AD/AS 355/85 Amdt 4 - Sliding Door Rear Fitting Pin

The Directive is structured around a short set of core technical concepts that determine compliance and operational impact.

• Applicability and scope. The Directive applies only to AS 355 models E, F, F1, F2 and N "equipped with sliding door(s) pre-MOD 073298 and/or pre-MOD 073308" (Applicability). The scope is therefore limited by model and by whether the sliding doors have already been modified by the two specified MODs. If a helicopter has had the relevant MOD applied, the prohibitions and replacement obligations may not apply.
• Inspection-driven process. The Directive establishes a recurring inspection cycle tied to accumulated flight hours of the sliding door assembly. It prescribes an initial inspection window (either upon reaching 110 flight hours or within 20 flight hours after 26 October 2006 depending on logged hours) and subsequent inspections at intervals "not to exceed 110 flight hours" (Compliance).
• Mandatory replacement/modification. Where the ASB procedures identify parts requiring replacement, the Directive mandates carrying out the replacement "in accordance with paragraph 2.B. of ASB No. 52.00.23" (Requirement). An earlier amendment converted the Requirement to an Alert Service Bulletin and "mandated modification action that cancels the inspection requirements of this Directive" (Background). Later amendments adjusted that position.
• Installation prohibitions. The Directive contains negative obligations: "No person shall install" certain sliding doors unless modified per MOD numbers, and "No person shall install" identified part numbers (Requirement). The prohibition targets both assemblies and discrete parts (rail roller pin 350A25-1275-20; cast roller support fittings 350A25-1270-20 and 350A25-1270-22).
• Interaction with manufacturer documentation and EASA approvals. Inspections and replacements are to be performed "in accordance with" specified paragraphs of Eurocopter ASBs, or "later EASA approved revision" of those ASBs. The Directive cross-references EASA AD 2007-0236 and notes that Amendment 4 was issued "in response to a new EASA AD" which requires repetitive inspections until replacement with improved parts and also prohibits installation of a particular fitting part number (Background). Thus the Directive legally imports, by reference, procedures published in manufacturer ASBs and any later EASA-approved revisions of those ASBs.
• Temporal effect. The AD is dated and signed 12 September 2007 and states the amendment becomes effective on 14 September 2007 (signature block; top of document). Compliance deadlines include the 30 September 2007 date for certain actions and earlier flight-hour-based windows (Compliance).

These concepts combine a safety rationale (addressing fatigue and metallurgical non-conformity discovered in specific hardware), inspection intervention until replacement, and a prohibition on installing identified parts or door assemblies unless modified per specified MODs.

The Directive identifies a narrow but technically specific set of affected parties. Those parties and their likely obligations are:

• Aircraft owners/operators of Eurocopter AS 355 models E, F, F1, F2 and N fitted with sliding doors installed before MOD 073298 and/or MOD 073308. The Applicability clause explicitly limits the Directive to these models and to sliding doors pre-dating the listed MODs. Owners/operators are the primary actors who must arrange inspections, replacements and any required modifications because compliance duties are framed as actions on the helicopter (Requirement; Compliance).
• Maintenance organisations and licensed engineers. The Directive requires inspections and parts replacement "in accordance with paragraph 2.B. of" the referenced ASBs or later EASA-approved revisions. That language imports manufacturer-prescribed procedures and implies that the work must be done to the ASB’s instructions. Maintenance organisations who perform or certify such work will therefore be affected by the requirement to follow those ASB paragraphs and any later approved revisions (Requirement).
• Installation and parts suppliers. The Directive prohibits installation of particular sliding doors unless they have been modified per MOD numbers and bans installation of explicit parts: rail roller pin 350A25-1275-20 and cast roller support fittings 350A25-1270-20 and 350A25-1270-22 (Requirement). Suppliers, vendors and stock-holders of those parts must ensure they do not supply or fit the prohibited items to affected aircraft without the specified MODs.
• Modification approval entities and designers. MOD numbers 073298 (left-hand doors) and 073308 (right-hand doors) are the required modifications for sliding doors to be permitted for installation. Organisations that implement or approve such MODs, and those who supply parts compliant with those MODs, will be engaged because installation is contingent on having those MODs applied (Requirement).
• Regulators and certification authorities. The Directive is issued by the Civil Aviation Safety Authority (delegate signature). EASA AD 2007-0236 is explicitly referred to; Amendment 4 was in response to a new EASA AD (Background). This creates a coordination effect between CASA directives and EASA-mandated requirements; regulatory and certification personnel will need to track related EASA ASB revisions to determine if a later EASA-approved revision changes the procedural obligations.

