Cessna 336 Series Aeroplanes
AD/CESSNA 336/13
Amdt 1
Seat Adjustment Mechanism 9/88
Applicability: Model Serial Number
Model 336 336-0001 to 336-0195
Requirement: Part 1:
(a) Measure each hole in the seat track(s) for excessive wear. If the wear dimension across any hole exceeds 10.67mm (0.42") to a maximum depth of 3.81mm (0.15"), replace the seat track prior to further flight.
Figure 1.
SECTION OF SEAT TRACK SHOWING HOLE WEAR
(b) Visually inspect the seat rail holes for dirt and any debris which may preclude engagement of the seat pin(s). Remove any such material prior to further flight.
(c) Lift up on the forward edge of each seat to eliminate all vertical play. With the seat in this position, measure the depth of engagement of each seat pin. If the engagement of any pin is less than 3.81mm (0.15") (see Figure 2), replace or repair necessary components to achieve a seat pin engagement of 3.81mm (0.15") or greater prior to further flight.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
FIGURE 2
(d) Visually inspect seat rollers for flat spots. Ensure all rollers and washers turn freely on their axle bolts (or bushings if installed) and move freely on the seat rails. Replace rollers having flat spots and any worn washers prior to further flight. If there is any binding between the bores of the rollers, washers, and axle bolts (or bushings if installed), remove, clean, and reinstall these parts prior to further flight.
Note: Do not lubricate rollers, washers, axle bolts or bushings as the lubrication will attract dust and other particles which can cause binding.
(e) Measure the wall thickness of the roller housing and the tang (see Figure 2). If the tang thickness has worn to less than 1/2 the housing thickness, replace the roller housing prior to further flight.
(f) Check the spring(s) that keep the lock pin(s) in position in the track holes for positive engagement action. Replace any spring which does not provide positive engagement prior to further flight.
(g) Visually inspect the seat tracks for cracks in accordance with Cessna SIL SE83-6, dated 11 March 1983. Any limitation imposed as a result of seat track cracking shall be endorsed on the Maintenance Release. Replace any seat rail exceeding the crack criteria as specified in SE83-6 with a serviceable rail prior to further flight.
Part 2:
In accordance with temporary schemes approved by the Secretary, modify seat adjustment mechanisms to permanently limit seat travel to 255mm (10") or to 153mm (6") as applicable, aft of the forward stop.
Note: FAA AD 87-20-03 R1 refers.
Compliance: A. (i) For aircraft with less than 1000 hours time in service as at 28 January 1988, prior to attaining 1100 hours time in service; or
(ii) For aircraft with more than 1000 hours time in service as at 28 January 1988, at the next inspection for Maintenance Release issue after 28 January 1988; and
(iii) Thereafter at each inspection for Maintenance Release issue closest to a 100 hour inspection interval or every 12 months, whichever is earlier.
B. Pending any component replacement necessary to fully comply with Requirement: Part 1, compliance with Requirement: Part 2 is an acceptable alternative until 30 June 1989.
Background: There has been a history of seat adjustment mechanism failure that has resulted in accidents. As there will probably be a high demand for replacement items, Part 2 of the Requirement enables continued flight. Schemes acceptable to the Secretary are available from Regional Offices.
Overview
The Cessna 336 Series Aeroplanes AD/CESSNA 336/13 Amendment 1, issued in 1988, was enacted to address safety concerns regarding the seat adjustment mechanisms in Cessna 336 aircraft. This legislation was introduced to mitigate the risk of accidents caused by seat adjustment failures. The enactment of this airworthiness directive is overseen by the Civil Aviation Safety Authority under the Civil Aviation Regulations 1998. The primary policy objective is to enhance aviation safety by ensuring that seat adjustment mechanisms in specified Cessna 336 aircraft are maintained and operated within safe parameters, thus preventing potential accidents due to mechanical failure.
Scope and Application
The Cessna 336 Series Aeroplanes AD/CESSNA 336/13 Amendment 1 applies specifically to Model 336 aircraft with serial numbers ranging from 336-0001 to 336-0195, targeting the seat adjustment mechanism to ensure the safety and airworthiness of these aircraft. This legislative instrument, issued under the Civil Aviation Regulations 1998, mandates comprehensive inspections and maintenance procedures for the seat adjustment mechanisms. The Act requires that various components of the seat track, including holes, rails, pins, rollers, and housings, be inspected and maintained or replaced as necessary to meet specified tolerances and conditions, with the aim of preventing accidents due to seat adjustment mechanism failures. The Act applies nationally across Australia, governed by the Commonwealth of Australia, and its requirements must be adhered to by aircraft operators, maintenance personnel, and aviation authorities to ensure compliance with safety standards.
Key Provisions
The legislative instrument AD/CESSNA 336/13 focuses on the maintenance and modification of seat adjustment mechanisms for Cessna 336 Series Aeroplanes. This is achieved through two main parts, which specify the requirements and compliance schedules. Part 1 (sections 1a to 1g) outlines the detailed requirements for the seat adjustment mechanism. It mandates the measurement of each hole in the seat track for excessive wear, visual inspection of seat rail holes for dirt and debris, and the elimination of vertical play in the seats. It also requires the inspection of seat rollers and washers, measurement of wall thickness for the roller housing, and the checking of springs in the lock pins. Finally, it requires visual inspection for seat track cracks and adherence to any limitations imposed by such findings.
These requirements impose specific obligations on the entities governed by the Act, primarily focusing on the maintenance personnel and the operators of the aircraft. They must ensure that the seat adjustment mechanisms are checked and maintained according to the specified parameters. This involves regular inspections and measurements, as well as the replacement of worn or damaged parts to prevent any potential failure that could lead to accidents. The compliance schedule (Part 2) further stipulates when these checks and modifications must be performed, particularly concerning the aircraft's time in service and inspection intervals.
The Act also outlines consequences for non-compliance. While the specific penalties are not detailed in the text, breaches of such aviation safety directives typically result in significant penalties under Australian aviation law. These may include fines, suspension of airworthiness certificates, or other regulatory actions that could affect the operation of the aircraft. Ensuring adherence to these requirements is crucial for maintaining the safety standards set by the Civil Aviation Safety Authority.