User manual

DodoSim 206 FSX User Manual

Page 70

Practice auto-rotations are usually performed by reducing the throttle to approximately 70% travel,

which reduces N2 to about 90%, disconnecting the transmission drive train, rather than reducing the

throttle all the way back to idle. The reason for this is that if the pilot needs to bring the power back in to

recover in the hover or abort the practice auto-rotation for any reason, the turbine does not have to

spool up so far and torque and temperature spikes can be avoided.

Pilot Information: It should be noted that at 90% N2 the engine is still transferring some power to the

rotor system. Pilots should bear this in mind and consider the fact that in a real engine off landing there

will be no power at all and rotor RPM will decay a lot faster during the final stages.

4.2.2 Engine Failures

4.2.2.1 Hot-Start

A “hot-start” is when the temperature inside the turbine exceeds design limits during the start-up

sequence and can be caused by several potential factors:

 Over-fuelling whilst accelerating to the turbine self-sustaining speed

 Tail-winds preventing exhaust gases from escaping the engine efficiently

 Wear or damage to the turbine blades, fuel jets or bearings

During the start sequence the pilot must monitor the “TURB OUT” Exhaust Gas Temperature

(EGT) gauge and be ready to move the throttle back past the idle stop to cut-off the fuel should the

limits be exceeded. In the DodoSim 206 FSX, the limits are:

 812°C for no more than 10 seconds

 927°C for no more than 1 second

If either of these conditions is met, the TOT light will illuminate. This cannot be reset by the pilot

and is an indication to subsequent pilots that damage may have previously occurred to the engine

and should be inspected by a mechanic.

Approx. 90% N2

812

927

TOT light