History of Flight

On August 16, 2009, about 1121 Pacific daylight time, a Cessna 152, N67361, descended into terrain about 1/4-mile southeast of the Hesperia Airport, Hesperia, California. The airplane was registered to and operated by M.Y. AIR, a flight school based in Redlands, California. Visual meteorological conditions prevailed at the time of the personal flight, and no flight plan had been filed. The airplane was substantially damaged, and the private pilot and passenger were killed. The flight was performed under the provisions of 14 Code of Federal Regulations Part 91, and it originated from Redlands about 1040.

M.Y. AIR's manager reported to the National Transportation Safety Board investigator that he holds a certified flight instructor (CFI) certificate. The manager stated that on August 13, 2009, he provided recurrent flight training to the accident pilot. The dual instructional flight lesson was performed in N67361, and it lasted about 1.1 hours. The purpose of the lesson was to provide the pilot recurrent training. The flight school's records indicate that, thereafter, the accident pilot flew N67361 for 1.3 and 1.0 hours on August 14 and 15, respectively.

On August 16, the pilot reported that he intended to rent the airplane again for another local area flight. The flight school's scheduling records indicate the pilot blocked out the airplane between 0900 and 1200. After the pilot acquired fuel, he and his passenger departed in the airplane.

The Federal Aviation Administration (FAA) coordinator reported that no evidence of a flight plan was found for the accident flight. No report of any distress call was received by FAA air traffic facilities. The pilot's route of flight between Redlands and Hesperia has not been determined.

A ground-based witness in an automobile, located near the Hesperia Airport, reported to the Safety Board investigator that he observed an airplane, which matched the make and model of the accident airplane. According to the witness, the airplane made a high and fast approach to runway 21. Unable to land, the airplane's pilot made a go around. The airplane returned for a second approach to runway 21, which was again flown high and fast. Thereafter, the pilot initiated another go-around. The witness described the airplane's climb and left low altitude crosswind leg turn into the traffic pattern as being unusual, in that the airplane's pitch attitude was upward about 45 degrees, and the airplane's left bank angle was about 60 degrees. Also, the airplane turned left for the left-hand traffic pattern very soon after overflying the departure end of runway 21. The witness stated that he lost sight of the airplane seconds later when he drove into an area where his view became obstructed by ground obstacles.

A few minutes later the witness observed the crashed airplane next to the road on which he was driving. The airplane was oriented in a northerly direction. The witness reported that the wind, estimated at 5 knots, was also coming from a northerly direction. (The witness was a former FAA controller and pilot.)

Personnel Information

According to FAA airman and medical record files, the 41 year old pilot held a private pilot certificate with an airplane single engine land rating, which was issued November 13, 1992. The most recent Third class medical certificate was issued on August 8, 2007, without limitations. The pilot is a Japanese national and in response to a request from the investigation the Japan Transport Safety Board reported that the pilot did not hold a Japan airman certificate.

An examination of the pilot's personal flight record logbook indicates he began taking flying lessons in September, 1992. He was issued a private pilot certificate in November, 1992, at a total time of about 59 hours.

With the exception of one duel lesson in a Piper PA-28, all of the pilot's recorded flying was accomplished in Cessna 150, 152, and 172 models of airplanes, and in the southern California geographic area.

Regarding the pilot's more recent flying activity, on August 13, 2007, he received a 1.1-hour-long combined flight review and Cessna 172 checkout. The CFI providing the instruction was affiliated with M.Y. AIR. Thereafter, the pilot flew 8 additional times during the remainder of the month for a total of 3.3 hours.

The pilot's next flight occurred on August 11, 2008. On this date he again flew with the same CFI in the accident airplane. The flight review lasted 1.2 hours. Thereafter, the pilot flew the airplane 6 times for a total of 4.7 hours.

The pilot's next flight occurred on August 13, 2009. On this date he again flew with the same CFI in the accident airplane. The flight review lasted 1.1 hours. Thereafter, the pilot flew the airplane on August 14 and 15 for a total of 2.3 hours. The accident occurred the following day after flying for 0.7 hours. By August 16, 2009, the pilot's total time was about 193.3 hours, of which 51.0 hours were acquired receiving duel flight instruction.

Aircraft Information

The following information was obtained through a review of the aircraft maintenance records, interviews with the operator’s maintenance personnel, and the operator's flight department records.
The aircraft was a Cessna 152, serial number 15281779, which was manufactured in 1978. As of the accident, the airframe had accrued a total time in service of 8344.6 hours. The most recent annual inspection was endorsed as completed on December 9, 2008, 297 hours prior to the accident. The most recent 100-hour inspection was completed on June 21, 2009, 93 hours prior to the accident.

