Helicopter Rotor Shafts Wear Faster, FAA Demands Checks
Published Date: 4/21/2026
Proposed Rule
Summary
If you fly or fix certain Sikorsky, Croman, Carson, Glacier, Robinson, or Siller helicopters, listen up! The FAA wants to update safety rules to check and replace main rotor shafts sooner because new info shows they wear out faster than we thought. These changes could mean earlier part replacements, so owners should plan for some extra maintenance costs and act before June 5, 2026, to share their thoughts.
Free Policy Watch
New rules are filed every week. Most people never see them.
Pick a topic. PRIA watches every federal rule and tells you when one hits your household.
Pick a topic to get started
Analyzed Economic Effects
4 provisions identified: 0 benefits, 4 costs, 0 mixed.
Main Rotor Shaft Life Cut in Half
The FAA would reduce the retirement life for certain Non-REL main rotor shafts from 13,000 hours time-in-service (TIS) to 7,300 hours TIS. If a Non-REL shaft already has 7,300 hours TIS or more, the rule requires removing it from service (at the next main gearbox overhaul if installed, or before further flight if uninstalled or in overhaul).
Estimated Compliance Costs and Affected Fleet
The FAA estimates this AD would affect 76 U.S.-registered helicopters. The agency estimates an NDI costs $305 per shaft, revising a log card costs $85, and replacing/removing an MRS is estimated at $81,471 per product (labor $255 + parts $81,216), with total replacement cost to U.S. operators estimated at $6,191,796.
Ongoing Inspections and Records Required
Operators must keep component history cards, count and record daily external lift cycles and hours TIS, calculate moving averages to determine REL vs Non-REL status, and perform nondestructive inspections (NDI) for cracks (first NDI within 1,100 hours TIS after November 24, 2015 for existing AD requirements). REL shafts must be marked and tracked for the rest of their service life.
Immediate Removal for Oversized Dowel Bores
The proposed AD requires removing from service any main rotor shaft with an oversized dowel pin bore (0.8860 inches diameter or greater) within 50 hours TIS after November 24, 2015. Operators who still have such shafts must remove them per the rule.
Your PRIA Score
Personalized for You
How does this regulation affect your finances?
Sign up for a PRIA Policy Scan to see your personalized alignment score for this federal register document and every other regulation we track. We analyze your financial profile against policy provisions to show you exactly what matters to your wallet.
Key Dates
Department and Agencies
Take It Personal
Get Your Personalized Policy View
Start a Free Government Policy Watch to see how policy affects your household, then upgrade to PRIA Full Coverage for year-round monitoring.
Already have an account? Sign in