Tail Rotor Drive System, Spline Damage

1 FAA Aviation Safety SPECIAL AIRWORTHINESS INFORMATION BULLETIN SUBJ: Tail Rotor Drive System, Spline Damage SAIB: SW-19-05 Date: April 4, 2019 This is information only. Recommendations aren’t mandatory.

Introduction This Special Airworthiness Information Bulletin (SAIB) alerts owners, operators, and maintenance personnel of an airworthiness concern on Bell Helicopter Textron Canada Limited (BHTCL) Model 206L-1, 206L-3 and 206L-4 helicopters with Air Comm Corporation’s Supplemental Type Certificate SH2750NM installed.

At this time, the airworthiness concern is not determined to be 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 Federal Aviation Administration (FAA) was notified of a number instances of the air conditioner pulley’s locking system (AC Pulley’s Drive Ring), which is installed on the Oil Cooler Drive Shaft’s splined quill, causing excessive spline tooth wear to itself and to the respective mating splines on the quill. The reported damage does not affect the tail rotor drive shaft’s Thomas coupling or the couplings connection to the Oil Cooler Drive Shaft.

Air Conditioner Drive Pulley Thomas Coupling (ref) AC Pulley’s Drive Ring Location of wear on the AC Pulley’s Drive Ring and the Oil Cooler Drive Shaft’s splined drive quill Tail Rotor Drive Shaft (ref) Oil Cooler Drive Shaft

2 Recommendation The FAA recommends that all owners, operators, and maintenance personnel of the affected aircraft listed in the introduction of this SAIB adhere to inspection and time of accomplishment instructions of Air Comm Service Bulletin SB206EC-18-07, Rev A or later revision “Bell 206 Air Conditioner Spline Inspection”. The FAA further recommends that the Air Conditioner pulley’s lock ring be routinely inspected when normal routine maintenance per Bell Helicopter maintenance requirements allows access.

For Further Information Contact Matthew Bryant (Aerospace Safety Engineer); Denver ACO Branch, 26805 East 68th Avenue, Room 214, Denver, Colorado 80249; phone 303-342-1092; fax 303-342-1088; e-mail [email protected]. If Mr. Bryant is unavailable, please contact the Denver ACO Branch directly at 303-342-1080 or email [email protected].

For Related Service Information Contact Air Comm Corporation, 1575 West 124th Avenue, Suite 210, Westminster, Colorado 80234; phone (303) 440–4075; email: [email protected]; Internet: www.aircommcorp.com.