Commonwealth legislation

AD/BELL 205/63 - Tail Rotor Yoke

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legislative instrument

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This Airworthiness Directive requires operators of specified Bell 205 and 205B helicopters to review the tail-rotor yoke’s incident and maintenance history, and where indicated (or by deadline) remove and replace the yoke with either a zero‑hour unit or one that has passed an x‑ray diffraction inspection. Specific replacement parts (flapping stop or trunnion) must be installed and recurring inspections are mandated at intervals not exceeding 25 flight hours or after any qualifying incident. The rule aims to prevent yoke failure that could lead to loss of the tail rotor.

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AD/BELL 205/63 - Tail Rotor Yoke

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Bell Helicopter Textron 205 Series Helicopters

AD/BELL 205/63 Tail Rotor Yoke 8/98 DM

Applicability: Model 205A-1 helicopters with tail rotor yoke assembly, part number (P/N) 212-011- 702-all dash numbers, or P/N 212-010-704-all dash numbers, or P/N 212-010-744- all dash numbers, and model 205B helicopters with tail rotor yoke assembly, P/N 212- 011-702-all dash numbers.

Requirement: 1. Review all historical records of the helicopter and the tail rotor yoke assembly for any static or dynamic incident history that could have imposed an excessive bending load on the yoke. If such a history exists, comply with Requirement 2 before further flight.

Note 1: Examples of excessive bending loads include exposure to high wind gusts (such as those from rotor wash or prop blast), improper ground handling (in which the tail rotor blade has been used as a hand hold), improper feathering bearing removal (in which the yoke is not properly supported when pressing out bearings), a static ground strike of some type (such as being struck by a vehicle), or an incident in which a damaged tail rotor blade was replaced due to a blade strike. An overload may also occur dynamically during a power-on or power-off sudden stoppage incident or hard landing.

2. Remove the yoke assembly and replace it with a serviceable yoke assembly having zero hours time in service, or with a serviceable yoke assembly (regardless of time in service) that has passed an x-ray diffraction inspection in accordance with Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) 205-96-68, Revision A, dated 18 May 1998, or ASB 205-96-69 or ASB 205B-96-25, both dated 3 September 1996, whichever is applicable. When the yoke assembly is replaced, for helicopters with a yoke assembly, P/N 212-011-702-all dash numbers, install a serviceable tail rotor flapping stop, P/N 212-011-713-103, and for helicopters with yoke assemblies, P/N 212-010-704-all dash numbers or P/N 212-010-744-all dash numbers, install a serviceable trunnion assembly, P/N 212-010-738-001. If any incident as described in Requirement 1 of this Directive occurs after 3 June 1998 and before compliance with this requirement, then compliance with Requirement 2 is required before further flight.

Note 2: Yoke assemblies that have passed an x-ray diffraction inspection at BHTI will have the letters FM vibro-etched on them following the serial number.

3. Inspect the trunnion assembly, and replace the yoke assembly and trunnion assembly, if required, in accordance with Part III, Paragraph 1, of ASB 205-96-68, Revision A; or inspect the tail rotor flapping stop and replace the yoke assembly and flapping stop, if required, in accordance with Part III, Paragraphs 1, 2, and 3, of ASB 205-96-69 or ASB 205B-96-25, whichever is applicable.

Note 3: FAA Priority Letter AD 98-11-14 refers.

Compliance: 1. Before further flight after 3 June 1998.

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

2. Before 3 December 1998.

3. After accomplishing the requirements of Requirement 2, thereafter at intervals not to exceed 25 hours time in service, or before further flight after any incident as described in Requirement 1.

This airworthiness directive becomes effective on 3 June 1998.

Background: This Directive reflects the issue of a Priority Letter AD by the FAA, which was prompted by an accident involving a BTHI Model 205A-1 helicopter in which the tail rotor yoke failed during flight. Investigation of the accident revealed that the tail rotor yoke assembly service life may be reduced due to unforeseen static and dynamic loading of the tail rotor. This condition, if not corrected, could lead to failure of the yoke, loss of the tail rotor, and subsequent loss of control of the helicopter.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/BELL 205/63 - Tail Rotor Yoke

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

Bell Helicopter Textron 205 Series Helicopters

AD/BELL 205/63 Tail Rotor Yoke 8/98 DM

2. Remove the yoke assembly and replace it with a serviceable yoke assembly having zero hours time in service, or with a serviceable yoke assembly (regardless of time in service) that has passed an x-ray diffraction inspection in accordance with Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) 205-96-68, Revision A, dated 18 May 1998, or ASB 205-96-69 or ASB 205B-96-25, both dated 3 September 1996, whichever is applicable. When the yoke assembly is replaced, for helicopters with a yoke assembly, P/N 212-011-702-all dash numbers, install a serviceable tail rotor flapping stop, P/N 212-011-713-103, and for helicopters with yoke assemblies, P/N 212-010-704-all dash numbers or P/N 212-010-744-all dash numbers, install a serviceable trunnion assembly, P/N 212-010-738-001. If any incident as described in Requirement 1 of this Directive occurs after 3 June 1998 and before compliance with this requirement, then compliance with Requirement 2 is required before further flight.

Note 2: Yoke assemblies that have passed an x-ray diffraction inspection at BHTI will have the letters FM vibro-etched on them following the serial number.