AD/CONVAIR/15 - Nose Landing Gear Aluminium Uplock Quadrant Lug

The directive centralises on three technical and regulatory concepts: the affected hardware, the detection method and the compliance regime.

Affected hardware. The focal component is the nose landing gear uplock quadrant lug assembly identified by part number P/N 240-5250109-6, an aluminium quadrant. The AD targets the lug for stress corrosion cracking detection. The directive also names an alternative replacement steel quadrant, P/N 240-5250109-9, which the AD treats as a terminating remedy (Requirement 1.c, Note 1).

Detection methods. The AD prescribes specific detection modalities: visual inspection using a 2x or stronger magnifying glass, or a dye penetrant method (Requirement 1.b). The inspections are to be carried out after removal of the AN3-21 bolt that attaches the release cable clevis and the emergency release cylinder to the uplock assembly (Requirement 1.a). The directive requires that, after inspection and any replacement, the AN3 bolt be reinstalled and the rigging of the nose landing gear uplock be checked in accordance with the applicable maintenance manual (Requirement 1.d). That cross-reference to the maintenance manual makes the final rigging standard contingent on the manual’s procedural detail rather than prescribing specific rigging measurements in the AD itself.

Compliance regime and timing. The AD sets a three-layer timing structure. First, an initial and short-term recurring inspection window: within 60 hours time in service after 11 May 2006, and thereafter at intervals not to exceed 60 hours time in service until a steel quadrant is installed (Compliance 1). Second, if operators install a new aluminium quadrant, the AD prescribes longer reinspection intervals for the steps in Requirements 1.a-1.d, not to exceed 600 hours time in service (Compliance 1.c). Third, a lifecycle retirement limit: aluminium quadrant P/N 240-5250109-6 must be retired before accumulating 1,200 hours time in service (Compliance 2). The AD therefore establishes both short-term intensified surveillance and an option for a one-time modification that removes the surveillance requirement.

Termination and references. Note 1 states that installing the steel quadrant P/N 240-5250109-9 constitutes terminating action for the AD’s requirements. Note 2 references FAA AD 77-10-11 Amdt 39-2905. The AD is explicit that the FAA required actions to detect stress corrosion cracking in the aluminium uplock quadrant lug were the background for this CASA directive (Background).

Document structure. The AD lists discrete numbered actions and compliance intervals, cross-references the maintenance manual for rigging checks, and provides part numbers and bolt identifications. The procedural prescription is operational and component-specific rather than performance-based.

Operators and owners of the specific aircraft models named in Applicability bear primary responsibility. The directive explicitly applies to Model 240, 340 and 440 aircraft, and to all such aircraft converted to turbopropeller power (Applicability). Those responsible for an aircraft’s airworthiness will need to implement the inspections, replacements and retirement schedule set out in the directive.

Maintenance organisations and maintenance personnel are operationally affected. The AD requires removal and reinstallation of the AN3-21 bolt, inspection using specified methods, and a rigging check “in accordance with the applicable maintenance manual” (Requirements 1.a, 1.b, 1.d). That places explicit tasks on personnel authorised to carry out line and base maintenance and on organisations that control the maintenance data and procedures referenced by the AD.

Parts suppliers and component manufacturers have a role. The directive identifies two alternative quadrant part numbers: the aluminium P/N 240-5250109-6 and the steel P/N 240-5250109-9. Availability of replacement units and lead times for steel quadrants will affect operators’ implementation choices because the AD treats the steel quadrant installation as terminating action (Note 1). The text does not state where parts must be sourced from.

Aircraft registrants and operators are decision-makers on compliance strategy. The AD allows operators a choice when cracks are detected: replace the aluminium quadrant with either a new aluminium quadrant P/N 240-5250109-6 or with the steel quadrant P/N 240-5250109-9, but if a new aluminium quadrant is fitted additional periodic inspections apply (Requirement 1.c). That creates a planning decision for registrants and operators about short-term inspection costs versus a one-off modification.

Record-keepers and audit functions are indirectly implicated. Although the AD does not specify recordkeeping requirements, the sequencing and hour-based compliance milestones (e.g. within 60 hours after 11 May 2006; 600 hour intervals; retirement before 1,200 hours) require accurate time-in-service tracking. Those responsible for compliance will therefore be the parties who maintain logbooks and maintenance records.

