AD/DART/32 - Fuel Burner Flow Calibration Checks

The AD is structured around a small set of interlocking concepts drawn from aviation airworthiness practice and the manufacturer’s service data. Those concepts are:

• Applicability by engine model and serial numbers. The AD lists specific Dart models and states that all serial numbers of those models are affected. The list includes groups such as Dart 528‑7E through 529D‑8Z variants, 531, 532‑series, 533‑2, 534‑2, 535‑series, 536‑series, 542‑4 series, 543‑10 series, 550‑2, and 552‑series. See the AD’s Applicability table for the full enumerated set. The AD also supplies two notes: Note 1 identifies typical aircraft types that carry these engines, clarifying that the list of aircraft is not exhaustive; Note 2 identifies an exclusion for engines incorporating Rolls‑Royce modification 1946 via SB Da72‑533.

• Mandatory conformity with a Service Bulletin. The Requirement section makes the Rolls‑Royce SB the operative technical document for how checks and follow‑up are to be done: “Accomplish the checks and follow‑up actions, as necessary, and in accordance with the instructions contained in Rolls‑Royce SB Da73‑A87 Revision 3 dated 19 November 2007.” The Compliance section ties the calendar and recurring‑check requirements to the SB’s thresholds, intervals and limits.

• Safety risk linkage: burner fuel flow variability and mechanical consequence. The Background statement identifies the causal chain the AD addresses: high burner fuel flow variations can produce HP turbine disc diaphragm stresses, be associated with vibratory excitation of HP turbine blade assemblies, accelerate wear between blade platforms and shrouds, and potentially create high stresses in the disc rim. The ultimate harm the AD seeks to prevent is engine damage and loss in flight.

• Cross‑regulatory reference. The AD explicitly refers to EASA AD 2008‑0004, indicating an international regulatory relationship and that the subject has been considered by the European Aviation Safety Agency. The AD also notes a specific Rolls‑Royce modification (1946) and a separate SB (Da72‑533) granting an exemption for motors with that mod incorporated.

• Effective date and issuer. The AD is dated 11 February 2008 (signed by a CASA delegate) and states an effective date of 10 April 2008. The AD is therefore a retrospective regulatory instrument signed prior to its effective date, and the Compliance section places obligations on operators after that effective date.

These concepts define the AD’s structure: identify the affected fleet; require specific calibration checks; require adherence to a named SB for methods, thresholds and intervals; exclude clearly defined modified engines; set an effective date; and rely on both CASA authority and the manufacturer SB as the technical standard. The AD does not itself restate the calibration procedure or the numerical thresholds and intervals; it delegates those technical specifics to the named SB.

The AD names the affected population by engine model (and implicitly by aircraft types). The direct obligors are any operators, owners, lessees, or maintenance organisations responsible for aircraft fitted with the enumerated Rolls‑Royce Dart engines, where those engines do not incorporate Rolls‑Royce modification 1946 via SB Da72‑533. The AD’s Applicability section explicitly lists engine models and states that the engines affected are “all serial numbers” of those models. Therefore an operator’s immediate question is whether the installed engine model and serial number appears on the list, and whether Rolls‑Royce modification 1946 has been recorded as incorporated.

The AD’s Note 1 clarifies that these engines are known to be installed on, but are not limited to, Fokker F27 series aircraft, Maryland Aircraft Industries (formerly Fairchild) F‑27 and FH‑227 series aircraft, and BAE Systems (Operations) Ltd HS.748 series aircraft. That indicates owners and operators of those airframes are likely to be within the affected population where the listed Dart engines are installed. However, the AD’s applicability is to engines themselves; the AD does not specify affected airframes beyond the illustrative note. Responsibility therefore falls to whoever holds operational control or maintenance responsibility for the aircraft and its engines , commonly the aircraft operator, aircraft owner, or maintenance provider , to determine applicability and ensure compliance.