Who pays and who decides: the text places action obligations on "No person" and on the aircraft, which practically means aircraft owners/operators must ensure inspections, replacements, and that prohibited parts are not fitted. Maintenance organisations and suppliers decide how to implement the ASB-prescribed procedures and whether parts meet the MOD/ASB criteria. The Directive does not spell out cost allocation or compensation; the source requires the physical actions without allocating financial responsibility.

The Directive imposes affirmative duties, negative duties (prohibitions) and procedural dependencies on manufacturer documentation.

Affirmative duties

• Inspect. The Directive requires a check of "the support shaft of the rear roller and the rear fitting of the sliding door(s) for cracks" and ties that inspection to "paragraph 2.B. of Eurocopter AS 355 Alert Service Bulletin (ASB) No. 05.00.45 original issue, or later EASA approved revision" (Requirement 1). Inspections must be scheduled according to the Compliance table: aircraft with less than 90 flight hours at the time of the Directive must be inspected upon accumulating 110 flight hours and thereafter every 110 flight hours; aircraft with 90 or more flight hours must be inspected within 20 flight hours after 26 October 2006 and thereafter not to exceed 110 flight hours between inspections (Compliance).
• Replace. The Directive requires replacement of the roller support shaft and fitting of either the left-hand and/or right-hand sliding doors "in accordance with paragraph 2.B. of ASB No. 52.00.23 original issue, or later EASA approved revision" (Requirement 2). The Compliance section contains a line: "Unless already accomplished, before 30 September 2007" (Compliance), which the Directive places against the replacement/mandatory modification item.
• Follow ASBs and EASA-approved revisions. All inspection and replacement procedures are tied to specific ASB paragraphs or "later EASA approved revision(s)". That means the technical content and the acceptable repair/modification method are those contained in the referenced ASB paragraphs and any subsequent EASA-approved revisions (Requirement).

Negative duties (prohibitions)

• Do not install specified sliding doors unless modified per MODs. "No person shall install, on any AS 355 helicopter, sliding doors listed in paragraph 1.A.2. of ASB No. 52.00.23 Revision 1, or later EASA approved revision, unless these sliding doors have been modified per MOD 073298 for LH doors, and per MOD 073308 for RH doors" (Requirement).
• Do not install particular part numbers. The Directive prescribes: "No person shall install, on any AS 355 helicopter, rail roller pins part number 350A25-1275-20 and cast roller support fittings part numbers 350A25-1270-20 and 350A25-1270-22" (Requirement). Amendment 4 specifically refers to the prohibition on installation of roller support fitting part number 350A25-1270-22 (Background).

Rights and procedural features in the Directive

• The Directive does not create a procedural right of appeal within its text; it sets technical obligations. It does allow reliance on later EASA-approved revisions of the referenced ASBs when performing the required work (Requirement). This affords an operator or maintenance organisation the ability to use a later EASA-approved ASB revision as the prescriptive method, which is a limited procedural flexibility.
• The Directive indicates that when parts are replaced in accordance with the specified ASB/modification, "the modification action cancels the inspection requirements" (Background, Amendment 2). However, the later Amendment 4 modifies that regime: a new EASA AD required repetitive inspections until replacement with improved parts, so the cancellation of inspection requirements depended on later developments in EASA directives (Background). The practical consequence is that replacement or modification may eliminate the inspection obligation if the ASB/modification is carried out and accepted by the authority, but that outcome depends on subsequent EASA direction.

The Directive is expressed in mandatory terms: "No person shall..." and "Check... Replace..." and sets compliance timing. The text does not specify exceptions, variances, or procedural avenues within the document itself. Compliance is operationally tied to following ASB paragraphs and any EASA-approved revisions referenced.

