Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
AIR-21-11
July 22, 2021
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) alerts
owners and operators of Robinson Helicopter Company (Robinson) Model
R66, Model R44, and R44 II helicopters with D212-1, D212-5, D212-6,
hydraulic servos manufactured before April 2014.
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 Regulation (14 CFR) part 39.
Background
In October 2020, an operator of a Robinson R66 reported that the cyclic
control had become stiff on final approach/landing. The stiffness only
occurred in certain directions of cyclic travel resulting in some
difficulty controlling the aircraft. There were no reported anomalies
for the preceding two hours of flight or on prior flights. The operator
returned the servo to Robinson facility for disassembly. Robinson found
excessive internal wear of the servo components during examination.
Wear on the drive assembly could cause the link not to move the control
valve into a fully open position, restricting fluid flow and causing
sluggish (stiff feeling) control inputs.
Recommendations
We recommend that owners/operators of Robinson Model R44, R44 II, and
Model R66, helicopters with hydraulic servos manufactured before April
2014 perform the pre-takeoff check identified in R44 Service Bulletin
SB-109 dated 30 June 2021, and R66 Service Bulletin SB-39, dated 30
June 2021.
For Further Information Contact
Patrick Farina, Aerospace Engineer, Cabin Safety and Environmental
Systems Branch, AIR-795, FAA, Los Angeles ACO, 3960 Paramount
Boulevard, Lakewood, CA 90712-4137; telephone (562) 627-5344; fax (562)
627-5210.; email patrick.farina@faa.gov.
For Related Service Information Contact
Robinson Helicopter Company, 2901 Airport Drive, Torrance, CA 90505;
telephone 310-539-0508; fax 310-539-5198; or at
https://www.robinsonheli.com.