Engines and Props

Question 1

What type of engines does the Braz have

Answer 1

PW 118 A

Question 2

What is the rated power output of engine

Answer 2

1800 SHP

Question 3

How many compressors does the engine have

Answer 3

2 Centrifugal compressors

Question 4

How many turbines does the engine have

Answer 4

3
2 x Single stage axial turbines
1 x 2 stage axial turbine

Question 5

At what point will the starter generator switch over to being generator

Answer 5

50% Nh

Question 6

As well as lubrication what is an additional use of the oil

Answer 6

Heat the fuel

Question 7

Each engine has how many compressor bleed ports

Answer 7

2 x Low Px, Station 2.5, 12 o’clock / 2 o’clock

1 x High Px, Station 3, 10 o’clock

Question 8

On approach with auto-feather armed, if the engine fails will it feather

Answer 8

No, conditions not meet
PLA (PWR LVR ANG) greater than 62
Tq greater than 62%

Question 9

What type of combustion chamber

Answer 9

Reverse Flow annular, 14 nozzles

Question 10

Engine power control is maintained by

Answer 10

Electronic Engine Control (EEC) and the Hydromechanical Control unit (HMU)

Question 11

What controls the fuel flow in the absence of electrical power, EEC failure

Answer 11

Hydromechanical Control unit (HMU)

Question 12

The EEC (Electric Engine Control) is powered by

Answer 12

Emergency DC Buses

and b/up emergency Dc buses

Question 13

The EEC normally what position

Answer 13

TO - AUTO

Question 14

What does the Illumination of the glare shield EEC light indicate

Answer 14

Respective EEC failure detected

Question 15

Oil Pressure Light activates at?

a. Limitations (note 11)

Answer 15

40 psid light
40 mins with oil between 40 - 55 only if NH below 75%
(i.e. flt idle)

Question 16

Condition Lever job is to?
Positions and guards
Min FLT , Taxi

Answer 16

RPM
Mechanically connected to PCU, also HMU for shutdown
Fuel Shut OFF / Feather Min RPM / Max RPM
80% Np Min FLt
50% NP Taxi

Question 17

Power Lever function is to?
Positions and guards
Provides direct control over

Answer 17

FLT Ops NH
Mechanically connected to HMU ( Power lever angle (PLA) controls fuel schedule) and electrically to EEC
PCU (for ground Ops in Beta range), controls pitch for fixed Np - taxi(50%Np) and reverse(80.5%Np EEC controlled)
*Controls Low pitch lock schedule PCU

Question 18

Ignition system
Auto
On
Off

Answer 18

Auto - will activate during start sequence and auto disconnect at 50% Nh changing from starter to generator
On - Ignition circuit is continuously energized
Off - De-energized - used for DRY motoring
Clearing fuel after WET start
Lowering T6 after HOT start

Question 19

Fuel flow to the engine is metered by

Answer 19

HMU / EEC

Question 20

EEC has a Fail____ Function

a. This does what

Answer 20

Fixed - sensor fail only, not full EEC fail
Freezes Torque motor to prevent spool backs during T/Off, fix prop pitch
-Active below FL140-

Question 21

What is the role of the 14K and 10 K switches

Answer 21

14 K changes fuel schedule for the HMU passing FL140,
Leans climbing through and enrichens on descent,allows EEC to adjust fuel schedule
If 14K fails passing 10K this switch throws a fault warning

Question 22

EEC control functions activates at

Answer 22

25% Nh

Question 23

What props does the Braz have

Answer 23

Hamilton Sundstrand 14 RF-9 Commuter Propeller

Constant Speed, reversible, Full Feathering

Question 24

Prop tip clearance

Answer 24

18”

Question 25

Normal ops Props max governed speed

Answer 25

1300 RPM (range 1300 - 1313)

Question 26

Pitch range

Answer 26

-15.0 through to +79.2 - measured at 42"

Question 27

What controls Np? During ground Ops? In Flt?

