Aviation Accident Summaries

Aviation Accident Summary LAX93FA315

BIG BEAR, CA, USA

Aircraft #1

N3233C

BEECH E35

Analysis

THE PILOT SAID TO A WEATHER BRIEFER THAT HE MAY STOP EN ROUTE, AND THE ACCIDENT OCCURRED DURING AN APPROACH TO AN AIRPORT APPROXIMATELY MIDWAY BETWEEN THE DEPARTURE AND DESTINATION AIRPORTS. THE AIRCRAFT COLLIDED WITH TREES AND POWER LINES WHILE ON FINAL APPROACH. A PILOT WITNESS WATCHED THE AIRCRAFT IN THE PATTERN AND NOTED THAT THE AIRCRAFT WAS FLYING A CLOSE IN DOWNWIND AND BASE CONTRARY TO NOISE ABATEMENT PROCEDURES AND HIS TURNS WERE VERY STEEP. THE PILOT STATED TO PARAMEDICS THAT HE HAD LOST POWER ON FINAL. THE AIRCRAFT HAS FIVE SELECTABLE FUEL TANKS. THE MAIN SELECTOR WAS FOUND ON THE LEFT MAIN TANK. THE LEFT TANK WAS OF AN ORIGINAL DESIGN UNBAFFLED CONFIGURATION, WHICH WAS ON THE INSIDE OF ALL THE TRAFFIC PATTERN TURNS. THE AIRCRAFT FLIGHT MANUAL CAUTIONS AGAINST PROLONGED TURNS OR SLIPS WITH LESS THAN 10 GALLONS IN THE SELECTED TANK. EXAMINATION OF THE ENGINE REVEALED NO EVIDENCE OF A PREIMPACT MECHANICAL MALFUNCTION OR FAILURE.

Factual Information

On August 7, 1993, about 1635 Pacific daylight time, a Beech E35, N3233C, collided with trees and power lines following a loss of engine power in the traffic pattern at the Big Bear, California, airport. Visual meteorological conditions prevailed at the time and a VFR flight plan was filed for the operation. The aircraft was destroyed in the collision sequence and postcrash fire. The certificated commercial pilot and passenger sustained fatal injuries. The flight originated at Modesto, California, on the day of the mishap about 1438 hours as a personal cross country flight to Phoenix, Arizona. Prior to departure from Modesto, the pilot contacted the Rancho Murietta Automated Flight Service Station (AFSS) by phone at 1409 hours for a preflight weather briefing and to file a VFR flight plan to Phoenix, Arizona. The pilot stated that he may stop enroute and if he did he would cancel his flight plan. The pilot estimated four hours enroute with six hours and forty-five minutes of fuel on board. While enroute at 1602 hours, the pilot provided the Hawthorne AFSS a pilot report as to the flight conditions enroute. The accident occurred while the pilot was in the traffic pattern for landing at the Big Bear airport, which is approximately midway between the departure and destination airports. A family member stated that the passenger frequently required a restroom stop on cross country flights. In a verbal statement to emergency medical personnel who responded to the scene, the pilot said that the aircraft was in the traffic pattern for runway 26 at the Big Bear airport when the engine lost power. The pilot said he was unable to make the runway and collided with trees and power lines short of the runway. A ground witness, who is also a pilot with about 4,000 hours of flight experience, observed the aircraft in the traffic pattern. He stated that the aircraft was flying close in downwind and base legs contrary to noise abatement procedures at the airport. The witness reported that the aircraft made turns which were very steep. PERSONNEL INFORMATION At the pilot's last FAA medical examination on December 4, 1991, he reported a total flight time of 6,100 hours with 40 hours flown in the last six months. AIRCRAFT INFORMATION The aircraft, a Beech E-35, was manufactured about 1954. The airplane had been modified with the addition of wing tip and baggage compartment fuel tanks for a total of five selectable fuel tanks and a total capacity of 90 gallons of fuel. On May 4, 1984, the original Continental E-225-8 engine was removed and replaced by a Continental IO-470-N engine and an electric fuel boost pump. The installation was approved under Supplemental Type Certificate (STC) number SA 2361 SW. A pilot operator handbook for a Beech P-35/N-35 was located in the cockpit area during the on-scene examination. METEOROLOGICAL INFORMATION The Big Bear Automated Weather Observation Service (AWOS) was reporting at 1620 hours: Clear below 12,000; visibility 10 miles; temperature 73 degrees fahrenheit; dew point 47 degrees fahrenheit; wind 220 degrees at 9 knots; altimeter 30.14 inches of mercury. The density altitude was computed to be 8900 feet. WRECKAGE AND IMPACT INFORMATION According to witnesses, the airplane was straight and level when it collided with the first tree which was estimated to be about 90-feet tall. Witnesses reported that after hitting the first tree the aircraft rolled to the left about 40 degrees then collided with the second tree. An on-site measurement was made to the second disturbed tree, which was about 198 feet from the first tree on a magnetic bearing of about 252 degrees. After hitting the second tree, the airplane collided with a utility pole about 78 feet further along and burst into flames. According to the utility company, the pole was 40-feet tall and had been severed at about 24-feet above ground level. A post crash fire had consumed major portions of the aircraft structure. Electrical arcing was found on the aircraft structure. The main wreckage was located entangled in electrical cable about 20 feet beyond the utility pole. The fuselage was oriented on a direction measured to be about 330-degrees magnetic. The engine and engine compartment had separated at the firewall and continued on a measured wreckage path of about 249 degrees for about 36 feet. The nose landing gear was found about 35 feet beyond the engine. Examination of the wreckage revealed that the landing gear actuator was in the down position. The flap actuators were observed in the fully extended position. The ruddervator trim tabs were measured to be about four degrees tab down. Control cable continuity was established for the ruddervators and the ailerons. Examination of the fuel system revealed that both of the original main fuel tanks were of the unbaffled configuration and were fire damaged. The main fuel selector was found on the left main tank. Both tip tank selectors were found in the off position. Approximately eight gallons of fuel was drained from the left wing tip tank. The right tip tank was destroyed. Approximately six gallons of fuel was drained from the baggage compartment fuel tank. The engine was examined on August 12, 1993, after removal from the accident site. No fuel was found in the three lines connected to the engine driven fuel pump or in the fuel pump itself. The fuel pump drive spline was found to be intact. Minor contamination was observed in the throttle body metering unit fuel screen. A small quantity of fuel was found inside the fuel distribution manifold, and the screen was clean. All 12 spark plugs exhibited a light covering of oily soot. Both magnetos produced sparks from all points when rotated by hand. All cylinders with the exception of number 3 produced compression. Accessory gear and valve train continuity was established. The valves for cylinder 3 operated normally, and the rocker arms and shafts appeared normal. The intake and exhaust valves for cylinder 3 exhibited heavy combustion deposits. MEDICAL AND PATHOLOGICAL INFORMATION The pilot survived for several days after the accident. There were no toxicological samples or analysis performed prior to the pilot receiving medication by responding EMT personnel. ADDITIONAL INFORMATION The wreckage was released to representatives of the owner's insurance company on August 12, 1993.

Probable Cause and Findings

A LOSS OF ENGINE POWER DUE TO UNPORTING OF THE SELECTED MAIN FUEL TANK AT A CRITICAL TIME, WHICH WAS CAUSED BY THE PILOT'S FAILURE TO FOLLOW THE DIRECTIVES IN THE FLIGHT MANUAL REGARDING PROLONGED TURNS OR SLIPS WITH LESS THAN 10 GALLONS IN THE SELECTED TANK.

 

Source: NTSB Aviation Accident Database

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