AD/HS 125/89 Amdt 3 - Elevator Mass Balance Side Plate and Spigot

Applicability: The AD applies to "All models up to and including BAe 125-800B series" (Applicability). That is the defined scope for the mandatory requirement. Any aircraft within that scope must be treated as subject to the directive unless an operator can show the specified action has already been accomplished.

Incorporation by reference: The AD does not contain step‑by‑step maintenance procedures; instead it incorporates the FAA directive by reference: "Action in accordance with FAA AD 89-18-07 R1, amendment 39-10878, effective 18 December 1998" (Requirement). Practically, the referenced FAA AD is the operative technical source for inspection intervals, inspection methods, and required repairs or replacements. The CASA amendment therefore functions as a regulatory trigger requiring Australian operators to follow the FAA's specified procedures.

Temporal mechanics: Two dates are central. The amendment itself is effective 7 June 2010, while the compliance condition requires that, unless already done, the action must be completed "before further flight after 21 June 2010" (Compliance; Amendment). The Background explicitly records that Amendment 3 alters compliance and effective dates to provide an adequate period between them. The result is a window in which operators must plan and execute the mandated action.

Safety rationales and failure mode: The Background describes the reported defect and its plausible consequence. Corrosion on the elevator mass balance side plate and balance weight spigot could cause "displacement of the side plate leading to control surface interference." The chain here is corrosion → displacement of a mass-balance structural component → interference with the elevator control surface. The AD's inspection and corrective action objective is to remove or mitigate that failure mode before it leads to compromised control-surface function.

Maintenance schedule interaction: The Background notes that the FAA AD "does not formally quote the on-going maintenance schedule inspection period as did Amendment 1 to this AD," and then records that "The maintenance schedules of the applicable aircraft series contain the on-going structural inspection requirements (each 2 years) for the elevator mass balance side plates, spigots and installation." Thus there are two inspection reference points: (a) the FAA AD actions required by this AD and (b) the aircraft-series maintenance schedules prescribing two-year structural inspections for the same items. Operators must address both where they intersect.

Regulatory lineage: The AD documents a long-running regulatory process: original AD in 1987, an Amendment 1 clarifying periodicity, Amendment 2 harmonising with the FAA's requirements and expanding applicability, and Amendment 3 adjusting dates (Background / Amendment history). The concept of harmonisation with the State of design's AD is explicitly present.

Administrative signature and issuance: The instrument is signed by "Mike Higgins, Delegate of the Civil Aviation Safety Authority" and dated 24 May 2010; that establishes the issuing authority for this amendment (signature block).

Aircraft operators and owners: The primary economic agents affected are owners and operators of BAe 125 series aeroplanes within the specified applicability, "All models up to and including BAe 125-800B series" (Applicability). These parties bear responsibility for ensuring the actions required by the AD are carried out and completed by the compliance date, unless already accomplished (Compliance).

Maintenance organisations and personnel: Licensed maintenance organisations and personnel who perform inspections and structural repairs to BAe 125 elevators are materially affected. The AD obliges that the FAA AD’s procedures be followed; therefore maintenance providers must have access to, understand and apply FAA AD 89-18-07 R1 (Requirement). They will perform the inspections of the elevator mass balance side plates and spigots and carry out any rectification work specified.

Regulators and delegates: The Civil Aviation Safety Authority (CASA) is the issuing authority; the AD bears the CASA delegate's signature. While the text does not set out enforcement processes in this document, CASA’s role in issuing the AD makes it the competent authority for this instrument (signature block). Any follow-up compliance monitoring or queries about the directive will flow to the regulator and its delegates.

Flight operations planners and schedulers: Because compliance is tied to a "before further flight after 21 June 2010" deadline, operators planning near-term flights must incorporate the inspection work into flight schedules. This can require aircraft ground time, coordination with maintenance providers and, if defects are found, unscheduled repairs.

Supply chain participants: If inspections reveal corrosion that requires replacement parts (e.g. side plates, spigots, balance weights or fasteners), parts suppliers and logistics providers will be engaged. The AD does not specify parts procurement arrangements; however any required physical repairs will create demand for compatible parts and possibly engineering approvals if non-original parts are proposed.

