BOULDER CITY, NV, USA
N600EE
Piper PA-31-350
After a complete loss of power from the left engine, the airplane was unable to maintain altitude on one engine and collided with large rocks during a landing on a beach at a recreation lake. Following a maximum gross weight takeoff, the airplane climbed to a cruise altitude of 9,500 feet msl. About 20 minutes into the flight, the pilot heard a loud "pop" sound and the left engine surged once. The pilot immediately turned around and started back toward lower terrain. He then attempted to restore power by following the checklist items, but was unsuccessful, and he then completed the shutdown and feather checklists. While proceeding to the closest airstrip for a landing, the airplane would not hold altitude at best single engine rate of climb airspeed and began to drift down. The pilot believed he would have an insufficient altitude margin to make any of the nearby landing airstrips or clear the mountainous terrain between his position and the departure airport. The pilot elected to land on the beach of a lake. During the landing rollout, the aircraft encountered moderately sized rocks and collapsed the nose and left landing gear. The left engine was installed on a test stand and examined. The only discrepancy was a fractured fuel injector line for the No. 6 cylinder injector nozzle. The fracture was completely through the line near the manifold end at a brazed joint between the line and a larger diameter ferrule end. No support clamps were observed on this line between the manifold and the injector nozzle. Support clamps were found on the injector lines to the remaining 5 cylinders. The fractured fuel injector line on the No. 6 cylinder was replaced with a serviceable line and the engine was started, accelerated to full power, and met all specifications. Metallurgical examination of the fractured fuel injector line found that it failed in fatigue from multiple origin sites on the line's outer surface. No material defects or mechanical damage, which could have contributed to the crack initiation, was found at any origin site. No evidence of clamps was found at any point along the line length. AD 93-02-05 applied to this engine and mandated compliance with Lycoming Service Bulletin 342A. The provisions of the AD and the SB require a one time inspection, then recurring inspections of the fuel injector lines at each 100-hour inspection, at each overhaul, and after any maintenance has been performed where the lines have been disconnected, moved or loosened. The line inspection involves looking for any evidence of cracks, dents, or other unserviceable wear indicators. The SB requires that any line found without clamps supporting the line run must be replaced, and that each line must be clamped. Specific clamping points for each line are noted on a diagram for each engine model incorporated within the Service Bulletin. The engine was last inspected on July 14, 2000, 23 hours prior to the accident. The fuel injection system on this engine is a constant flow type and a leak in any one line would reduce the flow to the other cylinders, which would result in an excessively lean condition. Based on both the pilot's report of the conditions at the landing site and the METAR from the closest aviation observation station, the density altitude on the surface was calculated to be 4,700 feet. The outside air temperature at the site, and the estimated temperature at the aircraft's cruise altitude, were outside of the temperature envelope for a positive rate of climb on the aircraft's single engine climb performance chart in the Airplane Flight Manual. According to Piper, the temperature lines on the charts are limits and no extrapolation can be made for points outside of the temperature lines.
