Communication Control Systems (CCS)

Question 0

Where are the HEU fitted?

Answer 0

Cabin Roof
Left hand side No 1  (Co Pilot) + 3 (Snr PAX) 
Right hand side No 2 (Pilot)
Rear AV Bay
No 4 (TETRA)
No 5 (ARC 231)

Question 1

What are the LRU’s of the SCCS?

Answer 1

Digital Audio Mixing Unit (DAMU)
Communications Control Panel (CCP) x 3
Headset Electronic Unit (HEU) x 5
Signal Conversion Interface Unit (SCIU) x2
Signal Conversion and Switch Matrix (SCMU)
Emergency Intercom Radio Amplifier (EIRA)

Question 2

Why has each HEU got 2 channels?

Answer 2

It allows multiple users of the same HEU and CCP to be allocated to different nets.

Question 3

Where is the DAMU?

Answer 3

Rear avionics bay, centre shelf, slot 4.

Question 4

What is the purpose of the DAMU?

Answer 4

It is the central data controller for the SCCS and controls all selected intercom and radio functionality. (The brain)

Question 5

How are communications between the DAMU and other LRU’s transmitted?

Answer 5

Digitally via dual redundant fibre-optic cables which mitigate TEMPEST risk and reduce aircraft weight.

Question 6

What is the purpose of the SSCIU?

Answer 6

Interfaces audio to and from encryption devices and includes an external connector for the telebrief.

Question 7

What is the purpose of the CSCIU?

Answer 7

Provides audio and interfaces for the V/UHF + HF radios.
Receives audio from :
DF
SIFF
DAS
AWG
Nav systems.

Question 8

Where are the SCIU powered from?

Answer 8

SSCIU - Dual power DC Gen BB no 1 + 2

CSCIU - Dual power DC engine start BB no 1 + 2

Question 9

What is the purpose of the SCMU?

Answer 9

Controls the allocation of the three KY-100.

Question 10

How is the SCMU controlled?

Answer 10

Entirely by the DAMU but has a 1553b Databus connection for sending status information to the CDNU.

Question 11

What is the purpose of the EIRA?

Answer 11

provides back up comms system in event of SCCS failure.

Question 12

How is the EIRA powered?

Answer 12

DC Essential BB 1 + 2.

Question 13

Where is the EIRA located?

Answer 13

Cabin roof (right side)

Question 14

In the event of a failure what happens? (EIRA)

Answer 14

Pilot/co Pilot are automatically connected to a dedicated clear intercom net.
Assigned V/UHF 2 + 1 respectively.

Question 15

What is the purpose of HEU 4+5?

Answer 15

To convert fibre optic DAMU data into analogue audio for BOWMAN

Question 16

What happens when the PTT/CALL switch is put in the CALL position?

Answer 16

It disregards the NET switch and connects all 3 NETS together.

Question 17

How long can you be in CALL before the switch times its self out?

Answer 17

2 minutes.

Question 18

What is the first pressure on the 2 position trigger on the collective used for?

Answer 18

Mutes all the radios and only allows intercoms to be heard.

Question 19

What is the second pressure on the two position trigger on the collective used for?

Answer 19

CWS audio cancel.

Question 20

What is the function of the TONE switch on the CCP?

Answer 20

Transmits a 1Khz tone for morse code in the event of a mic failure.

Question 21

How do you transmit through TELEBRIEF?

Answer 21

By holding the TB button on the CCP whilst the telebrief cable is attached to the aircraft.

Question 22

What happens when the CCP’s go into REV mode?

Answer 22

Only the aircrew have intercoms
pilot gets V/UHF 2
co-pilot gets V/UHF 1
fixed audio for AWG and SIFF codes
passengers and crewmen lose mics