On May 5, 2019, a Beech A60 was substantially damaged when it was involved in an accident near Santa Rosa, New Mexico. The commercial pilot and one passenger were killed in the crash.
The flight originated from Arlington Municipal Airport (KGKY) in Texas and was destined for Santa Fe Municipal Airport (KSAF), in New Mexico.
The airplane’s Insight GEM-1200 engine monitor device recorded that, about 2.25 hours into the flight, the left engine exhaust gas temperature and cylinder head temperature began to decrease. About that same time, the pilot contacted air traffic control (ATC) and asked to divert to the nearest airport because of a fuel pump issue. He did not provide any details about the fuel pump issue, but stated that the request was precautionary. He did not declare an emergency.
The controller suggested Santa Rosa Route 66 Airport (KSXU) in New Mexico, and the plane turned from a northwest heading to a southwest heading toward KSXU. The controller asked the pilot to provide the remaining fuel quantity. He responded that he did not have the time to provide that information and that he was switching to the airport’s UNICOM frequency.
Three witnesses reported seeing the plane flying at an altitude of about 100 feet agl. Two of these witnesses also reported that the airplane rolled to the left and then hit terrain, which was followed by a postcrash fire.
The wreckage was located on a small tree- and rock-covered knoll about a mile west of KSXU. The plane came to rest on a heading of about 176° and at an elevation of about 4,645 feet msl. The inboard sections of the wings and the lower fuselage were damaged by the fire.
All major structural components of the airframe were located at the accident site. An examination of the airframe revealed no pre-impact mechanical malfunctions or failures that would have precluded normal operation.
The left engine fuel selector was in the OFF position, and the right fuel selector was found between the ON and OFF positions. The left boost pump functioned properly when power was applied. The right boost pump was heavily damaged in the crash and was not operational when power was applied.
The left engine fuel hose was found with a trace amount of fuel (estimated to be about one ounce) between the outlet from the fuel injector servo to the inlet of the flow diverter shutoff valve. The right engine fuel hose was damaged by fire and was found with no fuel between the outlet from the fuel injection servo to the inlet of the flow diverter shutoff valve.
The left engine-driven fuel pump was found displaced from the engine with the drive couple separated. The right engine-driven fuel pump was found displaced from the engine with the pump drive intact.
The left engine-driven fuel pump was sent to the National Transportation Safety Board’s Materials Laboratory for examination. The examination revealed that the relief valve cover had fractured into multiple pieces due to impact and that, as part of the impact, the adjustment screw was displaced downward, leaving an impression on the spring seat. The lower side of the spring seat had two wear marks that were separated by about 120°. The diaphragm plate, which was in contact with the spring seat, had one wear mark. The diaphragm (below the diaphragm plate) was torn and exhibited regions in which the lower rubber layer had cracked, with chips of rubber separated from the diaphragm. The poppet valve, part of the pressure relief system, contained multiple fractures around the perimeter of the valve disk.
Examination of the fracture surfaces found that the fractures had initiated along the lower surface of the disk due to high-cycle fatigue in upward bending. The valve seat and the beveled edge of the valve had no wear marks, impact marks, or other notable features. The valve guide exhibited opposing wear marks near the lower guide opening. The drive shaft to the pump rotor spline coupling exhibited wear of the external and internal spline teeth.
Probable Cause: The pilot’s loss of airplane control due to his failure to maintain appropriate control inputs and airspeed after shutting down an engine because of a progressive failure of the pressure relief valve in the fuel pump, which resulted in variable fuel pressure in the engine.
Did the right fuel selector position indicate that the pilot may have inadvertently shut off the wrong fuel? Maybe he caught it, tried to reset it and got too flustered to continue safely flying the aircraft. Regarding the progressive failure mode of the engine, that can create a situation of wishful thinking that keeps the pilot from decisively handling a partial loss of power. It’s there, it’s gone, it’s back, oh wait its sputtering again. Just shut it off, get it on the ground.
This May 2019 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