Regulatory signatory. The AD is issued by a CASA delegate, recorded as David Villiers, Delegate of the Civil Aviation Safety Authority, dated 31 March 2006. The document thereby records the issuing authority and effective date (31 March 2006 signature; effective 11 May 2006).

Duties imposed by the AD are expressed as mandatory actions and intervals. The principal duties are:

• Remove the AN3-21 bolt that attaches the nose landing gear uplock release cable clevis and the emergency release cylinder to the uplock assembly (Requirement 1.a). This is a preparatory action to permit inspection of the uplock quadrant lug.

• Inspect P/N 240-5250109-6 nose landing gear uplock quadrant for cracks using either a 2x or stronger magnifying glass, or a dye penetrant method (Requirement 1.b). The AD prescribes two acceptable inspection modalities, setting a minimum magnification requirement for visual inspection.

• If cracks are detected, before further flight replace the quadrant with either a new aluminium quadrant P/N 240-5250109-6, or a steel quadrant P/N 240-5250109-9 (Requirement 1.c). The AD requires removal from service of cracked hardware prior to the next flight.

• If a new aluminium quadrant is installed, accomplish Requirements 1.a through 1.d at the intervals specified in Compliance 1.c (Requirement 1.c, referencing Compliance). This creates a duty to continue repeated inspections if the aluminium part is replaced by an aluminium replacement instead of the steel terminating part.

• Reinstall the AN3 bolt attaching the release cable and emergency release cylinder and check the rigging of the nose landing gear uplock installation in accordance with the applicable maintenance manual (Requirement 1.d). The AD does not itself specify rigging tolerances but delegates the rigging procedure to the maintenance manual.

• Retire P/N 240-5250109-6 aluminium quadrants at the specified interval (Requirement 2). Compliance 2 clarifies this to be before accumulating 1,200 hours time in service.

Rights and options embedded in the AD. The directive gives operators a limited choice when a crack is found: replace with another aluminium quadrant or with the steel quadrant (Requirement 1.c). Importantly, Note 1 makes clear that installation of the steel quadrant P/N 240-5250109-9 is terminating action for the AD’s requirements; that creates an option to eliminate future AD-mandated inspections by electing a one-time retrofit.

Procedural cross-reference and delegation. The AD delegates certain procedural detail to the “applicable maintenance manual” for the rigging check (Requirement 1.d). That means compliance will involve following approved maintenance manual procedures rather than detailed specification within the AD text.

Timing duties. The AD sets time-in-service (TIS) thresholds: initial and recurring inspections within 60 hours TIS after 11 May 2006 and thereafter at intervals not exceeding 60 hours TIS until the steel quadrant is installed; if a new aluminium quadrant is installed, the 1.a-1.d steps are to be repeated at intervals not exceeding 600 hours TIS; aluminium quadrants must be retired before 1,200 hours TIS (Compliance).

Absence of penalty detail. The AD does not in its text set out sanctions or penalties for non-compliance. The directive’s operative content is the set of required maintenance actions and timing constraints; it does not identify civil or administrative penalties within the document itself.

The instrument itself does not set out any penalty or enforcement provisions in the body of the text provided. The AD is presented as a prescriptive safety document that becomes effective on 11 May 2006 and is signed by a CASA delegate (effective date and signature appear in the text). The AD specifies mandatory actions and hour-based compliance timings but does not in the included text specify the legal penalties, sanctions or enforcement mechanisms for failure to comply. The document contains no operative enforcement clauses, infringement schedules or notice-of-penalty provisions.

Practical implications for enforcement and compliance risk. Because the AD prescribes inspection and replacement actions that must be accomplished within defined time windows relative to time in service, non-performance exposes the aircraft to operating with potentially defective critical hardware. The AD also designates a terminating modification (installation of the steel quadrant). The presence of explicit mandatory actions and defined time in service thresholds implies an expectation of regulatory oversight, inspections and verification by responsible authorities, although the AD text does not itself set out the oversight mechanism.

Absence of procedural enforcement detail in the AD is an important gap in the text for readers who need to know the downstream administrative process: the AD does not state how compliance will be certified, whether an approval by CASA is required for fitting a steel quadrant, or how CASA will evidence non-compliance. The AD likewise does not address whether operators must lodge compliance reports, nor does it specify any post-action reporting timelines. The only procedural cross-reference in the AD is to the applicable maintenance manual for the rigging check (Requirement 1.d).

