B-1A Secondary Power Systems Flashcards
How many SPS units are in the B-1A?
Two.
Name the components that comprise the integrated propulsion system of the B-1A.
Propulsion engines, ETCS, AICS, SPS, engine & APU fire detection / extinguishing systems.
The SPS contains an:
Auxiliary power unit.
What do the APU’s & ADG’s do?
- Provide power for starting engines & driving ADG’s to power IDG’s & hydraulic pumps.
- ADG’s act as power path for engines to provide torque to power IDG’s & hydraulic pumps when coupled up.
The APU start motor is:
Hydraulic.
Are the APU’s constant-speed?
Yes.
The two SPS APU’s provide shaft power to do what two functions?
- Motor & start propulsion engines.
* Supply torque to drive respective ADG’s.
The APU gearbox is mechanically connected to which part of the APU turbo machinery?
The APU compressor.
During normal APU operation, the APU gearbox transmits shaft power to:
- APU accessories
* The ADG(s) it’s coupled up to.
APU oil is contained where?
In the APU gearbox sump.
APU gearbox sump capacity is rated at:
4.0 quarts (2.5 quarts usable).
At max oil consumption rate, 4.0 quarts of oil will last:
50+ hours.
The APU fuel system is composed of:
- Fuel control assembly
- Fuel SOV
- Fuel flow divider valve
- Primary & secondary fuel manifolds / nozzles
What purpose does the ECA serve in the secondary power system?
The ECA controls the APU’s & associated auxiliary drive systems.
What does ECA mean?
Electronic control assembly.
Exactly how does the ECA work with the SPS?
The ECA contains the logic circuits to control both the APU’s & ADS’s in response to internal signals and flight crew control inputs from SPS / ADS controls.
Does the ECA monitor SPS operation?
Yes, both APU’s and ADG’s.
Is the ECA a MIMO, SIMO, SISO, or MISO system?
MIMO.
Output signals from the ECA go to:
- APU T5 indicators
- APU RUN lights
- HYD pump depress. valves
- Master caution & ADS lights
The APU ALERT START & STOP buttons are electrically connected to the:
APU fire, start, hold delay, & hydraulic pump ground lockout relays.
The left APU start module is powered by the:
No. 2 hydraulic system.
The right APU start module is powered by the:
No. 3 hydraulic system.
The APU START, FIRE, hold delay, RUN, and HYD pump ground lockout relays have electrical inputs from:
- Fire detection system
- L/G load sensors
- Engine start switches
The APU relay outputs also go to which fuel supply system components?
- Tank isolation valves
* APU firewall fuel SV’s
How many power paths are there between the engines and APU’s?
Three paths.
Name the three power paths of the APU-engine-ADG system.
- Engine-ADG path
- APU-ADG path
- APU-engine path
Explain the engine-ADG path:
- Normal mode of driving accessories
* Torque is transmitted through a PTO-ADG shaft.
Explain the APU-ADG path:
- Used to drive ADG accessories when engines are not operating
- Controlled via ADS couple knobs
Explain the APU-engine path:
- Used for engine motoring or starting
* Torque is transmitted via a torque converter in ADG and through the PTO-ADG shaft to engine.
When setting ADS couple knob to any position other than DISEN, what occurs?
The ADG acceleration control device is energized, allowing the APU PTS to drive accessories (HYD pump & IDG).
Once the ADG is coupled, the accessories reach operating speed within how much time?
4 seconds.
The torque converter is drained automatically at what N2 speed?
57%-59% N2.
