Final Report: SA-226 took off with known deficiency
Swearingen SA-226T, Teterboro, N.J., May 31, 2005–The NTSB blamed the pilot’s “improper decision to depart with a known deficiency, which resulted in a loss of control during landing at the destination airport. A factor was the fuel control units’ improper flight idle fuel flow rate.”
The airplane made a “sudden turn to the right” on the initial takeoff attempt. The pilot aborted, did an engine runup and took off again. The crew reduced power on landing at the destination airport, while the left engine accelerated to 60-percent power. The pilot reported “one engine surging and another engine that seems like I lost control or speed.” Regaining control, he landed and the engine surged to 65 percent power with the throttle lever in idle. The airplane immediately turned to the right, the right wing “dropped” 30 degrees and hit the ground. The pilot was seriously injured.
Tests of the fuel control units and fuel pumps revealed the flight idle fuel flow rate was 237 and 312 pounds per hour (pph), for the left and right engines, respectively, higher than the new production specification of 214 pph. According to the manufacturer, flight idle fuel flow affects thrust produced when the power levers are set to the flight idle position and differences in fuel flow can result in asymmetrical thrust.