Insurance and financial stakeholders: Insurers, lessors and financiers who have an interest in airworthiness may be consequentially affected for oversight and compliance assurance. The AD's compliance deadline, and any resulting grounding or repair, can affect utilisation and revenue for an aircraft asset.

Persons not affected: Aircraft outside the specified series, or BAe 125 aircraft whose work has already been accomplished in accordance with the FAA AD prior to the compliance cut-off, are expressly outside the immediate new obligation in this instrument. The Compliance note uses the qualifying “Unless already accomplished” language to exempt prior-compliant aircraft from redoing action for this AD cycle.

Primary duty to act: Operators of applicable BAe 125 aircraft must carry out the actions prescribed in FAA AD 89-18-07 R1, amendment 39-10878, effective 18 December 1998, as incorporated by this CASA AD (Requirement). The AD does not replicate the FAA AD text; therefore the substantive inspection steps, intervals, inspection methods and repair instructions are those found in the FAA AD. The AD imposed an absolute operational timing for that duty: "Unless already accomplished, before further flight after 21 June 2010" (Compliance). That places the obligation on the operator to ensure the action is completed prior to flying the aircraft after that date.

Ongoing inspection duty: The Background references the applicable aircraft series' maintenance schedules, which contain "the on-going structural inspection requirements (each 2 years) for the elevator mass balance side plates, spigots and installation." While this AD specifically requires action per the FAA AD, the Background makes clear that ongoing structural inspections every two years are part of the series' maintenance regime for these components. Practically, that means operators will need to fold the FAA-prescribed actions into the recurring 2-year structural inspection process where appropriate.

Right to rely on prior compliance: The Compliance text permits an operator who has already accomplished the required action to avoid additional immediate work under this amendment: "Unless already accomplished". This functions as a carve-out for prior compliance, allowing operators who can document that they already completed the FAA AD actions to continue operations without repeat action solely because of this Amendment.

Duty to consult the referenced AD: Because the AD imports an FAA document by reference, a duty arises to obtain and follow the FAA AD to understand exactly what inspections or repairs are mandated. The CASA instrument does not instruct on alternative methods of compliance or provide technical variation; the "Action in accordance with FAA AD" language means the FAA AD is the technical norm.

Operational timing duty: There are two administrative timing elements to respect. The Amendment becomes effective on 7 June 2010, and the compliance cut-off is a functional constraint "before further flight after 21 June 2010." Operators must plan maintenance to meet the before-flight requirement despite the effective date being earlier. The Background explains that Amendment 3 adjusted these dates to ensure an adequate period between them; nonetheless an operator that does not have the work already accomplished carries the duty to complete the FAA AD action before flying after the stated compliance date.

No explicit rights to relief or alternative compliance in the text: The AD text does not articulate alternative compliance routes, deferral mechanisms, or an administrative carve-out beyond the "Unless already accomplished" phrasing. The instrument also does not itself enumerate processes for seeking exemptions or extensions. Those matters, if available, would be handled under CASA's broader regulatory processes, but they are not specified in this document.

Recordkeeping and demonstrative obligations: The AD does not specify recordkeeping requirements within its text. The practical implication of a "before further flight" obligation is that operators should be able to demonstrate compliance if queried, but the AD itself does not set out documentary form, timing or retention periods.

This Amendment text does not set out specific penalties, sanctions or an enforcement regime; the document records the mandatory action and the compliance timing but contains no punitive schedule or explicit enforcement procedure. The AD identifies the issuing authority by signature, "Mike Higgins, Delegate of the Civil Aviation Safety Authority" and includes dates (signature and effective date), which establishes the instrument as a CASA-issued mandatory directive (signature block; Compliance).

Because the AD does not detail penalties, the instrument leaves any question of enforcement mechanism and sanctioning to the reader’s knowledge of broader regulatory frameworks. The AD itself confines its content to applicability, the prescriptive requirement to act in accordance with the FAA AD, the compliance timing, and background history of the defect and previous amendments. No clause within the supplied text authorises specific fines, licence actions or criminal penalties, nor does it specify who conducts compliance inspections or how non-compliance will be processed administratively.

