AD/SD3-60/70 - Engine and Landing Gear Control Cables

The AD concentrates on a discrete technical failure mode and prescribes a regulatory response built from four concepts: targeted inspection, condition‑triggered replacement, defined inspection periodicity, and reference to a manufacturer Service Bulletin and an EASA emergency AD.

1. Targeted inspection: The AD requires inspection of "affected cable assembly end fittings" per Short Brothers PLC SB SD360‑76‑A12 Revision 1 or later EASA‑approved revision (Requirement 1). The SB is the prescribed method for how to inspect and what to look for. The AD thus delegates the procedural detail to the manufacturer SB while making compliance to that SB mandatory.

2. Condition‑triggered replacement: If inspections reveal pitting, corrosion or cracking, the AD mandates replacement of the affected cable assembly with a new cable assembly (Requirement 3). The compliance timing for replacement is immediate in operational terms: "before further flight after the effective date of this AD" (Compliance 3).

3. Periodic surveillance: The AD sets two different periodicities depending on outcome. If no defect is found, inspections must be repeated "within 12 months of the original inspection and thereafter at intervals not to exceed 12 months" (Requirement 2; Compliance 2). For new cable assemblies installed after a defect is found and replaced, the AD requires repeated inspections "in accordance with" the SB (Requirement 4) and states a distinct compliance interval "after replacement at intervals not to exceed 15 years" (Compliance 4). The instrument therefore links inspection frequency to the state of the part and to replacement history.

4. Referential legal layering: The AD explicitly permits operators to use later EASA‑approved revisions of the named SB and cites EASA Emergency AD 2007‑0039‑E as relevant (Note: EASA Emergency AD 2007‑0039‑E dated 16 February 2007 refers). The AD thus creates an interaction between the CASA‑issued AD, the manufacturer SB, and the EASA AD and approval regime.

The AD identifies the technical root cause from the manufacturer's examination: stress corrosion cracking of SAE‑AISI 303 stainless steel, initiated by pitting corrosion on the surface. The background describes the initiating environment as "sustained tensile stress in a corrosive (warm, humid and salty) atmosphere" and notes that multiple occurrences were identified during ground maintenance inspections across the SD3 fleet. Bombardier Shorts performed the examinations and analysis as recorded in the AD Background.

Mechanically, the AD is limited in scope to aircraft type SD3‑60 and the specified fittings; it does not, within the text provided, specify approved part numbers for replacements beyond "a new cable assembly", nor does it include alternative methods of compliance within the text. It does, however, allow later EASA‑approved revisions of the SB to be used.

Primary affected parties named in the AD are operators of Short Brothers PLC SD3‑60 aeroplanes, maintenance organisations servicing those aeroplanes, and the supply chain for the particular cable assemblies (manufacturers and parts suppliers). The AD's "Applicability" statement is limited to "Short Brothers PLC SD3‑60 aeroplanes." The Requirements compel inspection and, where necessary, replacement of control cable end fittings; those duties will fall upon the holder of the aircraft maintenance responsibilities and the operator that must ensure continuing airworthiness.

The AD text identifies the specific hardware at issue as "control cable end fittings (type MS21260)" used in the cable‑operated control systems on the SD3 aircraft types. Bombardier Shorts is named in the Background as the entity that received reports, performed examinations and established the root cause. The AD also references Short Brothers PLC Service Bulletin SD360‑76‑A12 Revision 1; users of the SB , typically maintenance organisations or the operator’s maintenance department , will need access to and to follow that document. The AD explicitly allows use of later EASA‑approved revisions of that SB, which implicates the operator’s obligation to ensure that any later revision used is EASA‑approved.

The regulator issuing the AD is the Civil Aviation Safety Authority, via its delegate David Punshon, as stated in the signature block dated 20 February 2007. The AD becomes effective on 23 February 2007; that effective date and the listed compliance timings assign operational deadlines to operators and maintenance providers (for example the initial inspection to be done "no later than 9 March 2007").

Secondary effects will be on logistical functions within operators: procurement to secure replacement cable assemblies where defects are found, planning to ensure inspections occur within the prescribed windows, and recordkeeping to demonstrate compliance. The AD itself does not detail who pays for inspections or replacements, nor does it detail how parts are to be certified after replacement beyond the generic requirement to install "a new cable assembly" and to inspect new assemblies in accordance with the SB and the stated intervals.

