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On November 26, 2006, about 1700 Pacific standard time, a Beech B36TC, N3144D, experienced a loss of engine power and descended into a single family residence in Buena Park, California. The airplane and a portion of the private residence sustained substantial damage. The private pilot and passenger sustained serious injuries; there were no injuries to people on the ground. The pilot was operating the airplane under the provisions of 14 CFR Part 91. Visual meteorological conditions prevailed, and an instrument flight plan was filed. The personal cross-country flight originated from the Benton Field Airport (uncontrolled), Redding, California, about 1400, with a planned destination of Fullerton Municipal Airport (controlled), Fullerton, California.
The National Transportation Safety Board investigator-in-charge (IIC) reviewed the pilot's flight plan and cross-country preparation documents that were within the wreckage. The documents indicated that the pilot intended to fly the airplane from Redding en route to Fullerton at 9,000 feet mean sea level (msl) at a true airspeed of 188 knots. The pilot had estimated a time en route of 2 hours 38 minutes, with the total fuel on board listed as 4 hours 53 minutes.
The IIC interviewed a Fullerton air traffic controller who was in communication with the pilot. He stated that the accident airplane was established on the downwind leg of the traffic pattern for runway 24. The pilot transmitted that the engine experienced a loss of power and subsequently declared an emergency. The controller cleared the pilot for a straight-in approach to runway 06, and made visual contact with the descending airplane. Minutes later, the pilot transmitted a radio call stating that he would be unable to make it to the runway.
During a conversation with the IIC, a witness stated that he noticed the accident airplane as he was egressing his car that he had just parked in front of a residence [adjacent to the accident site]. The airplane was flying low and moving directly toward his location, giving the appearance that it might collide with his car. He noted that the airplane appeared to be in a left bank [from the pilot's perspective], with the propeller windmilling in front, as if it were not producing power.
The pilot submitted a Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2 more than 4 months after the accident. He stated that due to his injuries sustained in the accident, he does not recall "the flight, the emergency, the crash landing, or post crash extrication."
According to the Federal Aviation Administration (FAA) Airman and Medical records files, the pilot held a private pilot certificate with airplane ratings for single engine land and instrument flight. The pilot was issued a third-class medical certificate on March 22, 2004, with the limitation that he must wear corrective lenses.
In a written statement, the pilot reported his flight time as 2,138 hours total flight experience, of which 750 hours were flown in the same make and model as the accident airplane.
The pilot added that he had flow the same route as the accident flight numerous times and experienced no difficulties or anomalies.
The IIC reviewed both the airplane's maintenance logbooks and material maintained by the FAA in the Aircraft and Registry files. The Beech B36TC single engine airplane, serial number EA-472, was manufactured in 1987. The most recent annual inspection of the airframe and engine was performed on September 21, 2006, corresponding to 31.5 flight hours prior to the accident. The pilot reported that the Teledyne Continental Motors TSIO-520-R engine, serial number 294309-R12, had accumulated a total time of 1,195 hours and 175 hours since last major overhaul.
Fueling records at the Redding airport disclosed that the aircraft was last fueled prior to departure with the addition of 45 gallons of 100LL aviation fuel. According to the pilot, the addition of the fuel filled the aircraft tanks to a total of 90 gallons (45 in each tank). The staff member that fueled the airplane was contacted several days after the accident. He indicated that he did not fill each tank to the maximum capacity, rather he evenly distributed the 45 gallons of fuel to each side, as per the pilot's request.
According to the airplane's Pilot Operator's Handbook (POH) the 108-gallon fuel system consisted of two interconnected bladder-type fuel cells located in each wing leading edge. Each wing's total fuel capacity was 54 gallons, of which 3 gallons were unusable. Each wing was equipped with a fuel quantity sight gage that read within the calibrated areas of 25 to 30 gallons.
The POH further revealed that the airplane was equipped with a fuel selector located forward and to the left of the pilot's seat. It was equipped with an "OFF," "LEFT MAIN," and "RIGHT MAIN" selection. The POH indicated that during takeoffs and landings the fuel selector should be positioned to the tank that contains the greater amount of fuel. It noted that to select the "OFF" position the pilot must depress a lockout spring, while rotating the handle to the full counterclockwise detent.
WRECKAGE AND IMPACT
On November 27, 2006, the Safety Board IIC, as well as several inspectors from the Federal Aviation Administration, completed the on-scene investigation.
The accident site was in a residential area, about 2,100 feet from the approach end of runway 06, on a bearing of 045 degrees. The surrounding area was densely populated with residences. A path of wreckage debris, ground scars, and property destruction was noted extending on a 075-degree magnetic bearing, over a stretch of 150 feet through two residences and their respective back yards. The main wreckage had come to rest partially inside an empty bedroom with the empennage section in the back yard of the approximate 1,600-square-foot single-story house.
Power lines about 40 feet in height were located at the beginning of the debris field, about 145 feet west of the main wreckage. The power lines were oriented in a north-south direction and appeared not to have sustained any damage. A portion of the airplane's left wing tip was located between the power lines and the apex of the westerly residence's roof, which was identified as the first point of impact. The airplane's left wing (including the detached flap and aileron) and left horizontal stabilizer were found in the west residence's back yard and swimming pool.
