COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
McDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters
AD/HU 369/37 Tail Rotor Swashplate Bearing Locknut - Inspection and Increase in Torque
6/79
Applicability: All model 369D with S/Nos. from 0003D to 0409D, not modified in accordance with Hughes SIN DN-37.
Requirement: 1. Visually inspect the tail rotor swashplate bearing as follows;
(a) Pull back the non-rotating boot P/N 369D21806 from the tail rotor pitch control assembly P/N 369D21800 and check the locknut and tang washer by hand for looseness.
(b) If the locknut or tang washer is loose, remove and replace the tail rotor pitch control assembly with a serviceable assembly with a white dot on the locknut, before further flight.
2. Modify the tail rotor swashplate in accordance with Hughes SIN DN-37. For aircraft maintained in accordance with ANO 100.5.1, Part 1 of this Directive shall be entered on the maintenance release as maintenance required. The inspection may be performed by the pilot in command, in which case certification is not required. In all other cases certification may be made on the maintenance release. This inspection may also be performed and certified by any Licensed Aircraft Maintenance Engineer.
Compliance: For Part 1 - At each preflight inspection, until modified in accordance with Part 2.
For Part 2 - Within 100 hours time in service after 10 May 1979.
Background: To prevent loosening of the tail rotor swashplate bearing locknut and possible loss of tail rotor control, the tightening torque of the locknut is increased. Until this is accomplished, the locknut is to be inspected prior to each flight.
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Overview
The Civil Aviation Regulations 1998, specifically under Part 39 - 105, includes Airworthiness Directives (AD) issued by the Civil Aviation Safety Authority (CASA). AD/HU 369/37, enacted in 1979, was introduced to address safety concerns regarding the tail rotor swashplate bearing locknut on McDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters, particularly those with serial numbers from 0003D to 0409D that have not been modified according to Hughes SIN DN-37. The problem this directive seeks to resolve is the potential for the locknut to loosen, leading to a loss of tail rotor control, which could compromise flight safety. The policy objective is to ensure that the tail rotor swashplate bearing is inspected prior to each flight and subsequently modified to increase the torque of the locknut, thereby preventing loosening and enhancing safety.
The directive mandates a visual inspection of the tail rotor swashplate bearing at each preflight inspection for helicopters not yet modified, and requires modification within 100 hours of time in service after 10 May 1979. This inspection can be performed by the pilot in command, a Licensed Aircraft Maintenance Engineer, or another certified individual, and must be documented on the maintenance release. The purpose of these measures is to maintain the integrity of the tail rotor control system, ensuring that any looseness in the locknut is identified and rectified promptly to prevent potential flight hazards.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all McDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters with serial numbers (S/Nos.) from 0003D to 0409D, unless they have been modified in accordance with Hughes Service Instruction Notice (SIN) DN-37. This regulation is administered by the Civil Aviation Safety Authority (CASA) and thus has a national jurisdictional reach throughout Australia. The regulation mandates a visual inspection of the tail rotor swashplate bearing to check for looseness of the locknut and tang washer, which must be carried out at each preflight inspection until the aircraft is modified as specified. The modification, which involves increasing the tightening torque of the locknut to prevent loosening and potential loss of tail rotor control, must be completed within 100 hours of time in service after 10 May 1979. This inspection and modification can be performed by the pilot in command, a Licensed Aircraft Maintenance Engineer, or any authorised personnel, with appropriate certification depending on the case.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39, Section 105, addresses airworthiness directives for certain aircraft models, including the McDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters, in AD/HU 369/37. This directive focuses on the inspection and modification of the tail rotor swashplate bearing locknut to prevent potential loss of tail rotor control. Under section 1, all model 369D helicopters with serial numbers from 0003D to 0409D, which have not been modified according to Hughes SIN DN-37, must undergo a specific inspection process. The inspection requires the visual check of the locknut and tang washer for looseness, which involves pulling back the non-rotating boot from the tail rotor pitch control assembly and examining these components by hand.
Section 2 of the directive mandates that if the locknut or tang washer is found to be loose, the tail rotor pitch control assembly must be replaced with a serviceable one that has a white dot on the locknut. Furthermore, the tail rotor swashplate must be modified in accordance with Hughes SIN DN-37. For aircraft maintained under ANO 100.5.1, Part 1 of this directive must be recorded on the maintenance release as maintenance required. The pilot in command can perform the inspection, in which case certification is not necessary. However, in other cases, certification can be made by a Licensed Aircraft Maintenance Engineer.
Compliance with these directives is essential and is detailed further in the regulation. For Part 1, the inspection must be conducted at each preflight inspection until the modification specified in Part 2 is completed. For Part 2, the modification must be carried out within 100 hours of time in service after 10 May 1979. Failure to comply with these provisions may result in civil or criminal penalties. The seriousness of non-compliance stems from the potential safety hazards, including the risk of loss of tail rotor control, which could lead to severe accidents. The maximum penalties for breaches of these regulations are not explicitly stated in the text, but they can include fines and imprisonment, depending on the severity and intent of the breach.