On July 23, 2000, at 1330 hours Pacific daylight time, a Piper PA-31-350, N600EE, collided with rocks and collapsed the landing gear during a forced landing on a beach at the Lake Mead National Recreation Area near Boulder City, Nevada. The forced landing was precipitated by a loss of power in the left engine during cruise flight and the inability of the pilot to maintain altitude on one engine. The airplane was operated by Air Bridge as a nonscheduled, domestic, passenger flight under 14 CFR Part 135 of the Federal Aviation Regulations. The airplane incurred substantial damage. The airline transport pilot and nine passengers were not injured. Visual meteorological conditions prevailed and a VFR flight plan was filed for the nonstop flight, which departed Boulder City at 1250 with a destination of Grand Canyon, Arizona. In both a telephone interview and his written statement, the pilot said the airplane departed Boulder City at maximum gross takeoff weight and climbed to a cruise altitude of 9,500 feet msl. About 20 minutes into the flight, the pilot heard a loud "pop" sound and the left engine surged once. The pilot immediately turned around and started back toward lower terrain. He advanced both throttles; however, the left engine did not respond. The instruments for the left engine were showing manifold pressure at the bottom of the gage scale and zero fuel flow. Turning on the boost pump for the left side had no effect. He then attempted to restore power by following the checklist items, but was unsuccessful, and he then completed the shutdown and feather checklists. While proceeding back toward the closest airstrip for a landing, the airplane would not hold cruise altitude at best single engine rate of climb airspeed and began to drift down. The pilot said he believed he would have an insufficient altitude margin to make any of the nearby landing airstrips or clear the mountainous terrain between his position and Boulder City. At this point his only options were to land in the water of Lake Mead, or on a beach area that was the only clear flat terrain available. The pilot elected to land on the beach. During the landing rollout, the aircraft encountered moderately sized rocks and collapsed the nose and left landing gear. Following recovery of the aircraft, the left engine was examined by Federal Aviation Administration (FAA) inspectors from the Las Vegas, Nevada, Flight Standards District Office with technical assistance provided by Textron Lycoming. After removal from the firewall, the engine was installed on a test stand and an external examination was performed. The only discrepancy noted was a fractured fuel injector line for the No. 6 cylinder injector nozzle. The fracture was completely through the line and observed to be near the manifold end at a brazed joint between the line and a larger diameter ferrule end. No support clamps were observed on this line between the manifold and the injector nozzle. Support clamps were found on the injector lines to the remaining 5 cylinders. The fractured fuel injector line on the No. 6 cylinder was replaced with a serviceable line and the engine was started for a test run. The engine was accelerated to full power and met all specifications. The fractured No. 6 cylinder fuel injector line was submitted to the Safety Board's Materials Laboratory for a metallurgical examination. The examination disclosed that the fracture face was smooth and perpendicular to the line's longitudinal axis. High optical magnification of the fracture found striations perpendicular to the crack propagation direction and consistent with fatigue. Multiple origin sites were identified on the line's outer surface and the fatigue region of the crack covered nearly the entire fracture surface. No material defects or mechanical damage, which could have contributed to the crack initiation, was found at any origin site. Detailed examination of the line disclosed no evidence of clamps at any point along the line length. Airworthiness Directive (AD) 93-02-05 was issued June 14, 1993, and applies to all Textron Lycoming fuel injected engine models, except for the TIO-540-S1AD. The engine in the accident aircraft was a TIO-540-J2BD. AD 93-02-05 mandated compliance with Textron Lycoming Service Bulletin (SB) 342A. The provisions of the AD and the SB require a one time inspection, then recurring inspections of the fuel injector lines between the fuel manifold and the injector nozzle at each 100-hour inspection, at each overhaul, and after any maintenance has been performed where the lines have been disconnected, moved, or loosened. The line inspection involves looking for any evidence of cracks, dents, or other unserviceable wear indicators. The SB requires that any line found without clamps supporting the line run must be replaced. According to the SB, the lines are required to be clamped. Specific clamping points for each line are noted on a diagram for each engine model incorporated within the Service Bulletin. According to the operator's statement, the engine was last inspected on July 14, 2000, 23 hours prior to the accident. According to Textron Lycoming, the fuel injection system on this engine is a constant flow type. A leak in any one line would reduce the flow to the other cylinders, which would result in an excessively lean condition. In his report, the pilot noted that the outside air temperature at the landing site was 105 degrees Fahrenheit (40.6 degrees Centigrade), which was consistent with the closest aviation reporting station's observation noted on page 4 of this report. With the estimated pressure altitude of the accident site and the barometric pressure at the closest official reporting station, the density altitude at the surface was calculated to be 4,700 feet. Review of the single engine climb performance charts from the FAA Approved Airplane Flight Manual disclosed that the surface temperature was outside of the temperature envelope on the chart for a positive climb. Assuming a standard atmospheric lapse rate, the temperature at the aircraft's cruise altitude would have been outside of the charts temperature envelope for a positive single engine climb. According to Piper Aircraft, the temperature lines are limits and cannot be extrapolated for temperatures that fall outside of the lines.
The fatigue fracture and separation of the No. 6 cylinder fuel injector line due to the company maintenance personnel's failure to comply with an Airworthiness Directive. A factor in the accident was the company's decision to operate the aircraft in environmental conditions, which were outside of the single engine performance capability of the aircraft.
Source: NTSB Aviation Accident Database
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