The engine installed in the airframe was a Lycoming O-235-L2C, serial number L-15117-15. The engine was overhauled on August 9, 2007, and installed in the airframe on August 14, 2007. At overhaul, the engine total time in service was 8,507.6 hours. At the accident, the engine total time in service was 9,446.8 hours, with 939.2 hours of operation accrued since major overhaul.

A document titled "Aircraft Maintenance History" can be found in the public docket for this accident and it summarizes the significant maintenance actions on the engine over a two year period from its August 2007 overhaul and installation in the airframe until the accident on August 16, 2009. In pertinent part, this history documents multiple instances of magneto maintenance, change outs, and timing adjustments, particularly to the left magneto. In general, the review found that the magneto timing had to be adjusted at roughly 50-hour intervals.

An August 8, 2009, entry in the flight department rental log sheet for this aircraft lists a pilot squawk of a rpm drop of 225 when the left magneto was tested during the run-up procedure before a flight. According to the Cessna POH for this airplane, the maximum allowed rpm drop on either magneto is 125. Review of the aircraft and maintenance department records found no corresponding maintenance record in response to this pilot discrepancy.

On August 20, the individual in charge of the operator's maintenance shop was interviewed concerning the magneto drop pilot write-up. He stated that he cannot explain why there is no entry in the aircraft logs for the work that was accomplished. He stated that in response to this reported magneto drop, the spark plugs were removed, gapped, and tested. According to the interviewee's statement, most of the top and all of the bottom plugs were lead fouled. He stated that he is not certain, but the plugs may also have been replaced. The engine timing also checked and confirmed at 20 degrees BTDC on both magnetos.

Airport Information

The Hesperia airport is a non-towered public airport at an elevation of 3,390 feet msl. It has one asphalt runway, 03 - 21, that is 3,910 feet long and 50 feet wide.

Meteorological Information

The closest official weather observation station is the Victorville, California, airport, which is located 13 nautical miles north of the accident site. At 1050, the station was reporting winds from 220 degrees at 4 knots, with clear skies and a 10 mile visibility. The temperature was recorded at 28 degrees, and the altimeter setting was 29.90 in hg. Based on this weather report and the Hesperia airport field elevation of 3,390 feet msl, the density altitude was calculated to be 5,754 feet.

A security video recorder located at the airport was operating at the time of the accident flight. Review of the recorded video showed the airport's wind tee and co-located wind sock indicating runway 03 was favored, based upon the prevailing northerly wind. Based on the wind sock's deflection from horizontal, the wind speed was estimated to be between 5 and 10 knots. Also, the shadow of an airplane appears on the video as an airplane overflies in a southwesterly direction over the approach end of runway 21. Based upon the camera's orientation angle, the overflying airplane's flight was too high to be recorded by the video camera. The time of the airplane's over flight was about 1119. No other airplanes were observed overflying, taking off, or landing, within over 5 minutes before or after the accident time.

Medical and Pathological Information

The pilot sustained fatal injuries in the accident and an autopsy was performed by the San Bernardino County Medical Examiner's office. During the procedure, tissue and fluid samples were taken for toxicological examination. According to the autopsy report, the cause of death was ascribed to multiple blunt force traumatic injury. The results of the toxicological examination were negative for alcohol and all screened drug substances.

Wreckage and Impact Information

On August 16 and 17, 2009, the Safety Board investigation team performed an on-scene examination of the accident site and structural examination of the airplane wreckage. The accident airplane was found on near level soil about 1/4-mile southeast of runway 21's departure end. The airplane was in a nose down attitude, with the engine buried in the sandy soil to an estimated 1-foot depth at about a 45 degree angle. No evidence of ground scar consistent with impact marks from the crashed airplane was observed in the terrain surrounding the impact crater. Several gallons of fuel were observed in the left fuel tank, and evidence of fuel spillage was reported to the Safety Board investigator by first responders. There was no fire.

The fuselage and empennage were found attached to the engine compartment. These airframe components were at ground level, and they were in an upright, near wings level, attitude. The leading edges of both wings were found accordioned in an aft direction. The engine compartment and instrument panel were displaced in an aft direction, which reduced the occupiable space in the cockpit. All flight control surfaces remained attached to their respective hinges and cables. The cables had retained their integrity to the area of the crushed cockpit.

Chordwise score marks were present over the entire span on the cambered side of the propeller. On the face of the propeller, chordwise score marks were present over the outboard approximate 1 foot of its span. The outboard, approximate 1 foot span of both blades were bent in an aft direction. Nicks were present in the leading edge of the propeller.

The engine and attached propeller assembly were recovered from the accident site.