Maintenance organisations and licensed engineers who carry out engine work are secondary addressees of the AD. The AD requires calibration checks and “follow‑up actions, as necessary,” done in accordance with the Rolls‑Royce SB. Those checks will typically be performed by appropriately rated maintenance personnel or approved organisations, which means maintenance providers will bear execution costs and scheduling duties.

Regulatory actors are also named implicitly. The AD is issued by a delegate of the Civil Aviation Safety Authority and cross‑refers EASA AD 2008‑0004. This indicates that national regulators and, through the cross‑reference, international regulators, are parties in the compliance ecosystem. The AD does not name enforcement agencies beyond the issuing delegate, nor does it set out civil or criminal penalties; it does, however, create a mandatory safety obligation for the identified engine population.

Finally, manufacturers or parts suppliers may be affected to the extent that “follow‑up actions” specified in the SB require replacement parts, overhaul procedures, or design changes. The SB is the operative technical document; if it requires parts or modifications, then parts suppliers will see demand generated by the AD.

Duties

• Perform the specified checks. The AD’s Requirement section states: “Accomplish the checks and follow‑up actions, as necessary, and in accordance with the instructions contained in Rolls‑Royce SB Da73‑A87 Revision 3 dated 19 November 2007.” Operators and maintenance organisations therefore must implement the calibration checks described in that SB.

• Follow SB thresholds, intervals and limits. The Compliance section requires operators to act “after the effective date this AD at the thresholds and within the time intervals and limits as indicated in Rolls‑Royce SB Da73‑A87 Revision 3.” The SB therefore controls when the first check is due, the periodicity of checks, and the numerical acceptability criteria and limits that trigger follow‑up action.

• Undertake follow‑up actions where checks indicate they are necessary. The Requirement wording includes follow‑up actions “as necessary,” which delegates judgement back to the SB’s defined accept/reject criteria and to maintenance personnel acting under the SB’s procedures. The AD thereby requires corrective action if calibration checks reveal fuel burner flow variations outside the SB’s allowed limits.

• Exclude engines with a specified mod. Operators whose engines have had Rolls‑Royce modification 1946 incorporated via SB Da72‑533 do not have to comply with this AD, per Note 2. The duty therefore includes confirming whether that modification is recorded for the engine in question.

Rights and procedural implications (as stated or implied in the AD)

• Right to rely on the SB. The AD expressly adopts the SB as the technical avenue for compliance. Operators and maintenance providers are thereby eligible to meet the AD through actions prescribed in SB Da73‑A87 Rev 3.

• Right to interpret applicability by serial number. The AD lists engine models and indicates “all serial numbers” for those models. Operators have the right and duty to check serial number records to determine applicability; the AD does not require an operator to assume applicability without checking serial numbers and mod records.

• Right to documentation-based exclusion. Engines on which modification 1946 is recorded as incorporated via SB Da72‑533 are excluded; operators have the right to rely on accurate maintenance records to establish that status.

Missing duties and silent points in the AD text

• The AD does not itself specify record‑keeping obligations, nor does it specify enforcement mechanisms or penalties within the text provided. The AD also does not reproduce the calibration procedure, thresholds, or intervals , these are contained in the referenced SB. The practical effect is that the AD delegates technical detail to the Rolls‑Royce SB, while making adherence to that SB a regulatory duty.

Who decides operationally

• The AD identifies the Civil Aviation Safety Authority through its delegate as the issuing authority. Operationally, the required decisions , whether an engine requires follow‑up action based on a calibration check, and what that follow‑up action is , are decided by the maintenance procedures set out in the SB and by the maintenance personnel who apply those procedures. The AD therefore places decision rights for technical corrective steps with the combination of the SB (a manufacturer specification) and the certificated maintenance organisation or licensed engineer executing the work.

