AD/S-PUMA/67 - Main Gearbox Casing

The AD deploys a short list of technical and operational concepts as the mechanism to manage identified risk. These concepts are set out in the AD language and in the Eurocopter ASB it incorporates:

• Applicability by aircraft type and operational profile. The AD attaches to specified AS 332 variants (AS 332 C, C1, L, L1) on all serial numbers, but only where the helicopter is averaging more than four torque variation cycles per flight hour. This makes applicability conditional on an operational metric rather than solely on serial number or modification status.

• Inspection trigger and method. The mandated action is a visual check, focused on absence of oil leaks on the right-hand face of the main gearbox main casing. The AD directs that the check be performed in accordance with the instructions in paragraph 2.B of Eurocopter ASB No. 05.00.66.2 (or later DGAC‑approved revision), which the AD incorporates by reference for procedural detail.

• Dual quantitative thresholds expressed in time and usage. Compliance intervals are framed in both flight hours (FH) and torque cycles, with the initial inspection required within 20 FH or 400 torque cycles after the effective date, and recurring inspections at intervals not exceeding 110 FH or 2,200 torque cycles. Each time-usage pairing uses “whichever occurs first”, so operators must monitor both metrics and act on the earlier trigger.

• Mandatory corrective action before further flight. If an oil leak is found on the specified face of the MGB main casing, the AD requires replacement of the MGB before the helicopter may be flown again. The ASB paragraph 2.B.2.b is the procedural reference for replacement.

• Continuity of inspection obligation. The AD explicitly provides that replacement of the MGB does not terminate the repetitive inspection requirements of the AD. Therefore replacement is not a terminating action; inspections remain required even after installing a new MGB.

• Cross‑jurisdictional reference. The AD references an EASA emergency AD (2006‑0361‑E) and permits use of later DGAC‑approved revisions of the Eurocopter ASB, indicating that the directive is calibrated to align with European regulator actions and the manufacturer’s service instructions as approved by the French DGAC.

Each of these concepts specifies what operators must monitor (flight hours and torque cycles), what they must inspect (MGB main casing RH face for oil leaks), how to proceed depending on inspection outcome (resume or replace), and the recurrence of the inspection obligation. The AD therefore combines an operational exposure threshold with a recurring visual‑inspection regime and a strict “replace before further flight” corrective step if an oil leak is found.

The AD names the affected aircraft classes and defines the operational condition that brings individual aircraft within scope. Specifically:

• Aircraft types named. The applicability line states: “AS 332 C, AS 332 C1, AS 332 L and AS 332 L1 helicopters, all serial numbers” (applicability). There is no serial‑number carve‑out; the type/model list is exhaustive within the AS 332 family listed.

• Operational trigger. The AD applies only “if averaging more than 4 torque variation cycles per flight hour.” This phrase makes the AD conditional on an operator’s duty cycle. Aircraft of the listed types that do not, in practice, average more than four torque variation cycles per flight hour are outside the AD’s applied scope (per the AD’s own language).

• Operators and maintainers who must act. The text requires that inspections be performed “in accordance with the instructions given in paragraph 2.B of Eurocopter AS 332 Alert Service Bulletin (ASB) No. 05.00.66.2”, and that replacements be done in accordance with the ASB’s paragraph 2.B.2.b. Those procedural directions imply obligations on operators, maintenance organisations, and certified maintenance personnel who are responsible for carrying out inspections and replacements in line with the ASB.

• Time‑sensitive duty holders. The compliance timetable (initial inspection within 20 flight hours or 400 torque cycles after the AD’s effective date, with recurring inspections at intervals not exceeding 110 FH or 2,200 torque cycles) imposes explicit timing obligations from the effective date (4 December 2006). Anyone operating an applicable helicopter that meets the operational trigger from that date must schedule and carry out the required inspections in the stated windows.

• Parties required to track usage metrics. Because compliance is framed in both flight hours and torque cycles, affected operators must measure and record both metrics to determine applicability and to comply with the inspection schedule. The AD’s terminology places a monitoring obligation on the operator to know whether the “averaging more than 4 torque variation cycles per flight hour” threshold applies and to count torque cycles and flight hours to manage inspection timing.

