(2023) Service Bulletin 23063 Rev A: GSU 75H MOD 1 and MOD 2

PRODUCTS AFFECTED:

Garmin GSU 75H units listed below that are installed with the connector facing towards the rear of the aircraft are affected:

• GSU 75H p/n 011-03094-20 serial numbers 4AY000300 through 4AY004133 not marked with Mod 2
  
• GSU 75H p/n 011-03094-21 serial numbers 4AY100000 and 4AY100008 not marked with Mod 1
  

Garmin STCs that are affected are:

NOTE
All GSU 75H units installed from the factory in an AS350 or Bell 505 have been determined to have a connector forward orientation and no further action is required.

• Garmin GFC 600H AFCS STC SR02647SE
  
• Garmin GFC 600H AFCS STC SR01961WI
  

For owners and operators with a Non-Garmin AFCS connected to the GSU 75H, contact the STC or TC holder to determine applicability.

COMPLIANCE:

Mandatory: This Service Bulletin must be accomplished no later than December 31, 2023.

PURPOSE:

Due to a supplier issue there is a chance of inadequate EMI gasket compression around the mating surface of the connector and rear endplates to the chassis. Units may experience erroneous AHRS data output to AFCS systems, that could lead to potential deviation in aircraft trajectory when exposed to HIRF.

WARRANTY INFORMATION:

This modification is warranty reimbursable with a deadline of December 31, 2023.