AD/CONVAIR/25 - Main Landing Gear Piston and Axle Assembly

The primary affected parties named in the AD are operators and owners of General Dynamics/Convair Models 340 and 440 series aircraft, and the maintenance personnel and organisations that service those aircraft. The Applicability clause expressly limits the AD to Convair Models 340 and 440. The Compliance clause ties the action to times when the main landing gear gland nut is reinstalled after the AD’s effective date, therefore operators who conduct maintenance that involves disassembly and reassembly of the main landing gear gland nut are directly affected.

Maintenance engineers, licensed aircraft maintainers, and organisations performing landing gear work bear responsibility to follow the prescriptive four-step installation procedure (Requirement, steps 1-4). Because the AD specifies particular part numbers for the gland nut, outer cylinder and fasteners, parts suppliers and stores that manage inventories for Convair 340/440 operators are indirectly affected: they must be able to supply the specified parts (Requirement).

Regulatory administrators within the Civil Aviation Safety Authority are implicated as the issuing body, evidenced by the delegate’s signature and the effective date (21 June 2006; effective 3 August 2006). The AD’s reference to General Dynamics/Convair maintenance manuals and an FAA AD indicates that manufacturers, their technical documentation managers, and any foreign regulators or operators using the FAA AD as a cross-reference are stakeholders (Requirement, Note).

The AD does not specify passengers, insurers, or airports as addressees, nor does it state explicit obligations for airworthiness inspectors, continuing airworthiness managers, or the broader supply chain beyond the identified parts and the maintenance action. However, by creating a mandatory action tied to reinstallation, the AD places ongoing operational constraints on owners/operators whenever the gland nut is disturbed.

Costs created by the AD, as stated or implied in the source, will fall on the operator or owner who pays for the maintenance labour and any specified parts (the source prescribes particular P/Ns). The AD itself does not allocate costs to government, nor does it set out compensation or funding for compliance.

The AD imposes a single, specific duty: when the main landing gear gland nut is reinstalled after the AD’s effective date (3 August 2006), the gland nut installation must follow the four-step procedure laid out in the Requirement. Those steps are, in order: (1) screw gland nut P/N 528062 onto outer cylinder P/N 528402 until tight; (2) unscrew the gland nut until the first tapped hole is opposite one of the milled slots in the cylinder; (3) screw lock screw P/N AN 501A-416-8 into the tapped hole so the screw protrudes into the milled slot; and (4) screw set screw P/N 500305-4 into an adjacent tapped hole and safety both lock screw and set screw with lockwire (Requirement, steps 1-4).

The AD thereby creates an obligation for whoever performs the reinstallation (maintenance personnel or the operator) to ensure the mechanical orientation and locking devices are correctly fitted each time the gland nut is reinstalled after the effective date (Compliance). The duty is process-oriented and procedural: it prescribes a method, parts and the use of lockwire as a final safety measure.

The AD text does not identify any affirmative rights for operators, such as rights to a grace period, alternative means of compliance, or appeal mechanisms. It does note that General Dynamics/Convair maintenance manuals cover the same subject, which may imply that compliance with those manuals will achieve the same technical outcome, but the AD itself prescribes the action to be taken (Requirement, Note). The AD also cross-references FAA AD 65-12-01 Amdt. 39-75; the text does not state whether compliance with that FAA AD would substitute for compliance with this CASA AD, although the presence of the reference suggests technical alignment.

The AD does not specify recordkeeping duties, continuing monitoring, or inspection intervals beyond the trigger event (each reinstallation). Therefore, any additional administrative duties ordinarily associated with maintenance releases, logbook entries, or continuing airworthiness documentation are not stated in the supplied text.

In practice, the effect of the AD is to make the described installation method mandatory at the specified trigger point. The AD identifies the exact parts to be used; therefore a duty arises for maintainers to source the correct hardware (P/Ns) and to apply lockwire safety as described.

