Mounting Tube Installation - Garmin GNS 480 Installation Manaul

Installation Procedures
2.6 Equipment Mounting
The GNS 480 is designed to mount in the avionics stack. The installation kit supplied with the GNS 480
includes a mounting tube with a separate connector plate for ease of mounting, connections, and service of
the unit. Allow an additional one-inch clearance to the rear of the mounting frame for connectors and
cables. See Figure 2-3 for dimensions.
The GNS 480 does not require external cooling; however, when mounting the GNS 480, ensure that the
fans at the rear of the unit are not blocked. As with all electronic equipment, avoid locating the GNS 480
near sources that produce high levels of heat.
2.6.1

Mounting Tube Installation

Use the dimensions shown in Figure 2-3 to prepare the mounting holes for the GNS 480. You may also
use the GNS 480 mounting tube itself as a template for drilling the mounting holes. Care must be taken
when installing the mounting tube to ensure you can properly insert and secure the unit. There must be a
minimum vertical spacing of 0.040 inches between units to prevent interference with the cam locking
mechanisms. Mounting tubes with clearance dimples help maintain the proper clearance. The mounting
tube must be installed with the clearance dimples pointing up.
2.6.1.1 Securing the Mounting Tube
Secure the mounting tube to the instrument panel structure using AN507 6-32 or MS24693 6-32 cadmium
plated carbon steel screws with a 100° countersink head. It is recommended that the installer use eight
screws, four on each side. The mating holes in the instrument panel structure must also be countersunk to
accept the screw head so that the screw head is flush with the inside surface of the mounting tube. Take
care that the mounting tube is not distorted when it is attached to the instrument panel and structural supports.
Shims may be necessary to properly install the mounting tube. If the mounting tube is distorted out of square,
the unit may either bind when being inserted or the cam lock may not engage.
Failure to properly countersink the mounting holes will result in damage to the GNS
480. Mounting screw heads must not protrude into the mounting tube.
The front of the mounting tube should be flush to the instrument panel and allow sufficient clearance for the
back of the bezel of the GNS 480 to mount flush to the mounting tube. Sufficient clearance must exist in the
instrument panel opening to allow ease of insertion and removal of the GNS 480.
If the back of the GNS 480 bezel does not mount flush to the mounting tube (within
0.020"), the connector may not engage fully.
2.6.1.2 Mounting Frame Assembly
The order of assembly of the mounting tube frame with connector plate and connectors is at the installer's
preference or may be determined by how the installation is fit into the aircraft.
An illustration how to assemble the mounting tube is shown in.
All screws holding the connectors to the back plate and back plate to the mounting tube should be
tightened to approximately to 7 – 9 in-lbs. After mounting the coax connectors to the connector plate,
make sure that the coax connectors are floating or have slight movement.
2-10
CAUTION
CAUTION
560-0982-01 Rev L GNS 480 (CNX80) Installation Manual