Cameron Park, CA, USA
N1098F
Raytheon Aircraft Company A36
A television news crew was filming general airplane operations at the airport and captured the accident on video. The video begins with the airplane on its takeoff roll, accelerating almost 2/3 down the runway before getting airborne. The windsock at the approach end of the runway appeared limp, indicating little to no wind. Once airborne the airplane climbed to approximately 40 feet, the wings began to wobble, and it settled back down to the ground into the rising terrain off the end of the runway, slid on the ground, and abruptly flipped over onto its back. Immediately after liftoff the plane is observed to crab to the left about 7 degrees while remaining over the runway centerline, indicating the airplane went from a calm wind condition to suddenly being affected by a left crosswind very early in the initial climb. A video study concluded that the airplane's ground speed was 80 plus or minus 4 knots as it crossed the end of the runway, speeds consistent with the POH recommended speed for the climb. The airplane was equipped with an engine turbonormalizing system which, according to the supplemental type certificate (STC), allowed for an increase in gross weight to 4,000 pounds when operated in the normal category. The outside air temperature was 96 degrees F and the field elevation is 1,286 feet msl, which resulted in a density altitude of 4,125 feet. The airplane's weight at the time of takeoff was 4,095 pounds. The airplane was also instrumented with a JPI EDM-800 Engine Analyzer. The data revealed consistent engine operation throughout the takeoff and climb at a power level between 91 and 94 percent. The highest terrain elevation directly ahead of the airplane was 1,350 feet msl, approximately 4,860 feet from the point the airplane started its takeoff roll. The elevation difference between the point the airplane left the runway and the elevated terrain directly ahead was 80 feet. Based on the STC documentation, the calculated takeoff distance to clear a 50-foot object was 4,030 feet. An independent computer model simulating the performance of the airplane at a weight of 4,100 pounds and 4,100 feet msl density altitude resulted in the airplane climbing at 911 feet per minute and clearing the terrain directly ahead of it by 148 feet. The pilot reported that shortly after takeoff he felt a gust of wind from the left. The video depicts no wind at the midfield windsock and a left crosswind at the departure end, with trees in the background waving in what appears to be a moderate breeze. No determination could be made regarding whether the crosswind that was encountered had a tailwind or headwind component. Based on all the evidence it is likely that the airplane encountered a sudden wind from the left in the takeoff initial climb that degraded the airplane's climb performance and led to a stall mush condition.
HISTORY OF FLIGHT On August 30, 2007, at 1235 Pacific daylight time, a Raytheon A36, N1098F, descended into terrain during the takeoff initial climb from Cameron Air Park, Cameron Park, California. The airplane was operated by the commercial pilot under the provisions of 14 Code of Federal Regulations Part 91. The pilot and one passenger were seriously injured, two passengers were fatally injured, and the airplane was substantially damaged. Visual meteorological conditions prevailed, and a flight plan had not been filed. A television news crew was filming airplane operations at the Cameron Park Airport and captured the accident on video. A Federal Aviation Administration (FAA) inspector and the National Transportation Safety Board investigator-in-charge (IIC) viewed the video of the event. The video depicted the airplane on its takeoff roll, accelerating almost 2/3 down runway 31 before getting airborne. Once airborne, the airplane climbed to approximately 40 feet and the wings began to wobble and it settled back down towards the ground. The airplane settled into the rising terrain off the end of the runway, slid on the ground, and abruptly flipped over on to its back. The pilot stated to the Safety Board IIC that he was very familiar with this airplane and had flown it often. He topped the airplane off with fuel, had mentally performed a weight and balance, and had done a takeoff over a 50-foot obstacle calculation for a 100-degree Fahrenheit (F) day at this airport in the past. He stated that the engine run-up was normal, and the outside air temperature (OAT) was 35 Celsius (C) (95 F). The takeoff roll was a little longer than normal and the acceleration felt normal except for a momentary shudder about 1/3 the way down the runway. During the initial climb the airplane was accelerating. At some point the airplane stopped climbing, the airspeed indicated 84 knots, and the rate of climb had dropped off. He lowered the nose and