COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Airtractor AT-300, 400 and 500 Series Aeroplanes
AD/AT/19
Amdt 1
Flap System Overrun Prevention 3/99
Applicability: Models AT-300, AT-301, AT-302, AT-400, AT-400A, AT-401, AT-401A, AT-401B,
AT-402, AT-402A, and AT-402B aircraft, serial numbers 300-0001 through 401B- 1063; and, models AT-501, AT-502, AT-502A, AT-502B, and AT-503A aircraft, serial numbers 502-0001 through 502B-0500; that do not have a part number (P/N) 70975-1 flap actuator overtravel stop installed in accordance with the Rework Instructions section of Snow Engineering Co. Service Letter 165, dated May 15, 1998.
Requirement: Replace the existing flap actuator overtravel stop with a new one of improved design, P/N 70975-1. Accomplish this replacement in accordance with the Rework Instructions section of Snow Engineering Co. Service Letter 165.
Note: FAA AD 98-25-01 Amdt 39-10922 refers.
Compliance: Unless already accomplished, within 50 hours time in service after 25 March 1999.
This Amendment becomes effective on 25 March 1999.
Background: Investigations have shown that it is possible for the flap control system to overrun through disengagement of the flap actuator overtravel nut. As a result of this overrun it is possible for the flap control pushrod to interfere with the aileron control pushrod to the extent that aileron control is lost. A modification introduced a new overtravel stop with improved security to prevent flap actuator overrun.
Amendment 1 is issued in response to a new FAA AD which was prompted by reports of the flap actuator jackscrew breaking through the roll pin hole on three of the affected aircraft that were already in compliance with Snow Service Letter 140, Revised (FAA AD 96-23-19). This Directive requires installation of a new improved overtravel stop that is secured to the jackscrew by a welding method.
The original issue of this Airworthiness Directive became effective on 27 March 1997.
Overview
The Civil Aviation Regulations 1998, enacted by the Commonwealth of Australia's Parliament, provide a comprehensive framework for ensuring the safety of civil aviation operations within Australia. One aspect of these regulations, specifically within PART 39 - 105, addresses the issuance of Airworthiness Directives to rectify identified safety issues. The Civil Aviation Safety Authority (CASA) issues these directives to ensure that aircraft meet the necessary safety standards. The directive AD/AT/19Amdt 1, effective from 25 March 1999, pertains to Airtractor AT-300, 400, and 500 Series aeroplanes and aims to prevent flap system overrun by requiring the installation of an improved flap actuator overtravel stop. This directive responds to findings that the existing flap control system could potentially disengage, leading to aileron control loss, and follows reports of flap actuator jackscrew failures in compliant aircraft. The overarching policy objective is to enhance aircraft safety by mitigating risks associated with flap system malfunctions.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105 under the Civil Aviation Safety Authority, address the Airworthiness Directives for Airtractor AT-300, 400, and 500 Series Aeroplanes. This regulation applies to certain models of Airtractor aircraft, specifically those that have not installed a particular part number (P/N) 70975-1 flap actuator overtravel stop as per Snow Engineering Co. Service Letter 165 dated May 15, 1998. The directive applies to a defined set of serial numbers for these aircraft models, ensuring that they meet specific safety standards. This regulation operates under the Commonwealth of Australia and is enforced by the Civil Aviation Safety Authority, indicating its national reach and applicability across the country. Compliance with this directive is mandatory for the specified aircraft to ensure their safe operation, with a requirement to replace the existing flap actuator overtravel stop with the new improved design within 50 hours of service after 25 March 1999. This regulation aims to mitigate risks associated with the flap control system, particularly the potential for flap actuator overrun that could lead to significant safety hazards.
Key Provisions
The main operative sections of the AD/AT/19 Amendment 1 (paragraph 3) require that the flap actuator overtravel stop on specified models of the Airtractor AT-300, 400, and 500 Series aeroplanes must be replaced with a new part of improved design, P/N 70975-1. This replacement must be conducted in accordance with the Rework Instructions section of Snow Engineering Co. Service Letter 165 (paragraph 4). The compliance deadline for this replacement is set within 50 hours of time in service after 25 March 1999 (paragraph 5). The amendment itself became effective on 25 March 1999 (paragraph 6).
The obligations imposed on the parties or entities governed by this legislation primarily revolve around ensuring that the specified flap actuator overtravel stop replacement is carried out in a timely manner. This includes adhering to the specified instructions outlined in Snow Engineering Co. Service Letter 165, ensuring that the replacement part, P/N 70975-1, is correctly installed. Operators and owners of the affected aircraft must ensure that the compliance deadline is met to maintain the airworthiness of their aircraft.
Breaches of these obligations can result in significant civil or criminal consequences. Although the specific penalties are not detailed in the provided text, under Australian civil aviation law, non-compliance with airworthiness directives can lead to severe penalties. This can include fines, suspension or revocation of air operator certificates, and other regulatory actions. Additionally, failure to comply with such directives could potentially lead to criminal charges if it is determined that such non-compliance contributed to an aviation accident or incident.