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40 Cards in this Set

  • Front
  • Back
What Voltage is the AW139 Electrical Sytem?
How many Electrical systems are on the AW139?
2, LH & RH
What 6 components comprise each electrical system on the AW139?
6 Components
1. Generator/Starter
2. Battery
3. Essential Buss ESS
4. Main Buss - MAIN
5. Non-Essential Buss - NON ESS
What Battery is associated with the LH Electrical System on the AW139?

The RH System?
LH Electrical System = Main Battery

RH System = Aux Battery
What is the purpose of the Battery Buss on the AW139?

What Battery is it supplied by?
Battery Buss - To supply power to the On-Board recorders

It is supplied by the AUX BATT
How are the ESS Busses protected so that they cannot feed any other buss?
Diodes and Circuit Breaker in case of short circuit.
Are the Main Buss 1 & 2 Interconnected?
Main Buss 1 & 2 are normally Isolated from one another. A Buss Tie Contactor K 10 is energized to connect them.
Where is External Power connected the busses?

What Busses are powered when External Power is connected?
Eternal Power connected to the Main Buss 1

All of the busses are powered when External Power is connected.
How are the remaining busses powered when External Power is provided to Main Buss 1?
-Ext Power Main Buss 1 to main buss 2 through Buss Tie Contactor K10
-Power from Main busses to respective Essential Busses through protection diodes
- Power to Non-ESS busses through K7 & K8 Contactors energized when EXT PWR Switch Engaged
What power are the 2 Starter Generators in the AW139
What respective busses are Gen 1 and 2 Connected to?
Generator # 1 is connected to Main Buss 1

Generator # 2 is connected to Main Buss 2
How are the Starter Generators cooled?

What affect does this have on electrical performance?
Generators are cooled by a Mechanically driven fan.

This method limits the load as Hp (Pressure Altitude) Increases and is Placarded
How many GCU GCU's are there on the AW 139?

Where are they located?

What functions do they control?
2 GCU's

Located : Aft Avionics rack in the Cargo Compartment .

Control : Voltage Regulation, Starter Generator Mode & Line Contactor Control
What Protection Functions do the GCU's Provide?

What two conditions do they monitor?
Protection : OverVoltage/UnderVoltage , Reverse Current and Overcurrent (Short Circuit)

They Monitor External Power and Starter Speed for mode switching
At what speed does the starter mode disengage and the become a generator?

What Controls this?
49-50% NG

GCU monitoring the speed sensor on the starter.
What type of batteries are installed in the AW139?

What amperage?
2 Nickel Cadmium Batteries

44Ah Main and 28Ah Aux
What functions is the Main battery utilized for?
ESS Busses & Main Buss During Dual Gen Failure or on ground with no Ext Power available/Connected
What functions is the Aux Battery utilized for?
ESS Busses during Engine Start or During Dual Generator Failure or on ground with no Ext Power Available

Power the Battery Buss for CVR, FDR and Central Maintenance Computer (CMC)
Can the Batteries be online while the External Power is connected?

What Controls this?
Need Info when how why...
How long must the Aux Battery remain connected after power is removed or the aircraft is shutdown?

5 Minutes

To successfully shutdown the Data Recorders CVR/FDR & CMC
What are the PDP's

How many of them are there?

Where are they located?
PDP - Power Distribution Panels

There are 2 (1 and 2)

They are located in the Forward Portion of the PAX Cabin Center Overhead
What is the purpose of the Shunts in the AW 139?

How many are there?
The Shunts sense the load being drawn by the aircraft total electrical system and display the Load on the Indicators.

There are 4
What is the function of the DC current Transformers?

How many are there?
DC Current Transformers sense the DC current flowing to the busses and pass a signal to the GCU to de-energize the contactor in case of an overload or short circuit.
Where are the Shunts and DC Current Transformers located?
In the top of the aft avionics bulkhead in the cargo compartment.
What is functions are associated with the External Power Receptacle ?

Is the Long Nose and Short Nose Different?
External Power Door open switch with associated CAS Message

Yes. Long nose has an Ext HeadSet Jack as well as ICS PTT and a circuit breaker for the External Power Contactor.
What is the function of the PDP's?
It contains all the contactors controlled by the GCUs for power distribution form batteries and generators and external power.
What busses does the #1 Overhead Circuit Breaker Panel Control?

What Side of the cockpit is it on?
#1 CB Panel Controls the ESS, Main, Non ESS Busses

It is on the LH Side
What busses does the #2 Overhead Circuit Breaker Panel Control?

What Side of the cockpit is it on?
# 2 CB Panel Controls the ESS, Main, NON ESS Busses as well as the BATT Buss

It is on the RH Side
What is the function of the ESS BUSS TIE Circuit Breaker?
It interconnects the Flight ESS Busses and protects against short circuit in one damaging the other.
How are the Flight ESS Buss Circuit Breakers Labeled?

Main Buss?

Non ESS Buss?
Single Squares either Side of the breaker [ O ]

Double Squares = O =

No Markings either side of Breaker O
What are the functions of the 3 positions on the Buss Tie Contactor Switch?

ON - Main Buss 1 & 2 Interconnected

Auto - Buss Tie Contactor and Main Busses controlled by CGU

Reset - Overrides Short Circuit Logic that is Preventing Closed condition
What is the Function of the GEN 1 or 2 Switch


ON Requests GCU close Generator Contactor either
When the Master Battery Switch is set to ON

What relays Energize?

What Busses are connected to the Batteries?
Master Battery to ON:

Relays K1 and K2 are energized .

Power is supplied the #1 and #2 Flight ESS Buss
When the MAIN BATTERY Switch is set to ON

What Relays Energize?

What Buss is connected to the Battery?

Contactor K3 is energized

The Main Battery 24VDC is applied to the MAIN BUSS #1
When The AUX BATT Switch is set to ON

What Relays Energize?

What Buss is connected to the AUX BATT?

Contactor K4 is Energized

The AUX Battery is connected to the MAIN BUSS #2 but the CR5 Diode only allows the Battery to be charged from MAIN BUSS 2 not to Supply it. So, MAIN BUSS 2 is NOT Energized
With the Engines not running, What is the purpose of setting Gen 1 & 2 Switches to on?
GEN 1 & 2 Switches ON (Engines OFF)

Sets GCU to Monitor Speed Sensor in starter to Energize the Generator contactors when conditions are met.
What Contactors are energized to apply the Generators to the Busses?
Generator Contactors

K5 & K6
What is the Minimum Buss Voltage Prior to Start in the AW139?
What contactor is the Buss Tie Contactor?

Why is it set to on Prior to # 2 Engine Start on Batteries?
Buss Tie Contactor = K10

K10 is energized prior to starting #2 Engine to allow Battery Voltage/Amperage from Main Buss 1 to be interconnected with Main Buss 2 for Engine Starting
What Contactors are controlled by the Master Battery Switch?

What Busses are Energized when MASTER BATT is ON?

If MAIN BATT & AUX BATT are set to ON what additional Busses are energized?
Master Battery Contactors K1 & K2

Without Main Batt & Aux Batt Switches ON then only the Flight ESS Buss 1 & 2 are energized.

Main Buss 1 Will be powered by MAIN BATT thru Contactor K3 but Even though K4 will be energized for AUX BATT the Main Buss 2 will not be energized unless the K10 Buss Tie Contactor is energized due to CR5 in the AUX BATT circuit.