The Directive sets mandatory technical requirements and compliance windows, but the text provided does not include quantified or specific penalty provisions. The document shows:

• A formal direction from the Civil Aviation Safety Authority delegate, with an effective date: "This Amendment becomes effective on 14 September 2007" and signature by "Charles Lenarcic, Delegate of the Civil Aviation Safety Authority" (signature block). This establishes the Directive's regulatory provenance and effective date.
• The substantive obligations are set as mandatory actions ("No person shall install...", "Check...", "Replace...") and include compliance timings (Compliance). However, the Directive text as supplied does not detail enforcement mechanisms, fines, demerit processes, or administrative penalty amounts.

What the text does allow a reader to infer, and what the text itself states:

• The Directive clearly mandates actions that must be taken by aircraft owners/operators and those who install parts. Failure to comply would leave the aircraft in non-compliance with this AD. The AD does not itself enumerate the sanction regime within its body.
• The Directive explicitly refers to manufacturer ASBs and EASA ADs as the technical standards to be followed; compliance therefore means carrying out those procedures and meeting the prescribed timing windows. The presence of an effective date (14 September 2007) and deadlines (for example, "before 30 September 2007" and flight-hour thresholds) indicates the timeline for when the regulated parties must have acted to be in compliance.

Limits in the source text

• The Directive does not describe investigative, audit or enforcement procedures, nor does it set out civil or criminal penalties for non-compliance in the text provided. It also does not specify whether completion of the mandated modifications or replacements confers any certificate or approval statement, or the mechanism for recording compliance. Those operational enforcement and record-keeping aspects are not in the supplied text.

Practical effect for operators

• Given the Directive’s mandatory language and effective date, an operator who does not perform the required inspections and replacements, or who installs prohibited parts, would be operating in breach of the AD itself. The text does not specify the consequences of that breach; it simply imposes the technical duties and timing. Any enforcement action would therefore have to be inferred from the broader regulatory framework or pursued under separate authority, which is not reproduced in the document supplied.

The Directive explicitly cross-references and imports content from other regulatory and manufacturer instruments; the supplied text provides the following anchors for interaction.

Reference to EASA airworthiness directives

• The Requirement notes "Note: EASA AD 2007-0236 refers." and the Background states Amendment 4 "is issued in response to a new EASA AD, which requires repetitive inspections until replacement of current parts with improved parts and also prohibits installation of another roller support fitting part number 350A25-1270-22 on any AS 355 helicopter" (Requirement; Background). The Directive therefore operates in conjunction with, and in reaction to, EASA airworthiness directives. Conformance with the CASA Directive will therefore require attention to the referenced EASA ADs. The Directive instructs that ASB procedures used must be those of "original issue, or later EASA approved revision", explicitly tying permissive technical methods to EASA approvals (Requirement). Reference to Eurocopter Alert Service Bulletins and MODs
• The Directive makes compliance dependent upon specific Eurocopter documentation: "paragraph 2.B. of Eurocopter AS 355 Alert Service Bulletin (ASB) No. 05.00.45 original issue" and "paragraph 2.B. of ASB No. 52.00.23 original issue" (Requirement). It also conditions installation on specific MODs: "unless these sliding doors have been modified per MOD 073298 for LH doors, and per MOD 073308 for RH doors" (Requirement). Those ASBs and MODs are manufacturer-produced technical documents and modifications; the Directive therefore effectively incorporates manufacturer technical requirements into the regulatory obligation. The Directive permits the use of "later EASA approved revision" of those ASBs, thereby aligning CASA’s technical compliance standard with EASA-approved changes. Temporal interaction and amendment history
• The Background traces a series of amendments: Amendment 1 addressed reports of cracking and failure of the roller support shaft rear attaching fitting; Amendment 2 "converted the Requirement document to an Alert Service Bulletin with the same reference number, and mandated modification action that cancels the inspection requirements of this Directive"; Amendment 3 extended compliance times for Requirements 2, 3, and 4; and Amendment 4 responded to a new EASA AD requiring repetitive inspections until replacement with improved parts (Background). This history shows that the Directive’s current obligations are the product of interaction with manufacturer findings and EASA ADs, and that the AD’s requirements evolved as that external material changed. Limits on interactions stated in the text
• The Directive ties its technical methods to EASA approval of ASB revisions; it does not reference other domestic statutory instruments or procedural enforcement mechanisms within its text. The supplied instrument does not set out how compliance should be recorded, nor does it state whether conformity with the ASBs constitutes a formal amendment to the aircraft’s maintenance log or certificate , those procedural points are not included in the text provided.
• The Directive’s reliance on external EASA approvals and Eurocopter ASBs creates a dynamic interaction: later EASA-approved ASB revisions can change the content of the required works that satisfy the AD, and EASA ADs can trigger CASA AD amendments. This means the legal obligation in CASA’s Directive is partly shaped by, and responsive to, EASA-adopted technical rulings and manufacturer service bulletins.