Answer 27

In Flight PCU On the Ground fixed Power lever via the BETA valve MIN RPM 50% Np / MAX RPM 65%Np

Question 28

What sort of screw is used in governor

Answer 28

acme reverse thread screw, changes actuators position to allow oils to flow from different chambers

Question 29

What is pitch lock? | How is it achieved

Answer 29

Pitch lock gap | Change of 1% or 2Np closed the gap trapping oil and stopping further reductions in prop pitch

Question 30

What do the BETA lights on glareshield indicate? In flight On the ground?

Answer 30

In flight FLASHING - primary low pitch stop has failed secondary low pitch stop is working Normal on GRD

Question 31

What is the BETA valve? | What does it do?

Answer 31

In flight controls Low Pitch Back Stop, controls speed governor not allowing prop pitch below established values Power lever below FLT Idle Control blade angle for ground Ops, activated when Commanded directly by Power lever

Question 32

What if the function of the Least select valve

Answer 32

Hydraulic Discriminator between Governor section and Over speed governor

Question 33

Prop sync is activated by

Answer 33

Switch Only Operates between 80% - 100& Np Left prop is master won't activate if Np diff greater than 2.5%

Question 34

PCU Oil Pressures

Answer 34

Aux Oil tank feed approx 100 psi Propeller Oil Pump boosts to 780 psi Aux Pump Px 820 psi for feathering

Question 35

Reverse Valve

Answer 35

Controlled by Power lever selects either governor or Beta valve to control prop pitch FLT Idle up - Governor Grd Ops - BETA Valve

Question 36

How many Spools does PW118a have

Answer 36

3 Low Press High Press Power Spool

Question 37

Which spool drives the starter generator start sequence

Answer 37

High Press spool

Question 38

What is the purpose of the S Shaped duct in the air induction inlet

Answer 38

Inertial separator, removes FOD by bending the airflow

Question 39

How many fuel injector nozzles are there in the combustion chamber

Answer 39

14

Question 40

Where is the T6 temp measured

Answer 40

Between the 2nd stage turbine and the power turbine | HP Spool and Power Spool

Question 41

How much does the RGB reduce the RPM going to the prop shaft

Answer 41

15:1 reduction through 2 stage gearbox, reduces RPM and increases the torque

Question 42

Is the HMU driven by the TMM gearbox (HP spool)

Answer 42

No located on it through the fuel pump, | Fuel pump driven by gearbox but HMU not driven by it

Question 43

How is the AUX oil tank (EFP),( electric feather pump reservoir) replenished

Answer 43

Automatically filled by oil system when engine is running or being dry motored Dry motoring, turning starter without adding fuel to spin the engine

Question 44

What safe guards does prop heat have on the ground

Answer 44

Will only function when oil press is above 40 psid | Engine low oil pressure switch

Question 45

What does the abort selection on starter switch do

Answer 45

Aborts the start by sending an artificial NH 50% to the GCU - this ends the start cycle

Question 46

Is a generator alone sufficient to an engine

Answer 46

No, requires assistance from the main battery

Question 47

At what point does pilot introduce fuel during the start sequence

Answer 47

Passing NH 10% condition lever moved from Cut Off to Feather | -make sure temp below 200, hot start delay fuel input-Prior to 19%

Question 48

What is the time limits for "light Up" during engine start?

Answer 48

10 secs for light Off (T6 begins to rise)

Question 49

Nh Governing Speeds

Answer 49

EEC maintains Ground Idle Nh 62% | Flight idle Nh 72%

Question 50

EEC safety features Nh Overspeed Nh undespeed

Answer 50

Nh under 60% EEC switches OFF | Nh over 103% EEC switches OFF

Question 51

EEC failure, signs and actions

Answer 51

EEC lights on GLARESHIELD System reverts to HMU, resulting in power loss Add 20% Torque