C5 Dash 8 Component Acronyms

Question 1

RGB

Answer 1

Reduction Gear Box

Reduces high RPM of Power Turbine to lower RPM of the Propeller

Driven off the RGB are:

1. Hydraulic Pump
2. AC Generator
3. Propeller Control Unit
4. Propeller Overspeed Governor

Question 2

PSEU

Answer 2

Proximity Sensor Electronics Unit

1. Sequences gear and doors during gear movement
2. Controls gear and door advisory lights
3. Activates Warning Horn
4. Routes inputs into other non-gear systems.

Question 3

WOW

Answer 3

Weight on Wheels Switch

Feeds into multiple systems

Question 4

HPSOV

Answer 4

High Pressure Shut Off Valve

Controls High Pressure Bleed Air

1. HPSOV will on close on the ground at pressures above 65 psi.
2. In flight HPSOV will remained closed above 55 psi.
3. Activation of Deice Boots opens HPSOV in flight.

Question 5

NSOV

Answer 5

Nacelle Shut Off Valve

Controlled by Bleed Air Control Switches. (selecting OFF also closes HPSOV)

Shuts off all bleed air from a given nacelle, preventing Bleed Air from entering ACM supply ducts.

Question 6

HBOV

Answer 6

Handling Bleed Off Valve

Allows LP Bleed Air to cool HP Bleed Air via a heat exchanger. LP Air is then vented overboard.

Also prevents conpressor surges and stalls during slam acceleration / deceleration.

Question 7

ECU

Answer 7

Engine Control Unit

(also refered to as the EEC)

Provides electronic control functions to the engine and related components.

Controlled by ECU Panel: TOP, MCL, and MCR on the -200, TOP only on the -300.

1. Refines the manual fuel scheduling of the MFC
2. Controls N_P Underspeed Governing
3. Controls HBOV
4. Provides Power Uptrim

Question 8

PROV

Answer 8

Pressure Regulator Valve

(-200 Only)

Regulates Bleed Air Pressure to ACM.

18 psi Consumer

Question 9

PRSOV

Answer 9

Pressure Regulator and Shut Off Valve

(-300 only)

Both regulates Bleed Air Pressure and can cut off Bleed Air Supply to either pack.

Controlled by Pack Switches

Question 10

APU

Answer 10

Auxiliary Power Unit

(-300 only)

Provides Bleed Air to AC Packs and 28v DC Power to Right Main Bus.

Question 11

ESU

Answer 11

Electronic Sequence Unit

(-300 only)

Provides automatic control of APU operation. Controlled by APU Control Panel

Question 12

MFC

Answer 12

Manual Fuel Controller

Mechanical fuel metering unit.

Mechanically linked to both Power and Condition levers, uses lever angle and pneumatic inputs to detirmine manual fuel scheduling.

Question 13

PCU

Answer 13

Propeller Control Unit

Controls Propeller Blade Angle by metering engine oil to one side of a double acting pitch change mechanism.

Receives mechanical inputs from Condition Levers for constant speed operation.

Receives mechanical inputs from Power Levers while in Beta Mode.

Question 14

POG

Answer 14

Propeller Overspeed Governor

Provides Protection from Propeller Overspeed conditions.

In flight POG will dump fine pitch oil to drive prop towards feather, thereby reducing prop speed.

On ground POG will bleed P₃ air from MFC, accomplishing a reduction in engine speed.

Question 15

TRU

Answer 15

Transformer Rectifier Unit

Converts AC from 115 vAC Bus to 28v DC to power Secondary Buses.

Question 16

BBPU

Answer 16

Bus Bar Protection Unit

Part of the DC Logic system that monitors Main DC Buses for potential bus faults.

Upon detecting a fault BBPU will automatically protect the DC electrical system from the fault.

Question 17

EADI

Answer 17

Enhanced Attitude Direction Indicator

Electronic Attitude Indicator and Single Cue Flight Director.

Receives pitch and roll inputs from associated AHRS. Graphics generated by associated Symbol Generator. Unit can be driven by other AHRS or Symbol Generator using reversionary modes.

Question 18

AHRS

Answer 18

Attitude Heading Reference System

Provides aircraft attitude and heading information to the EADI, EHSI, and RMI.

Question 19

SG

Answer 19

Symbol Generator

Combines inputsProvides graphical information to EADI.

Question 20

EHSI

Answer 20

Electronic Horizontal Situation Indicator

Receives heading information from the AHRS.

Question 21

ACM

Answer 21

Air Cycle Machine

Uses bleed air to provide air conditioning and pressurization.

Question 22

GCU

Answer 22

Generator Control Unit

Controls DC Starer / Generator units. One for each engine.

1. Converts respective Starter / Gen from starer to gen mode during automatic start sequence at roughly 60% N_H
2. Monitors and regulates Starter / Gen’s voltage output to maintain a constant 28v output.
3. Prohibits the DC electrical system by taking generator offline and isolating it in case of fault.

Question 23

RSOV

Answer 23

Rudder Shut Off Valve

Isolates the #2 Rudder Actuator and #2 SPU in case of major fluid loss in #2 hydraulic system, thereby providing rudder control.

18 psi Consumer

Question 24

ARPS

Answer 24

Alternate Rudder Power System

Consisting of #2 Standyby Hydraulic Pump, #2 Rudder Actuator, and RSOV, the system provides hydraulic power to the rudder in the event of major fluid loss in #2 hydraulic system.

Question 25

TCAS

Answer 25

Traffic Alert and Collision Avoidance System Uses Mode C and Mode S readouts from nearby aircraft to provide Traffic Alerts (TA) and Resolution Advisories (RA)

Question 26

EGPWS

Answer 26

Enhanced Ground Proximity Warning System Relies on a variety of aircraft parameter inputs and provides flight crew with aural alert messages and visual annunciations when any proximity envelope is exceeded.

Question 27

ADC

Answer 27

Air Data Computer Receives input from Pitot / Static system, temperature probes and supplies information to systems on the aircraft.

Question 28

FMS

Answer 28

Flight Management System

Question 29

HGS

Answer 29

Heads-Up Guidance System AKA HUD, or Heads Up Display

Question 30

RASU

Answer 30

Remote Airspeed Select Unit Used to select desired target airspeed for HGS approaches.

Question 31

HCP

Answer 31

HGS Control Panel Used to select: 1. HGS Mode 2. Runway Elevation for the approach 3. Glideslope Angle for the approach

Question 32

SPU

Answer 32

Standby Power Unit Another name for the Standby Hydraulic Pumps. Powered by 115v variable AC. #2 SPU normally powered by left 115 vAC Bus. In case of left bus failure #2 SPU will automatically switch to right AC BUS and illuminate #2 SPU AUX PWR warning light.

Question 33

PTU

Answer 33

Power Transfer Unit Assists in retracting the landing gear in the event of a #2 engine failure. Is triggered the the PSEU senses loss of #2 engine oil pressure coupled with a gear up command. Consists of hyraulic motor driven by the #1 hydraulic system mechanically coupled to a hydraulic pump running the #2 hydraulic system. Can be manually activated per E&A checklist to extend landing gear in event of #2 engine failure.