AD/EC 225/4 Amdt 1 - Main Rotor Hub Dome Fairing Attachment Screws

This Airworthiness Directive (AD), AD/EC 225/4 Amdt 1, requires operators of certain Eurocopter EC 225 LP helicopters to perform a specific inspection and torque re‑adjustment of the screws securing the main rotor hub dome fairing support to the dome fairing. The AD mandates an initial check before further flight after 9 April 2009, and repetitive checks at intervals not exceeding 165 flight hours. The checks must be conducted in accordance with the instructions in Eurocopter EC 225 Alert Service Bulletin (ASB) No. 05A005 Revision 1 (or any later EASA approved revision).

The AD has two core mechanical requirements. First, the operator must check that there is no crack in the dome fairing support and readjust the tightening torque of the screws that secure the dome fairing support to the dome fairing. Second, the operator must readjust the tightening torque of the dome fairing support attachment screws on the dome fairing. Both tasks are performed using the procedures described in ASB 05A005 Revision 1.

The directive also introduces a terminating action: if a crack is found during any check, the operator must, before further flight, remove and replace the dome fairing support and the associated coning stop support assembly in accordance with Eurocopter Service Bulletin (SB) No. 62‑007 (original issue or later EASA approved revision). That replacement stops the need for further repetitive checks. The terminating action can also be performed proactively - the AD states that replacement per SB 62‑007 constitutes terminating action for the repetitive checks required by Requirement 2. Presumably, any helicopter that has already been modified during production with MOD 0743718 or in‑service per SB 62‑007 is outside the applicability of the AD entirely.

Amendment 1 updates the previous version of the AD. The original AD/EC 225/4 referred to ASB No. 05A005 at original issue. Amendment 1 changes the required document to Revision 1 and adds the reference to terminating action via SB 62‑007. The AD also notes that checks and corrective actions accomplished before the effective date (9 April 2009) in accordance with ASB No. 05A005 at original issue are acceptable compliance with the initial requirements of Requirements 1 and 2. After that date, repetitive checks must follow Revision 1.

The background explains the safety justification: two cracks in the dome fairing attachment on the dome fairing support were discovered. The cracks were fatigue cracks caused by loss of tightening torque of the screws. In time, the cracks could lead to loss of the dome fairing in flight. The AD is thus an emergency directive, imposing immediate compliance obligations on operators. The amendment responds to a new EASA AD that introduced the latest revision of the required document and the terminating modification.

The compliance timeframe is strict. For Requirement 1 (initial check), unless already done, the operator must comply before further flight after 9 April 2009. For Requirement 2 (repetitive check), the operator must comply at intervals not exceeding 165 flight hours until the terminating SB is complied with. The AD does not specify a grace period for the repetitive check after the initial check; presumably the first repetitive check is due 165 flight hours after the initial check.

From an economic perspective, the AD imposes a recurring compliance cost of inspecting and re‑torquing fasteners every 165 flight hours. For a helicopter flown 800 hours per year, that means roughly five inspections annually. Each inspection involves labour, possible downtime, and the cost of replacing any cracked parts if found. The terminating action (SB 62‑007) is a one‑off cost that eliminates future repetitive checks. Operators must weigh the cost of the modification against the ongoing inspection burden. The AD forces that decision but does not subsidise it.

Airworthiness Directive (AD): An AD is a legally enforceable notification issued by the Civil Aviation Safety Authority (CASA) under the Civil Aviation Safety Regulations 1998 (CASR 1998). It mandates an action to correct an unsafe condition in an aircraft, engine, propeller, or component. Compliance is compulsory. This AD is an “emergency” directive, meaning the unsafe condition requires immediate action before further flight.

Applicability: The AD applies to Model EC 225 LP helicopters, all serial numbers, except those modified during production with MOD 0743718 or in‑service with Eurocopter EC 225 Service Bulletin No. 62‑007 original issue, or later EASA approved revision. MOD 0743718 is a production modification that presumably addresses the crack issue. The exclusion means those helicopters already have the terminating action incorporated and are not subject to the AD.

Dome fairing support and dome fairing assembly: The dome fairing is a structural component around the main rotor hub. The support attaches the fairing to the hub. The AD concerns the screws that secure the support to the fairing. The safety concern is fatigue cracking in the support due to loss of torque in those screws.