• Interaction with manufacturer and regulator approvals. The AD requires adherence to the Eurocopter ASB as approved by the DGAC (or later DGAC‑approved revisions). This brings into scope the manufacturer’s maintenance instructions and the French DGAC’s approval role; operators must ensure that the ASB revision they use is DGAC‑approved as the AD specifies.

In short, the economic and operational burden falls on operators and maintenance providers for the specified AS 332 models that meet the torque‑cycle threshold. Those parties must monitor flight hours and torque cycles, perform the visual check per the Eurocopter ASB, and effect replacement if a leak is discovered. The directive, as drafted, does not name other third parties (for example lessors or parts suppliers) explicitly, but the replacement requirement will involve procurement of an MGB, and the ongoing inspection requirement will involve maintenance labour and scheduling.

The AD creates a small set of clear duties and one explicitly stated limitation on a remedial action:

• Duty to determine applicability. Operators must determine whether their helicopter meets the operational trigger: averaging more than four torque variation cycles per flight hour. The AD’s applicability clause conditions the entire directive on that operational metric.

• Duty to inspect. Where applicability is met, the operator must visually check for absence of oil leaks on the MGB main casing right-hand face “in accordance with the instructions given in paragraph 2.B of Eurocopter AS 332 Alert Service Bulletin (ASB) No. 05.00.66.2” (requirement). The AD places the procedural content of the inspection in the ASB.

• Duty to act on findings. The AD prescribes two mutually exclusive courses depending on inspection findings (requirement and analysis of results):

  • If no oil leak is found, the operator may “resume flights in accordance with the instructions specified in paragraph 2.B.2.a of AS 332 ASB No. 05.00.66 or later DGAC approved revision.”
  • If an oil leak is found, the operator must “before further flight, replace the MGB in accordance with the instructions specified in paragraph 2.B.2.b of AS 332 ASB No. 05.00.66 or later DGAC approved revision.”

• Duty to repeat inspections. The AD imposes recurring inspection intervals: initial inspection within 20 FH or 400 torque cycles after the effective date, thereafter at intervals not exceeding 110 FH or 2,200 torque cycles (compliance). The phrase “thereafter at intervals not exceeding” makes the inspection regime ongoing.

• Limitation on remedial finality. The AD explicitly states that “Replacement of the MGB does not constitute terminating action for the repetitive inspection requirements of this AD.” This removes the ability for an operator to treat replacement as an end to the inspection obligation; inspections must continue even after installation of a replacement gearbox.

• Reference dependency. The AD delegates procedural specifics to an external document (the Eurocopter ASB), and it conditions acceptable procedure on that ASB or any later DGAC‑approved revision. Practically, the operator’s duty is to follow the ASB as approved by the DGAC; the AD does not itself contain the step‑by‑step instructions.

• Effective timing. The AD states its effective date: 4 December 2006. The initial compliance window is measured from that date. Operators therefore have a defined start date from which the timing of the initial inspection is calculated.

The AD does not specify rights such as exemptions, extensions, or alternative methods of compliance within its text. The only indication of flexibility is that the ASB can be used in a later DGAC‑approved revision. The AD also refers to EASA Emergency AD 2006‑0361‑E in a note, but it does not create procedural rights or alternative compliance pathways in the AD’s own language. Any operator seeking an alternative means of compliance would therefore need to look to broader CASA processes, which are not set out in this AD.

The AD text itself does not set out specific penalties, sanctions, or enforcement mechanisms. The document is presented as an Airworthiness Directive issued by the Civil Aviation Safety Authority (CASA) , signed by a delegate (James Coyne) , and it states the effective date and inspection and replacement obligations, but it does not include provisions describing penalties for non‑compliance or the enforcement process to be used.

From the AD’s structure and language the following points can be observed on enforcement‑related matters that are explicitly present in the source:

• Normative force as an AD. The document is an Airworthiness Directive. It prescribes mandatory actions (inspection and replacement obligations) and an effective date. The AD’s language is prescriptive (“Ensure that there is no crack by visually checking for absence of oil leaks…”, “If an oil leak is found, before further flight, replace the MGB…”, “This Airworthiness Directive becomes effective on 4 December 2006”). Those prescriptive obligations are set out without internal penalty clauses in the text.

