Engine SYS - 2 Flashcards
The EDECU will display a torque signal of?
25%
what is the connection between NP and NR?
1way mechanical connection via the freewheeling unit
what function of DEC keeps NP at 100%?
NP governing
how do you manually turn off starter?
pull down on PCL
3 modules of engine
cold, hot, power turbine, accessory
How does the cockpit receive the NG signal?
from the NG winding of the alternator
how does DEC get power?
primarily through alternator
secondary through AC airframe power
Where does the engine receive its electrical power?
Engine Alternator
describe load demand system
provides mechanical input directly from the collective
output flight control mixer to the engine HMU to reduce transient engine and NR droop.
Alternator windings (3)?
NG speed, DEC power, ignition power
cabin heat is provided how?
sce/ht switch to engine
When does the DEC go into 2.5min limiting?
when torque of one engine is 50% below the other
3 main functions of DEC
NP governing, torque match, single fault validation, hot start prevention,
The pneumatic start system (EPU) uses air turbine engine start motor for?
engine starting
oil holds ___
Has to be __________ for flights more than 6 hrs
______ for flights less than 6 hrs.
7quarts
at the full line
above the fill line
How does eng. oiling occur?
liquid to liquid cooler, oil from the scroll vanes
When will fuel flow be automatically be shut off to the engine during the start sequence (hot start prevention)
when TGT reaches 900c,
what controls air/fuel mix?
hmu through fuel scheduling
Oil from the chip detector passes through the oil cooler and is cooled by?
transferring heat from the oil to fuel
if NG signal is lost, what happens?
engine out warning light and audio 0% NG
where is the oil drawn from in an emergency
sumps a and b
Overservicing is not possible because oil will?
flow out the filler port
What are are the 2 operational sections of the engine?
NG and NP
primary functions of ODV
Hot start prev
Fuel purge
fuel sequencing/12 injectors
Overspeed shuts off (120%)
fuel flow process? _ _ _ _ _ _
pump, fuel filter, HMU, liquid to liquid cooler, ODV, nozzles
TGT will be indicated on the Power Pod when?
TGT > 793
Difference of 75* or more
Eng out (NG <55%)
torque affected with anti ice on how?
up to 20% of torque loss and additional 5% with heater on
what does ODV do?
sequences fuel and sends to the injectors (last part of fuel).
NP overspeed protection (120% +-1)
purges fuel on shut down
Hot start prevention? a function of the ___ and __ that ___ prevents over temp during starts by shutting down the engine
DEC
ODV
compressor stall?
loud popping/banging accompanied by a rapid increase in TGT and fluctuations in NG ! and P
Other than bleed air, what is used to assist in the engine anti-ice function?
hot engine oil provides passive anti ice
what circuit in the DEC is not powered by the alternator?
HSP
Is the NG mechanically linked to the NP?
No
when is eng inlet anti-icing system avail?
4c and below it must activate. may not be active 4-13 and must not be avail 13c and above.
The HMU operates what part of the compressor section?
Variable guide vanes
What drives LRU accessories on gearbox?
gas generator (at varying speeds)
what controls 3 variable geometry fins in engine?
HMU
NG governing is influenced by what input to the HMU?
T2 Sensor
When does NG appear on power pod?
When NG exceeds 100%
less than 55% eng out
difference of 5%
how is the generator turbine connected to the accessory gear box
mechanically
When will TGT limiting not work?
lockout
compressor stall
start up
what drives the accessory gearbox?
gas generator at a varying speed
What controls electrical function of the engine and transmits systems information to the cockpit?
DEC
What section of the engine mechanically drives NR?
NP
what operation section of the engine drives the rotors?
NP (power turbine) (it is a one way freewheeling unit)
DEC is powered by __ primarily and ___ secondary
Alternator
Aircraft power
What drives NP governing?
DEC ODV
How many stages in the compressor section?
5 axial, 1 centrifugal
How does the oil system overcome high oil pressure during cold starts?
oil bypass
the ____ provides added protection from heat-seeking weapon systems by mixing hot exhaust with rotor downwash
UES
The engine alternator supplies AC power to what?
The ignition exciter and DEC/EDECU and the NG signal to cockpit
