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ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT 1
Rev.
7
10-4
Aug
28/17
SECTION 4
SYSTEM MAINTENANCE
NOTE
Removal or installation of equipment will change the aircraft empty
weight and empty weight c.g. These changes will be recorded on the
Basic Weight and Balance Record, as required.
4-1. GNC
255A
NOTE
All work must be accomplished in accordance with the Enstrom
F-28F/280F Series Maintenance Manual.
4-1-1. Cleaning
A. The front bezel, keypad, and display can be cleaned with a microfiber cloth or with a soft
cotton cloth dampened with clean water. DO NOT use any chemical cleaning agents. Care
should be taken to avoid scratching the surface of the display.
4-1-2. Removal
A. Remove power to the GNC 255A unit. Pull the
COM
and
NAV
circuit breakers out. Disable
the circuit breakers by installing a cable tie or other similar device around each circuit
breaker stem.
B. Insert the 3/32-inch hex drive tool into access hole on the unit face. Rotate the hex tool
counterclockwise until the unit is forced out about 3/8 inch and the hex drive tool
completely stops.
C. Carefully pull the unit from the rack.
4-1-3. Installation
NOTE
Do not use excessive force when inserting the GNC 255A into the
rack. This may damage the connectors, unit, and/or unit rack.
A. Insert the GNC 255A unit into the rack by sliding it straight in until it stops, about 3/8 inch
short of the final position.
B. Insert the 3/32-inch hex drive tool into access hole on the unit face. Rotate the hex tool
clockwise while pressing on the left side of the bezel until the unit is firmly seated in the
rack. Do not overtighten the unit into the rack. Exceeding 15 in-lbs/1.7 Nm can damage
the locking mechanism.
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