Tightening torque: The rotational force applied to a fastener. Each screw must be tightened to a specified value. Over time, vibration can cause the torque to decay (loss of tightening torque). The AD requires periodic re‑torquing to the correct value.

Crack check: The AD requires a visual or other non‑destructive inspection for cracks in the dome fairing support at the attachment points. If a crack is found, immediate replacement is required.

Terminating action: An action that, once performed, ends the need for further repetitive checks. Here, replacement of parts in accordance with SB No. 62‑007 (the service bulletin that installs MOD 0743718 is terminating action. An operator can choose to perform the terminating action proactively, even if no crack is found, to avoid ongoing 165‑hour inspections. The AD does not mandate the terminating action unless a crack is found, but it is an available compliance pathway.

EASA approved revision: The AD incorporates by reference any later revision of ASB 05A005 or SB 62‑007 that is approved by the European Aviation Safety Agency. This creates a moving target - if EASA approves a later revision, that revision becomes the required standard under this AD without further CASA amendment. Operators must monitor EASA approvals to stay compliant.

The primary parties affected are operators of Eurocopter EC 225 LP helicopters registered in Australia, or operated under Australian airworthiness jurisdiction, that have not been modified per MOD 0743718 or SB 62‑007. These operators are directly subject to the AD’s mandatory checks and potential grounding. The AD also affects maintenance organisations that perform the inspections and torque adjustments. The labour required to perform the check and re‑torque each screw, and possibly to remove and replace cracked parts, falls on these organisations. The cost of those labour hours is passed to the operator.

Helicopter owners and lessees bear the financial burden. For a helicopter used in commercial operations (e.g., offshore oil and gas transport, search and rescue), each hour of downtime for inspection reduces revenue. The 165‑hour interval means a helicopter flying 800 hours per year would be grounded for inspection roughly five times a year. If the inspection takes one man‑day, that is one week of lost revenue annually. The terminating action, if chosen, would eliminate that recurring downtime but at a substantial upfront cost (procurement of the replacement parts, labour for the modification). Smaller operators with limited cash flow may be forced to continue the repetitive checks rather than invest in the modification.

The AD indirectly affects passengers and clients who rely on EC 225 services. If the helicopter is grounded for inspection or modification, service reliability decreases. In worst cases, if a crack is found, the aircraft is grounded until replacement parts are sourced. Parts availability for an older model may be limited, leading to extended AOG (aircraft on ground) periods. Insurance companies may also be affected - they may require evidence of AD compliance before covering the helicopter for flight.

Parts suppliers and Eurocopter (now Airbus Helicopters) are involved. The terminating service bulletin (SB 62‑007) likely involves installing a kit supplied by the manufacturer. The AD creates demand for that kit. The manufacturer may benefit from increased parts sales. Conversely, if many operators choose to continue with repetitive checks, the manufacturer sees less kit revenue.

CASA itself is affected: the AD must be enforced, which consumes regulator resources for surveillance, investigation, and potential enforcement action. The AD also affects the broader aviation regulatory ecosystem: the reference to EASA approved revisions means CASA has effectively delegated certain standard‑setting authority to EASA, which may influence future regulatory decisions.

Duties: The duty is set out in the two Requirements.

Requirement 1: Check for cracks in the dome fairing support and readjust the tightening torque of the screws that secure the dome fairing support to the dome fairing, per ASB 05A005 Rev 1 paragraph 2.B.2.

Requirement 2: Readjust the tightening torque of the dome fairing support attachment screws on the dome fairing, per ASB 05A005 Rev 1 paragraph 2.B.3. This is repetitive at intervals not exceeding 165 flight hours.

The AD imposes a duty to comply before further flight after the effective date for the initial check. That is immediate grounding risk. For the repetitive checks, the duty continues until either the helicopter is permanently removed from service or the terminating action is performed.

If a crack is found, the operator has a duty to remove and replace the dome fairing support and associated coning stop support assembly in accordance with SB 62‑007 before further flight. The duty to ground is explicit.

Rights: The AD grants operators certain rights.

Right to use earlier compliance for initial requirement: Checks and corrective actions accomplished before the effective date in accordance with ASB No. 05A005 at original issue are acceptable for compliance with the initial requirements of Requirements 1 and 2. This means an operator who had already performed the check using the original ASB before 9 April 2009 does not have to redo that initial check under Revision 1.

