw displayed 2.9 inches of thread between the screw and actuator housing, which corresponded to 10-degree (1/3) flap deployment. The main and nose gear were in the stowed position. The engine controls within the cabin were in the full forward position, with the exception of the rear engine mixture control, which was about 10 degrees short of full forward.

The horizontal stabilizer had separated from the tailbooms and sustained crush damage along the entire length of its leading edge. The elevator and associated trim tab remained attached to the stabilizer; the elevator trim tab actuator position could not be determined accurately due to its cabling having been pulled through the structure during the impact sequence.

The propeller for the front engine remained attached to the crankshaft and exhibited leading edge gouges, chordwise scratches, and tip twist to both blades. The spinner along with the propeller hub dome sustained radial gouge marks.

The rear engine's propeller had separated at the crankshaft and was located behind the truck. Both blades remained attached to the hub; one blade exhibited 15 degrees bending along its entire length, the second blade had twisted about 60 degrees forward and exhibited chordwise scratches at the tip.

Both propeller domes contained markings consistent with the counter weights making contact with it during impact. The orientation and position of the markings were consistent with the propeller blades being at a flat pitch (power) setting.

Engine Examinations

Both engines were removed from the airplane and transported to the facilities of Continental Motors Incorporated (CMI) for examination by the NTSB investigator-in-charge and representatives from the FAA, Cessna Aircraft Company, and CMI. A complete examination report is contained within the public docket.

Rear Engine

The rear engine sustained thermal discoloration and sooting throughout.

Both magnetos remained attached to the crankcase; the spark plug leads were thermally damaged and continuous to the spark plugs. The propeller governor remained attached to the forward crankcase, with its control linkages continuous through to the firewall. The propeller synchronization motor and gears remained attached. The governor unit was removed and the input shaft rotated smoothly by hand. A brown-colored oil flowed from the passages of the unit and the screen was noted to be free of debris. The control arm moved freely. Disassembly revealed the pump gears, fly weight, and drive gear to be intact.

The engine driven fuel pump remained attached to the forward crankcase. An external examination revealed that it appeared undamaged, was coated in black soot, and all fuel lines were firmly attached at their fittings on the pump. The mixture control arm was bent; its control cable and eyebolt remained attached and continuous through to the firewall.

All upper ancillary components, including the fuel manifold valve, induction manifold risers, and fuel metering unit exhibited black discoloration. All lines to the fuel injection nozzles were intact with their fittings tight. The fuel pump and metering unit exhibited thermal damage to all internal components consistent with post-impact fire.

Due to the thermal damage sustained, an engine test run could not be performed. As such, the engine core was disassembled and the turbocharger examined; no anomalies were found that would have precluded normal operation.

Front Engine

The front engine remained partially attached to its mounts and had sustained varying degrees of impact damage to the sump, left magneto (which had broken away from the pad), both magneto harnesses, starter motor, and the number one cylinder.

The right magneto remained attached to the engine case, and did not display any obvious indications of damage. Its timing to the engine was tested utilizing a magneto synchronizer. The test revealed that the magneto points opened at 1 degree after top dead center (TDC) instead of the nominal 20 degrees before TDC. According to representatives from CMI, a 20-degree change in crankshaft angle corresponds to a circumferential change of 0.5 inches at the magneto flange, which equals about 16 degrees of angular rotation to the magneto.

The engine was installed in a test cell and an engine run was performed with the right magneto remaining in its as-found position of one degree after TDC. A replacement left magneto was attached and set to the same 1 degree after TDC position in an effort to gauge engine performance with two incorrectly timed magnetos. The engine started after two attempts and was run at 1,000 rpm for 5 minutes at which point the oil reached its standard operating temperature. The throttle was then advanced to a fully open position and the engine speed increased. The maximum speed that could be attained was 1,850 rpm at an indicated manifold pressure of 38.5 inHg; with the throttle in the full open position, the engine should have been able to reach a speed of at least 2,400 rpm. A magneto check was then performed in accordance with the Cessna P337H Pilots Operating Handbook (POH), and the engine speed was observed to drop 200 rpm for each magneto. According to the POH, the rpm drop should not exceed 150 rpm on either magneto, or 50 rpm differential between magnetos.

The left magneto was then set to the correct ignition timing of 20 degrees before TDC and another engine run was performed. The engine started immediately and responded smoothly to throttle inputs. A magneto check was performed at 1,800 rpm, and a drop of 20 rpm was observed when the left magneto was selected, and a drop of 240 rpm with the selection of the right magneto. The engine appeared to run normally and was capable of reaching maximum rpm.

A final series of engine runs were performed with both magnetos set to 20 degrees BTDC. The engine operated smoothly throughout its rpm range, and was able to achieve its maximum speed at a corresponding nominal manifold pressure.

A post engine test cylinder leakage test was performed in accordance with the latest revision of CMI Service Bulletin SB03-3 and normal pressure readings were attained.

The right magneto was subsequently removed and examined; the internal timing was correct, and no anomalies were noted that would have precluded normal operation. The original left magneto was installed on a test stand and operated at speeds varying between 500 and 2,100 rpm. All leads produced a spark in proper firing order and the impulse coupling triggered appropriately.

The airplane's POH documented the following emergency procedures for continuing a takeoff with an engine inoperative:

1. Throttles -- FULL FORWARD.

2. Propeller Controls -- FULL FORWARD.

3. Mixture Controls-- FULL FORWARD.

4. Inoperative Engine -- IDENTIFY from manifold pressure, RPM, fuel flow and EGT (if installed) indications....NOTE Verify inoperative engine by momentarily closing throttle and noting power response to throttle movement.

5. Windmilling Propeller-- FEATHER PROMPTLY.

6. Wing Flaps -- RETRACT slowly.

7. Airspeed-- 89 KIAS (80 KIAS with obstacles ahead).

8. Landing Gear -- RETRACT (after immediate obstacles are cleared).

9. Inoperative Engine -- SECURE.

Furthermore, a single engine rate of climb of 440 feet per minute would have been possible at sea level, with a temperature of 20 degrees C, under the following conditions:

-Weight 4,400 pounds

-Inoperative Propeller Feathered

-Flaps Up

-Gear Up

-37 Inches Hg

-Mixture Set at 140 PPH

-Cowl Flaps Open on Operating Engine

-Cowl Flaps Closed on Inoperative Engine

The sea level landing distance under similar conditions and utilizing the short field landing technique would have been about 810 feet.