The AD text supplied does not specify any particular penalties, fines, or criminal sanctions for non‑compliance. The instrument states the safety requirement, the operative technical reference (Rolls‑Royce SB Da73‑A87 Revision 3), and the effective date (10 April 2008), but it contains no express enforcement provisions or penalty schedule in the text provided. The only enforcement‑adjacent elements shown are:

• Issuing authority and signature. The AD is signed by “David Punshon, Delegate of the Civil Aviation Safety Authority,” dated 11 February 2008. The presence of an authorised regulator’s delegate signature indicates the AD is an instrument of regulatory authority. In aviation regulatory practice, an AD issued under a national regulator is a mandatory requirement; however, the AD text itself does not reproduce or attach a statute or administrative code provision that sets out enforcement processes or sanctions.

• Cross‑reference to EASA AD 2008‑0004. The AD “Note 3” indicates that EASA AD 2008‑0004 dated 11 January 2008 is referred to in the SB reference, signalling that the subject has international regulatory alignment. EASA ADs often sit within an enforcement regime in EASA’s member states; this cross‑reference shows the issue has been considered in another regulator’s AD, but the current AD text does not import specific EASA enforcement measures.

What the AD does not say about enforcement

• No specific civil or criminal penalty descriptions. The AD text contains no enumerated consequences for failing to perform the checks as required, nor any administrative process for notices, rectification orders, or penalties. The AD likewise does not specify audit, inspection, or reporting obligations in the supplied text.

• No appeals, exemptions, or variation process described. The AD does not set out procedural steps for seeking an exemption, alternative method of compliance, or applying to defer work. If such processes exist in the relevant regulatory framework, they are not reproduced in the AD text provided.

Implications for operators

• Because the AD makes the SB’s methods and thresholds mandatory, an operator who does not perform the required calibration checks and follow‑up actions will be out of compliance with the AD as written. The immediate practical enforcement risk is that an aircraft or engine may be grounded by regulatory inspection, or that an operator’s certificate or maintenance approvals may be challenged, but the AD text does not itself describe those enforcement mechanisms or penalties.

• The lack of expressed penalties or procedure in the AD text means operators must look to the broader Civil Aviation Safety Authority regulatory framework, their operating and maintenance manual obligations, and any national aviation acts or regulations for the explicit enforcement and sanction mechanisms applicable to AD breaches. The AD itself is a mandatory directive, but the supplied text leaves enforcement specifics to the wider regulatory system which is not reproduced here.

The AD’s text contains limited explicit cross‑references, but those it does contain indicate the intended regulatory and technical interactions.

• Interaction with Rolls‑Royce service documentation. The AD explicitly incorporates Rolls‑Royce SB Da73‑A87 Revision 3 dated 19 November 2007 by reference as the required procedure for calibration checks and follow‑up actions. Mechanically, the AD imports the SB into the regulatory requirement, so compliance with the SB satisfies the AD. The AD also references SB Da72‑533 as creating an exclusion for engines incorporating Rolls‑Royce modification 1946. Thus the AD interacts directly with manufacturer service documentation: it makes that documentation the operative technical standard. Operators must therefore treat the SBs as primary compliance documents for this directive.

• Cross‑regulatory interaction with EASA. Note 3 in the Requirement section says: “EASA AD 2008‑0004 dated 11 January 2008 refers.” That indicates the same technical concern has been the subject of an EASA AD and that outcomes or methods in EASA’s filing inform or parallel the CASA AD. The AD therefore interacts with international regulatory instruments, at least as a point of reference, and potentially as harmonised safety practice.

• Interaction with maintenance and airworthiness responsibilities. The AD targets engine airworthiness and specifically requires calibration checks and corrective actions on burners. That places the AD within the domain of maintenance obligations which normally sit inside an operator’s Continuing Airworthiness Management arrangements and approved maintenance organisation obligations. Although the AD text does not restate those wider statutory responsibilities, operators will need to harmonise their maintenance planning, logbooks, and continuing airworthiness records with the AD’s requirements.

• Exclusion by prior modification. The AD renders engines incorporating modification 1946 via SB Da72‑533 out of scope. That creates an interaction with prior modification records and the chain of maintenance documentation. Operators who have incorporated the earlier SB must ensure records reflect that status to rely on the exclusion. Conversely, operators without such a modification cannot rely on that exclusion. Thus the AD interacts with the record‑keeping and modification entry systems used to evidence compliance with prior mandatory or optional modifications.

