The iStart computer samples the engine temperature, starts the
fuel boost pump and injects the precise amount of fuel for engine priming, cranking and idling.
Testing also demonstrated that the
fuel boost pump inlet screens could be blocked sufficiently to restrict fuel flow by ice, although data from the British Airways 777 shows that the boost pump low-pressure switches did not trigger throughout the flight, appearing to rule out that the screens had been blocked.
The device protects against comprehensive electrical fault and provides
fuel boost pump automatic shut-off for centre tank fuel systems.
A flow might go something like this for a simple single: Master Off, Switches off, Circuit Breakers in, Avionics Master off, Throttle cracked, Mixture rich, Carb Heat cold, Master on, Lights as required,
Fuel Boost Pump on, Fuel Pressure checked, "CLEAR," crank the engine, Oil Pressure checked,
Fuel Boost Pump off, Fuel Pressure checked, Throttle to 1000 rpm, Mixture lean for taxi.
A short time later, the right generator also failed which automatically activated the emergency generator and
fuel boost pump. As the utility pressure continued to decrease to zero, Col Holdaway lost power to the control stick boost pitch compensator due to a failure in the hydraulic switchover valve.
The pilot verified that the mixture was full rich and the
fuel boost pump was on.
The student pilot lowered the nose of the airplane and maintained controlled flight but did not turn the
fuel boost pump to the "ON" position as the DPE requested.
The left and right fuel selectors were in the "on" position, and both
fuel boost pump switches were in the high position.
The pilot responded by activating the
fuel boost pump. The engine continued to run rough and then experienced a total loss of power.
The electric
fuel boost pump revealed no anomalies.
"The local chief of police, a certificated pilot, reported turning off the
fuel boost pump, the magnetos, and moving the fuel selector from the right tank position to the off position upon his arrival at the scene.
The local chief of police, a certificated pilot, reported turning off the
fuel boost pump, the magnetos and moving the fuel selector from the right tank position to the off position upon his arrival at the scene.