Practical enforcement consequences that can be inferred from the structure of an AD are limited by the document’s silence. The AD makes compliance mandatory for the listed aircraft; failure to follow the AD by the compliance date will mean the specified safety action has not been taken. The source text does not say whether an aircraft that has not complied will be grounded, will be considered unairworthy, or how CASA will record or pursue non-compliance , those are not stated in the supplied instrument. Similarly, the text does not set out notification, reporting, or rectification deadlines beyond the "before further flight" rule.

Where the AD references the FAA AD by incorporation, operators who are uncertain about enforcement or the consequences of non-compliance must refer to CASA’s broader regulatory materials or contact the authority for administrative guidance. The AD itself only sets the technical obligation and the time window for compliance; it does not provide the enforcement pathways or penalties within this document.

Incorporation of a foreign (State of design) AD: This instrument explicitly incorporates by reference a United States FAA AD: "Action in accordance with FAA AD 89-18-07 R1, amendment 39-10878, effective 18 December 1998" (Requirement). That creates a cross-jurisdictional regulatory interaction where CASA requires Australian operators to implement a State of design authority’s prescriptive measures. The AD therefore operates in tandem with the FAA instrument: CASA’s directive imposes the FAA AD’s technical requirements as mandatory for Australian-registered aircraft within the applicability.

Maintenance schedule interplay: The Background notes a divergence in wording between this AD’s amendments and the FAA AD: "Note that the FAA AD does not formally quote the on-going maintenance schedule inspection period as did Amendment 1 to this AD." The AD then states that the aircraft series’ maintenance schedules themselves contain "on-going structural inspection requirements (each 2 years) for the elevator mass balance side plates, spigots and installation." That means operators must reconcile three possible sources: (a) this CASA AD which compels action per the FAA AD, (b) the FAA AD’s own text, and (c) the aircraft series’ published maintenance schedules that specify a biennial inspection period. Where these sources overlap, operators must ensure all obligations are met; where they differ, the CASA AD’s incorporation-by-reference makes the FAA AD mandatory under CASA's jurisdiction, while maintenance schedule obligations remain part of the aircraft’s continuing airworthiness programme.

Regulatory harmonisation and amendment lineage: The Background records that Amendment 2 "introduced the requirements of the State of design AD and increased the applicability to include the 800 series aircraft." That shows prior amendments were used to align CASA’s AD with the FAA AD and to change scope. This AD continues that harmonisation pattern by referring back to the FAA AD and preserving the mutual relationship.

Absence of stated interaction with criminal or civil liability regimes: The AD text does not address interaction with Australian criminal law, civil liability, or insurance frameworks. It does not state whether non-compliance has automatic civil liability consequences or affects insurance cover. Those interactions are left unaddressed in the text provided.

Operational aviation law implications: The AD creates an airworthiness obligation that must be satisfied before flight for applicable aircraft after the compliance date. While the AD itself does not articulate how that obligation interacts with air operator certificates, maintenance organisation approvals, or airworthiness directives regime procedures, the practical effect is that compliance with the incorporated FAA AD is required for continued operation of affected aircraft. The AD’s silence on processes for relief, alternative methods of compliance or variance means interaction with broader regulatory pathways may be necessary in contested or exceptional cases, but those pathways are not specified in this document.

Documented lineage: The instrument includes a short amendment history embedded in the Background. The chronology provided in the text is:

• Original AD raised in 1987. The initial AD responded to the corrosion issue reported in service (Background).
• Amendment 1 clarified the inspection periodicity. The text notes that Amendment 1 "clarified the inspection periodicity" and that Amendment 1 "formally quoted the on-going maintenance schedule inspection period" whereas the FAA AD did not (Background).
• Amendment 2 introduced the requirements of the State of design (the FAA AD) and increased the applicability to include the 800 series aircraft. The Background states: "Amendment 2 introduced the requirements of the State of design AD and increased the applicability to include the 800 series aircraft."
• Amendment 3 (this instrument) changes the compliance date and the effective date to ensure there is an adequate period between the two dates. The AD record says: "Amendment 3 changes the compliance date and the effective date to ensure there is an adequate period between the two dates." Amendment 3 is dated 24 May 2010, states an effective date of 7 June 2010, and sets compliance as "before further flight after 21 June 2010" (signature and Compliance lines).