Reference to FAA AD. The AD references FAA AD 77-10-11 Amdt 39-2905 (Note 2), showing a connection to prior FAA action. The CASA directive states that the FAA required actions to detect stress corrosion cracking form the background; it does not, within the provided text, provide further legal detail about mutual recognition or reciprocal enforcement between CASA and the FAA.

In sum, the AD imposes mandatory technical duties without setting out within its own text the enforcement sanctions or procedures. Practitioners contemplating compliance should therefore treat the AD’s substantive technical requirements as compulsory while noting that the text given does not include the enforcement and reporting mechanics that may appear in CASA’s broader regulatory or enforcement instruments.

The AD text explicitly references FAA regulatory action as background and as a cross-reference: “Note 2: FAA AD 77-10-11 Amdt 39-2905 refers,” and the Background states that the FAA required certain actions to detect stress corrosion cracking in the aluminium uplock quadrant lug on the nose landing gear. That indicates that CASA’s AD is substantively aligned with FAA airworthiness concerns for the same hardware. The AD does not, however, set out any formal mechanism of legal effect between CASA’s directive and FAA obligations; it simply notes the FAA AD as a relevant reference and background reason for the CASA action.

Within the document provided, there is no express cross-reference to other Australian statutes, regulations or parts of the Civil Aviation Safety Authority regulatory framework. The AD does not, in the supplied text, cite specific enabling provisions under Australian legislation that authorise CASA to issue airworthiness directives, nor does it identify how the AD interacts with regulations governing continuing airworthiness, maintenance recordkeeping or sanctions. The AD does, however, explicitly require that certain post-inspection rigging checks be done “in accordance with the applicable maintenance manual” (Requirement 1.d), creating an operational interaction between the AD and the maintenance procedures and standards embodied in each aircraft’s maintenance manual. That cross-reference means compliance will require reference to existing maintenance documentation and procedures approved for the aircraft.

The AD’s designation of part numbers and the terminating action (installation of steel quadrant P/N 240-5250109-9) creates an interface between the AD and any approvals regime that governs parts and modifications for these aircraft. The AD itself does not state whether fitting the steel quadrant requires further approval, supplemental type certificate, or entry in aircraft modification records; those matters are not set out in the provided text.

Because the AD specifies time-in-service thresholds (for example, inspections within 60 hours TIS and retirement before 1,200 hours TIS), it interacts operationally with the systems that measure and record time in service. The AD does not specify recordkeeping procedures in the text provided. Practitioners must therefore reconcile the AD’s hour-based requirements with the applicable regulatory requirements for maintenance records and airworthiness logs, but those interactions are not described in the AD text itself.

In short, the AD references and aligns with an FAA AD as background, delegates procedural detail to the applicable maintenance manual, and creates a practical interface with parts approval and maintenance-record systems, while not specifying, within the text presented, the legal mechanisms or cross-references to other Australian statutory provisions or enforcement rules.

The provided document does not contain an amendment history table or a record of prior Australian amendments to AD/CONVAIR/15. It presents a single promulgation of the AD: the document is dated 31 March 2006 (signed by David Villiers, Delegate of CASA) and states that “This Airworthiness Directive becomes effective on 11 May 2006.” The header metadata shows a reference of 5/2006, and the AD name includes AD/CONVAIR/15. There is no subsequent amendment text or revision history contained in the supplied material.

The AD does, however, refer to FAA AD 77-10-11 Amdt 39-2905 in Note 2. That reference indicates that there has been prior FAA-level airworthiness action on a related subject, but the CASA text does not inventory that FAA AD’s amendment history or specify whether CASA’s directive is an adoption, modification or update of earlier CASA directives. The document’s background statement that “The FAA requires certain actions to detect stress corrosion cracking in the aluminium uplock quadrant lug on the nose landing gear” explains the impetus for the AD but does not constitute an internal amendment history.

Readers requiring a chronological amendment record for AD/CONVAIR/15 will not find one in this document. The AD’s operative dates are: signature 31 March 2006 and effective date 11 May 2006. No other dates of amendment, supersession or revocation are given in the provided material.

The AD text as provided does not include any litigation history, judicial review citations, or references to disputes or cases arising from the directive. The document includes the technical directive language, the effective date, and a reference to FAA AD 77-10-11 Amdt 39-2905, but it contains no entries, annotations or footnotes concerning litigation, challenges, or precedent.

