Bell Helicopter 204B tail rotor oitch change chain configuration control - Civil Aviation Safety Alerts (CASA) No. 2017-07


Owners, operators and maintainers of Bell model 204B Helicopters

Issuing Office: Continuing Airworthiness
File Classification No. : Z 5000-35
RDIMS No. : 13012059
Document No. : CASA 2017-07
Issue No. : 1
Effective Date: 2017-08-29


The purpose of this Civil Aviation Safety Alert (CASA) is to ensure that affected personnel are aware that use of tail rotor pitch change chain assembly, part number (P/N) 205-001-721-001 on the model 204B helicopter is no longer supported by Bell Helicopter.


Operators have reported, and accident investigations have found, cracked tail rotor pitch change chains on Bell Model 204B helicopters. Transport Canada and the Federal Aviation Administration (FAA) have issued Airworthiness Directives (ADs) that require various actions to mitigate the risk of cracking, including more frequent and effective inspections and modification of the helicopter.

FAA AD 2013-18-07 is the AD that is currently in force. It mandates shorter inspection intervals than a previous FAA AD and requires the installation of a chain damper kit to ensure continuing airworthiness of the chain. This AD applies to several P/Ns, but it does not apply to P/N 205-001-721-001. Until recently, this P/N was applicable to the model 204B helicopter.

In early 2017, Bell Helicopter Textron Inc. revised the Illustrated Parts Breakdown for the model 204B, BHT 205B IPB Figure 07-78, to remove P/N 205 001-721-001.

Recommended Action:

Operators should note that use of P/N 205 001 721 001 on the model 204B is not supported by the manufacturer.

Operators should ensure that the systems they use to maintain configuration control are updated to ensure P/N 205-001-721-001 is not installed on the model 204B.

Contact Office:

For more information concerning this issue, contact a Transport Canada Centre or contact Ross McGowan, Continuing Airworthiness in Ottawa, by telephone at 1-888-663-3639, by fax at 613-996-9178 or by e-mail at

Original signed by Rémy Knoerr

Chief, Continuing Airworthiness

The Transport Canada Civil Aviation Safety Alert (CASA) is used to convey important safety information and contains recommended action items. The CASA strives to assist the aviation industry's efforts to provide a service with the highest possible degree of safety. The information contained herein is often critical and must be conveyed to the appropriate office in a timely manner. The CASA may be changed or amended should new information become available.