The Directive itself summarises a short amendment history across four amendments; the supplied text sets out the core steps and the reasons for each.

• Original issue and initial problem report. The Background begins with the manufacturer receiving "a report of failure and a report of cracking of the sliding door rear roller support pin." Metallurgical analysis found cracks starting from a spring pin bore that grew by fatigue and a "heat treatment non-conformity of the pin material" (Background). The original Requirement evidently instituted inspections and/or part replacement in response to that discovery.
• Amendment 1. Prompted by additional reports: "Amendment 1 was prompted by reports of cracking and failure of the roller support shaft rear attaching fitting." The Amendment appears to have expanded or clarified the affected parts and the required actions to address cracking at another attachment point (Background).
• Amendment 2. A structural change to how the requirement was implemented: "Amendment 2 converted the Requirement document to an Alert Service Bulletin with the same reference number, and mandated modification action that cancels the inspection requirements of this Directive." That is, at Amendment 2 the Authority (in conjunction with manufacturer procedures) mandated a modification which, if accomplished, would remove the need for the recurring inspections that earlier rules had required (Background).
• Amendment 3. Administrative timing change: "Amendment 3 extended the compliance time for Requirements 2, 3, and 4." The AD text does not reproduce the former or extended times in full but records that compliance windows for certain requirements were lengthened (Background).
• Amendment 4 (current). The present AD is Amendment 4. It was issued in response to a "new EASA AD" and reintroduced or required "repetitive inspections until replacement of current parts with improved parts" and "also prohibits installation of another roller support fitting part number 350A25-1270-22 on any AS 355 helicopter" (Background). In short, Amendment 4 adjusted the earlier regime where modifications could cancel inspections by requiring inspections to continue until replacement with improved parts and adding an installation prohibition for a specific part number.

Dates and effectivity

• The AD is marked "11/2007 DM" and the document is dated and signed 12 September 2007 by the CAS A delegate; it states "This Amendment becomes effective on 14 September 2007" (signature block; top). The Compliance table includes an instruction "Unless already accomplished, before 30 September 2007" for a requirement that the document links to replacement/modification actions (Compliance). The Compliance table also references inspection windows keyed to flight hours and a 26 October 2006 anchor for those with 90 or more flight hours (Compliance).

Cross-references

• The Amendment history records conversion from a standalone requirement document to reliance on manufacturer ASBs (Amendment 2), and links later amendments to EASA ADs. The AD explicitly notes "Note: EASA AD 2007-0236 refers." These cross-references indicate that the AD’s content and timing have been influenced by both manufacturer findings and EASA regulatory decisions.

The supplied text does not reproduce the full texts of the earlier amendments, ASBs or the EASA ADs, but it summarises why each amendment was made and the practical effect (inspection versus modification regimes, timing extensions and added prohibitions).

The supplied Directive text contains no information about litigation. It contains:

• No citations of judicial decisions, tribunal rulings, or administrative appeals related to the Directive.
• No indication of court challenges to the Directive or to any of its amendments.
• No reported case names or litigated disputes in the Background, Requirement or Compliance sections.

Therefore, based solely on the text provided, there is no documented litigation history associated with AD/AS 355/85 or its amendments in this instrument. Any litigation arising from compliance disputes, enforcement actions, or contractual claims between operators and suppliers would not be captured by this Directive as supplied. The Directive simply records the technical safety obligations, the amendments, and the reasons for those amendments; it does not record legal proceedings or adjudicative outcomes.

If users require information about any subsequent legal challenges or enforcement actions, that information is not contained in the supplied AD text and would need to be sourced from case law databases, administrative records, or regulatory enforcement publications outside this instrument.

The Directive contains several technical and procedural features that create practical pitfalls for operators, maintainers and parts suppliers. These are concrete points in the text that commonly cause compliance errors or operational disruption.