Consequently, this AD record contains no court decisions, no administrative appeals and no litigation outcomes in the supplied text. If litigation or enforcement actions relating to AD/CONVAIR/15 exist, they are not recorded in the material provided.

Ambiguities and formatting irregularities in the AD text create practical compliance risks. The directive deploys a set of numbered Requirements and a Compliance section that appears to use sub-numbering with overlapping content; careful reading is necessary to identify which interval applies in which circumstances.

• Overlapping intervals. The Compliance text requires an inspection “Within 60 hours time in service after 11 May 2006, and thereafter at intervals not to exceed 60 hours time in service; until a P/N 240-5250109-9 steel quadrant is installed.” Separately, Compliance 1.c states “Accomplish Requirements 1.a. through 1.d. at intervals not to exceed 600 hours time in service.” Those statements create two distinct regimes: a short 60-hour regime that operates until a steel quadrant is installed, and a 600-hour regime that applies where a new aluminium quadrant is installed. The AD does not explicitly state how to transition between these regimes for aircraft that have already passed through multiple short-interval inspections before a new aluminium quadrant is fitted. Practitioners must interpret the text to apply the 60-hour regime until the terminating steel quadrant is fitted, or, if a new aluminium quadrant is installed, commence the 600-hour regime for subsequent inspections. The text’s numbering and punctuation are not fully clear and could lead to inconsistent operational application.

• Retirement timing. Requirement 2 says “Retire P/N 240-5250109-6 aluminium quadrants at specified interval.” Compliance 2 sets the retirement to be “Before accumulating 1,200 hours time in service.” That is explicit, but operators must ensure their time-in-service tracking for the specific installed aluminium quadrant is accurate. The AD does not provide a method for calculating time-in-service for parts that may have been in service across different operators or airplanes. Record continuity and traceability for the particular part P/N will be essential.

• Inspection modality specificity. The AD permits visual inspection with “a 2x or stronger magnifying glass, or dye penetrant method.” The AD does not provide acceptance criteria for the dye penetrant process or specify whether other NDT methods (for example, eddy current or borescope) are acceptable. The AD likewise does not specify how to document the inspection findings. That leaves interpretative room for maintenance organisations and certifying staff.

• Removal and reinstallation of AN3-21 bolt. Requirement 1.a requires removal of the AN3-21 bolt that attaches the release cable clevis and the emergency release cylinder. Repeated removal and reinstallation may have implications for torque setting, thread condition and component life. The AD requires the rigging check “in accordance with the applicable maintenance manual” after reinstallation (Requirement 1.d), but gives no guidance about torque, locking methods or acceptance criteria for the bolt itself.

• Terminating action logistics. Note 1 states that installing the steel quadrant is terminating action. However, the AD does not state whether fitting the steel quadrant requires specific approvals, whether it is a standard catalogued replacement, nor whether it requires entry on an aircraft’s modification or maintenance documents beyond the usual maintenance recording. Supply-chain or certification constraints for the steel quadrant could delay operators choosing terminating action.

• No enforcement, reporting or recordkeeping rules stated. The AD does not provide the administrative mechanics by which compliance is to be demonstrated to the regulator. Without explicit reporting steps in the AD text, operators need to determine which records to make and how to present them in an audit or inspection. That is left to other regulatory instruments or to organisational procedures.

• Document anomalies. The supplied AD text contains repeated headings and formatting duplications in the closing pages (multiple variants of the AD name, repetition of “5/2006”, and an embedded image reference). Those artifacts do not change the substantive requirements but could create confusion when parsing and filing the AD in a regulatory library.

Practitioners should therefore treat the AD’s technical steps and time-in-service thresholds as binding operational requirements while planning for the administrative ambiguities by ensuring robust time-in-service tracking, parts traceability, clear maintenance manual cross-references, and documented inspection records.

Stepwise compliance actions based on the AD text are as follows. Each step cites the clause of the AD that prescribes it.

1. Establish applicability. Confirm that the aircraft is a Model 240, 340 or 440, or a conversion of those models to turbopropeller power (Applicability). Only aircraft within that applicability group are subject to these requirements.

2. Schedule the initial action window. The AD requires an initial inspection “within 60 hours time in service after 11 May 2006” and thereafter at intervals not to exceed 60 hours TIS until a steel quadrant is installed (Compliance 1). If an operator did not complete that initial inspection within the stated window, the AD’s effective date and compliance window create an obligation to take the first available action and document the deviation and rectification; the AD text itself, however, does not specify remedial steps for missed initial windows.