Tests and Research

The subject wreckage and engine were examined August 24, 2009, at the facilities of Aircraft Recovery Service of Chino, California, by the National Transportation Safety Board, Investigator in charge (NTSB-IIC) and the designated parties to the investigation.
The powerplant is a four cylinder, air cooled, direct drive, horizontally opposed, normally aspirated (carburetor), internal combustion engine rated at 118hp @ 2800rpm.
The engine remained attached to the airframe by the engine mount. The engine had sustained moderate impact energy deformation to the forward bottom area encompassing the exhaust and induction system. The carburetor and alternator had been displaced from their respective mountings. Visual examination of the engine revealed no evidence of pre-impact catastrophic mechanical malfunction or fire.

The propeller was removed to facilitate the examination. The top spark plugs were removed, examined and photographed. The crankshaft was rotated by hand utilizing a tool. The crankshaft was free and easy to rotate in both directions. "Thumb" compression was observed in proper order on all four cylinders. The complete valve train was observed to operate in proper order, and appeared to be free of any pre-mishap mechanical malfunction. Normal "lift action" was observed at each rocker assembly. Lubrication oil was observed at all four rockerbox areas. Mechanical continuity was established throughout the rotating group, valve train and accessory section during hand rotation of the crankshaft.

The subject engine was partially disassembled to be further examined and photographed. The cylinder’s combustion chambers and barrels remained mechanically undamaged, and there was no evidence of foreign object ingestion or detonation. The valves were intact and undamaged. There was no evidence of valve to piston face contact observed. The pistons were intact. The ring assemblies at each piston were intact and free to rotate within their respective ring land. The gas path and combustion signatures observed at the spark plugs, combustion chambers and exhaust system components displayed coloration consistent with normal operation. The bottom plugs exhibited excessive lead deposits. There was no oil residue observed in the exhaust system gas path. Mechanical continuity of the rotating group and internal mechanisms were established visually during the partial disassembly and examination of the engine. The accessory gears including the crankshaft gear, bolt and dowel were intact and remained undamaged by any pre-impact malfunction. There was no evidence of lubrication deprivation observed. The crankshaft and attached connecting rods remained free of heat distress. The camshaft was intact and each of the camlobes appeared normal in their shape.

Both magnetos had been displaced from their respective mounting pads; however, when the left magneto was removed investigators noted that the castellated nut, washer and cotter pin that secure the magneto drive gear and impulse coupler was missing. The respective threads on the shaft were undamaged. The nut and associated washer were found in the oil sump. There was no cotter pin found that is used with the castellated nut. Wear signatures on the associated magneto parts, engine case and metal particles found in the oil filter indicated a condition that existed for a sustained period of time. The left magneto sustained impact damage which precluded functional testing.

The magneto drive gear that attaches to the subject magneto shaft, which is an engine part and must be installed onto the magneto by field maintenance technicians, exhibited no visible witness marks on the inside bore. These witness marks would have been present if the cotter pin had been in place and “worked” its way out of the castellated nut and shaft during operation of the engine. The rear of the engine case within the accessory section which corresponds to the location of the magneto drive gear exhibited a rotational burnishing signature consistent with having prolonged contact with the subject gear while the engine was operating. Additionally, there were shiny metal shavings observed inside the oil filter media when opened for examination.

The right magneto “E-gap” was found to be excessively out of manufactures specifications during the exam; however, the magneto produced spark during hand rotation of the drive. Investigators determined that once the T-118 timing pin was inserted to locate “E-gap” position and then removed, the drive could be rotated counter-clockwise 34° ± 1.5° until the magneto timing light indicated points opening. According to the magneto manufacture, ± 5° is the excepted normal allowable range for internal timing.

According to the magneto manufacture, the serial number on each magneto indicates the date of manufacture. The left magneto was manufactured December 2003 and the right magneto was manufactured January 2007.

Magneto Maintenance Requirements

According to Unison Industries, Slick Aircraft Products SB2-80C, page 4, section I, the 4300 series magnetos should be inspected externally every 100 hours and internally every 500 hours. The aforementioned Service Bulletin is also incorporated within Lycoming Service Letter L173C, dated March 10, 2006.

All procedures to perform the 100/500 hour inspections are detailed in the 4300/6300 Series Magneto Maintenance & Overhaul Manual (L-1363).

The Lycoming Table of Limits, SSP-1776, page 1-35, item 903 specifies a torque value of 120-300 in/lbs for the drive shaft gear attaching nut.

The Lycoming O-235 parts manual PC-302, page 4-4, 4 requires that a cotter pin be installed onto the castellated nut.

According to the magneto manufacture, no Airworthiness Directives (AD) were applicable to the 4300 series magnetos at the time of the accident.

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