FAA Issues Airworthiness Concern Sheet for R44/R66 Separated Push-Pull Tube 

The FAA has issued an Airworthiness Concern Sheet (ACS) for Robinson R44, R44 II and R66 helicopters regarding whether loose hardware near the hydraulic servo-to-swashplate push-pull tube interface is being found on R44 and R66 helicopters. 

Description of Airworthiness Concern 

On March 23, 2026, a Robinson Helicopter R44 rotorcraft (N478AT) impacted the roof of a warehouse facility in Boynton Beach, Florida. During the NTSB’s on-site examination of the main rotor flight controls, the upper right push-pull tube was found separated from the lower rod end (part number D173-2), which remained attached to the upper hydraulic servo piston shaft at the clevis (part number D200-1). 

The palnut and jam nut that secure the upper right push-pull tube to the rod end could not be rotated by hand on the rod end threads. The upper right push-pull tube was observed to be elongated at the threaded end. Remnants of torque stripe paint were present on the push-pull tube, palnut, and jam nut. The palnuts and jam nuts on the left and aft lower rod ends and below the hydraulic servo clevis were found to be finger-tight. Reference NTSB preliminary report ANC26FA021 for more information. 

Request for Information 

This ACS is intended as a means for FAA Aviation Safety Engineers to coordinate airworthiness concerns with aircraft owners/operators through associations, like NAAA. At this time, the FAA has not made a determination on what type of corrective action (if any) should be taken. The resolution of this airworthiness concern could involve Airworthiness Directive (AD) action or a Special Airworthiness Information Bulletin (SAIB), or the FAA could determine that no action is needed at this time. The FAA’s final determination will depend in part on the information received in response to this ACS. 

The FAA is interested in receiving information of abnormal damage around the hydraulic servo-to-swashplate push-pull tube connection (see figure 2), including but not limited to: 

  • loosening hardware 
  • broken, missing, or inadequate torque striping 
  • palnut or jam nut damage 
  • corrosion 
  • fretting dust or damage to the internal threads of the servo clevis or push-pull tube 

Please provide any or all the following information for past or current issues: 

  • Aircraft details and associated flight hours 
  • Component(s) found discrepant or damaged 
  • Component flight hours or time, if available 
  • Method of discovering discrepant components (preflight or annual inspection, component overhaul, etc.) 
  • Corrective action taken 
  • Date of finding 

FAA recommends operators perform Robinson R44 Service Bulletin SB-119 and R66 Service Bulletin SB-45 dated May 11, 2026 or later revisions. If completed, please provide the information requested in Step 12 of the bulletin to the FAA. 

Please provide any other information you feel may be helpful for FAA to consider as part of their evaluation to the contact listed on the ACS. 

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