Cross-reference to FAA AD: The Requirement clause points directly to FAA AD 89-18-07 R1, amendment 39-10878, which itself had an effective date of 18 December 1998. That indicates the FAA’s amendment history is part of the substantive technical background for the CASA AD: CASA adopted that FAA AD’s prescriptions into Australian regulation via Amendment 2 and maintains the linkage thereafter.

Purpose of the amendments as stated: The Background explains the rationale for each amendment in a descriptive way. Amendment 1: inspection periodicity clarification. Amendment 2: alignment with State of design AD and extension of applicability. Amendment 3: administrative adjustment of dates to provide an adequate interval between effective and compliance dates.

Administrative formality: The signature block and dates provide a record of the most recent amendment being promulgated by CASA’s delegate. The presence of the image placeholder and signature detail indicates this document is an administrative amendment to an ongoing AD record, not a stand-alone piece of technical guidance.

No other amendments recorded in this text: The provided instrument’s amendment history is limited to the items described. The AD does not reference any subsequent amendments, revocations, or supersessions beyond Amendment 3.

The supplied text contains no information on litigation, judicial review, or any court proceedings relating to AD/HS 125/89 or any of its amendments. There are no cases, judgments, appeals or administrative law reviews cited in the instrument. The document is purely administrative in character and limited to regulatory content: applicability, requirement, compliance timing and background.

Because the instrument does not provide any litigation or dispute resolution history, readers who require information on any court or tribunal decisions engaging with this AD will need to consult external legal databases, CASA records or court registries. The AD text itself does not record any legal challenges, interpretations by courts or examples of enforcement proceedings.

Incorporation by reference without reproducing detail: The CASA AD requires operators to act "in accordance with FAA AD 89-18-07 R1, amendment 39-10878, effective 18 December 1998" but does not reproduce the FAA AD’s detailed inspection, measurement, or repair instructions (Requirement). A common operational pitfall is assuming the CASA AD alone supplies the technical steps. Operators must obtain and follow the FAA AD to know the precise inspection method, acceptance criteria and corrective actions. Relying on the CASA AD in isolation risks incomplete compliance.

Timing trap between effective date and compliance date: Amendment 3 sets the Amendment effective date as 7 June 2010 and the compliance requirement as "before further flight after 21 June 2010." The Background explains Amendment 3 adjusted these dates to ensure an adequate interval, but the relatively short window between effective and compliance dates can create scheduling pressure. Operators who have not already accomplished the FAA AD action must schedule inspections and any required repairs within that window to avoid non-compliance. The text’s “Unless already accomplished” qualifier does not relieve those who have not done the work.

Divergence between FAA AD and aircraft maintenance schedules: The Background notes that the FAA AD "does not formally quote the on-going maintenance schedule inspection period as did Amendment 1 to this AD," while observing the aircraft maintenance schedules set a two-year structural inspection for the same items. Operators must reconcile the FAA AD’s specific prescriptions with their own maintenance programme’s biennial checks. Failure to integrate both obligations may lead to duplication or missed inspections.

Scope inclusions: The wording "All models up to and including BAe 125-800B series" is the stated applicability. Operators should verify their model designations carefully; an incorrect reading of model suffixes or subvariants can lead to mistakenly treating an aircraft as inapplicable. The AD gives no guidance on model identification beyond that phrase.

No enforcement or penalty information in the text: The AD does not state penalties or enforcement processes. That absence can create uncertainty for operators uncertain about consequences of delayed compliance or the process for seeking relief. Operators should not treat the absence of penalties in the AD as an absence of regulatory consequence, but the AD itself does not record what those consequences are.

Parts and repair detail not included: If inspection reveals corrosion requiring physical replacement, the AD does not specify approved parts, drawing references, or alternative means of compliance. That practical gap can create logistic delays when parts are required or when engineering approvals are needed. Operators should plan for potential sourcing and engineering approval lead times.

Documentation and proof of prior compliance: The Compliance phrase "Unless already accomplished" implies that evidence of prior compliance is acceptable. However, the AD does not specify what documentary proof is sufficient. Operators should prepare clear maintenance records showing the FAA AD action was completed to avoid argument about compliance.

