OEI TRAINING MODE
The OEI Training mode is an EEC function available when in AEO
conditions in order to simulate an engine flame-out and the corresponding
single engine response and rotor speed characteristics for training purposes.
The mode is selected by moving the OEI TNG switch on the Engine Control
Panel to either #1 or #2 position, which selects the engine to be simulated in
OEI conditions (the other engine is simulated OFF); the switch is
magnetically retained in the selected position.
The OEI Training mode logic uses twin engine power to simulate an initial
"single engine" transient to “maximum torque” and rotor droop. Then both
engines are used but they are limited to a maximum total PI of 140%.
In order to simulate the transient following an engine failure the engine
selected to OEI TNG will accelerate to a maximum of 110% to then reduce
to approximately 70%, to while the inoperative engine will decelerate to a
minimum of approximately 25% TQ then accelerate to around 70% TQ.
When the Training Mode is activated, the PI displays one engine as
"inoperative" (an amber OEI TNG legend is displayed vertically on-side) and
the engine switched to OEI TNG as the sum of the two engine actual PI.
On the Pwr Plant page of the MFD, the actual engine parameters are
displayed while on the NR/NF indicator the coloured ranges are modified,
from AEO to OEI, to allow NR/NF droop to 90% as required by the cat A
procedures (ref. RFM, Supplement 12).
When in Training Mode and within the OEI TNG 2.5-minute range, the 2.5 m
legend is displayed aside the PI of the active engine:
• in amber normal inverse video while within the 2.5-minute range
• flashing in red inverse video when within 10 sec from expiry
• in steady red inverse video when the 2.5-minute limit has been
exceeded.
During OEI TNG mode operation the PFD presents the simulated OEI
conditions while the MFD, for safety reasons, presents the real AEO
conditions.
The OEI training mode is disabled if any of the following occurs:
• either engine is in MANUAL mode
• a critical or non-critical fault exists on either EEC
• either engine flames out
• the torque limiter switch is OFF
• the ENG switch is not in FLIGHT position on either engine
• the Nr speed drops below 87%
In case the above conditions apply when the OEI training mode is selected,
the switch is automatically reset to the centre (OFF) position.