# AIR760-2007-11-S-3100-ACS: GSM 85 Servo Gearbox Units

- Type: Airworthiness concern sheet: the FAA asks for information before deciding whether an AD is needed
- Status: Current
- Issued: July 6, 2007
- Systems (JASC): [3100 - Indicating/Recording System](https://openairdocs.org/jasc/3100)
- Product type: Aircraft, Small Airplane
- Products: Cessna 182T, T182T, 206H, T206H, G36 Bonanza, G58 Baron, 40, 40F, 350, 400, Ovation 2 GX, Acclain and 2 more
- Data sheets: [TCDS 3A13](https://openairdocs.org/tcds/3A13), [TCDS 3A15](https://openairdocs.org/tcds/3A15), [TCDS 3A16](https://openairdocs.org/tcds/3A16), [TCDS A47CE](https://openairdocs.org/tcds/A47CE), [TCDS A16SW](https://openairdocs.org/tcds/A16SW), [TCDS A00003SE](https://openairdocs.org/tcds/A00003SE), [TCDS 2A3](https://openairdocs.org/tcds/2A3)
- ADs it names: [AD 2008-02-06](https://openairdocs.org/ad/2008-02-06)
- PDF: https://openairdocs.org/files/sha256/e8/ec/e8ecdd7a57b060bcebb1303270a5cb6081703cd5885c251c23e90ad2d1a45d4d
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FAA00000000000ACS_760200711S3100.0001
- DRS record last changed: December 19, 2025
- Page: https://openairdocs.org/acs/AIR760-2007-11-S-3100-ACS

## Text

Airworthiness Concern Sheet

Date: July 6, 2007 Full Name: Roger Souter Title: Aerospace Engineer Organization: FAA Department: Wichita ACO (ACE-119W) Address: 1801 Airport Road, Rm 100 City State Zip: Wichita, KS 67209 Telephone/Fax Number E-Mail 316-946-4134 / 316-946-4107 Roger.Souter@FAA.GOV Make, Model, Series, Serial No.:

May be installed on but not limited to the following Aircraft Cessna 182T Cessna T182T Cessna 206H Cessna T206H

Hawker Beechcraft G36 Bonanza Hawker Beechcraft G58 Baron

Diamond DA 40/40F

Columbia 400 Columbia 350

Mooney Ovation 2 GX Mooney Acclaim Mooney Ovation 3 Mooney Bravo GX Reason for Airworthiness Concern:

Foreign object contamination inside gear-assembly housing could cause GSM 85 gear jam. If this occurs, the pilot must overcome the GSM 85 slip clutch torque to control that axis of the aircraft.

We are considering potential Airworthiness Directive action.

FAA Description of Airworthiness Concern (Who, What, Where, When, How? Attachments: RA and appropriate data) and Request for Information (Proposed Alternate Inspection/Repair Procedures, Cost Impact, Etc. Note: Any comments or replies to the FAA need to be as specific as possible. Please provide specific examples to illustrate your comments/concerns.):

Who Garmin International, Olathe Kansas 66062

What Two GSM (Servo Gearbox) 85 units have been returned from installations (one from an experimental aircraft installation, one from an OEM production aircraft) that have the tumbling media inside the assembly. In both instances, the contamination was noticed during GSM 85 installation or removal.

Where GSM 85, part of Garmin GFC 700 autopilot system, Garmin part numbers:

011-00894-00 011-00894-02 011-00894-04 011-00894-06 011-00894-07 011-00894-08

011-00894-09 011-00894-10 011-00894-11 011-00894-14

When May 3, 2007

How The gear-assembly housing is composed primarily of an aluminum extrusion. Tumbling media used to deburr the extrusion may get caught in extrusion cavities and come loose at a later time presenting the possibility of jamming the gear assembly.

Attachments: *SDR(s) *A/IDS *SL(s) *SAIB *FAASR/NTSBSR *AD *AMOC *RA

Notification: FAA *AOPA X *EAA Type Club *TC Holder Other: GAMA X :

Response Requested __/__/__: Emergency (10 days) Alert (30 days) Information (90 days) X (Word 97 Version: Manually Check Appropriate Boxes)

*Service Difficulty Reports (SDRs); Accident/Incident Data System (A/IDS); Service Letter (SL); Special Airworthiness Information Bulletin (SAIB);

Federal Aviation Administration (FAA)/National Transportation Safety Board (NTSB) Safety Recommendation (FAASR/NTSBSR); Airworthiness Directive (AD); Alternate Method of Compliance (AMOC); Risk Assessment (RA); Aircraft Owners & Pilots Association (AOPA);

Experimental Aircraft Association (EAA); Type Certificate (TC)

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