Longview, TX, USA
N72066
LUSCOMBE 8A
The commercial pilot departed on the personal flight with about half fuel. During the departure climb, the airplane experienced a loss of engine power. The pilot subsequently performed a forced landing to a field, and, during touchdown, the airplane nosed over and impacted the ground. Postaccident examination of the airplane revealed no evidence of mechanical malfunctions or failures that would have precluded normal engine operation. The pilot reported that he did not use carburetor heat during the takeoff. The use of full carburetor heat during takeoff and landing was stipulated by the airplane's type certificate data sheet, which indicated that a placard is required stating, "Full carburetor air heat required for takeoff and landing." However, the accident airplane did not have that placard installed. Further, a special airworthiness information bulletin (SAIB) applicable to this airplane configuration noted the need for procedures to prevent the possible loss of power on takeoff and climb and stated that flight testing revealed that fuel flow could be interrupted from the fuselage-mounted tank as a result of acceleration and higher pitch attitudes commonly encountered in takeoff and climb. The SAIB stated that the use of full carburetor heat on takeoff is unconventional yet necessary to ensure continuous fuel flow to the engine. Thus, the pilot's failure to use carburetor heat resulted in the loss of engine power.
On June 1, 2018, at 0734 central daylight time, a Luscombe 8A airplane, N72066, experienced a loss of engine power during a departure climb from runway 13 at East Side Airport (3TS0), near Longview, Texas. The pilot/mechanic performed a forced landing to a field near Longview, Texas. The airplane sustained substantial damage. The commercial pilot received serious injuries and a passenger was uninjured. The airplane was registered to an individual and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as a personal flight that was not operating on a flight plan. Day visual meteorological conditions prevailed at the time of the accident. The local flight was originating at the time of the accident. The airplane had not flown for approximately 10 years and underwent a complete restoration and an engine overhaul. Prior to the accident flight, the airplane had flown for the about two hours since the restoration. The airplane design did not have a cockpit mixture control and the airplane was not equipped with a mixture control. The airplane was equipped with one fuel tank, did not have a fuel quantity gauges, nor did it have an electrical system. The airplane was equipped with an originally equipped vented fuel cap, a fuselage mounted main fuel tank, and a Continental A-65-1 engine (the serial number was not provided and is unknown). The accident flight was intended to be a personal flight flown by the pilot/mechanic, who restored the airplane along with the passenger, who had painted the wings of the airplane. The pilot stated that prior to the accident flight, the airplane fuel quantity was checked using a dipstick, and the quantity was half full, about 7-8 gallons, and the total fuel capacity was 15 gallons. The pilot stated that he did not use carburetor heat for the takeoff. During the departure climb, the engine lost partial power while climbing through about 200 ft above ground level (AGL), regained power for about 10 seconds, and then lost all power while climbing through about 400 ft AGL. The pilot subsequently performed a forced landing to a field while avoiding powerlines and houses. During touchdown, the airplane nosed over and impacted the ground. The pilot's recommendation of how the accident could have been avoided was that takeoffs should not be performed with less than full fuel because the fuel tank is located behind the pilot seat and was shoulder high, and the carburetor is located about below the engine and at a height equal to that of the rudder pedals. In a climb attitude, the carburetor and fuel tank are the same height and the gravity fed fuel will stop flowing. He stated the he had previously flown the airplane for a total flight time of 7 hours and had no issues during the takeoff phase of those flights with full fuel. Several hours passed before the airplane was recovered and a post-accident examination of the airplane was performed. The examination revealed the presence of fuel staining on the ground where the airplane had been overturned. Fuel had drained from the airplane fuel tank due to the nosed-over attitude of the airplane. There was no debris in the fuel tank when visually inspected through the fuel cap filler. The gascolator was broken off from impact, and there was no fuel in the lines leading to the carburetor. The carburetor screen did not contain debris. The carburetor jet was unobstructed and had a normal spray pattern when tested using water. Engine control continuity from the cockpit throttle control to the carburetor was confirmed. The cockpit primer control was extended about 3/8 inch. One propeller blade was relatively straight, and the second propeller blade was bent backwards, consistent with a lack of torsional rotation. The engine exhibited compression, valve train continuity, and drive train continuity. Electrical continuity of the ignition system was confirmed. The spark plugs exhibited normal coloration except for one of the spark plugs that was wetted with engine oil consistent with the cylinder rings in the respective cylinder having not been seated during engine break-in. Special Airworthiness Information Bulletin (SAIB) CE-14-09, dated February 13, 2014, was issued for all Luscombe Model 8A airplanes equipped with a fuselage mounted main fuel tank and Continental A- 65-1 engines (the original production configuration), specifically the need for procedures to prevent the possible loss of power on takeoff and climb. Flight testing revealed that fuel flow could be interrupted from the fuselage mounted tank as a result of acceleration and higher pitch attitudes commonly encountered in takeoff and climb. The SAIB stated that use full carburetor heat on takeoff is unconventional yet necessary to assure continuous fuel flow to the engine. Also, the vented fuel cap must be installed with the vent opening facing forward into the prevailing air stream. It is physically possible to install the fuel cap backwards; this condition will decrease fuel flow from the tank. The cap should have lettering indicating the forward direction. If the "forward" lettering is missing or obscured it should be renewed. During pre-flight inspection, while the cap is removed, it is advisable to check the vent function by blowing into the vent tube. The airplane type certificate data sheet, A-694, revision 25, dated February 12, 2014, Section II Model 8A approved March 27, 1939, stated that a placard was required stating, in part: 'Full carburetor air heat required for takeoff and landing'… The airplane was certified under CAR 3; and due to the certification basis, it was not required have an approved flight manual. The placard, part number 18856, was part of the airplane type certificate and was a required installation. The placard stated: "FULL CARBURETOR AIR HEAT REQUIRED FOR TAKE-OFF AND LANDING" The accident airplane did not have the placard installed.
The pilot's failure to use carburetor heat for takeoff, which resulted in an interruption of continuous fuel flow to the engine and a loss of engine power during climb. Also causal was the lack of required placarding warning of the need to use full carburetor heat on takeoff and landing.
Source: NTSB Aviation Accident Database
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