• No expressed sanctions or administrative penalties in the AD. The source contains no wording about fines, administrative enforcement steps, or criminal liability in the event of non‑compliance. It does not include a compliance‑reporting regime, nor does it define an inspection certification or sign‑off format inside the AD text itself; instead it references the Eurocopter ASB for procedural detail.

• Dependency on other regulatory mechanisms. Although the AD does not itself set out enforcement procedures, an AD typically operates within a wider aviation regulatory system. This AD references other regulatory instruments (Eurocopter ASB as DGAC‑approved and an EASA Emergency AD). The AD’s text provides no detail on how CASA would monitor, audit, or sanction operators who fail to follow the directive, and it does not identify which CASA processes would be used to seek compliance.

Because the AD contains no express enforcement or penalty clause, anyone needing to understand the consequences of non‑compliance would have to consult the broader CASA regulatory framework and relevant aviation safety statutes and regulations for enforcement mechanisms applicable to breaches of airworthiness directives. Those statutory and regulatory enforcement mechanisms are not described in this AD and are not part of the source text provided.

The AD identifies and cross‑references two external documents and the role of a foreign regulator, thereby situating itself within a broader regulatory and manufacturer instruction context. The AD’s internal text provides the following interactions:

• Eurocopter ASB as the procedural source. The AD requires actions “in accordance with the instructions given in paragraph 2.B of Eurocopter AS 332 Alert Service Bulletin (ASB) No. 05.00.66.2” and additional paragraphs for the analysis (2.B.2.a and 2.B.2.b). The AD therefore makes compliance dependent on following the manufacturer’s service bulletin, as approved by the French DGAC. The AD explicitly permits the use of “later DGAC approved revision[s]” of the ASB. This means the AD’s requirements are implemented by following the ASB material that has obtained DGAC approval.

• Reference to EASA Emergency AD. The AD contains a “Note: EASA Emergency AD 2006‑0361‑E dated 30 November 2006 refers.” That reference indicates alignment or possible derivation from an emergency AD issued by the European Aviation Safety Agency. The AD does not reproduce EASA’s text but points operators to a related emergency AD. The AD therefore signals cross‑jurisdictional correspondence between CASA’s directive and EASA’s emergency action.

• DGAC approval requirement. By requiring that the ASB used be a DGAC‑approved revision (either the stated revision or a later DGAC‑approved revision), the AD places weight on the French Direction Générale de l’Aviation Civile’s approval process for the manufacturer’s service documents. Operators must therefore ensure that any later ASB revision they rely on carries DGAC approval.

• No explicit interaction text with domestic statutory provisions within the AD itself. The AD does not quote or otherwise expressly identify the CASA statutory authority or the domestic aviation statutes or regulations under which the AD is issued. The AD is a CASA instrument by appearance and signature, but the AD text does not set out the enabling statute or domestic enforcement provisions.

• No mention of other administrative relief or alternative methods of compliance (AMOCs) inside the text. The AD does not itself provide a pathway for alternative compliance or exemptions. If such pathways exist in the domestic regulatory regime they are not detailed in this AD and would need to be sought through CASA’s standard regulatory channels; the AD text does not specify those channels.

In short, the AD interacts directly with the Eurocopter ASB (procedural content) and points to an EASA emergency AD (context and cross‑jurisdictional alignment), while conditioning procedural acceptability on DGAC approval. The AD does not, within its text, set out the domestic statutory basis for the directive, enforcement mechanisms, or alternative compliance procedures; those aspects lie outside the four corners of the AD itself.

The AD text supplied contains only a single directive entry and does not list any formal amendments or superseding material within the document. The elements present relevant to amendment and revision are:

• Reference to ASB revisions. The AD explicitly permits the use of “AS 332 ASB No. 05.00.66 or later DGAC approved revision.” This language allows operators to use later revisions of the Eurocopter ASB so long as those revisions have DGAC approval. That is a limited form of dynamic incorporation: the AD’s procedural requirements are tied to whichever DGAC‑approved revision of the ASB is current.

• Cross‑reference to EASA emergency AD. The AD notes EASA Emergency AD 2006‑0361‑E dated 30 November 2006. The existence of that emergency AD may form part of the evolution of regulatory responses to the defect identified. The AD itself does not recite any subsequent amendments or supersessions.