The provided text of AD/CONVAIR/25 does not set out penalties, sanctions, or an explicit enforcement regime. The document is titled and presented as an Airworthiness Directive and is issued by the Civil Aviation Safety Authority (signed by a named delegate), and it states the effective date; however, the AD text itself contains no statutory penalty clauses, no administrative fine schedules, and no procedural enforcement steps such as audits, notices to comply, or suspension measures.

Because the AD text does not articulate enforcement measures, readers should treat the AD’s operative instructions as the technical mandatory requirements it sets. The AD states "This Airworthiness Directive becomes effective on 3 August 2006" and is signed by James Coyne, Delegate of the Civil Aviation Safety Authority (21 June 2006). The act of issuing an AD in this format signals regulatory intent but, within the text supplied, the mechanism by which failure to comply will be addressed is not described.

The AD also does not identify an issuing regulation, penalty provision, or an administrative contact for compliance queries. It refers to General Dynamics/Convair maintenance manuals and to FAA AD 65-12-01 Amdt. 39-75, but contains no cross-reference to the underlying enforcement provisions of CASA’s regulatory framework, nor does it indicate the consequences of non-compliance, such as grounding, denial of certificate or prosecution. Those matters are outside the explicit text provided.

Therefore, based solely on the source as supplied, there is no statement of monetary penalties, demerit systems, or enforcement process within the AD text. Users requiring certainty about enforcement should seek the fuller regulatory context or CASA’s administrative guidance outside this document; such material is not included in the supplied AD text.

The AD text itself interacts explicitly with two technical documents: the General Dynamics/Convair Models 340 and 440 Maintenance Manuals, which "cover this same subject", and an FAA Airworthiness Directive, FAA AD 65-12-01 Amdt. 39-75, which is referred to in the Note (Requirement, Note). The AD thereby situates its technical requirements in relation to both manufacturer maintenance documentation and an analogous foreign regulator instrument.

The AD does not, in the text provided, reference particular statutory provisions, civil aviation regulations, or administrative codes beyond naming the Civil Aviation Safety Authority as the issuing body. The act of issuing an Airworthiness Directive implies a point of regulatory authority, but the AD itself does not reproduce the enabling statute or cross-reference specific regulatory clauses. Therefore the only concrete interactions stated in the source are with the manufacturer’s maintenance manuals and the FAA AD.

Practically, the AD requires a specific installation method that maintenance organisations will have to reconcile with their approved maintenance data and standard maintenance procedures. The AD explicitly states that the manufacturer's maintenance manuals "cover this same subject", which creates a direct technical alignment: operators can compare the AD procedure with the maintenance manual procedure to ensure consistency. The combined references imply that compliance with the AD will likely align with compliance with the maintenance manuals, but the AD text does not say whether compliance with the manuals alone is sufficient to demonstrate compliance with the AD.

The reference to FAA AD 65-12-01 Amdt. 39-75 suggests that the FAA previously addressed a similar issue. The AD’s inclusion of that reference creates a technical link that may influence operators who are subject to both CASA and FAA oversight, or who use FAA ADs as a source of continuing airworthiness information. The AD text does not state any precedence rule or conflict-resolution mechanism where the maintenance manual and the AD might differ.

No other laws, such as industrial safety legislation, contract law, or customs/import requirements for parts, are mentioned in the AD text. Any interactions with those legal regimes are therefore not stated in the supplied source.

The supplied text contains a single dated instrument, AD/CONVAIR/25, dated 8/2006, signed 21 June 2006, with an effective date of 3 August 2006 (signature block and effective date statements). There are no amendment entries, versioning notes, or repeal clauses in the document as supplied. The AD title, number and date are repeated in the document; otherwise no later amendments or prior versions are referenced.

The AD also includes a note referring to FAA AD 65-12-01 Amdt. 39-75 and states that General Dynamics/Convair maintenance manuals cover the same subject. Those are references to other documents rather than amendments to this AD. The text does not indicate whether AD/CONVAIR/25 replaces, modifies, or supplements any prior CASA AD concerning the Convair 340/440 gear assembly.

