601D Engine Flashcards
DEC/EDECU functions
IN FLT HOTT
Isochronos NP governing.
NP Reference (96-100)
Fault indications (Q indicator and FMS DEC status page)
Load sharing/torque match - increase Q of low side to match Np no more than 3% above reference
Transient droop comp - compensates, uses collective position indicator
History counter - sends signals to history counter
Hot start preventer - tells ODV to shut off @ 900 degrees Ng<60 Np<50
DEC/EDECU maintains constant power turbine speed of
100% (NG)
What does TGT limiting limit at
879 +/- 9 - 10 min limit
903 +/- 10 - 2.5 min limit
Load sharing keeps both engines matched within
5% torque
Overspeed protection kicks at
120% +/- 1% Np
Torque matching
-Increases power on lower Q engine to keep Qs approximatly equal
-System will not allow high engine to reduce power to match
-If engine fails highside, good engine should only attempt to increase Q until NP is 3% above reference
When does TGT limiting not work
Engine start, compressor stall, lockout
Define LOCKOUT
Manual control of engine RPM while bypassing DEC/EDECU TGT limiting
How can you override Hot start prevention for an engine start?
By holding either ENG OVSP TEST A or B buttons with the engine being started during the start sequence
Is overspeed protection disabled in lockout
No
Parameters to bypass 10 minute TGT limit
to go beyond 879 degrees;
DEC - One engine below 50% Q
EDECU -
- Np drops below 96
-Greater than 3% difference between Np and Np reference
-Greater than 5% per second drop to, or below Np reference
What can be seen in AC with both a DEC and an EDECU
Torque splits in a “contingency situation”
Can you push from idle to fly with rotor brake engaged?
No. There is a rotor brake interlock tab that should prevent this
How does the load demand system work
DEC and HMU respond to collective signals
Load sharing keeps engines within
5% torque