Right to perform terminating action: Replacement of parts per SB 62‑007 (or later EASA approved revision) terminates the repetitive check requirement. The operator can choose to do this at any time, even if no crack has been found. The AD does not make terminating action mandatory unless a crack is found, but it gives the operator the option to stop the 165‑hour cycle.

Right to use later EASA approved revisions: The AD permits the use of later EASA approved revisions of the required documents. If EASA approves Revision 2 of ASB 05A005, an operator may use it for compliance. This right is important because it allows the operator to stay current without waiting for CASA to issue a new AD. However, it also imposes a duty to monitor EASA approvals - ignorance of a later revision is no excuse for non‑compliance.

Right to rely on the AD’s note: The AD notes that EASA AD 2009‑0023 refers. While this is merely an informational note, it clarifies that the Australian AD is aligned with the European regulatory approach. Operators who have already complied with the EASA AD (on an aircraft under EASA jurisdiction) may find the Australian AD familiar, but they must still ensure their records show compliance with the Australian AD specifically.

The text of AD/EC 225/4 Amdt 1 does not itself prescribe any penalty for non‑compliance. The enforcement regime is found in the primary legislation under which the AD is issued: the Civil Aviation Act 1988 (Cth) and the Civil Aviation Safety Regulations 1998 (CASR 1998).

Under CASR 1998 Part 21 (Certification of aircraft and aeronautical products), it is an offence to operate an Australian civil aircraft that does not comply with an applicable airworthiness directive. Regulation 21.104 (as in force at the relevant time) made it a strict liability offence to operate an aircraft contrary to an AD. The penalty for an individual could be up to 50 penalty units (which was $5,500 at the time, but penalty rates changed). For a body corporate, the penalty could be up to 250 penalty units ($27,500 at 2009 rates, roughly). However, the specific applicability at the time depended on the version of CASR in effect. This deep dive does not access the exact penalty rate from 2009; the key point is that non‑compliance carries a significant financial penalty.

Beyond fines, enforcement action by CASA can include suspension or cancellation of the aircraft’s certificate of airworthiness. An aircraft that does not comply with an AD is not considered airworthy. Operating such an aircraft could also lead to criminal prosecution if the non‑compliance is reckless or intentional. CASA may also issue an enforcement demand requiring the operator to rectify the non‑compliance within a specified period.

In practice, the most potent enforcement tool is the grounding risk. The AD itself states that certain actions must be done “before further flight”. If an operator ignores that requirement and flies the aircraft, CASA can take immediate action, including detaining the aircraft. The potential for grounding is a powerful compliance incentive, especially for commercial operators who lose revenue from an AOG.

The AD does not specify a reporting requirement to CASA of compliance findings. Nevertheless, under CASR, an operator must maintain records of AD compliance, and those records can be inspected by CASA. Failure to maintain proper records is itself an offence.

Additionally, under the Criminal Code Act 1995 (Cth), corporate liability for reckless conduct can lead to fines potentially in the hundreds of thousands of dollars if the failure to comply creates a risk of death or serious injury. The AD’s background specifically warns of the risk of “loss of the dome fairing in flight”, which could cause an accident. Therefore, non‑compliance could be prosecuted as a reckless endangerment offence.

Civil Aviation Act 1988 (Cth) and Civil Aviation Safety Regulations 1998: The AD is a legislative instrument made under these laws. It operates as a delegated quasi‑legislative rule. Its legal force derives from the Act and Regulations. Compliance with the AD is mandatory, and the Act provides the framework for enforcement, penalties, and reviews.

EASA regulatory framework: The AD explicitly references EASA AD 2009‑0023 and incorporates by reference documents approved by EASA. This creates an interaction between Australian law and European airworthiness regulation. The AD does not adopt the EASA AD wholesale; it adapts it to the Australian jurisdiction. However, the use of the phrase “EASA approved revision” means that future EASA approvals of revised documents are binding under Australian law without separate CASA approval. This is a notable delegation of regulatory authority. If EASA revises the ASB, that revision automatically becomes the required procedure in Australia. Operators must stay abreast of EASA decisions.

Other Australian airworthiness directives: This AD sits within a family of CASA ADs. It is specific to the EC 225 LP model. It does not supersede or conflict with other ADs unless they address the same component. Operators must check for interactions; for example, if another AD requires a different torque value for a related screw, compliance may require careful reconciliation.

