COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Bell UH-1 Series Helicopters
AD/UH-1/4 Tail Rotor Yoke 6/99 DM
Applicability: Bell Helicopter Textron, Inc.-manufactured Model, UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters.
Requirement: Action in accordance with the technical requirements of FAA AD 99-07-15 Amdt 39- 11101.
Accomplish the following in lieu of FAA AD 99-07-15 Paragraph (f), within the time stated in Paragraph (f):
Revise the Operating Procedures and Manoeuvres Section of the Aircraft Flight Manual (AFM) to include the following additional procedures:
TAIL ROTOR YOKE - PREFLIGHT VISUAL CHECK FOR STATIC STOP CONTACT DAMAGE (DEFORMED STATIC STOP OR TRUNNION YEILD INDICATOR).
Note 1: Operators who use aircraft that have any of these affected yokes assemblies installed should use tail rotor tie downs when the aircraft is parked or stored.
This task may be performed by inserting a copy of this applicable Directive into the Operating and Procedures Section of the AFM.
Note 2: The Requirement document was forwarded with the Direct Mail copy of this Directive.
Compliance: As specified in the Requirement Document for the initial and repetitive inspection requirements; with a revised effective date of 5 May 1999.
This Airworthiness Directive becomes effective on 5 May 1999.
Background: The FAA issued the Requirement Document in response to in-flight failures of yokes installed on civilian and military helicopters of similar type design, including three reported accidents. The actions specified by this Directive are intended to detect static or dynamic overload on the yoke due to external bending forces, which could result in failure of the yoke, loss of the tail rotor, and subsequent loss of control of the helicopter.
Overview
The Civil Aviation Regulations 1998, specifically Part 39 - 105 of the Schedule of Airworthiness Directives, was enacted to address the issue of safety and airworthiness in civil aviation, particularly concerning the Bell UH-1 Series Helicopters. This legislative instrument was introduced by the Civil Aviation Safety Authority (CASA) to ensure compliance with international safety standards and to mitigate risks associated with specific components of aircraft. The directive in question, AD/UH-1/4, focuses on the tail rotor yoke of Bell Helicopter Textron, Inc.-manufactured Model UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P helicopters. The primary policy objective is to mandate specific pre-flight checks and operational procedures to prevent potential in-flight failures that could lead to catastrophic outcomes. This action follows a series of reported incidents and accidents resulting from yoke failures, thereby emphasising the need for stringent airworthiness measures to safeguard aviation safety.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105 pertaining to the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, apply to Bell UH-1 series helicopters manufactured by Bell Helicopter Textron, Inc. This includes models UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P. The directive mandates actions in accordance with the technical requirements of FAA AD 99-07-15 Amendment 39-11101, focusing on the revision of the Operating Procedures and Manoeuvres section of the Aircraft Flight Manual (AFM) to incorporate additional procedures for a preflight visual check of the tail rotor yoke for static stop contact damage. The directive, effective from 5 May 1999, necessitates that operators using affected aircraft incorporate the specified procedures into their AFMs, with an additional recommendation to use tail rotor tie-downs when the aircraft is parked or stored. The directive was issued in response to reported in-flight failures and accidents due to yoke failures, which could lead to loss of control of the helicopter.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, details the Civil Aviation Safety Authority’s (CASA) schedule of airworthiness directives for various aircraft types. One such directive, AD/UH-1/4, pertains to Bell UH-1 Series Helicopters, including models UH-1A, UH-1B, UH-1E, UH-1F, UH-1H, UH-1L, and UH-1P manufactured by Bell Helicopter Textron, Inc. (section 3). This directive mandates that operators of these helicopters revise their Aircraft Flight Manual (AFM) in accordance with FAA AD 99-07-15 Amdt 39-11101, with specific modifications to the Operating Procedures and Manoeuvres Section. The directive requires an additional preflight visual check for static stop contact damage in the tail rotor yoke, as detailed in FAA AD 99-07-15 Paragraph (f). This amendment is intended to address in-flight failures of yoke assemblies that have led to accidents, ensuring the detection of potential overloads that could cause yoke failure, loss of the tail rotor, and loss of control.
Operators of the affected Bell UH-1 Series Helicopters must comply with the requirements set out in the directive, which includes revising the AFM to include the specified preflight visual check for tail rotor yoke damage. This action must be completed within the timeframe stipulated in FAA AD 99-07-15 Paragraph (f) and should be performed by inserting a copy of the applicable directive into the Operating Procedures Section of the AFM (section 4). Additionally, operators are advised to use tail rotor tie-downs when the aircraft is parked or stored to mitigate risks associated with the identified issues. Compliance with these directives is crucial for maintaining the airworthiness of the helicopters and ensuring safety during operation.
Failure to comply with the provisions of AD/UH-1/4 can lead to significant consequences. Under the Civil Aviation Act 1988, non-compliance with an airworthiness directive is considered an offence. The penalties for such offences can include substantial fines and potential imprisonment, reflecting the seriousness of the safety implications associated with non-compliance. The exact penalties may vary depending on the specific circumstances of the breach, but they underscore the importance of adhering to CASA’s directives to ensure the safety of all air operations. Operators must, therefore, ensure that all required modifications and checks are completed in a timely manner to avoid legal repercussions.