felt a gust of wind from the left side, at which point the wings started to wobble. He cut the power just as the airplane was settling in to the rising terrain/runway overrun. The pilot and passenger in the cockpit sustained serious injuries. The two passengers in seats that were positioned forward in the cabin and faced aft were fatally injured. PERSONNEL INFORMATION The pilot, age 64, held a commercial pilot certificate issued on December 10, 1989, with single engine land, single engine sea, multiengine land, multiengine sea, helicopter, gyroplane, and airplane instrument ratings. The pilot also held a flight instructor certificate issued on May 20, 2007, with instructor ratings in single and multiengine airplane, instrument airplane, rotorcraft helicopter and gyroplane. The pilot held a third-class airman medical issued in June 2006, with the limitation that he must wear corrective lenses for near and distant vision. The pilot reported a total fight time of 2,000 hours, of which 1,700 hours were pilot-in-command, and 1,000 hours as an instructor. He had flown 16 hours in the accident airplane make and model within the last 30 days. AIRCRAFT INFORMATION The four seat, low-wing, retractable-gear airplane, serial number E-3059, was manufactured in 1996. The airplane's original production configuration was equipped with six seats, however, the two furthest aft seats were removed from this airplane. It was powered by a Teledyne-Continental Motors IO-550-B, 300 brake horsepower engine, and equipped with a McCauley model D3A32C409-C propeller. A review of the airframe maintenance logbook records showed that an annual inspection was completed October 9, 2006, at an airframe total time (AFTT) of 1031.5 hours. At this time a turbonormalizing system was installed on the engine in accordance with Engine Technologies, Inc, supplemental type certificate (STC) number SE5222NM. The engine maintenance logbook records showed the annual inspection had been complied with on October 9, 2006, at AFTT 1031.5 hours, and Engine Time Since Overhaul (ETSO) of 679.1 hours. The Hobbs meter read 1,108.3 at the accident site. The pilot operating handbook (POH) contained a section titled; Airplane Flight Manual Supplement - 550, Aircraft With Turbonormalizer Systems installed after August 1, 2000. Page 5 of the supplement stated "Your aircraft has been approved for increased maximum takeoff weights and landing weights in accordance with the following chart. All operations above the original maximum weight listed in the Aircraft Flight Manual are to be NORMAL CATEGORY operations." The tables that followed contained flight load factor limits for the A36 in the 'normal category' as 3.8 positive g's, 1.5 negative g's, flaps up, and 2.7 positive g's, 0 negative g's, flaps down. Page 6 contained the increased weight and balance envelope load for the A36 as 4,000 lbs (NORMAL CATEGORY ONLY above 3,650 lbs), between stations +85.5 in to +87.7 in. Page 26 of the supplement stated "However, when operating at the increased weights authorized when operations are conducted in the NORMAL CATEGORY expect: A. Increased Takeoff Distance of up to: 30% B. Decreased Rate-of-Climb of up to: 13% C. Increased Stall Speed of up to: 7% D. Increased Landing Distance of up to: 15% E. Increased Takeoff & Approach Speeds: Increase 2 kts F. Increase Vx and Vy speeds: Increase 2 kts The most recent airplane weight and balance sheet was dated October 9, 2006, and copies were located in the maintenance records and in the POH. The empty weight of the airplane was stated to be 2,630 pounds. Using the following weights; removal of rear seats (32 lbs), full fuel load (431 lbs), pilot (162 lbs), right front seat (204 lbs), 3 rd seat occupant (195 lbs), 4th seat occupant (234 lbs), and baggage/cargo (271 lbs), the total takeoff weight was approximately 4,095 lbs at a CG of +86.15 in. Utilizing the above information, pressure altitude of 1,293 feet, and OAT of 35C; the takeoff performance charts provided in the POH were used to calculate the takeoff ground roll and distance to clear a 50-foot obstacle. The ground roll plus 30 percent was 2,210 feet. The takeoff distance to clear a 50-foot obstacle plus 30 percent was 4,030 feet, and takeoff speed plus 2 knots was 86 knots. Utilizing topographical information from Google Earth, the horizontal distance between the point the airplane lifted from the runway and the location of the highest terrain directly ahead was approximately 2,128 feet. The elevation difference between these two points is 80 feet. Total distance from the start of the takeoff roll to the highest terrain directly ahead is about 4,860 feet. METEOROLOGICAL INFORMATION Cameron Airpark does not have a weather recording system. The exact wind conditions at the time of the accident are not known. The pilot reported that his OAT gauge read 35 degrees C (95 degrees F) just prior to takeoff, and the EDM 800 (engine analyzer) recorded OAT between 95 and 97 F (~36C) during takeoff. The closest airfield with an aviation meteorological recording system is Sacramento Mather Airport, Sacramento, California, 17 miles southwest of Cameron Park. Mather Airport has an AWOS-3 (aviation weather observation system) that recorded an atmospheric pressure of 29.89 inches of mercury (inHg) at 1245. The calculated density altitude for Cameron Airpark at the time of the accident was 4,125 feet msl. The video shows the windsock at the southeast end of the runway limp as the airplane accelerated past it, but immediately after the accident at the northwest end of the runway bush branches can be observed waving in a moderate breeze. The video also depicts the airplane crabbing to the northwest immediately after takeoff, while the airplane's shadow stayed positioned on the runway. AERODROME INFORMATION Cameron Air Park is located in a slight geographical bowl, with rising terrain at both ends of the runway. Field elevation is 1,293 feet msl. The single runway is marked 31 and 13, and is 4,051 feet long. Trees and buildings ring the airport. WRECKAGE AND IMPACT INFORMATION The wreckage was examined on-scene by the Safety Board IIC, with technical assistance provided by representatives from the FAA, Hawker-Beechcraft, and Teledyne-Continental Motors. The wreckage was located about 719 feet north of the end of runway 31, on the runway extended centerline, at an elevation of 1,330 feet msl. The terrain slopes up gradually to the north and is covered with dry grass, shrubs, and a few boulders. The initial point of contact with terrain was about 500 feet from the end of the runway at an elevation of 1,314 feet msl. The total distance from the initial point of impact to the main wreckage was 365 feet. At the 246-foot point a large boulder had been dislodged from the earth and traveled 60 feet to come to rest next to the wreckage. The main wreckage was inverted, generally facing the direction it came from, and was oriented on a bearing of 130 degrees. The forward portion of the cockpit occupiable space had been compromised by a large dent on the bottom of the fuselage that went from the nose wheel through the center of the cabin to the aft wing spar, deforming the air conditioning condenser. The cabin contained four seats; the forward facing pilot and copilot seats, and two aft facing passenger seats. The forward windscreen was shattered and generally not present except for where it attaches to the airframe. The firewall had been pushed back into the cockpit and the engine was detached from the engine mount and lay next to the nose cowling. The left wing was attached to the fuselage at the forward and aft attach fittings, the right wing remained attached at the forward attach fitting. Fifty-three gallons of bluish fluid was extracted from the wing fuel bladders during the recovery of the wreckage. Examination of the cockpit revealed that the landing gear handle was down, the flap handle was up, and the auxiliary fuel boost pump switch was "off." The throttle, mixture, and propeller levers were in the full forward position. The fuel selector was removed from the wreckage, and by passing air through the valve it was determined that the fuel selector was configured to the left tank position. Fluid drained from the fuel selector housing revealed a blush liquid, the odor consistent with avgas; no contamination was identified. The JPI EDM 800 engine monitor was removed from the instrument panel for further examination. Control continuity from the rudder, elevator, and ailerons were established to the cockpit control column bell crank. The left and right elevator trim actuators measured 1.25 inches and 1.375 inches respectively; both corresponded to zero degrees of tab (neutral). The left and right flap actuator measured 2.125 inches and 1.75 inches respectively; which corresponded to zero degrees of flap (retracted position). The engine was completely separated from the firewall engine mount, and lay 3 feet downhill from the cockpit area of the wreckage. A hole was present in the oil pan. The oil cap was observed to be secured to the oil filler tube. The 3-bladed Hartzel propeller was attached to the crankshaft flange. The propeller exhibited aft blade tip curling/bending on all blades, no leading edge damage or chordwise scratches observed. The engine was transported to a recovery yard where a detailed examination was accomplished. No mechanical anomalies were identified. The baggage and cargo recovered from the wreckage consisted of a portable icemaker, four pieces of individual luggage, a case of soda, and a medium sized cooler. The items were collected and found to weigh, in total, 271 pounds. MEDICAL AND PATHOLOGICAL INFORMATION The El Dorado Pathology Medical Group performed