Maintenance regulations (CASR Part 42 and Part 145): Operators and maintenance organisations must comply with AD requirements as part of their continuing airworthiness management obligations. Part 42 of CASR (continuing airworthiness management) requires the operator to have an airworthiness management system that includes monitoring and complying with ADs. Part 145 requires approved maintenance organisations to use current technical data, including ADs. The AD’s requirements must be incorporated into maintenance schedules and work orders.

Contract law: Aircraft lease agreements, charter contracts, and insurance policies typically include clauses requiring compliance with airworthiness directives. Failure to comply with this AD could put the operator in breach of contract, giving the lessor the right to repossess the helicopter or the insurer the right to deny coverage. The AD thus interacts with private law obligations; it raises the cost of non‑compliance beyond regulatory penalties.

Work health and safety legislation (state and territory based): Operators owe a duty of care to employees and third parties. Non‑compliance with an AD that addresses an in‑flight failure risk could result in prosecution under work health and safety laws if a worker is injured or killed. The AD provides evidence of the known risk, which strengthens any claim.

The source document is AD/EC 225/4 Amdt 1. It is an amendment to an earlier directive, AD/EC 225/4. The original AD/EC 225/4 was issued sometime before 25 February 2009 (the date of this amendment). The original directive required the checks using ASB No. 05A005 at original issue. No details of the original AD’s effective date are in the source, but it was presumably issued after the discovery of the initial two cracks.

Amendment 1 is dated 25 February 2009 and becomes effective on 9 April 2009. The amendment responds to a new EASA AD (EASA AD 2009‑0023) that introduced a revision of the required document and a terminating modification. The key changes from the original are:

• The required document version changed from ASB No. 05A005 at original issue to ASB No. 05A005 Revision 1. Note: for checks accomplished before the effective date using the original issue, those are still accepted for the initial requirements.
• The amendment added the concept of terminating action: replacement of parts per SB No. 62‑007 (original issue or later EASA approved revision) ends the repetitive checks.
• The amendment added the applicability exclusion for helicopters modified during production with MOD 0743718 or in‑service with SB 62‑007. The original AD likely applied to all EC 225 LP helicopters without that exclusion.
• The background section acknowledges the new EASA AD as the trigger for the amendment.

The amendment also clarifies that after the effective date, repetitive checks must be in accordance with Revision 1.

The source does not indicate any subsequent amendments. There is no history of court challenges or regulatory appeals to this amendment. The AD remains in force unless superseded or cancelled by a later CASA instrument. Over time, the AD may have been incorporated into an “airworthiness directives consolidation” by CASA, but that is not mentioned in the source.

From a legislative drafting perspective, amendment 1 improved the AD by providing a clear path to end inspections (terminating action) and aligning with the latest EASA guidance. The amendment likely reduced the long‑term compliance burden for operators who chose to perform the terminating action. For those who did not, the AD continues to require 165‑hour inspections under the new revision.

The amendment process appears to have been swift: the EASA AD triggered an immediate Australian amendment. This suggests that CASA closely monitors EASA ADs for aircraft types that are common in the Australian fleet. The speed of amendment is typical for emergency ADs that adopt recognised international standards.

The source document records no litigation history. There are no references to any court case or tribunal decision involving AD/EC 225/4 or its amendment. This is common for airworthiness directives, which are technical regulatory instruments rarely challenged in court. When litigation does arise, it is usually an appeal against CASA’s decision to issue the AD on procedural or jurisdictional grounds, or a dispute over enforcement.

The Civil Aviation Act provides for merits review of certain CASA decisions by the Administrative Appeals Tribunal (AAT). Whether an AD is reviewable depends on the type of decision. A typical AD is a legislative instrument, not a reviewable decision. However, an operator could seek judicial review in the Federal Court under the Administrative Decisions (Judicial Review) Act 1977 (Cth) on grounds such as procedural error or that the AD is ultra vires. No such challenge appears to have been made for this AD.

There is also the possibility of litigation if an accident occurred and a party argued that the AD was inadequate or that the operator failed to comply. Out‑of‑court settlements would not be recorded in the source.

Australia’s courts have generally deferred to CASA’s technical expertise in airworthiness matters. A challenge would need to show that the AD is irrational or unsupported by evidence. Given the AD is based on a EASA AD and the discovery of actual cracks, a challenge would be highly unlikely to succeed.

Thus, for practical purposes, this AD has no litigation history. Operators should treat it as settled law.

