click below
click below
Normal Size Small Size show me how
CE750 APU
APU
Question | Answer |
---|---|
In the normal mode, which fuel boost pump will automatically run when the APU is operating? | Left boost pump |
What does the APU supply to the aircraft? | Bleed air and 28VDC |
What is APU bleed air used for? | Engine starting, air conditioning, service air |
Can the APU share electrical loads on the split bus aircraft? | No |
Can the APU share electrical loads on the non-split bus aircraft? | YES |
What is max operating altitude for APU? | 31,000' |
What is max airspeed for APU airstart between 20,000 and 31,000? | 300 knots |
What is max speed for APU airstart below 20,000? | Vmo |
What is the normal source of fuel for the APU? | Left wing hopper tank |
What system monitors the APU during operation? | The Electronic Control Unit (ECU)/Electronic Control Box (ECB) |
What happens in the ECB detects a fire in the APU? | 1. APU shutdown 2. APU Fire annunciator illuminates 3. Master Warning flashes 4. Aural chimes |
Does APU have its own fire bottle? | Yes |
If the APU Fire Push switch is depressed, how will you know that the fire is out? | APU Fire annunciator and CAS messages go away |
Does the APU master switch have to be on to operate the APU? | Yes |
What power sources can start the APU? | 1. Batteries 2. GPU 3. Engine generator |
What bus is required for APU operation? | Emergency bus |
When pressing the APU test button, what should the RPM, EGT, and DC Volts displays read? | RPM: 50% EGT: 500 DC Volts: current system voltage |
If the APU fire bottle is low, how will that show up during the APU test? | APU Fail light will remain illuminated CAS will read Fire Bottle Low APU in cyan |
Max number of successful APU starts in one hour? | 6 |
After 6 successful APU starts how long is the cool off period? | 1 hour |
What are the limitations for unsuccessful APU starts using the aircraft batteries? | 2 attempts (30 seconds each) Followed by 30 minute cooling period 2 more attempts (30 seconds each) Followed by 1 hour cooling period |
What are the limitations for unsuccessful APU starts using a GPU or engine generator? | 2 attempts (15 seconds each) Followed by 20 minutes cooling period 2 more attempts (15 seconds each) Followed by 40 minute cooling period (No more than 4 attempts in one hour) |
What is the minimum battery voltage required to start the APU? | 22 volts |
If the APU fails to shut down using the STOP position switch, what could be done to shut off the APU? | Hold the test switch for 6 seconds, or until the APU shuts down |
What RPM will the APU normally operate at? | 100% |
What is the max EGT for normal APU operations? | 718 degrees C |
What does the APU annunciator Ready TO Load mean? | APU is ready to provide bleed air and electricity to the aircraft |
What RPM is an APU overspeed? | 108% |
If APU bleed air switch is in the off position, is service air available? | Yes |
If APU bleed air switch is in the off position, is engine starting air available? | No |
If APU bleed air switch is in the off position, is environmental bleed air available? | No |
During engine starts, do the Max Cool and PAC valves close? | Yes |
In Max Cool, is PAC overheat automatic shutdown protection available? | NO |
Describe the APU generator | Same generator as the engine generators, but lower amp rating |
What are Max APU amps for flight and ground ops? | Flight: 200 amps Ground: 300 amps |
Should the APU be shut down while it is still loaded? | Yes |
Where is the external APU shutdown button located? | Tailcone area, next to the tailcone light switch |
If the APU detects a fire, will it automatically discharge the APU fire bottle? | No. This is why the aircraft must be attended during APU operation |
How much fuel does the APU burn per hour, and from which tank will it draw fuel? | 125-150 lbs/hour from the Left wing hopper tank |