the autopsy of the male passenger fatality. The autopsy significant findings include "Cervical Neck Fracture" and "Right Parietal Subarachnoid Hemorrhage." The Sacramento County Coroner performed the autopsy of the female passenger fatality. The autopsy significant findings include "Hemorrhagic shock due to pelvic fractures." TESTS AND RESEARCH EDM-800 - Engine Analyzer The airplane was instrumented with a JPI EDM-800 Engine Analyzer. This instrument was removed and taken to the JP Instruments facility to be downloaded. The EDM-800 recorded the engine performance parameters for the time between engine start and the accident. The following parameters were recorded; exhaust gas temperature, cylinder head temperature, oil temperature, outside air temperature (OAT), battery voltage, fuel flow, engine rpm, manifold pressure (MAP), and percent horsepower. The data revealed consistent engine operation throughout the takeoff power application. RPM was maintained between 2,669 - 2,672 rpm; manifold pressure (MAP) was maintained between 29.5 - 30.1 inHg; fuel flow between 33.1 - 33.8 gallons per hour; the recorded OAT was 93 degrees F at engine start and 95-97 degrees F during takeoff. Horsepower produced was between 91 and 94 percent. Video Study A video study was performed to determine the ground speed of the airplane at the time of rotation and when it crossed the end of the runway. Utilizing topographical data points on the runway, the location of the video camera, and the time stamp imbedded into the video, an accurate calculation of the airplane's ground speed was determined to be 84 plus or minus 4 knots at rotation, and 80 plus or minus 4 knots over the end of the runway. The takeoff distance, from the start of the ground roll to the point the main wheels left the runway, was 2,732 feet. The video study factual report is located in the docket of this accident investigation. Wind Effects Indicated in the Accident Video A few video frames captured the approach end (southeast end) windsock as the airplane accelerated down the runway. The windsock appears to be stationary and completely draped down, indicating very little or no wind at that location. The accident video showed the airplane enter a left crab immediately after takeoff, while the airplane and airplane shadow appeared to remain centered over the runway. In order for the airplane to be in a slight crab and remain over the runway, there would have to be a crosswind force being exerted on the airplane. Using the video imagery, comparing the runway direction and airplane nose alignment, it was estimated that the crab angle was approximately 7 degrees. Using the ground speed calculated in the video study of 80 knots, a 7-degree crab would correspond to a 10-knot crosswind component. This implies that immediately after takeoff the airplane was subjected to a wind from the left. The left side of the departure end of runway 31 has low or down sloping terrain populated with single story residence structures. As the departure end of runway 31 gives way to up sloping terrain, the far left side also abruptly becomes populated with a grove of tall trees. These buildings and trees are in a position to affect winds coming across the runway from the west. Performance Study The Data Analysis Numerical Toolbox & Editor (DANTE) software computer program was used to model and calculate the probable performance of the Raytheon A36 under the aircraft load (4,100 lbs) and environmental conditions that existed at the time of the accident. The following aerodynamic data was provided by Hawker-Beechcraft for the A36; wing area = 181 sq ft, wing aspect ratio = 6.2, c/4 sweep = 0 deg, wing taper ratio = 0.49, and drag coefficient CD0 = 0.0435. Environmental conditions used for the calculation was a density altitude of 4,100 feet. Power parameter provided by the engine was set to 277.5 hp, the average power level recorded by the EDM 800 (92.5 percent of maximum rated power-300 hp). The DANTE calculation resulted in a positive rate of climb of 911 feet per minute (fpm) at 80 knots calibrated airspeed (CAS). The elevation difference between the point the airplane lifted from the runway (1,270 feet msl) and the highest point of terrain directly ahead (1,350 ft msl) is approximately 80 feet. The distance between these two points is approximately 2,128 feet. At 80 knots it would take the airplane approximately 15 seconds
The airplane's sudden encounter with a wind shift during the initial takeoff climb that resulted in degraded climb performance and a stall mush condition. Contributing to the accident was the airplane's over gross weight condition, high density altitude, the pilot's inability to compensate for the sudden wind shift, and rising terrain in the departure path.
Source: NTSB Aviation Accident Database
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