A cinderblock cement wall that ran north-south about 5.5 feet tall separated the two residential properties. The wall had sustained damage consisting of two semicircular u-shaped holes, both of which were about 5 feet in diameter along the top of the wall and spaced about 3 feet apart. Transmission lines were located above the wall with the lowest wires between 14 and 16 feet (.5 inches in diameter), the middle wires about 20 feet, and the tallest wires at 40 feet. The lowest wire was severed between the transmission towers, with the middle and high wires remaining intact.
On the east residence property, adjacent to the wall, were two bare trees spaced about 37 feet apart. Numerous branches on both trees had been broken, with signatures consistent with being recently detached from their respective tree.
The main wreckage consisted of the fuselage, right wing, vertical stabilizer (with rudder affixed), and right horizontal stabilizer (with elevator affixed). Numerous people at the accident site noted that around the area of the main wreckage was a pronounced odor consistent with that of 100LL aviation gasoline.
The entire wreckage was positioned with the right side higher consistent with the airplane attitude in a 35-degree left bank. The instrument panel and fuselage forward of the front seats sustained aft crush deformation and were fragmented. The right wing was hyperextended upward with the outboard section resting on the roof of the house. The right main landing gear was in the down and locked position; there were no markings on the tire. The outboard 3 feet of the right wing was separated and found several feet from the wing. The inboard section of the right wing's leading edge was accordioned rearward; the outboard section was punctured in numerous areas.
The outboard fuel bladder was visible through the punctures and appeared to have been ruptured as a result of the impact. The inboard fuel bladder was drained via the bottom sump and found to have about 1 gallon of fluid, which had a coloration and odor consistent to that of 100LL Avgas. The wing flap remained attached to the right wing at its respective hinges and was crushed in the most inboard section. The control surface was nearly flush with the upper wing surface, consistent with the flaps being in the retracted position.
The instrument panel had been displaced from impact forces. The landing gear lever was found in the down position; the auxiliary fuel pump switch was in the "off" position; the trim wheel was found in the 11 degrees tab up position; the master switch was in the "on" position; and the fuel selector was in the "off" position. The emergency response supervisor stated that a first-responder turned the fuel selector to the "off" position. The specific individual could not be determined.
The engine was displaced from its mounts and came to rest about 3 feet in front of the instrument panel. The data plate affixed to the engine indicated that is was a Teledyne Continental Motors model TSIO-520-UB. Investigators removed the cowling from the engine, noting it was clean with no oil present. The engine casing appeared to be intact and no holes or perforations were observed. Removal of the fuel manifold top revealed that the cavity contained a liquid that was consistent in smell and odor to that of 100LL Avgas. All three propeller blades were still attached to the hub and bent aft.
The left wing and left horizontal stabilizer came to rest propped up along the wall in the property of the east residence. The left aileron and outboard portion of the elevator were at the bottom of the full swimming pool. The left wing was crushed aft on the outboard 4 feet, with the wing tip severed off. Removal of the inspection panels revealed that the fuel bladders were intact. While manipulating the wing's attitude, investigators looked inside the bladders. Several ounces of fluid consistent with that of Avgas were found within the outboard bladder; no other fluid was found in the left wing.
TESTS AND RESEARCH
The engine was shipped to the facilities of Teledyne Continental Motors and examined under the auspice of a Safety Board investigator on February 5, 2007. After replacing several items that were impact damaged, the engine was mounted in a test cell. A test propeller was installed and the engine was started. A complete test protocol was performed on the engine, including operating it through various rpm ranges. Additionally, several abrupt throttle changes from high to low rpm were conducted. The engine responded relative to throttle motion. No mechanical malfunctions or failures with the engine were found that would have precluded it from operating normally. The complete engine report is contained in the public docket for this accident.
Engine Data Monitoring Device
The airplane was equipped with a JP Instrument, Inc., EDM 700 engine data management system. The non-volatile memory was removed and downloaded following the accident. The last flight recorded was dated the same day of the accident. That flight displayed engine operation between 2230:22 to 0209:46, equating to a total time of 3.66 hours. Based on the display time that showed during the download, the clock was 9 hours 6 minutes ahead of Pacific standard time. The data was recorded in 6-second intervals.
The EDM 700 data further disclosed that the total fuel used during the last flight was 64.3 gallons. The data revealed that 17.8 gallons of fuel remained. The instrument was programmed to the parameter that full fuel was set at a quantity of 102 gallons. The fuel remaining was computed from the pilot's entry of fuel quantity selected prior to flight. The instrument was additionally programmed to give a visual notification if the fuel remaining was either less than 10 gallons or 45 minutes of flight time.
The data revealed that at 0208:28 the fuel flow dropped from 15.9 to 7.1 gallons per hour, with the turbine inlet temperature increasing from 1493 to 1559. Six seconds later the turbine inlet temperature dropped to 731, and for the rest of the recorded hits it oscillated between 467 and 611. At 0208:34, the fuel flow was .3 gallons per hour and then plummeted to 0 for the next 18 seconds. Thereafter, the fuel flow fluctuated between 1.6 to 6.2 gallons per hour. At 0208:34, the exhaust temperatures dropped to less than half of the temperature (from around 1500 to 700), and then fluctuated between 414 and 583 the remainder of the flight. The cylinder head temperature additionally reduced during that time frame from about 300 to 230.
At 0209:16, the battery voltage dropped to 27 volts from 28.2 volts where it had stayed constant for the approximate 3 hours prior. Six seconds later the battery voltage dropped to 25.3 volts.