A Transport Canada safety alert is calling attention to a recent change by Bell Helicopter that removed tail rotor pitch change chain assembly part number (P/N) 205-001-721-001 from the OEM's illustrated parts breakdown for the Bell 204B.
“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,” Transport Canada said in the August 31 alert. A parts-breakdown revision released earlier this year removed the part, Transport Canada added.
Bell 204B and Bell 205A pitch-change chain cracking has been a known issue for years, with the FAA's initial Airworthiness Directive (AD) coming out in 1976. In 2013, the agency issued an AD against a new chain, designed for the Bell 204B.
None of the directives apply to P/N 205-001-721-001, however. “Operators should note that use of [this -001 part] on the model 204B is not supported by the manufacturer,” Transport Canada said.