Aviation Accident Summaries

Aviation Accident Summary WPR12FA349

Santa Monica, CA, USA

Aircraft #1

N41KA

CESSNA P210N

Analysis

About 15 minutes after departure, the pilot contacted air traffic control and requested a return to the departure airport without indicating the reason. About 10 minutes later, the pilot was instructed to enter a right base leg for the runway and was subsequently cleared to land behind traffic. One minute later, the pilot declared an emergency, but he did not identify the nature of the emergency. No further transmissions were made by the pilot. The airplane then collided with treetops on a southeasterly heading about 3 miles northeast of the airport and continued about 200 feet before striking the top of a palm tree and falling to the ground. A postcrash fire consumed the majority of the airplane. Postaccident examination of the airframe revealed no mechanical anomalies that would have precluded normal operation. The engine spark plugs were covered in heavy, dark soot indicative of an extremely rich mixture condition, which could have resulted in a loss of engine power. The engine was examined and subsequently placed on a test stand. After repairs were made to facilitate an engine run, the engine started, ran, and responded to throttle movements with no discrepancies noted. The reason for the return to the departure airport and subsequent reported emergency could not be determined. The investigation found that the pilot may have had therapeutic levels of doxylamine, a sedating antihistamine, in his blood about the time of the accident. However, based on the circumstances of the accident, it is unlikely that pilot impairment from doxylamine contributed to the accident. Further, the carbon monoxide present in the pilot's blood is consistent with postaccident exposure to combustion products.