Because the supplied text contains no explicit amendment entries, amendment history as recorded in this document is limited to the date of issue (21 June 2006) and the AD’s effective date (3 August 2006). There is no indication within the supplied AD of subsequent modifications, revocations, or supersessions. Users requiring a full amendment history must therefore consult the issuing authority’s records outside the content of this AD; those records are not included in the supplied text.

The AD text as supplied does not include any litigation history, judicial decisions, administrative determinations, or references to appeals or disputes. No cases are named in the document, and there are no citations to judicial authority. The AD is a technical directive containing requirements and references to manufacturer manuals and an FAA AD; it does not narrate or summarise any litigation connected to the subject.

Because the supplied text contains no litigation history, there are no reported judicial interpretations of this AD in the document. If litigation has occurred relating to AD/CONVAIR/25, that material is not present here and would need to be obtained from court records, enforcement filings, or CASA archives outside the AD text.

For users who require judicial or contested-administrative context, the absence of litigation references in the AD means that the document itself cannot be relied on to inform the existence, outcome or legal reasoning of any disputes. The AD provides only the technical requirement and administrative facts surrounding issuance; the supplied instrument contains no record of subsequent legal challenges or case law.

Several practical matters in the AD text can cause confusion or lead to non-compliance if not carefully managed.

1. Trigger condition is narrow and ongoing. The Compliance clause requires the prescribed installation only "At each time the main landing gear gland nut is reinstalled after the effective date of this AD." That means if a gland nut was installed prior to the effective date and is not reinstalled thereafter, the AD’s procedure does not require immediate retrospective rework under the text supplied. Operators and maintainers who misread the trigger could either fail to act when they should, or perform unnecessary work when a reinstallation has not in fact occurred. Clear maintenance planning is therefore required to identify when the gland nut is removed and replaced.

2. Precision of mechanical alignment matters. Step 2 requires unscrewing the gland nut until "the first tapped hole is opposite one of the milled slots in the cylinder." The AD depends on an accurate visual and mechanical alignment between tapped holes and milled slots; human error or worn parts could produce ambiguity. The AD specifies the parts (gland nut P/N 528062; outer cylinder P/N 528402), so maintainers must ensure the correct components are present and not substituted with similar but not identical parts that might have different hole/slot relationships.

3. Part-number specificity creates supply dependency. The AD names exact part numbers for gland nut, outer cylinder, lock screw and set screw. If the specified hardware is out of stock, substituted parts (even if dimensionally similar) could be non-compliant with the AD as written. Maintainers who use alternative parts without express substitution authority risk not meeting the AD’s literal requirements.

4. Safetying with lockwire is required as final step. The AD requires safetying the lock screw and set screw with a lockwire. If lockwire sizes or types are omitted from consideration, a maintainer might secure the screws with a different method and thereby fail to satisfy the AD’s stated method.

5. Interaction with maintenance manuals and FAA AD. The AD notes the manufacturer’s maintenance manuals "cover this same subject" and references an FAA AD. Operators may be unsure whether compliance with the maintenance manual or the FAA AD alone satisfies the CASA AD. The AD does not state equivalence or provide an alternative means of compliance, which could create ambiguity.

6. No stated enforcement or recordkeeping. The AD contains no express enforcement steps or logbook entries. Operators and maintainers cannot rely on this document alone to know what administrative evidence of compliance is required; failure to retain proof of compliance could create problems in audits or oversight, despite the AD’s technical action being performed.

7. Missing penalty and administrative detail. Because the AD does not set out penalties or the handling of non-compliance, those seeking to understand legal consequences must consult the broader regulatory framework. The AD itself gives no guidance on the consequences of non-compliance.

8. Temporal gap between issue and effective date. The document is signed on 21 June 2006 and becomes effective on 3 August 2006. Maintenance that occurs in the window between those dates must be handled with awareness of the effective date trigger; mistakes could occur if staff assume the AD is effective immediately upon signature.

9. Ambiguity in “first tapped hole” language. The phrase "the first tapped hole" could be ambiguous if the gland nut has multiple tapped holes in differing orientations relative to the milled slots; technicians need clear interpretation to ensure they align the correct tapped hole with a milled slot.