Because the AD references an EASA Emergency AD and requires the SB or later EASA‑approved revisions, it also affects the interface between operators in Australia and international regulatory approvals and manufacturer documentation. The AD therefore imposes obligations that potentially reach beyond a single maintenance event to ongoing parts management and maintenance scheduling for the SD3‑60 fleet.

Duties imposed by the AD are concrete and time‑bound. The AD specifies the following duties for operators and maintenance organisations:

• Perform the initial inspection of affected cable assembly end fittings in accordance with Short Brothers PLC SB SD360‑76‑A12 Revision 1 or a later EASA‑approved revision (Requirement 1; Compliance 1: no later than 9 March 2007).
• If the inspection reveals no pitting, corrosion or cracking, repeat the inspection within 12 months and then at intervals not to exceed 12 months (Requirement 2; Compliance 2).
• If the inspection reveals pitting, corrosion or cracking, replace the affected cable assembly with a new cable assembly before further flight (Requirement 3; Compliance 3).
• After replacement, repeat inspection of the new cable assembly end fittings in accordance with the SB (Requirement 4; Compliance 4: after replacement at intervals not to exceed 15 years).

The AD prescribes the inspection procedure by reference to the manufacturer’s Service Bulletin, thereby delegating procedural detail to the SB. Operators have the duty to ensure the specific SB revision used is EASA‑approved if it is a later revision than Revision 1. The AD also refers to EASA Emergency AD 2007‑0039‑E, creating a duty to consult that EASA AD for related requirements or context.

Rights and flexibilities within the AD text are limited but present:

• The AD allows the use of "Revision 1 or later EASA approved revision" of the Service Bulletin. That language gives the operator the right to adopt a later SB revision provided it is EASA‑approved, instead of being bound only to Revision 1.
• The AD does not specify approved alternative methods of compliance or repair within the text provided. The absence of alternative‑method provisions in the AD as printed means an operator cannot rely on an undocumented alternative unless authorised under separate regulatory processes (not described in the AD).

What the AD does not state is as important as what it does. The AD does not specify:

• Which organisational role (operator, continuing airworthiness manager, CAMO, maintenance organisation) is accountable for carrying out and certifying the inspections in the AD text.
• Any financial allocation for the cost of inspections or replacement assemblies.
• Any particular part number or supplier for the "new cable assembly" beyond the generic description, nor the airworthiness approval standard for replacements.
• Any domestic process for approval of deviations or alternative methods of compliance within the text provided.

Because the AD requires replacement "before further flight" where defects are found (Compliance 3), operators have a duty to remove affected aircraft from service until the replacement is completed. The AD therefore imposes both an operational constraint (grounding until part replaced if defect found) and a maintenance duty with recurring inspection obligations. Responsibility for scheduling and documenting those inspections and replacements rests with the party charged with compliance under applicable aviation regulations; the AD text itself does not allocate detailed administrative responsibilities.

The AD text supplied does not include explicit penalty provisions, monetary fines, or criminal sanctions. It is an instrument issued by the Civil Aviation Safety Authority via its delegate (David Punshon) and becomes effective on 23 February 2007. The AD therefore creates mandatory safety obligations that are enforceable under the broader statutory and regulatory framework governing civil aviation in Australia, but the AD text as provided does not set out enforcement mechanisms or penalties itself.

Practical enforcement implications that follow from the instrument’s content are as follows, based on what the AD requires:

• Compliance is time‑bound. The AD sets a very near initial deadline for inspection: "no later than 9 March 2007" (Compliance 1). Non‑compliance with the inspection requirement could expose an operator to action under prevailing aviation safety legislation or regulatory enforcement processes, although those enforcement mechanisms are not described in this AD text.
• Replacement is mandatory when pitting, corrosion or cracking is discovered and must occur before further flight (Requirement 3; Compliance 3). Operating an aircraft with an identified defective cable assembly contrary to that requirement would be inconsistent with the AD.
• The AD references EASA Emergency AD 2007‑0039‑E and requires the use of the manufacturer’s SB or later EASA‑approved revisions. Failure to use the specified procedures could be identified in an audit or inspection and form the basis for enforcement action.

