What happened
On February 13, 2013, a Cessna T337C, registration N2576S, crashed in a farm pasture near New Smyrna Beach Municipal Airport (EVB) during a local maintenance test flight. Shortly after takeoff, the pilot transmitted a "mayday" call over the tower frequency. Witnesses observed the aircraft in a left-wing-down bank before it struck a tree, severed power lines, and hit a second tree before coming to rest.
The pilot sustained 1 fatal injury. The flight was conducted under VMC weather conditions with a visibility of 7 miles and winds from 230 degrees at 15 knots.
The investigation
Investigators examined the aircraft's engines and fuel systems. Data from an engine monitor revealed that the rear engine had exhibited erratic fuel flow starting two days before the accident. While the front engine showed no malfunctions, the rear engine propeller was found at a low pitch angle with low-to-no power at the time of impact.
Post-accident testing of the engine-driven fuel pump showed it delivered fuel flow higher than manufacturer guidelines with low pressure. Although the mechanic had adjusted the pump's adjustment screw to meet bench standards, the engine still failed to reach full power. Further inspection of the throttle assembly revealed potential debris between the brass and stainless steel plates, which likely caused the power loss. The source of this debris was not definitively identified but was suspected to have originated from the fuel or a fuel tank.
Findings
- Maintenance personnel failed to follow published directives when calibrating the continuous flow fuel system.
- The use of a JPI engine monitor and an external gauge instead of the manufacturer-recommended Model 20 ATM-C Porta Test Unit resulted in inaccurate calibration.
- The mechanic failed to accurately diagnose the presence of debris within the throttle assembly.
- The pilot did not follow the manufacturer's approved engine-out emergency procedures, which required immediate feathering of the propeller and specific landing gear configurations to maintain a climb rate of at least 275 feet per minute.