COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes
AD/CL-600/29 Horizontal Stabiliser Trim Actuator 6/95
DM
Applicability: All Canadair CL-600 aircraft as follows:
Model Serial Numbers
CL-600-1A11 1004 to 1085
CL-600-2A12 3001 to 3066
CL-600-2B16 5001 to 5299 excluding 5138 Requirement: 1. Perform the following operational check of the Horizontal Stabilizer Trim
Actuator (HSTA) brake:
- Press the CHAN 1 INOP/CHAN 2 INOP switch/light and then the OVSP/CHNG CHAN switch/light on the centre pedestal control panel.
b. Set and hold the pitch trim switch on the pilot’s control wheel until the stabilizer is in full NOSE UP position.
c. Set and hold the pitch trim switch on the pilot’s control wheel to NOSE DOWN position and while the stabilizer is moving, press the PITCH TRIM DISC switch on the pilot’s control wheel when the needle on the stabilizer trim position indicator reaches the first marking of the take-off configuration green band. Verify that both CHAN INOP lights are on.
d. Verify that the stabilizer over-travel is less than one degree, as read on the stabilizer trim position on the centre instrument panel.
Note: One increment on the stabilizer trim position indicator is equal to one degree of stabilizer travel.
If the stabilizer over-travel is less than or equal to one degree, the pitch trim brake performance meets the ground performance requirements and is serviceable.
If the stabilizer over-travel is more than one degree, refer to Requirement 2.
2. Action in accordance with the Accomplishment Instructions Part A of Bombardier Inc, Canadair Business Aircraft Division Alert Service Bulletin A600-0645 or A601-0443, both dated 11 January 1995, as applicable.
3. Action in accordance with the Accomplishment Instructions Part B of Bombardier Inc, Canadair Business Aircraft Division Alert Service Bulletin A600-0645 or A601-0443, both dated 11 January 1995, as applicable.
Note: Transport Canada Aviation AD CF-95-02 dated 28 February 1995 refers.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Compliance: 1. a. Initially, if there has not been a report of a previous HSTA overspeed annunciation, within 20 hours time in service from 31 March 1995 and thereafter every 100 hours time in service, or
- b. If there has been a report of a previous HSTA overspeed annunciation then, before each flight after 31 March 1995.
2. Before further flight, if the aircraft fails the Requirement 1 checks.
3. a. If there have been previous reports of HSTA overspeed annunciation, then within 50 flight cycles after 31 March 1995, or
3. b. Within 50 flight cycles following a reported incident of HSTA overspeed annunciation after 31 March 1995.
Note: If either the HSTA or the Horizontal Stabilizer Trim Control Unit (HSTCU) was replaced in accordance with Requirements 2 or 3 then the Requirement 1 operational check is only required every 100 hours time in service unless another overspeed annunciation occurs.
Background: There have been several reported instances of HSTA overspeed conditions.
Investigation by Canadair has indicated that, in these cases, the no-back device on the HSTA (a design feature to prevent uncommanded movement of the HSTA screw jack when air loads are applied on the horizontal stabilizer) may have slipped (become reversible), resulting in overspeed annunciation. Each time this condition occurred, the HSTA mechanical brake prevented a HSTA runaway. Further in-depth investigation has identified some internal degraded conditions that may exist in the no-back device which could adversely affect the irreversibility, especially at low temperature and under high air loads. The actions required by this Directive are designed to assist in the early detection of defective HSTA or HSTCU components.
Flight Manual Amendments A/600-1A11/17, A/600-2A12/36, A/600-2B16/22 and A/600-2B16H/24 are complementary to this Directive, providing additional advice to aircrew.
Overview
The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, include a schedule of airworthiness directives aimed at ensuring the safety of aircraft operating within Australia's airspace. One such directive, AD/CL-600/29, targets Bombardier (Canadair) CL-600 (Challenger) Series Aeroplanes, specifically addressing the issue of overspeed conditions in the Horizontal Stabilizer Trim Actuator (HSTA). This directive was introduced to mitigate risks associated with potential slips of the no-back device on the HSTA, which could result in overspeed annunciations and subsequent safety hazards. The policy objective is to mandate regular operational checks and specific actions to detect and rectify any issues with the HSTA, thereby maintaining the airworthiness of these aircraft and ensuring the safety of all those on board. Compliance with these directives is required for specified flight hours and conditions, reflecting a commitment to stringent safety standards in civil aviation.
Scope and Application
The Civil Aviation Safety Authority Schedule of Airworthiness Directives applies to specific Bombardier (Canadair) CL-600 (Challenger) Series aeroplanes, namely those with the serial numbers as specified for each model variant: CL-600-1A11 (1004 to 1085), CL-600-2A12 (3001 to 3066), and CL-600-2B16 (5001 to 5299, excluding 5138). This regulation mandates particular checks and actions for the Horizontal Stabilizer Trim Actuator (HSTA) to ensure safe operation and compliance with airworthiness standards. The directive is part of the Civil Aviation Regulations 1998, which operate under the Commonwealth of Australia and are enforced by the Civil Aviation Safety Authority (CASA). Compliance with this directive is mandatory for the specified aircraft, and it involves regular operational checks and specific actions in response to HSTA overspeed conditions to prevent potential safety issues.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, include the Civil Aviation Safety Authority Schedule of Airworthiness Directives for Bombardier (Canadair) CL-600 (Challenger) series aeroplanes, which addresses the Horizontal Stabiliser Trim Actuator (HSTA) as per AD/CL-600/29 6/95DM. The directive applies to all Canadair CL-600 aircraft, with specific serial numbers provided for each model (section 1). The primary requirement outlined in this directive is the operational check of the HSTA brake, which involves a series of actions such as pressing certain switches, setting and holding the pitch trim switch, and verifying the stabilizer over-travel, with specific steps and checks mentioned (section 1). If the stabilizer over-travel exceeds one degree, further actions are required in accordance with Bombardier's Alert Service Bulletins A600-0645 and A601-0443, dated 11 January 1995.
The directive imposes several obligations on the operators of the affected aircraft. Operators must perform the HSTA operational check within 20 hours from 31 March 1995 and then every 100 hours, or before each flight if there has been a previous HSTA overspeed annunciation (section 2). If the aircraft fails the Requirement 1 checks, the operator must ensure that further flight is not undertaken until the checks are successfully passed. Additionally, if there have been previous reports of HSTA overspeed annunciation, the operator must comply within 50 flight cycles after 31 March 1995, or within 50 flight cycles following a reported incident of HSTA overspeed annunciation. If the HSTA or Horizontal Stabiliser Trim Control Unit (HSTCU) has been replaced in accordance with the directive, the operational check is only required every 100 hours unless another overspeed annunciation occurs (section 3).
The Civil Aviation Regulations 1998 do not explicitly outline specific offences, penalties, or consequences for non-compliance with AD/CL-600/29 6/95DM. However, non-compliance with airworthiness directives in general could lead to serious safety risks, potential grounding of the aircraft, and enforcement actions by the Civil Aviation Safety Authority (CASA). CASA has the authority to issue fines, suspend or revoke airworthiness certificates, and take other regulatory actions against non-compliant operators. The specific penalties for non-compliance would depend on the severity and impact of the non-compliance, as determined by CASA.