Potential for divergent interpretations: Because the AD cross‑references an FAA AD, there is scope for different interpretations between the CASA wording and the content of the FAA AD (for example, the FAA AD’s own effective date of 18 December 1998 vs CASA’s effective and compliance dates). Operators should align their compliance activities with both the CASA timelines and the FAA AD requirements as applicable.

Step 1 , Confirm applicability: Verify the aircraft model. The AD applies to "All models up to and including BAe 125-800B series" (Applicability). Confirm the aircraft’s model designation against maintenance records or the certificate of airworthiness to ensure the AD applies.

Step 2 , Obtain the referenced FAA AD: The CASA instrument requires actions "in accordance with FAA AD 89-18-07 R1, amendment 39-10878, effective 18 December 1998" (Requirement). Obtain that FAA AD document in full, and read its inspection methods, defect limits, and required corrective actions. The CASA AD does not reproduce those details.

Step 3 , Determine status of prior compliance: The Compliance text provides a conditional carve‑out: "Unless already accomplished." Check maintenance records to determine whether the FAA AD actions were previously completed. If so, ensure records clearly document the date, the work performed and the approving maintenance organisation or engineer.

Step 4 , Schedule inspection before the deadline: If the FAA AD action has not already been accomplished, schedule the required inspection and any necessary remedial work so it is finished before further flight after 21 June 2010 (Compliance). Given the effective date of this Amendment is 7 June 2010, the scheduling window may be short. Plan for potential aircraft downtime and availability of maintenance capacity.

Step 5 , Perform inspections and corrective actions per the FAA AD: Execute the FAA AD’s specified inspections, measurements and any required repairs or replacements, using appropriately certificated maintenance personnel and parts approved for the aircraft. If the FAA AD requires engineering approvals for certain repairs, obtain those approvals before re-entry into service.

Step 6 , Coordinate with the two-year maintenance schedule: The Background notes the aircraft series maintenance schedules contain ongoing structural inspection requirements every two years for these parts. Integrate the FAA AD work with the recurring two-year structural inspection programme to avoid duplication and to ensure continuing compliance.

Step 7 , Document completion: Although the AD does not specify documentary form, maintain clear records showing the FAA AD actions were performed, including date, work scope, parts used, approval signatures and any engineering documentation. These records will be necessary to demonstrate that the work was "already accomplished" if queried under this or subsequent directives.

Step 8 , Plan for parts and logistics: If inspection reveals corrosion requiring replacement of side plates, spigots or balance weights, arrange for procurement of approved parts and any necessary engineering evaluations. Because the AD does not specify parts, ensure any replacement items are compatible with the aircraft’s type certificate data and the FAA AD’s instructions.

Step 9 , Follow up with CASA or delegate if unsure: The AD was issued by a CASA delegate (signature block). If there is uncertainty about compliance status, documentary sufficiency, or the application of the FAA AD to particular aircraft variants, contact CASA or its delegate function for administrative clarification. The AD itself does not set out relief procedures, so early engagement reduces risk.

Step 10 , Incorporate into continuing airworthiness records: After completing the required action, update the aircraft logbooks and continuing airworthiness records to reflect compliance with AD/HS 125/89 Amdt 3 and the referenced FAA AD action, and to reflect any parts replacement or repairs carried out. Also ensure the biennial structural inspection programme records are aligned with these entries.

Who pays and resource implications: The AD imposes a maintenance obligation on aircraft owners/operators. Costs for inspection, labour, parts, possible grounding and logistics fall to them. Maintenance organisations will provide labour and materials; operators should budget for potential unscheduled repair costs and downtime. The AD does not provide funding or compensation mechanisms.

Record retention and audit readiness: Maintain accessible records showing compliance and any associated maintenance action, because the instrument’s operational effect is to require the work be done before flight; demonstrable evidence will be the practical means to show compliance if questioned.

Summary action checklist (practical): (1) Confirm applicability; (2) obtain FAA AD 89-18-07 R1; (3) review maintenance records for prior compliance; (4) if not done, schedule and complete inspection/repair before further flight after 21 June 2010; (5) document work and integrate it with the two-year structural inspection programme; (6) retain records and engage CASA if clarification is needed.