1. Tight compliance deadlines: The initial check must be done “before further flight after 9 April 2009”. If the operator did not perform that check before the first flight on 9 April, the helicopter is immediately grounded. There is no grace period. An operator who did not read the AD in time may have an aircraft that is non‑compliant even if it has been flying the day before.

2. Reference to “later EASA approved revision” creates a moving target: The AD requires compliance with ASB 05A005 at Revision 1, or any later EASA approved revision. If EASA approves Revision 2, that becomes the required baseline automatically. An operator who continues to use Revision 1 after EASA approval of Revision 2 is non‑compliant, even though CASA has not issued an amendment. This imposes a duty to monitor EASA approvals for these documents indefinitely.

3. The terminating action is optional but has strings: The AD says replacement per SB 62‑007 “constitutes terminating action for the repetitive checks”. If an operator performs a different repair or uses a non‑approved modification, the repetitive checks continue. The operator must strictly follow SB 62‑007 (or later EASA approved revision) to stop the 165‑hour cycle. Any deviation may not be accepted.

4. No mention of alternative means of compliance: The AD does not include a statement like “Alternative means of compliance may be approved by CASA”. This means that an operator cannot unilaterally adopt a different inspection method or interval. They must follow the ASB to the letter. If an operator wants to use a different torque value or a different inspection technique, they must write to CASA seeking approval, and CASA may not grant it.

5. The 165‑hour interval is absolute: It is “not to exceed 165 flight hours”. The AD does not allow extension for any reason. If a helicopter flies 166 hours between inspections, it is non‑compliant. There is no grace margin. Operators must carefully track flight hours to avoid accidental overshoot.

6. The initial check may require re‑checking: If the operator had already done the initial check per the original AD before the effective date, that is accepted for the initial requirement. But what if that initial check was done 100 flight hours before? The AD then requires the first repetitive check within 165 hours of that initial check. The operator cannot wait 165 hours after the effective date; they must count from the actual initial check. This can be confusing.

Compliance must be systematic and documented. The following steps outline a practical compliance pathway for an operator of an EC 225 LP helicopter subject to AD/EC 225/4 Amdt 1.

Step 1: Determine applicability. Check if the helicopter’s serial number is within the applicability. If it has been modified during production with MOD 0743718, or if SB 62‑007 has been embodied in‑service (original issue or later EASA approved revision), the AD does not apply. If not, the AD applies.

Step 2: Obtain the required documents. Access the latest EASA approved revision of Eurocopter EC 225 Alert Service Bulletin (ASB) No. 05A005. Start with Revision 1, but check EASA’s website for any later revision. Also obtain Eurocopter EC 225 Service Bulletin (SB) No. 62‑007 (latest EASA approved revision). These documents contain the detailed procedures.

Step 3: Perform the initial check. If the initial check was not performed before 9 April 2009, the helicopter must be grounded until it is done. Using the instructions in ASB 05A005 Revision 1 (or later) paragraph 2.B.2, check for cracks in the dome fairing support at the dome fairing attachment points. Also readjust the tightening torque of the screws that secure the dome fairing support to the dome fairing. Record the findings, torque values, and any damage.

Step 4: Perform the torque re‑adjustment. Using ASB 05A005 Revision 1 paragraph 2.B.3, readjust the tightening torque of the dome fairing support attachment screws on the dome fairing. This is the same as the initial check but may be a separate step. For the initial check, both steps (2.B.2 and 2.B.3) are required.

Step 5: Schedule repetitive checks. After the initial check, schedule the next check at or before 165 flight hours from the initial check. The check each time must include both inspection for cracks and torque readjustment per paragraphs 2.B.2 and 2.B.3 of the current ASB revision. Continue at intervals not exceeding 165 flight hours.

Step 6: If a crack is found. Immediately ground the helicopter. Do not fly again until the dome fairing support and the associated coning stop support assembly are removed and replaced in accordance with SB 62‑007 (latest EASA approved revision). After replacement, the repetitive check requirement ends; no further 165‑hour checks are needed.

Step 7: Consider proactive terminating action. Even if no crack is found, the operator may choose to replace the parts per SB 62‑007 at a convenient maintenance opportunity. This is a one‑time cost that eliminates all future repetitive inspections. The AD encourages this by making it the only way to stop inspections. Operators should calculate the net present value of ongoing inspections versus the cost of the modification.