• Applicability tied to MOD status. The AD applies to AS 355 helicopters equipped with sliding doors "pre-MOD 073298 and/or pre-MOD 073308" (Applicability). If an operator’s logbooks do not clearly show whether MOD 073298/073308 has been embodied on the left-hand or right-hand doors, there is a compliance risk. The AD’s installation prohibitions hinge on the presence or absence of those MODs.
• Mixed obligations from amendments. Amendment 2 had previously mandated modifications that "cancels the inspection requirements of this Directive" (Background). Amendment 4, however, requires "repetitive inspections until replacement of current parts with improved parts" and forbids installation of certain parts (Background). The interaction between an operator having carried out an earlier modification and the later requirement for inspections until replacement may be confusing if record-keeping is incomplete. Operators must ensure that any prior modification is the specifically required MOD and that the replacement part is the "improved part" contemplated by the later EASA AD,those exact technical thresholds are defined in the referenced ASBs/EASA revisions, not fully in the AD text.
• Two distinct ASBs and paragraph references. The inspection and replacement actions reference two different ASBs and the same paragraph number in each ("paragraph 2.B."): ASB No. 05.00.45 for inspections and ASB No. 52.00.23 for replacements (Requirement). Following the wrong ASB or the wrong paragraph would not satisfy the Directive. The AD allows the use of "later EASA approved revision" of those ASBs, which introduces a live-document dependency: only EASA-approved revisions are acceptable.
• Part-number prohibitions. The AD expressly prohibits the installation of rail roller pins part number 350A25-1275-20 and cast roller support fittings part numbers 350A25-1270-20 and 350A25-1270-22 (Requirement). Installers and spare-part managers must ensure their stock-control and procurement systems block these part numbers for fitment on affected AS 355 helicopters. The prohibition on 350A25-1270-22 is singled out in Amendment 4 (Background). A failure to do so risks inadvertent non-compliant installations.
• Flight-hour timing complexity. The inspection schedule depends on whether the sliding doors have logged "less than 90 flight hours" or "90 or more flight hours" with different initial windows (Compliance). For aircraft with 90 or more flight hours, the anchor date is "within 20 flight hours after 26 October 2006" (Compliance). Operators who cannot conclusively determine the hours logged against the sliding door assembly risk missing the correct initial inspection window.
• Tight replacement deadline window. The Compliance section includes "Unless already accomplished, before 30 September 2007." The AD’s effective date is 14 September 2007 (signature block). Operators who defer activity close to the deadline may be left with narrow windows for parts procurement and scheduled maintenance.
• Reliance on "later EASA approved revision." The AD permits use of a later EASA-approved revision to the referenced ASBs. That is helpful, but it also shifts the compliance standard to a moving target; an EASA-approved revision could change technical instructions and timing, and operators must track those revisions and their approval status.
• No penalties in-text. The AD does not include penalty or enforcement mechanics in the supplied text (Penalties and enforcement). Operators may nonetheless face regulatory scrutiny for non-compliance, but the pathway and sanctions are not specified in the Directive itself.
• Records and proof of compliance not specified. The AD requires inspections and replacements but does not specify how compliance is to be recorded or what documentary proof will satisfy an auditor or regulator. This gap means meticulous maintenance logs and work cards are essential even though the AD does not set a record template.

Each of these practical pitfalls arises directly from the wording, timelines, part numbers and cross-references in the Directive. Operators and maintainers should treat the ASBs and EASA-approved revisions as the determinative technical guidance and ensure clear traceability between their maintenance records and the specific ASB paragraphs and MOD numbers cited.

The AD sets out concrete steps and timing; compliance consists of following those steps and recording the work. Below is a practical checklist grounded in the Directive language.

1. Establish applicability

   • Confirm the airframe model: AS 355 versions E, F, F1, F2 or N (Applicability).
   • Confirm sliding door MOD status: determine whether the sliding doors are pre-MOD 073298 (LH) and/or pre-MOD 073308 (RH). If those MODs are already embodied, the prohibitions on installation may not apply to those doors (Applicability; Requirement).

