User manual

DodoSim 206 FSX User Manual

Page 71

If either of these conditions have occurred or are believed to be about to occur, the pilot should

press the idle release latch and close the throttle fully whilst continuing to hold the starter

button down. The starter button can be released once EGT is observed to have dropped below

812°C once again.

The pilot should not motor the starter to bring the temperature down any further. The turbine

blades can warp or stretch if spun whilst exposed to such high temperatures and exposure to cold

air from the compressor could induce thermal shock and potentially crack or otherwise damage the

power turbine blades.

Should sufficient damage be caused during a single or subsequent hot-starts, where the pilot has

not acted quickly enough or appropriately to prevent it, the engine may suffer a mechanical failure,

(if the Difficulty Level and Failure Mode support it.) A fire may result until fuel is shut off and a

grinding noise will be audible. Once the turbine has slowed to a stop it will likely not spool up again

due to the damage, and servicing should be sought to rectify the problem.

Pilot Information: If for whatever reason the fuel is shut-off during a start, on no account should it

be re-introduced, as this will almost certainly cause the EGT to skyrocket and cause a hot-start.

4.2.2.2 Engine Flame-Out

Should the turbine suddenly stop combusting whilst in flight, it may be restored by an immediate

application of the starter button to re-ignite the fuel, assuming fuel is still flowing.

If engine speed has decayed then the pilot must close the throttle past the idle stop to shut off the

fuel before reapplying the starter button and reintroducing fuel as per a normal ground start-up

sequence. However, since the rotor is freewheeling, the reduced air pressure within the engine

should enable it to spool back up to normal operating speeds somewhat quicker.

The pilot should not attempt to restart the engine in the event of a mechanical failure as this could

cause greater damage or induce a fire.

If a flame-out occurs below 1,500’, the pilot should not concern himself with attempting to restart

the engine, but instead adopt the auto-rotation profile and prepare for an emergency landing.

4.2.2.3 Engine Mechanical Failure

In the event of a mechanical engine failure, the pilot should shut down the engine and shut off the

fuel flow, (either by closing the throttle fully past the idle stop, or by closing the fuel valve), in order

to isolate the hot engine from the fuel supply and thus prevent a fire. On no account should the

pilot attempt to restart the engine.

The pilot should adopt the auto-rotation profile and prepare for an emergency landing. Upon

landing, the helicopter should be vacated safely and all persons removed to a safe distance in case

of fire.

4.2.3 Transmission Failures

4.2.3.1 Main Transmission “Sprag” Clutch Failure

In the event of a main transmission failure, the throttle should be rolled back to idle. By closing the

throttle, the pilot effectively disengages the governor, ensuring that the FCU does not attempt to

manage the rotor RPM through the broken and unloaded transmission and consequently over-

speed, potentially causing engine damage.

The pilot should then auto-rotate to a safe landing after which the helicopter should be shut down

normally.