Factual Information

HISTORY OF FLIGHT On August 10, 2012, about 1811 Pacific daylight time, a Cessna P210N, N41KA, impacted trees and terrain about 3 miles northeast of the Santa Monica Airport (SMO), Santa Monica, California. The private pilot/owner operated the airplane under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. The pilot, the sole occupant, was fatally injured. The airplane sustained substantial damage in the post impact fire. Visual meteorological conditions prevailed for the flight that departed SMO about 1744, and no flight plan had been filed. According to a Los Angeles City fire fighter/paramedic, he was about a block away clearing a call when he heard tree branches snapping. He turned around and saw the accident airplane in a nose down attitude. The airplane struck a 30-foot-tall palm tree, rotated 90 degrees, and dropped straight down. The airplane was then involved in a post-crash fire. The witness stated that he did not recall hearing the sound of the airplane's engine. PERSONNEL INFORMATION The pilot, age 70, held a private pilot certificate with ratings for airplane single-engine land, and instrument airplane. He held a third-class medical certificate issued on October 21, 2011. According to his logbook, the pilot had accumulated a total time of 3,200 hours. According to the pilot's son, his father had flown from Santa Monica to Mammoth, California, Carson City, Nevada, Reno, Nevada, then to Monterey, California, Santa Barbara, California, and then back to Santa Monica, the week before the accident. He further stated that the flight before the accident, the airplane seemed to be operating normally. AIRCRAFT INFORMATION The accident airplane was a 1978 Cessna P210N, serial number P21000045. The pilot purchased the airplane in October 1997. Last annual inspection was performed on October 21, 2011, at an aircraft total time of 3,361.5 hours; tachometer time of 1,258 hours. A 50-hour airframe inspection was signed off on May 17, 2012, at an aircraft total time of 3,402.7 hours and a tachometer time of 1,299.2 hours. According to the engine logbook, a Continental Motors Inc. (CMI) TSIO-520-P7 serial number 513052 was removed and a factory remanufactured zero-time CMI TSIO-520-P7, serial number 278910-R, 300-horsepower engine was installed on December 16, 2002; the airplane total time was 2,455.0 hours, and tachometer time 357.0 hours. An entry dated October 21, 2011, recorded a total engine time of 906.5 hours, and a time since major overhaul of 906.5 hours. The last 50-hour engine inspection was signed off on May 17, 2012, at a total time of 947.7 hours. The accident airplane was refueled on August 4, 2012, by American Flyers at SMO with the addition of 32.2 gallons of 100-Low Lead Aviation fuel. COMMUNICATIONS According to the Federal Aviation Administration (FAA), the pilot had been in contact with both Santa Monica (SMO) Tower and Southern California Terminal Radar Approach Control (SCT) controllers. The flight departed SMO about 1744. The FAA reviewed the radar data and reported that the airplane departed over the ocean and made a right turn to the east, toward Burbank Airport. At 17:47, the pilot requested a frequency change to SCT, and contacted SCT at 17:48. The pilot requested flight following en-route to Mammoth Lakes, California. At 17:51, SCT instructed the pilot to contact a different SCT sector. The pilot checked in with the new SCT controller and reported that he was climbing out of 2,300 feet. At 18:00, the pilot contacted SCT with a request to return to SMO without giving a reason to the controller. Between 18:01 and 18:08, SCT queried whether the pilot wanted to transition east or west of Van Nuys Airport (VNY), Van Nuys, California, to SMO. The pilot responded that he would be transitioning east of VNY. The controller then instructed the pilot to contact SMO tower. At 18:08, the pilot contacted SMO Tower and reported that he was in the "pass" with Kilo; SMO tower instructed him to enter a right base for runway 21 and the pilot confirmed "right base." Radar data identified the aircraft tracking on a straight path and descending to enter the airport area on a right base leg. At 18:10, SMO Tower informed the pilot that he was number 3 and to follow the King Air, 2 miles straight-in, and to report if he had the aircraft in sight. The pilot subsequently reported that he had the King Air in sight. The controller then instructed the pilot to follow traffic, he was number 2 and cleared to land. The pilot acknowledged that he was cleared to land. At 1811 the pilot reported to SMO tower that he had an emergency. The tower controller queried the pilot as to the nature of the emergency; however, there was no response from the pilot. Radar data identified the last target on the aircraft at 1811:08 at an altitude of 400 feet. According to the FAA, tower personnel reported hearing an unidentified squealing noise in the background during the last transmission from the pilot. WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board investigator-in-charge (NTSB IIC) and an inspector from the FAA responded to the accident site. The accident site was about 3 miles northeast of the SMO airport. The first identified point of contact was the tree-lined street of South Glendon Avenue; several tree tops had been damaged about 200 feet west of the final resting spot of the airplane. The airplane had been on a southeasterly heading (140-degrees) before it impacted a 30 foot palm tree at the intersection of South Glendon Avenue and Mississippi Avenue. The airplane came to rest on a magnetic heading of 230-degrees at the base of the palm tree; the airplane impacted the top one-third of the palm tree. The majority of the airplane was thermally consumed in the post-impact fire, and the entire airplane came to rest at the accident site. The instrument panel had been destroyed in the fire. The engine along with the propeller assembly separated from the firewall and came to rest on its right side adjacent to the empennage and left wing. During the recovery of the airplane, as the left wing was picked up by the recovery personnel, fuel began to flow out of the wing. The wing had been compromised during the accident sequence. It was estimated that there was 25-gallons of fuel that spilled out. The fuel was not recovered. MEDICAL AND PATHOLOGICAL INFORMATION A postmortem examination was conducted by the County of Los Angeles Department of Coroner on August 13, 2012. The Coroner reported that the pilot had succumbed to burns over greater than 90-percent of his body. The FAA's Civil Aerospace Medical Institute performed forensic toxicology on specimens from the pilot. The results were negative for tested volatiles, and a cyanide test was not performed. There was a positive result for carbon monoxide 19-percent carbon monoxide was detected in blood. The specimens also tested positive for Dextromethorphan, which was detected in the pilot's urine and blood. Dextrorphan was detected in the pilot's urine, but not in his blood. Also detected in the pilot's blood was 0.168 (ug/ml, ug/g) Doxylamine. TEST AND RESEARCH On August 12, 2013, investigators from the NTSB, Cessna Aircraft Company (Cessna), and CMI, examined the airframe and engine at Aircraft Recovery Service, Pearblossom, California. The postaccident examination revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation of the airframe and engine. A detailed report is in the public docket for this accident. Flight continuity was established throughout the airplane via cables and associated hardware. The right wing had been consumed by fire. The left wing remained attached to the fuselage. The rudder remained attached to the empennage, and the left aileron remained attached to the left wing. The elevator and horizontal stabilizer were consumed in the fire. The right main and nose landing gear were extended down and locked; the left gear was in an intermediate position. The instrument panel sustained severe thermal damage and was destroyed with only the radio stack visible. The engine JPI was destroyed. The fuel selector was positioned to the left wing. The engine crankshaft rotated via the propeller and drive train and mechanical continuity was established. Rotation of the propeller also established continuity of the ignition system, resulting in a spark at each of the top ignition leads. The cylinders were borescoped with no signs of operational distress observed. All of the top sparkplugs were covered with heavy, black soot. The right side top spark plugs were also oil soaked. The turbocharger impeller revolved freely when rotated by hand. The 3-bladed propeller exhibited very little rotational damage (no leading edge gouging or chord wise scrapes). Two of the blades displayed slight bending, while one remained straight. The two blades that were slightly bent were free to rotate in the hub. The propeller governor remained intact and in place at the front of the engine. The engine was shipped to CMI for further examination. Under the auspices of an NTSB investigator, the engine was inspected and repairs were made to facilitate an engine run. The engine was started, ran, and responded to throttle movements with no discrepancies noted. The report is in the public docket for this accident. The engine's turbocharger (absolute pressure controller, wastegate, and pressure relief valve) were functionally tested at Hartzell Engine Technologies facility in Montgomery, Alabama, under NTSB oversight. All of the turbocharger components functioned within specification.

Probable Cause and Findings

The pilot's failure to maintain altitude during a return to the airport following an unspecified emergency; the nature of the emergency could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation.

 

Source: NTSB Aviation Accident Database

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