Garmin GRA 55 Maintenance Manual - Page 22

Maintenance Intervals

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4.4 Maintenance Intervals Table 4-1. Maintenance Intervals for GRA 55/5500 Item Description/Procedure Interval Equipment Removal and Replacement Removal and replacement of the following items. See Section 6 for removal and replacement instructions. • GRA 55/5500 Mount Rack • GRA 55/5500 LRU • Antenna On Condition Perform an electrical bonding check as follows: 1. Disconnect the wire harnesses from the GRA 55/ 5500 at P55001, TX, and RX connections. 2. Measure the resistance between the mounting rack and a nearby exposed portion of metallic structure. Verify that the resistance is less than or equal to 2.5 milliohms. 3. Measure the resistance between the GRA 55/5500 LRU and the mounting rack. Verify that the resistance is less than or equal to 2.5 milliohms. In the event of a bonding test failure, remove the LRU and rack, if required, and verify that the mating surfaces To be performed in for the LRU and/or mounting rack are free of corrosion alignment with Bell or any other debris. Clean, inspect and re-burnish (if Test - Bonding Check, required) all mating surfaces using approved methods GRA 55/5500 & and solvents per Bell specification MOUNT RACK BHT-ELEC-SPM CHP 8. 206B, 206L series maintenance schedule. Every 10 years or every 2000 Reinstall the mounting rack and GRA LRU to the hours, whichever designated location. comes first. Re-verify the resistance between the mounting rack and nearby exposed portion of aircraft metallic structure and ensure that the resistance is less than or equal to 2.5 milliohms. Re-verify the resistance between the GRA LRU the mount rack. Ensure the resistance is less than or equal to 2.5 milliohms. 4. Reconnect the previously disconnected wire harnesses ensuring that the coaxial connectors are reconnected into their respective locations. 190-01277-A3 Rev. 1 System Maintenance Manual GRA 55/5500 Bell 206 STC Page 4-2

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190-01277-A3
System Maintenance Manual GRA 55/5500 Bell 206 STC
Rev. 1
Page 4-2
4.4
Maintenance Intervals
Table 4-1.
Maintenance Intervals for GRA 55/5500
Item
Description/Procedure
Interval
Equipment Removal
and Replacement
Removal and replacement of the following items. See
Section 6 for removal and replacement instructions.
•
GRA 55/5500 Mount Rack
•
GRA 55/5500 LRU
• Antenna
On Condition
Test – Bonding Check,
GRA 55/5500 &
MOUNT RACK
Perform an electrical bonding check as follows:
1.
Disconnect the wire harnesses from the GRA 55/
5500 at P55001, TX, and RX connections.
2.
Measure the resistance between the mounting rack
and a nearby exposed portion of metallic structure.
Verify that the resistance is less than or equal to
2.5 milliohms
.
3.
Measure the resistance between the GRA 55/5500
LRU and the mounting rack. Verify that the
resistance is less than or equal to
2.5 milliohms
.
In the event of a bonding test failure, remove the LRU
and rack, if required, and verify that the mating surfaces
for the LRU and/or mounting rack are free of corrosion
or any other debris. Clean, inspect and re-burnish (if
required) all mating surfaces using approved methods
and solvents per Bell specification
BHT-ELEC-SPM CHP 8.
Reinstall the mounting rack and GRA LRU to the
designated location.
Re-verify the resistance between the mounting rack and
nearby exposed portion of aircraft metallic structure and
ensure that the resistance is less than or equal to
2.5 milliohms
.
Re-verify the resistance between the GRA LRU the
mount rack. Ensure the resistance is less than or equal
to
2.5 milliohms
.
4.
Reconnect the previously disconnected wire
harnesses ensuring that the coaxial connectors are
reconnected into their respective locations.
To be performed in
alignment with Bell
206B, 206L series
maintenance
schedule. Every 10
years or every 2000
hours, whichever
comes first.