• Effective date and publication metadata. The AD contains the effective date (4 December 2006) and a signature block showing it was signed on 1 December 2006 by James Coyne, Delegate of the Civil Aviation Safety Authority, with the AD designation AD/S‑PUMA/67 and a reference code 2/2007 TX. Those elements are metadata for the document but do not themselves describe amendments.

• No subsequent revisions recorded in the supplied text. There is no text in the document to indicate that AD/S‑PUMA/67 has been amended, superseded, or cancelled by a later AD, nor does it identify amendment dates or replacement AD numbers. The AD does not include a history log.

Operators and interested parties looking for amendments would need to consult CASA’s official AD database or regulatory registers to determine whether this AD has been amended, superseded, or revoked since the effective date; the supplied AD document does not provide that history.

The AD text contains no mention of litigation, legal challenges, appeals, or judicial review related to AD/S‑PUMA/67. The document does not record any proceedings, nor does it refer to court decisions or administrative appeals. The signature and issuance by a CASA delegate and the effective date are administrative actions recorded in the AD, but the AD itself does not recount any disputes or litigation history.

Because the source contains no litigation material, there is no case law or disputed interpretation in the supplied text to reference. Any enquiry into litigation history around this AD would require consulting external legal databases, court records, or CASA administrative records; such sources are not part of the AD supplied here and therefore are not reflected in this document.

The AD contains some specific drafting choices and conditional language that create potential pitfalls for operators and maintainers. These are matters that commonly lead to compliance lapses if not carefully understood:

• Applicability is conditional on an operational average, not just aircraft identity. The AD applies to the listed AS 332 models “if averaging more than 4 torque variation cycles per flight hour.” This is a threshold based on a measured average of torque variation cycles per flight hour. Operators must therefore calculate an average , the AD does not define the averaging period. The absence of an explicit averaging window in the AD means operators must crystallise an operational method for measuring whether the “averaging more than 4 torque variation cycles per flight hour” trigger is met. Failure to determine and document this average could lead to incorrect assumptions about whether the AD applies.

• Two metrics run in parallel and “whichever occurs first” governs. The compliance timing is expressed in both flight hours and torque cycles with “whichever occurs first” for initial and recurring inspections (initial within 20 FH or 400 torque cycles; thereafter not exceeding 110 FH or 2,200 torque cycles). Operators who track only flight hours or only torque cycles risk missing the earlier trigger and failing to meet the AD’s timing.

• Procedural detail sits in the ASB, not in the AD text. The AD requires inspections “in accordance with the instructions given in paragraph 2.B of Eurocopter AS 332 ASB No. 05.00.66.2” and directs actions to ASB paragraphs 2.B.2.a and 2.B.2.b. The AD therefore imports external procedural instructions. If an operator uses an ASB revision that is not DGAC‑approved, the AD’s requirement may not be met. Similarly, operators must ensure they are acting to the correct ASB revision cited or a later DGAC‑approved revision.

• Replacement is not a terminating action. The AD expressly says “Replacement of the MGB does not constitute terminating action for the repetitive inspection requirements of this AD.” Some operators may assume that installing a new MGB eliminates the need for further inspections; the AD prevents that assumption.

• “Before further flight” requirement for replacement. If an oil leak is found, replacement is required “before further flight.” That creates immediate grounding until replacement is effected, subject to the operator’s ability to source and install an MGB promptly in accordance with ASB paragraph 2.B.2.b. Operators who do not have spare gearboxes available may face operational disruption.

• Effective date may be earlier than signature date. The document shows it was signed on 1 December 2006 but states an effective date of 4 December 2006. Operators need to calculate the initial inspection window from the stated effective date, not from the signature date.

• Cross‑jurisdictional approval dependency. The AD permits “later DGAC approved revision” of the ASB. If Eurocopter issues a revised ASB that is not DGAC‑approved, an operator cannot rely on it to satisfy the AD; only DGAC‑approved revisions are acceptable under the AD’s terms.

• No internal enforcement or reporting procedure included. The AD does not set out how compliance is to be documented or reported to CASA. Operators must establish internal records showing inspection dates, torque cycles and flight hours, and corrective actions, because the AD itself does not provide a reporting framework.

• The AD references an EASA Emergency AD but does not reproduce it. Operators who wish to understand the full regulatory context must consult EASA Emergency AD 2006‑0361‑E separately, because the CASA AD only references it.