The AD’s signature block indicates it is issued by CASA's delegate. In administrative practice, CASA is the regulator that administers and enforces civil aviation safety obligations in Australia. Because enforcement and penalties are governed by the enabling legislation and general aviation regulatory regime rather than by this one AD text, parties should consult the applicable statutory framework and CASA guidance for details on enforcement processes, notices, civil penalties or any criminal liability that may attach to breaches of mandatory AD obligations. The AD itself does not provide those procedural or penalty details.

Within the AD text the direct legal interaction is with two main external instruments or authorities:

1. Short Brothers PLC Service Bulletin SD360‑76‑A12: The AD makes compliance with the SB mandatory by reference. Operators must perform inspections "in accordance with" SB SD360‑76‑A12 Revision 1 or a later EASA‑approved revision (Requirement 1). That creates an operational link between this AD and the manufacturer’s maintenance documentation. The SB contains the procedural detail of how inspections are to be conducted; the AD imports that content by reference.

2. EASA Emergency AD 2007‑0039‑E: The AD contains a note stating "EASA Emergency AD 2007‑0039‑E dated 16 February 2007 refers." The AD further allows use of "later EASA approved revision" of the SB. This creates a cross‑jurisdictional regulatory interaction: CASA’s AD references an EASA emergency directive and requires compliance using EASA‑approved SB revisions. The AD thereby embeds EASA procedural approvals into the Australian compliance route for this safety issue.

The AD text does not reference any Australian statutory provisions or specific parts of the Civil Aviation Regulations or Act, nor does it set out how conflicts between CASA directives and other legal instruments would be resolved. It also does not specify how to apply for alternative methods of compliance or how to obtain exemptions; those processes, if available, will be governed by the broader regulatory framework rather than by this AD text.

Because the AD mandates actions that affect the continuing airworthiness of aircraft, it will interact in practice with operators’ obligations under their continuing airworthiness arrangements, maintenance approvals and certifications. The AD’s requirement to install "a new cable assembly" and to inspect new assemblies highlights an interface with parts approval and procurement rules; however, the AD does not specify the airworthiness approval standard or particular part number for replacement assemblies.

In short, the AD operates by reference to:

• the manufacturer’s SB for procedural detail and inspection technique, and
• the EASA emergency AD and EASA approval process for SB revisions.

Any further interaction with domestic aviation law, enforcement mechanisms, approvals for alternative methods of compliance, or parts‑approval processes falls outside the AD text and must be determined under the applicable Australian aviation regulatory framework and CASA policy.

The AD document as supplied records the following dated steps and cross‑references, but it does not record any subsequent amendments within the text provided.

• AD identification: AD/SD3‑60/70, referenced also as "4/2007 TX" in the header blocks.
• Issue date and delegate: Signed by David Punshon, Delegate of the Civil Aviation Safety Authority, dated 20 February 2007.
• Effective date: "This Airworthiness Directive becomes effective on 23 February 2007."
• Initial compliance deadlines: Initial inspection "no later than 9 March 2007" (Compliance 1), and ongoing inspection intervals specified as "within 12 months of the original inspection and thereafter at intervals not to exceed 12 months" (Compliance 2). Replacement is mandated "before further flight after the effective date of this AD" if defects are found (Compliance 3). Post‑replacement inspection interval is stated as "after replacement at intervals not to exceed 15 years" (Compliance 4).
• Referenced documents: Short Brothers PLC Service Bulletin SD360‑76‑A12 Revision 1 is the baseline, with permission to use later EASA‑approved revisions. The AD also notes EASA Emergency AD 2007‑0039‑E dated 16 February 2007 as relevant.

No later amendments, revocations or superseding ADs are included in the material supplied. The AD does permit the use of later EASA‑approved revisions of the SB, which is a procedural flexibility rather than an amendment to the AD itself. If operators require an official amendment, revocation or replacement of this AD, that action would need to be recorded in subsequent CASA AD publications; none are present in the text supplied.

