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ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL SUPPLEMENT 1
Rev.
7
10-1
Aug
28/17
CHAPTER 10
GNC 255A
SECTION 1
SYSTEM DESCRIPTION
1-1. System
Description
A. The GNC 255A is a VHF communications transceiver combined with 200-channel VOR,
LOC, and GS navigation receivers. The com radio operates from 118.000 to 139.975 MHz
in either 25 kHz or 8.33 kHz channel spacing. Transmitting power is 10W.
B. The GNC 255A installation part number is 28-22063-5.
C. The components of the GNC 255A include the panel mounted GNC 255A unit and Nav
and Com antennas. The GNC 255A may be interfaced with a CDI, slaved compass
system, EHSI, or an EFIS system and may also be interfaced to either a VOX ICS or an
audio panel.
D. Power to the GNC 255A is provided via the
COM
circuit breaker (CB27) (5 Amp) and the
NAV
circuit breaker (CB39) (2 Amp) located on the left side of the lower instrument panel
console. If equipped with a second transceiver unit (such as the GTN 650), power is
provided via the
COM 1
or
COM 2
circuit breaker and
NAV 1
or
NAV 2
circuit breaker.
The
NAV
circuit breaker may also provide power to the CDI.
E. Refer to F-28F/280FX Rotorcraft Flight Manual Supplement 28-AC-074 for GNC 255A
limitations and basic operation instructions.
1-2. Vendor
Manuals
A. The following components listed in Table 10-1 are to be operated and maintained I/A/W
the current vendor’s instructions to ensure the continued airworthiness of the aircraft.
Table 10-1. Vendor Manuals
Component Publication
Vendor
GNC 255A
GTR 255/GNC 255 Installation Manual,
Document No. 190-01182-02, latest revision
Garmin International, Inc.
1200 East 151
st
Street
Olathe, KS 66062
Tele: (913) 397-8200
Fax: (913) 397-8282
www.garmin.com
GNC 255A/255B Pilot’s Guide, Document
No. 190-01182-01, latest revision
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