3. Prepare for removal of the AN3-21 bolt. The AD requires removal of the AN3-21 bolt that attaches the nose landing gear uplock release cable clevis and the emergency release cylinder to the uplock assembly as part of the inspection procedure (Requirement 1.a). Ensure maintenance personnel are authorised to remove and reinstall this bolt and have access to the applicable maintenance manual instructions for subsequent rigging checks.

4. Perform the inspection for cracks. Inspect the aluminium uplock quadrant P/N 240-5250109-6 for cracks using one of the two prescribed methods: visual inspection with a 2x or stronger magnifying glass, or dye penetrant inspection (Requirement 1.b). Use the method most appropriate to the condition and accessibility of the lug. If using dye penetrant, follow standard dye penetrant procedures applicable to the aircraft or organisation, noting the AD itself does not provide dye penetrant acceptance criteria.

5. Replace cracked hardware before further flight. If cracks are detected, replace the quadrant before further flight with either a new aluminium quadrant P/N 240-5250109-6 or a steel quadrant P/N 240-5250109-9 (Requirement 1.c). Selecting the steel quadrant is a terminating action for the AD’s requirements (Note 1); selecting an aluminium replacement carries forward additional inspection obligations (see step 7).

6. Reinstall the AN3 bolt and perform rigging check. After completing inspection or replacement, reinstall the AN3 bolt attaching the release cable and emergency release cylinder and perform the nose landing gear uplock rigging check in accordance with the applicable maintenance manual (Requirement 1.d). Follow the maintenance manual’s procedures and acceptance criteria; the AD delegates rigging specifics to that manual.

7. If fitting a new aluminium quadrant, observe the longer interval regime. Where operators have fitted a new aluminium quadrant P/N 240-5250109-6, the AD requires accomplishing Requirements 1.a through 1.d at intervals not to exceed 600 hours time in service (Compliance 1.c). Continue those inspections until the aluminium quadrant is retired or replaced by the steel quadrant.

8. Retire aluminium quadrants before 1,200 hours TIS. The AD requires retirement of P/N 240-5250109-6 aluminium quadrants “before accumulating 1,200 hours time in service” (Compliance 2). Ensure each aluminium quadrant’s accumulated hours are tracked and retirement occurs prior to the 1,200 hour threshold.

9. Consider terminating action. Installation of steel quadrant P/N 240-5250109-9 is terminating action for the AD requirements (Note 1). Operators should weigh lead times for the part, installation costs, and operational considerations when deciding whether to elect terminating action or continue with recurring inspections using aluminium replacements.

10. Maintain traceability and evidence of compliance. The AD does not specify recordkeeping procedures in the text provided, but the hour-based inspection and retirement schedule requires accurate tracking of each quadrant’s time in service and of inspection and replacement events. Record the part numbers fitted, serial numbers where available, dates and time-in-service at the time of inspection or replacement, and the person or organisation that performed the work. Document the maintenance manual reference used for rigging checks and the inspection method adopted (2x magnifying glass or dye penetrant). Maintain these records so that compliance with the AD’s hour-based thresholds is demonstrable.

11. Coordinate with parts suppliers and maintenance planners. If electing the steel quadrant as terminating action, confirm availability and any installation approvals required. If replacing with aluminium quadrant stock, plan for the recurring inspection intervals (600 hour intervals) and for eventual retirement before 1,200 hours TIS.

12. Verify conformity with maintenance manual. Because the rigging check is to be carried out according to the applicable maintenance manual, ensure that the manual’s rigging procedures are current and available to the maintenance team, and that any deviations or clarifications are handled through the organisation’s processes.

These steps reproduce and operationalise the AD’s prescriptions: removal of the AN3-21 bolt, inspection by specified methods, replacement if cracked, reinstallation and rigging check per the maintenance manual, adherence to the 60-hour, 600-hour and 1,200-hour thresholds, and the option to adopt the steel quadrant as terminating action. The AD’s effective date is 11 May 2006 and it is signed 31 March 2006 by the CASA delegate (signature block).

Operators should treat the AD’s specific part numbers and hour thresholds as binding directives in maintenance planning. The AD text does not specify reporting forms, enforcement procedures or approvals required for fitting the steel quadrant; those administrative steps will need to be reconciled with an operator’s regulatory compliance protocols and with CASA’s broader maintenance and modification approval processes.