Installation Manual

Prerequisites
98-152675-A Chapter 3: Installation 3-5
3333
Cobham Public
3.4.3 Grounding
It is the responsibility of the installer to ensure that the grounding between the LGA-5005
and the fuselage is in accordance with the airframe manufacturer’s requirements. The
primary method of grounding the LGA-5005 is through the mounting bolts. Grounding may
also be achieved through the mounting feet which are not painted, but chemically
converted to allow for grounding to unpainted surfaces (see Figure 3-2).
In the case where the LGA-5005 is installed with a mounting plate, the four LGA-5005 to
mounting plate bolts provide the primary grounding between the LGA-5005 and the plate.
As mentioned above, the mounting feet provide additional grounding to the matching
unpainted areas on the mounting plate.
3.4.4 Alignment and installation limitations
Consider the following factors that influence the final position of the antenna:
• Alignment and installation offset angles
• Lightning strike
• RF blockage
• Co-location with other antennas
• Fuselage Structure
• Engines and APU inlets
Alignment and installation offset angles
Install the LGA-5005 with its long axis facing fore/aft, with the ventilation/breathing holes
located in the aft position.
You may install the LGA-5005 slightly off the aircraft centre-line (roll offset), and/or with its
nose slightly up or down (pitch offset). In this manual these are called installation offset
angles.
The installation offset angles of the LGA-5005 are compensated for by the CSDU, in which
case you must measure the yaw-, roll- and pitch-offsets. It is recommended that the
CAUTION! The Installer must take corrosion effects into account
especially when dissimilar materials are involved.
Figure 3-4: Fore/aft of the antenna
Fore
Aft