4.14 INMARSAT

Question 1

What does INMARSAT stand for?

Answer 1

International maritime satellite

Question 2

What does BLOS stand for?

Answer 2

Beyond-line-of-sight

Question 3

What does BGAN stand for?

Answer 3

Broadband global area network

Question 4

Describe INMARSAT capability

Answer 4

BLOS
Worldwide data and voice communication
Over commercial satellite

Question 5

What is the max IP data connectivity for INMARSAT?

Answer 5

128 KB/SEC

Question 6

What voice comms are available via INMARSAT?

Answer 6

Flight deck voice comms

Question 7

In general, describe the INMARSAT signal flow once it leaves the aircraft

Answer 7

Four satellites, spot beam
Global beams cover a hemisphere
L-band 40 ground stations

Communication services are delivered through the spot beams from four INMARSAT satellites and global beams covering a complete hemisphere.
Approximately 40 ground stations handle user traffic on the L-band frequencies (1530 to 1660.5 MHz).

Question 8

What does NCTAMS stand for?

Answer 8

naval computer and telecommunications area master station

Question 9

What does ADNS stand for?

Answer 9

Automated digital network system

Question 10

What is the nomenclature for the INMARSAT terminal?

Answer 10

HSD-440

Question 11

What is the function of the HSD-440?

Answer 11

Comm link between the aircraft and the INMARSAT network

The HSD-440 (Figure 4-219) is a satellite communications terminal that provides a communication link with the INMARSAT satellite communication network and interfaces with the MCDS and FMCS.

Question 12

Where is the HSD-440 located?

Answer 12

Upper fuselage
Beneath the vert stab

The INMARSAT terminal is located in the upper fuselage beneath the vertical stabilizer accessible via an
access hatch adjacent to the aft door (Figure 4-218).

Question 13

What does ACU stand for?

Answer 13

Antenna control unit

Question 14

What is another name for the ACU?

Answer 14

BSU

Beam steering Unit

Question 15

What does D/LNA stand for?

Answer 15

Duplexes/low noise amplifier

Question 16

Where is the INMARSAT antenna system located?

Answer 16

Top of the vertical stabilizer

Question 17

Warning regarding INMARSAT transmissions

Answer 17

Failure to maintain proper standoffs may result in exposure to RF radiation.

Question 18

What is the function of the INMARSAT ACU?

Answer 18

Points the antenna based on info from the HSD-440

The ACU translates the antenna pointing signal received from the HSD-440 into motor drive signals to steer the antenna. The ACU provides filtered 28 Vdc power to the D/LNA and antenna. The ACU sends D/LNA and antenna BIT status to the MCDS via the HSD-440. The ACU is located aft of the antenna (Figure 4-220).

Question 19

What is the function of the D/LNA for the INMARSAT system?

Answer 19

Amplifies RF signals

The D/LNA assembly is a combined diplexer and low-noise amplifier. The diplexer combines the transmit and receive paths into a single path to the antenna. The LNA amplifies all received RF signals. The D/LNA is powered by the ACU. The D/LNA is mounted on the vertical stabilizer under the antenna (Figure 4-220).

Question 20

What is the function of the TACLANE?

Answer 20

Encrypts INMARSAT system

Question 21

Note regarding removing power from the TACLANE

Answer 21

TACLANE CIK is removed after power is secured to the

TACLANE components.

Question 22

Note regarding TACLANE keys when a tamper condition is detected

Answer 22

All keys are automatically deleted when a tamper condition is
detected.

Question 23

Briefly describe the INMARSAT signal flow internal to the aircraft

Answer 23

NA

Question 24

Where do you power on INMARSAT?

Answer 24

SPDS

Question 25

How long does INMARSAT take to power up initially? After cycling power?

Answer 25

INMARSAT components complete

initialization within 3.5 minutes of applying power and 2.3 minutes, if cycling power

Question 26

Where do you access INMARSAT via TOMS?

Answer 26

Comms PEP tab

OCM