2. Plan and carry out the required inspections

   • Use the referenced inspection procedure: perform the check of "the support shaft of the rear roller and the rear fitting of the sliding door(s) for cracks" in accordance with paragraph 2.B. of Eurocopter ASB No. 05.00.45 original issue, or a later EASA-approved revision (Requirement 1).
   • Apply the inspection intervals exactly as specified:
     • If the sliding door has logged less than 90 flight hours at the relevant anchor point, inspect upon accumulating 110 flight hours and thereafter at intervals not to exceed 110 flight hours.
     • If the sliding door has logged 90 or more flight hours, inspect within 20 flight hours after 26 October 2006 unless already done, and thereafter at intervals not to exceed 110 flight hours (Compliance).
   • Record the inspection: note the date, flight hours at inspection and the ASB revision used, and the findings for each door assembly.

3. Plan and perform replacement or modification where required

   • For replacement of roller support shaft and fittings, follow "paragraph 2.B. of ASB No. 52.00.23 original issue, or later EASA approved revision" (Requirement 2).
   • Meet the specified deadline: unless already accomplished, ensure required replacement/modification is carried out "before 30 September 2007" per the Compliance note.
   • If replacement/modification is performed in accordance with the ASB and accepted by the approving authority, the inspection regime may be impacted. Note the AD’s history: Amendment 2 mandated modification action that cancelled inspection requirements; Amendment 4 required repetitive inspections until replacement with improved parts per a subsequent EASA AD. Use the latest EASA-approved ASB revision to determine whether the modification performed eliminates the inspection schedule (Background; Requirement).

4. Prevent prohibited installations

   • Do not install sliding doors listed in paragraph 1.A.2. of ASB No. 52.00.23 Revision 1 (or later EASA-approved revision) unless the doors are modified per MOD 073298 (LH) and MOD 073308 (RH) (Requirement).
   • Do not install the specified parts on any AS 355 helicopter: rail roller pins part number 350A25-1275-20; cast roller support fittings part numbers 350A25-1270-20 and 350A25-1270-22 (Requirement). Update procurement and parts-inventory controls to flag these part numbers.

5. Use correct technical standard versions

   • When performing inspections or replacements, use the exact paragraph references cited: paragraph 2.B. of ASB No. 05.00.45 for inspections; paragraph 2.B. of ASB No. 52.00.23 for replacements (Requirement). The AD allows "later EASA approved revision" of those ASBs to be used; ensure any used revision is EASA-approved, not merely an internal manufacturer revision.

6. Document and retain evidence of compliance

   • Although the Directive does not specify a form of documentary proof, maintain detailed records: the ASB revision used, paragraphs followed, serial numbers and part numbers replaced, MOD numbers embodied, flight hours at action, and maintenance release documents.
   • Where a MOD is embodied, document the MOD reference (073298 or 073308), the embodiment date, and work order details, so that an audit can confirm whether the prohibition on installation applied or was lifted.

7. Coordinate with maintenance organisations and suppliers

   • Inform maintenance providers of the ASB paragraph references and the requirement to use only EASA-approved ASB revisions. Confirm that any replacement parts to be fitted are not the prohibited part numbers.
   • Inform parts suppliers and stores to quarantine and block the prohibited part numbers from being issued for fitment to AS 355 helicopters.

8. Monitor EASA and manufacturer communications

   • Because the AD ties compliance to "later EASA approved revision" of referenced ASBs and because Amendment 4 was issued in response to an EASA AD (Background), ensure continuous monitoring of EASA ADs and Eurocopter ASB revisions to capture any further changes to inspection intervals, replacement requirements or allowed parts.

9. Manage scheduling and downtime

   • The compliance windows include a flight-hour schedule and a calendar deadline ("before 30 September 2007"). For operational continuity, schedule inspections and any required replacements with sufficient lead time for parts procurement and maintenance resources.

10. If in doubt, seek clarification from the authority or the ASB originator

• The AD ties technical compliance to ASBs and EASA approval. Where documentation, part equivalence, or MOD embodiment status is uncertain, obtain clarification from the aircraft manufacturer or the approving authority. The AD itself does not specify appeal or variance avenues; seek formal guidance from the regulator or an authorised certifying authority as required.

Follow these steps in the stated order and keep contemporaneous records keyed to the ASB paragraph references and MOD numbers. The Directive’s own language makes the ASB paragraphs and any later EASA-approved revisions the governing technical standard for compliance.