Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
2023-01
February 14, 2023
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) is being
issued to alert owners, operators, maintenance technicians, and
inspectors of an airworthiness concern for Robinson Helicopter Company
R22/R22 ALPHA/R22 BETA/R22 MARINER rotorcraft due to potential wear on
the main rotor blade (MRB) spindle bearings, part number (P/N) A159-3.
At this time, the airworthiness concern is not an unsafe condition that
would warrant airworthiness directive (AD) action under Title 14 of the
Code of Federal Regulations (14 CFR) part 39.
Background
The FAA has seen an increasing trend in reports from local and
international operators of premature wear/damage to P/N A159-3 MRB
spindle bearings in R22-series helicopters. Investigation found
brinelling of the bearings which can present itself as cyclic
vibrations, increased cyclic force, or an unusual feeling in the
controls that has been described as “notchy”/“jerky”/“gritty”. These
conditions can become worse over the course of several flights.
Brinelling can occur due to an overspeed of the rotor system; however,
multiple reports have found brinelling without an observed overspeed
event. A maintenance check for brinelling can be performed by removing
the rotor blades and rotating the spindles by hand to check for
smoothness (reference Robinson maintenance documents).
Recommendations
The FAA recommends that all operators remain vigilant for any
unusual control system vibration or unusual control system feel. If
this is observed in flight, make a safe landing. If one or more of
these conditions are observed, the FAA recommends checking the MRB
spindle bearings in accordance with the appropriate maintenance manual
prior to next flight. Finally, if brinelling or other abnormalities are
observed on the spindle bearings, the FAA recommends submitting a
service difficulty report (SDR).
For Further Information Contact
James Guo, Aerospace Engineer, 3960 Paramount Blvd, Suite 100,
Lakewood, CA 90712, United States; phone: (562) 627-5357; e-mail:
james.guo@faa.gov.
For Related Service Information Contact
Robinson Helicopter Company, 2901 Airport Drive, Torrance, CA,
90505, United States; phone: (310) 539-0508; email:
ts1@robinsonheli.com; website: https://robinsonheli.com/.