SAIB Issued for R44 Belt-Tension Actuator Gearmotor Assembly
The FAA has received reports of loose P/N D276-1 and D276-3 gearmotors on Robinson Model R44-series helicopters. Investigation has determined the cause to be related to poor dimensional control of certain internal countersunk head screws and the potential absence of thread locking adhesive in a population of gearmotors that left the manufacturer.
Robinson updated the R44-series maintenance manual in September 2023 to add a gearmotor assembly torque stripe verification to the 100-hour / annual inspection procedures. Additionally, Robinson released R44 Service Bulletin SB-115, dated October 27, 2023; this service bulletin specifies a one-time verification of gearmotor security and application of a torque stripe for future visual inspections.
Special Airworthiness Information Bulletin SAIB 2024-05 was issued October 29, 2024 by the FAA recommending:
- Inspect the gearmotor assembly for looseness, replace if necessary, and apply the torque stripe for future visual inspections, in accordance with R44 Service Bulletin SB-115.
At every 100-hour/Annual Inspection, follow the Gear Motor Assembly Torque Stripe inspection procedure within R44 maintenance manual, dated September 2023.