APU/Fire Protection

Question 1

What and where is the APU on the Hawker?

Answer 1

Garrett GTCP36-150W Auxiliary Power System (don’t need to know) located in the rear equipment bay inside an enclosure

Question 2

What does the APU provide?

Answer 2

DC electrical power and bleed air

Question 3

Where is the information concerning the APU found in the AFM, and why?

Answer 3

Found in the supplements section, Hawker originally not certified with an APU so all APUs were installed via an STC

Question 4

What’s the advantage of an APU versus a GPU?

Answer 4

Always have the APU available to you

Question 5

Where is the APU control panel?

Answer 5

Cockpit entranceway behind the CA

Question 6

What does the APU control panel monitor?

Answer 6

RPM, EGT, AMPS

Question 7

What does the APU GEN annunciator mean?

Answer 7

APU generator offline

Question 8

What does the BLEED AIR ON annunciator mean?

Answer 8

APU bleed air load control valve is open

Question 9

What does the READY TO LOAD annunciator mean?

Answer 9

APU has reached operating speed

Question 10

What does the MAIN TEST switch do?

Answer 10

Switch for APU maintenance testing

Question 11

What does the LAMP TEST switch do?

Answer 11

Switch for APU annunciator lights test

Question 12

What does the GEN SWITCH do?

Answer 12

Opens or closes the APU generator contractor, providing APU power to aircraft

Question 13

What does the BLEED AIR SWITCH do?

Answer 13

Opens the load control valve, allowing the bleed air powered systems in the aircraft to run off APU bleed air

Question 14

What does the MASTER switch do? What are its positions?

Answer 14

START: energizes the APU starter, initiates automated start sequence

ON: this position powers the ECU

STOP: shuts down the APU, used to shut down the APU during all normal operations

Question 15

What happens when the APU MASTER switch is positioned in the STOP position?

Answer 15

Shuts down the APU, used to shut down the APU during all normal operations

Question 16

What does the FIRE EXTINGUISHER SWITCH on the APU panel do?

Answer 16

Discharges an additional APU fire extinguisher bottle (beyond the automatically released shot)

Question 17

What is the function of the APU FIRE SWITCHLIGHT?

Answer 17

APU off: tests fire indicators (lights and bells)

APU on: pressing shuts down APU

Question 18

What are some conditions that would automatically shut down the APU?

Answer 18

APU fire, low oil pressure, high oil temperature, loss of power to ECU, ECU overcurrent, loss of EGT signal, high EGT, overspeed (above 110%), loss of speed signal

Question 19

Where does the APU get its fuel?

Answer 19

Left fuel tank

Question 20

What controls the APU fuel shutoff valve?

Answer 20

APU MASTER switch

Question 21

What does the starter-generator do on the APU?

Answer 21

When acting as a starter, powered by the batteries or external power via the start bus

When acting as a generator, powers PS2 and PE buses (can power PS1 if bus tie contractor is closed)

Question 22

What is the function of the APU EMERG SHUT-OFF switch?

Answer 22

Shuts down APU from the switch in the rear equipment bay

Question 23

What are the APU starting cycle limitations?

Answer 23

1st Attempt: 30 seconds ON, 3 minutes OFF
2nd Attempt: 30 seconds ON, 3 minutes OFF
3rd Attempt: 30 seconds ON, 30 minutes OFF

Question 24

What are the APU operating limitations (altitudes)?

Answer 24

Operating: 0-30,000’ Pressure Altitude
Starting: 0-20,000’ Pressure Altitude

Question 25

What are the APU limitations? (Will be asked to list some on the quiz)

Answer 25

Maximum RPM 110%, Maximum Operating EGT 1,350ºF, Maximum Transient EGT 1,400ºF to 1,500ºF for 15 seconds, Shutdown APU if READY TO LOAD light not illuminated within 60 seconds, Do not attempt in flight start if both main generators fail, APU start prohibited with left engine shutdown due to fire or engine failure, Maximum Generator load 0.80, Maximum transient generator load 1.2 for less than 10 seconds, Simultaneous operation of APU and engine bleed air limited to 1 minute, Inflight operation of APU prohibited in icing conditions, APU must be shutdown during ground de-ice operations, APU operation must be attended with pax onboard, APU must not be started during refueling operations, APU operation refueling limited to single-point pressure refueling

Question 26

What are some of the limitations in regard to bleed air? 1-2-3

Answer 26

1 minute with main air valves and APU bleed operations running simultaneously 2 minute run with "no load" before placing bleed air load on the APU 3 minutes in between start attempts

Question 27

How many fire indications are in the cockpit? Why?

Answer 27

6 or 7 - 7 if engine instruments are on the SIC's PFD, 6 if not

Question 28

What is the engine fire protection system composed of?

Answer 28

Two sensing elements and responders per engine, roof panel indicators, warning bell, two engine extinguisher bottles, two test switches

Question 29

What is the APU fire protection system composed of?

Answer 29

Four overhead detectors, warning light, warning bell, one fire extinguisher bottle

Question 30

How are fires extinguished in the engines? Where are they located?

Answer 30

Two dual-head single use fire extinguisher bottles located in the rear equipment bay

Question 31

How do the extinguishing bottles work and which engine does each extinguish?

Answer 31

Each bottle is capable of discharging its total contents into zone one of either engine, both bottles can be discharged into a single engine, or one bottle can be discharged into each engine

Question 32

Which extinguisher shots are on which bus, and what bus are the warning circuits on?

Answer 32

SHOT 1 is powered by PE, SHOT 2 is powered by PS2. The warning circuits are powered by the PE bus

Question 33

What is the most basic thing that the fire detection system is telling us?

Answer 33

Something is hot

Question 34

What does each engine have for fire detection?

Answer 34

2 sensing elements, 2 responders, 2 zones

Question 35

How can we vent excess pressure from the engines?

Answer 35

Thermal pressure will blow out pressure relief disks under the left engine pylon, and the extinguishing agent will vent overboard

Question 36

What does the APU fire detection system compose of?

Answer 36

Four overheat detectors, warning light on APU control panel, fire bell, one fire extinguisher bottle

Question 37

What happens in the APU when a fire is detected?

Answer 37

Detection of overheat condition will illuminate APU FIRE indicator, activate fire bell, and automatically shut down APU

Question 38

When does the APU extinguisher bottle activate?

Answer 38

Automatically discharges 5 seconds after APU auto-shutdown due to overheat

Question 39

How can the APU extinguisher bottle manually be activated?

Answer 39

Red guarded toggle switch on APU control panel

Question 40

What does the REAR BAY OVHT annunciator indicate?

Answer 40

Overheat condition in rear equipment bay, red MWS flashers will activate, no fire extinguishing available.