The AD text includes duplicated header lines and a graphic element in the supplied material, but those are editorial elements of the published AD and do not constitute substantive amendments. The supplied AD therefore presents a single issuance dated February 2007 with the stated effective date and compliance schedule.

The AD text provided does not cite any litigation, court decisions, or administrative appeals arising from this AD. The document contains no record of legal challenges, stays, injunctions or judicial determinations concerning its content. The Background recounts manufacturer investigations and fleet‑level findings but makes no reference to any litigation.

Accordingly, based solely on the material supplied, there is no litigation history to report. Any administrative appeals, notices of disagreement, legal proceedings, or judicial review arising from this AD would not be reflected in the AD text itself unless they resulted in a formal amendment, suspension, or revocation published by the issuing authority; the AD as supplied contains no such notation. Parties seeking litigation history must consult CASA records or public court records outside the AD text.

This AD contains several concrete features and textual points that can create operational ambiguity or practical risk if not read carefully.

1. Tight initial deadline. The AD becomes effective 23 February 2007 and requires the initial inspection "no later than 9 March 2007" (Requirement 1; Compliance 1). That gives operators a narrow window (approximately two weeks from the effective date) to locate affected aircraft, obtain the Service Bulletin, and complete the inspections. For aircraft out of base or in remote locations that may be a meaningful logistical burden.

2. Two different recurring intervals. The AD sets a 12‑month recurring inspection interval if no defect is found (Requirement 2; Compliance 2), but states "after replacement at intervals not to exceed 15 years" for inspection of any new cable assembly end fittings (Requirement 4; Compliance 4). On its face this is a substantial difference in inspection frequency between unchanged parts and newly installed parts. The AD text does not explain the rationale for a 15‑year interval post‑replacement while insisting on annual inspection where no defect is found, which could cause confusion in maintenance scheduling and audit. Operators should treat these two compliance paragraphs as written in the AD and seek clarification from CASA if their interpretation would materially affect safety or operations.

3. "New cable assembly" undefined. The AD mandates replacement "with a new cable assembly" but does not specify approved part numbers, manufacturers, or airworthiness standards for that replacement. The AD also does not state whether a reconditioned or overhauled assembly is acceptable. The absence of such specificity means operators must ensure the replacement assembly meets regulatory airworthiness standards and any applicable SB or EASA requirements, and may need to obtain confirmation from the manufacturer or regulator.

4. Reliance on an external Service Bulletin revision and EASA approval. The AD requires compliance with SB SD360‑76‑A12 Rev 1 or "later EASA approved revision." Operators must ensure that any later revision they use is indeed EASA‑approved. The AD does not set out a domestic mechanism for recognising other approval authorities or for how to obtain equivalence; failure to use an EASA‑approved revision where required could be a compliance issue.

5. Immediate grounding risk. If pitting, corrosion or cracking is found during inspection, the AD requires replacement "before further flight" (Requirement 3; Compliance 3). That obliges the operator to take an aircraft out of service until the part is replaced. Depending on spares availability and maintenance capacity, this may cause unexpected aircraft downtime.

6. Geographic and environmental risk not quantified. The Background identifies the causal environment as "warm, humid and salty" atmospheres that sustain tensile stress and lead to stress corrosion in SAE‑AISI 303 stainless steel. The AD does not provide any geographic qualification or risk matrix for frequency of inspection by environment, but operators with aircraft operating in coastal tropical climates should note the identified mechanism and consider closer scrutiny.

7. Scope limited to SD3‑60. The AD is limited in applicability to the SD3‑60 type. If operators have similar fittings on other SD3 variants, the AD text as provided does not cover those types; operators should not assume broader applicability without further regulatory instruction.

8. No dispute or alternative‑method wording in the AD text. The AD text supplied does not include an alternative method of compliance clause or a process for requesting relief from any particular requirement. If an operator wishes to pursue a different inspection method or a different replacement part, they must follow the regulator’s separate processes, which are not described in the AD.

9. Recordkeeping and proof of compliance not specified. The AD does not set out the documentation to be retained or how compliance will be demonstrated in an audit. Operators should ensure their maintenance records capture inspection results, SB revision used, replacement parts fitted (with part numbers and certificates), and dates to support an audit trail.

