Aviation Accident Summaries

Aviation Accident Summary LAX93FA335

ALPINE, CA, USA

Aircraft #1

N2988B

BEECH D-35

Analysis

THE PILOT TOOK OFF FROM A DIRT STRIP WITH A CROSSWIND. THE AIRPLANE DRIFTED LATERALLY OFF THE STRIP IN AN OPEN AREA. THE AIRPLANE'S TAKEOFF PATH WAS OBSTRUCTED BY A TREE. THE PILOT INADVERTENTLY STALLED THE AIRPLANE AND ONE WING DROPPED AND STRUCK THE GROUND. THE AIRPLANE CAME TO REST UPRIGHT AND WAS DESTROYED BY A POST-CRASH FIRE.

Factual Information

History of the Flight On August 27, 1993, at 1245 hours Pacific daylight time (PDT), a Beech D35, N2988B, lost control and collided with the terrain during the initial takeoff climb from runway 36 at the On the Rocks Airstrip, located about five nautical miles south of Alpine, California. The pilot was conducting a visual flight rules personal flight to Brown Field, San Diego, California. The airplane, operated by the pilot/owner, was destroyed by impact forces and the resulting post impact fire. The certificated private pilot and student pilot/passenger were fatally injured. Visual meteorological conditions prevailed. The accident was witnessed by two of the airstrip owners. According to the witnesses, the pilot taxied the airplane to the south end of the airstrip, made a 180-degree turn, and started the takeoff roll without an engine run-up. The airplane lifted off after about an 800-foot takeoff ground run. The airplane pitch attitude increased without a corresponding gain in altitude. The airplane then drifted right of the airstrip. A forty foot tall tree located about 30 feet to the right of the airstrip now obstructed the airplane's flight path. The airplane climbed no higher than 30 feet above the ground when it rolled "violently" right before reaching the tree. The airplane descended and collided with the ground about 100 feet east of the airstrip. The airplane came to rest about 1,975 feet from the approach end of the runway with its nose oriented toward the east. A postimpact fire erupted. The witnesses stated the fire started forward of the cockpit in the engine cowling. The witnesses ran to the airplane which was engulfed in flames. The witnesses stated there was no movement inside of the airplane and the cockpit door was closed. The witnesses indicated the temperature at the time of the accident was between 88 degrees and 90 degrees Fahrenheit. Crew Information First Pilot The pilot held a private pilot certificate with an airplane single engine land rating. The most recent second class medical certificate was issued to the pilot on June 4, 1992, and contained no limitations. No personal flight records were located for the pilot. The aeronautical experience listed in this report was obtained from a review of the airmen Federal Aviation Administration records on file in the Airman and Medical Records Center located in Oklahoma City. Second Pilot Operation of the Beech D-35 does not require a second pilot; however, a student pilot was seated in the right front seat and did not have access to the throw over yoke which was found in the left position. The second pilot was not capable of manipulating the aircraft flight controls and his responsibilities during the accident sequence are listed as none. The second pilot information listed in Supplement E of this report was obtained from a review of the second pilot's airman records maintained by the FAA's Airman Certification Branch in Oklahoma City, Oklahoma. Meteorological Information Gilliespie Field, El Cajon, California, is the closest official weather observation station. At 1350 hours PDT, a scheduled record surface observation was reporting in part: clear skies; visibility, 15 statute miles; temperature, 85 degrees Fahrenheit; winds, 280 degrees at 10 knots; altimeter, 29.94 inHg. The density altitude for the airstrip was computed about 4,950 above mean sea level (msl) using the airstrip's field elevation and the temperature given by the witnesses. Aerodrome and Ground Facilities The On the Rocks Airstrip is a privately owned dirt strip. The published elevation of the airstrip is 2,650 feet msl. The airstrip has a single runway on a 360/180 degree magnetic orientation. The runway is 2,500 feet long by 80 feet wide. Wreckage and Impact Information The initial impact point was marked by the left wing position light. A three-foot long ground scar located about 110 feet south of the main wreckage had red lens glass and aluminum parts of the position light resting on the disturbed soil. The bearing from the ground scar to the fuselage measured at 320 degrees with a magnetic compass. The hydraulic brake reservoir was found along the wreckage path about 70 feet from the fuselage. The airplane came to rest upright with its nose pointed at 080 degrees. The airplane's fuselage was consumed by the postimpact fire. The postimpact fire traveled in a east-southeast direction (from the right to the left). The fire burnt several acres of grass and shrubbery all to the right of the runway. A fuselage fuel tank located behind the rear seats was found with the top half burnt away. The control cables were visible and found routed through the remains of the airframe. Continuity of the flight control cables to the cabin/cockpit area was established. The flap jackscrew was found extended 4.25 inches. According to Beech Aircraft Corporation, the measurement corresponds to a 14 degree flap position. The cockpit was destroyed. The airplane's instrument and electrical switches were destroyed. The position of switches and instrument readings could not be recorded. The engine compartment was damaged by the fire. The engine's accessory gearbox was melted. Several spark plugs were removed from their respective cylinders. There were no abnormalities noted with the spark plugs. The two-bladed constant speed propeller had one blade broken from the hub. The hub remained attached to the crankshaft. The separated blade was found on the west side of the runway about 140 feet from the fuselage. Both propeller blades exhibited "S-bending", twisting, and chordwise scoring. Both wing's auxiliary fuel tip tank were crushed at the leading edge along its chord line. The upper sheet metal of both internal wing tanks was burnt along with the top skin of the wing. The main landing gear was retracted and found in its respective wheel wells. The wing flap panels were extended about 15 degrees. Medical and Pathological Information Postmortem examinations were conducted by the San Diego County Medical Examiner's Office on August 28, 1993, with specimens retained for toxicological examination. The postmortem examination did not reveal any preexisting conditions that would have affected the pilot's ability to control the airplane. Toxicological analysis performed by the Medical Examiner's Office revealed positive results for carbon monoxide in both the pilot and passenger. The toxicological report for the pilot indicated an eight percent saturation, while the passenger indicated a ten percent saturation. The toxicological analysis revealed negative results for routine drug and alcohol tests for both the pilot and passenger. Toxicological tests were also completed by the FAA's Civil Aeromedical Institute (CAMI) on the pilot's submitted toxicological [blood and urine] samples. Tests on the blood were negative for carboxyhemoglobin and positive for cyanide. The concentration of cyanide was listed by CAMI as 1.010 ug/ml (under the 3 ug/ml lethal concentration). Tests on the pilot's urine were negative for ethanol and for drugs. Wreckage Release The wreckage was released to the representatives of the owner on October 27, 1993.

Probable Cause and Findings

THE FAILURE OF THE PILOT TO MAINTAIN DIRECTION CONTROL DURING THE INITIAL TAKEOFF CLIMB WHICH PLACED AN OBSTRUCTION IN THE AIRPLANE'S TAKEOFF FLIGHT PATH AND A SUBSEQUENT INADVERTENT STALL. A FACTOR IN THE ACCIDENT WAS THE EXISTING CROSSWIND.

 

Source: NTSB Aviation Accident Database

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