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GSA 8X/GSM 85(A) Installation Manual
Revision R
190-00303-72
2.3.2 Mounting
Requirements
The GSM 85(A) is to be mounted to a structurally sound, rigid bracket. This bracket should be firmly
attached to the aircraft structure. Servo gearbox bracket design varies between installations. The installer
should follow FAA guidance in the selection of bracket location, fabrication, and installation. The
bracket must have the correct cut-out for the servo gearbox being used. Consult Appendix A for outline
drawings showing these cut-outs.
The servo gear box is to be fastened to the bracket using AN3 bolts (or equivalent) with AN960-10
washers (or equivalent). Bolts should be torqued and inserted to the depth shown in Table 2-5. The GSA
8X servo actuator is fastened to the GSM 85(A) servo gearbox and torqued per Table 2-5 using AN3-4A
bolts with AN960-10L washers (or using AN3-5A bolts with two AN960-10 washers per bolt). Mounting
hardware is to be provided by the installing agency.
NOTE
When attaching the GSA 8X to the GSM 85(A), tighten the bolts per the following steps:
1.
Insert all bolts and thread in approximately two turns by hand.
2.
Starting with two opposite corner bolts, tighten all bolts until 1/64” to 1/32” (½ to 1
turn) from fully seated.
3.
Verify that GSA 8x is still slightly loose relative to GSM 85(A), ensuring there is still
relative movement between the two units.
4.
Starting with two opposite corner bolts, tighten all bolts to proper torque per
the specifications given in Table 2-5.
For all DO-160 categories in the GSM 85(A) Environmental Qualification Form (EQF, 005-00231-01 for
GSM 85 and 005-00231-06 for GSM 85A) to apply, the appropriate servo gearbox capstan cover
(included in the mounting hardware kit 011-01028-XX) must be installed as shown in Appendix A
Outline and Installation Drawings, of this document. The GSM 85(A) must have the appropriate servo
gearbox cover in place to ensure meeting the qualifications for “Waterproofness”, “Sand and Dust”, “Salt
Spray”, “Icing”, and “Fluids” listed in the Environmental Qualification Form.
For installations of the Universal Hub Medium Torque GSM 85(A), refer to the DO-160 tested weight
limit of parts attached to the universal hub in Table 2-5. This includes the weight of parts solidly
connected to the hub including screws and any hub cover spacers (115-00823-00 or 115-00823-10)
needed. However do not include the weight of the hub cover (117-00192-00, 115-00848-01, and any
associated seals or mounting screws) or any attachment part not solidly mounted on the hub such as a
chain or articulating rod arm.
Ensure cable payoff angles (angle between the cable and capstan groove where it exits) meet the
specifications of Table 2-5. Ensure the torque of screws holding capstan cover and cableguard parts meet
the specifications of Table 2-5.