10. Cross‑referenced EASA Emergency AD. The AD expressly notes that EASA Emergency AD 2007‑0039‑E "refers." Operators should obtain and review that EASA text in addition to the SB for any additional requirements or clarifications.

In sum, the AD imposes clear technical obligations but leaves several implementation details to the operator, the manufacturer SB, EASA approvals, and the broader regulatory framework. Those gaps can create operational uncertainty and should be addressed proactively.

Follow these steps derived from the AD text. Where the AD refers to the manufacturer’s Service Bulletin or an EASA AD, obtain and follow those documents; the AD makes compliance with them mandatory.

1. Identify affected aircraft and hardware:

   • Confirm fleet applicability: Short Brothers PLC SD3‑60 aeroplanes only, per the "Applicability" statement.
   • Identify control cable assemblies fitted with MS21260 type end fittings as described in the Background.

2. Obtain the procedural documents:

   • Obtain Short Brothers PLC SB SD360‑76‑A12 Revision 1 and any later revision that is EASA‑approved. The AD requires inspections "in accordance with" that SB (Requirement 1).
   • Obtain EASA Emergency AD 2007‑0039‑E dated 16 February 2007 for any additional or related requirements referenced by CASA.

3. Perform the initial inspection:

   • Complete the inspection of affected cable assembly end fittings per the SB no later than 9 March 2007 (Requirement 1; Compliance 1).
   • Ensure the inspection is carried out by appropriately certified maintenance personnel and that the SB revision used is recorded.

4. Follow the inspection outcome rules:

   • If no pitting, corrosion or cracking is found, schedule and perform repeat inspections within 12 months of the initial inspection and thereafter at intervals not to exceed 12 months (Requirement 2; Compliance 2).
   • If pitting, corrosion or cracking is found during any inspection, replace the affected cable assembly with a new cable assembly before further flight (Requirement 3; Compliance 3).

5. After replacement:

   • Inspect the new cable assembly end fittings in accordance with SB SD360‑76‑A12 Rev 1 or later EASA‑approved revision (Requirement 4).
   • Note the AD’s Compliance 4 statement that inspections of new assemblies are "after replacement at intervals not to exceed 15 years." Because this interval differs from the 12‑month interval for non‑replaced parts, document the schedule used and, if necessary, seek clarification from CASA regarding interpretation in your operational context.

6. Recordkeeping and certification:

   • Record the inspection report, the SB revision used, findings, and any replacement performed, including part identification and any certificates of conformity for new cable assemblies.
   • Ensure maintenance release and airworthiness paperwork reflect compliance with the AD, including the date and nature of inspections and replacements, and the signatory who certified the work.

7. Logistics and parts:

   • Source a suitable "new cable assembly" that meets applicable airworthiness standards. The AD does not specify supplier or part number. Verify conformity with the SB and with any relevant regulatory parts approval process.
   • Plan for potential aircraft downtime if defects are found, because replacement must be completed "before further flight."

8. Quality assurance and audit:

   • Incorporate the inspection intervals and replacement tracking into continuing airworthiness management systems.
   • Where the aircraft operate in corrosive climates (the Background identifies "warm, humid and salty" environments as the causal atmosphere), consider proactive scheduling to ensure inspections do not lapse.

9. Liaise with regulator/manufacturer if uncertain:

   • If there is any ambiguity about interpreting the differing intervals (12 months versus 15 years), the acceptability of particular replacement parts, or the use of an alternative inspection technique, obtain written clarification from CASA or an authorised representative before deviating from the AD text.
   • If an operator intends to propose an alternative method of compliance or a different part, follow CASA’s formal process for AMOC (alternative method of compliance) or equivalent, noting that the AD text does not itself set out an AMOC process.

10. Monitor for AD updates:

• The AD as supplied has no amendment history recorded. Operators should monitor CASA publications for any superseding ADs, amendments, or safety notices that change inspection intervals, acceptable parts, or the scope of applicability.

By following the inspection schedule and replacement requirement in the AD, and by documenting inspection procedures, findings, and parts used, operators will align with the duties prescribed in the AD text. Where the AD text leaves technical or administrative questions open, secure formal direction from CASA or refer to the referenced EASA AD and the manufacturer’s SB for further detail.