10. No explicit instruction for existing installations. The AD does not require immediate inspection or modification of gland nuts that remain installed from before the effective date; operators expecting an immediate, fleet-wide directive may be surprised by the AD’s narrower scope.

These points are derived directly from the language of the AD and reflect implementation risks and sources of interpretive uncertainty based on the supplied text.

The AD prescribes the operative compliance steps. To comply with the AD as written, perform the following actions when the main landing gear gland nut is reinstalled after the AD’s effective date (3 August 2006).

1. Confirm applicability. Verify the aircraft is a General Dynamics/Convair Model 340 or 440. The AD is applicable only to those models (Applicability). If the aircraft is not a listed model, the AD’s requirements, as written, do not apply.

2. Use specified parts. Ensure the gland nut is P/N 528062 and the outer cylinder is P/N 528402 as stated in the Requirement. Acquire lock screw P/N AN 501A-416-8 and set screw P/N 500305-4. The AD requires those specific part numbers in the installation sequence (Requirement).

3. Follow the installation sequence exactly. The AD sets a mandatory four-step installation method:

   • Step 1: Screw the gland nut P/N 528062 onto the main landing gear outer cylinder P/N 528402 until it is tight.
   • Step 2: Unscrew the gland nut until the first tapped hole is opposite one of the milled slots in the cylinder.
   • Step 3: Screw the lock screw P/N AN 501A-416-8 into the tapped hole so that the screw protrudes into the milled slot in the cylinder.
   • Step 4: Screw the set screw P/N 500305-4 into an adjacent tapped hole in the gland nut and safety the lock screw and set screw with a lockwire. These actions are mandated in the AD text as the required installation method (Requirement, steps 1-4).

4. Safety the fasteners with lockwire. As the AD specifies, safety both the lock screw and the set screw with lockwire as the final step of the described installation (Requirement, step 4).

5. Check alignment and protrusion. Ensure that the lock screw actually protrudes into the milled slot as required by step 3. The AD’s safety objective depends on correct mechanical engagement between the lock screw and the milled slot.

6. Cross-reference the manufacturer manual. The AD notes that the General Dynamics/Convair maintenance manuals cover the same subject. Review the relevant sections of the manufacturer’s maintenance manual to ensure the AD procedure is reconciled with any procedural detail or torque values the manual may specify (Requirement, Note). If the manual contains additional procedural safety steps, follow them as appropriate, while ensuring the AD-prescribed steps are met.

7. Plan for parts and training. Because the AD specifies precise part numbers and a specific assembly method, ensure parts inventory and maintenance staff are prepared. The AD text does not require particular training, but maintainers must be competent to carry out the specified mechanical alignment and safety methods.

8. Trigger-based application. Apply these steps at each reinstallation of the gland nut after the effective date. The AD’s Compliance clause is specific: the action is required "At each time the main landing gear gland nut is reinstalled after the effective date of this AD" (Compliance). Do not infer other inspection intervals or retroactive obligations from this text alone.

9. Recordkeeping and evidence of compliance. The AD does not stipulate recordkeeping obligations. Nonetheless, to demonstrate compliance in any oversight or audit process, maintain contemporaneous maintenance records that identify the work performed, parts installed by P/N and serial number where applicable, and the date of the reinstallation. Include a reference to AD/CONVAIR/25 in your maintenance entry so that the installation can be shown to be performed pursuant to the AD’s requirements. Note that while this recordkeeping advice is practical, the AD text itself contains no mandatory recordkeeping clauses.

10. Seek clarification where ambiguous. If there is uncertainty about the meaning of "the first tapped hole", the configuration of the milled slots, or acceptable alternative parts, obtain written clarification from CASA or the design approval holder (manufacturer). The AD refers to the manufacturer’s maintenance manual and an FAA AD; operators may consult those sources for additional technical detail, but the AD’s wording itself is controlling for the required action.

Following the steps above implements the AD’s stated requirements as provided in the source text. The AD does not provide details on enforcement, alternative methods of compliance, or administrative procedures; operators should ensure they retain adequate evidence that the AD-prescribed installation was executed when required.