Each of these points is grounded in the AD’s text and its cross‑references. Misinterpreting any of them can lead to non‑compliance with the AD as written.

The AD’s procedural demands are concise and are implemented by following the Eurocopter ASB paragraphs the AD references. The following sequence is a practical compliance checklist, drawn directly from the AD language and its timing rules:

1. Determine whether the AD applies to the helicopter in question. The AD applies to AS 332 C, AS 332 C1, AS 332 L and AS 332 L1 helicopters “if averaging more than 4 torque variation cycles per flight hour.” Operators must determine whether their operating profile meets that threshold. The AD does not define an averaging period; operators should document and retain the method used to calculate the average so that applicability can be demonstrated.

2. Obtain the correct procedural document. The visual inspection and any follow‑up actions must be performed “in accordance with the instructions given in paragraph 2.B of Eurocopter AS 332 Alert Service Bulletin (ASB) No. 05.00.66.2” and the analysis instructions in 2.B.2.a/b of the ASB (requirement). Ensure that the ASB revision used is the one cited in the AD or a later DGAC‑approved revision, as the AD conditions acceptability on DGAC approval.

3. Track the triggering metrics. Record and maintain accurate logs of flight hours and torque variation cycles. The initial inspection deadline is the earlier of 20 flight hours or 400 torque cycles from the AD’s effective date (4 December 2006). Subsequent inspections are required at intervals not exceeding the earlier of 110 flight hours or 2,200 torque cycles. Because the AD uses “whichever occurs first” language, the earlier‑occurring metric governs scheduling.

4. Perform the visual check. Within the initial compliance window (20 FH or 400 torque cycles from the effective date) perform the visual check of the MGB main casing RH face for absence of oil leaks, following the procedural steps set out in paragraph 2.B of the ASB. Document the inspection in the aircraft’s maintenance records consistent with usual maintenance recordkeeping practices and with sufficient detail to show the dates, flight hours, torque cycle counts, inspector identity, and findings.

5. Analyse and act on findings per the ASB:

   • If no oil leak is found, resume flights “in accordance with the instructions specified in paragraph 2.B.2.a of AS 332 ASB No. 05.00.66 or later DGAC approved revision.” Record the basis for resuming flight (ASB paragraph citation, inspector signature and metric counts).
   • If an oil leak is found, do not fly the helicopter further. Replace the MGB “before further flight” in accordance with paragraph 2.B.2.b of the ASB. Document the replacement details (part numbers, serial numbers, work performed, certifying maintenance personnel) in the aircraft’s maintenance logs.

6. Continue recurring inspections. Replacement of the MGB does not terminate the recurring inspection obligation. After initial compliance, continue to perform the visual inspection at intervals not exceeding 110 flight hours or 2,200 torque cycles, whichever occurs first. Maintain records showing each inspection’s metric basis and findings.

7. Use only DGAC‑approved ASB revisions. When applying the ASB instructions, ensure the revision used is DGAC approved. If more recent ASB revisions exist, confirm DGAC approval before relying on them to satisfy the AD’s requirements.

8. Cross‑check with related directives. The AD notes EASA Emergency AD 2006‑0361‑E. For completeness, operators may wish to consult that EASA AD for any additional context or related obligations, though the CASA AD is the operative domestic directive.

9. Maintain internal controls for immediate action. Because the AD requires replacement “before further flight” on discovery of an oil leak, operators should have procedures for rapidly grounding the aircraft, sourcing replacement MGBs, and effecting the swapping work in accordance with the ASB. Document all actions taken to return the aircraft to service.

10. Retain documentary proof of compliance. Although the AD itself does not specify a reporting mechanism to CASA, good compliance practice requires retaining inspection records, torque cycle and flight hour logs, and replacement records. These documents will substantiate that inspections and replacements were performed within the AD’s timing requirements and per the ASB.

Following the AD precisely means implementing a documented, reproducible programme of monitoring (flight hours and torque cycles), inspection (ASB paragraph 2.B visual check), corrective action (replace before further flight if leak found per ASB paragraph 2.B.2.b), and recurring inspection (every 110 FH or 2,200 torque cycles maximum). Replacement is not a cure that removes further inspection duties; the inspection obligation endures.