CORONA, CA, USA
N177JH
Cessna 177
The pilot aborted the first takeoff due to a rough running engine. He performed a run-up, determined that the engine seemed normal, and returned for another takeoff. After liftoff, the engine began to lose rpm and the pilot had difficulty gaining altitude. About 100 feet agl, he turned toward a grassy area parallel to the runway. The aircraft collided with the trees and came to rest upright on the ground. The Safety Board conducted a run-up of the engine. No abnormal sounds were noted at 2,000 rpm, but at full throttle, the engine began to run rough and the fuel pressure gauge was at or near the low scale indication. The aircraft has a separate fuel shutoff valve independent of the fuel selector. The shutoff valve is operated by a control knob near the pilot's right knee. It was noted that the fuel shutoff valve follower handle was partially closed at the valve while the control knob was in the ON position. The firewall-mounted clamp that secures the cable housing was loose and the cable housing was able to slide back and forth in the clamp. The valve could be hand actuated from the on to off position without any significant movement of the control knob. With the fuel shutoff valve properly configured and in the full on position, another engine run-up was conducted to full power with and without the auxiliary fuel pump. AD 70-24-04 concerning the fuel shutoff valve was complied with in 1984 by installation of Cessna Kit No. SK117-10. The fuel shutoff control knob is required to be safetied in the 'on' position. No safety wire was in place and no hole was drilled in the subject knob to accommodate the wire.
On July 29, 1998, at 1210 hours Pacific daylight time, a Cessna 177, N177JH, experienced a partial loss of engine power in the takeoff initial climb and collided with trees during the subsequent forced landing at the Corona, California, airport. The aircraft sustained substantial damage. The commercial pilot and passenger, the sole occupants, suffered minor injuries. The personal flight was originating at the time of the accident and no flight plan was filed. Visual meteorological conditions prevailed. The pilot reported that during the first takeoff attempt a rough running engine necessitated an aborted takeoff. He performed a subsequent run-up and determined that the engine seemed normal and returned to the runway for another takeoff. After liftoff, the engine began to lose rpm and the aircraft had difficulty gaining altitude. About 100 feet agl, the pilot initiated a left turn toward a grassy area that parallels runway 25. The aircraft collided with the trees and came to rest upright on the ground. Both wings were damaged and the landing gear was folded back. The Safety Board conducted an examination of the airframe and powerplant on August 6, 1998. The engine remained attached to the airframe by the engine mount. The fixed-pitch propeller remained attached to the crankshaft and had been straightened to facilitate an engine run-up. The engine driven fuel pump had sustained damage that detached the fuel line on the inlet side of the pump. The two magnetos were secured at their respective mounting pads. Engine control continuity was established to the cockpit controls. The air filter and inlet were free of debris. The fuel system consists of a vented tank in each wing, a three position selector valve (left, right, and both, with no "off" position), a separate fuel shutoff valve, a fuel strainer, an engine driven fuel pump, an electric fuel pump, a manual primer, and a carburetor. The fuel selector was placed in the left tank position and the auxiliary pump was turned on, with a subsequent fuel pressure indication on the cockpit-mounted pressure gauge. The engine was started and was advanced to 2,000 rpm, where a magneto check resulted in a smooth drop of 175 rpm on both magnetos with no abnormal sounds noted. The engine rpm was then advanced to full throttle. After approximately 30 seconds, the rpm began to falter and the engine began to run rough, at which time the fuel pressure on the cockpit-mounted pressure gauge was noted at or near the low scale indication. The throttle was retarded and the engine was shut down with the mixture control. A knob at the pilot's right knee, just below the instrument panel controls the fuel shutoff valve. According to Cessna Aircraft, this knob is normally safety wired in the open position, and is only to be used during emergency situations requiring fuel shutoff or during maintenance of the fuel system. The knob actuates a shutoff valve mounted at the firewall near the floor. Visual examination of the valve follower arm disclosed that it was in a partially closed position with the control knob in the full open position. Further examination revealed that the cable housing was loose in it's associated securing clamp. The cable housing was able to slide back and forth in the clamp. The valve could be hand actuated from the on to off positions without any significant movement of the control knob. The hardware securing the subject clamp utilized a locking-type AN nut that appeared to have about two threads visible. The nut and bolt were tightened about four full turns to secure the cable. The locking action of the subject nut felt normal and was adequate to maintain security after tightening. The cable was then secured in the clamp so that the actuation of the control knob operated the fuel shutoff valve normally from the "on" to the "off" positions. With the fuel shutoff valve properly configured and in the full "on" position, another engine run-up was conducted. The engine was operated with the auxiliary fuel pump "on" at full throttle with an indicated 2,400 rpm for about 1 minute. The fuel pressure remained in the green. The auxiliary fuel pump was turned off to ascertain whether the engine would maintain full power using gravity-fed fuel. The engine operated normally with no abnormal sounds or indications. According to the aircraft maintenance records, AD 70-24-04 Fuel Shut-off Valve, effective December 8, 1970, was complied with on August 18, 1984, by installation of Cessna Kit No. SK177-10. A copy of the AD is appended to this file. The AD lists Cessna Service Letter SE70-24 as the document to reference when installing the kit. SE70-24 states that "it should be noted that the fuel shut-off knob is safetied in the 'on' position during all normal operations." Furthermore, the installation instructions encompassed in SE70-24 require that the knob be safety wired with .018 mild steel wire at the completion of the kit installation. No safety wire was in place and no hole was drilled in the subject knob to accommodate the wire. The pilot reported that he had flown Cessna Cardinals quite a lot in the past. He stated that he was familiar with the fuel system; however, when asked to point to the fuel shutoff valve, he pointed to the fuel selector valve. Subsequent questioning disclosed that he was unaware that the accident aircraft had a separate fuel shutoff valve. The Cessna Operating Checklist for the Cardinal directs the pilot to check the fuel shutoff valve knob before starting the engine, and to check that it is safety wired to the "on" position.
The loss of engine power due to a partially closed fuel shutoff valve as a result of improper maintenance installation.
Source: NTSB Aviation Accident Database
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