• Silent interactions not reproduced in the AD text. The AD does not include wider statutory or regulatory references such as the enabling legislation for CASA, the offences or penalty provisions that might apply for failure to comply, or the processes for alternative methods of compliance. Those interactions therefore exist outside the AD text and must be determined from the applicable aviation regulatory framework. The AD’s importation of the SB means that any legal duties arising from using or failing to use manufacturer documentation become applicable insofar as they are adopted by the AD.

In summary, this AD primarily interacts with manufacturer service bulletins (it adopts SB Da73‑A87 Rev 3 and references SB Da72‑533), and it signals regulatory alignment with an EASA AD. The AD’s operational effect will thereby depend on how operators incorporate the SB procedures into their maintenance and airworthiness systems, and on their documentation of prior modifications which can alter applicability.

The AD text supplied identifies a small, concrete amendment history and document provenance. The key documentary dates and revisions in the text are:

• Rolls‑Royce SB Da73‑A87 Revision 3 dated 19 November 2007. The AD requires compliance with the checks and follow‑up actions “in accordance with the instructions contained in Rolls‑Royce SB Da73‑A87 Revision 3 dated 19 November 2007.” The SB revision date is therefore the operative technical baseline the AD adopts.

• EASA AD 2008‑0004 dated 11 January 2008. The AD references this EASA AD as relevant. The presence of this date indicates a prior or parallel regulatory action at the European level shortly before the CASA AD was signed.

• Civil Aviation Safety Authority signature dated 11 February 2008. The AD is signed by David Punshon, identified as a delegate of CASA, on 11 February 2008. That is the issuance date of the AD.

• Effective date of the AD: 10 April 2008. The AD explicitly states that it becomes effective on 10 April 2008. That establishes a lead time between issuance and the date after which the SB thresholds and intervals must be observed.

The AD document identifier itself is AD/DART/32 with the label 4/2008. That coding indicates the AD’s place in the CASA AD series for 2008. The AD does not include any subsequent amendments or superseding instruments in the supplied text. No later revision dates of the AD itself are present. The AD does not reproduce any historical versions of Rolls‑Royce SB Da73‑A87; it requires Revision 3 as the operative revision. The AD also notes a Rolls‑Royce modification (1946) incorporated via SB Da72‑533; that modification, where present, excludes the engine from the AD’s scope. The AD does not state whether earlier SB revisions were considered or mandated previously for the same issue.

Because the AD adopts a specific SB revision and references a specific modification SB for exclusion, the AD’s amendment history is primarily the intersection of SB revisioning and this AD issuance. Any subsequent change in the SB or new regulatory ADs would alter the compliance landscape, but those subsequent instruments are not part of the AD text provided.

The supplied AD text contains no information about litigation, disputes, judicial reviews, enforcement proceedings, or challenges to the AD. There is no mention of any legal proceedings either before or after issuance. The AD includes administrative metadata (issuing delegate, date, effective date) and technical and applicability instructions, but it does not record any legal contests or case names.

Accordingly, based solely on the provided text, there is no litigation history to report. If operators or other parties wished to challenge the AD, the AD text does not set out the procedural route for challenge, nor does it reference any past or pending legal proceedings. Any matters of litigation, if they exist, fall outside the supplied document and must be sourced from other records or regulatory files not included in the AD text here.

The AD text contains several concrete points that can cause incorrect compliance conclusions if they are overlooked. These practical pitfalls are drawn directly from the wording of the AD.

• Applicability is model‑specific but broad by serial number. The AD lists many Dart engine models and states “all serial numbers” for the listed models. A operator of a listed engine cannot assume exemption based on age or partial model similarity. You must check the engine model precisely and the serial number. Treat the list as exhaustive for engine models named, but do not assume that an aircraft type note (Note 1) limits the scope.

• Exclusion depends on an explicit modification and recorded SB incorporation. Note 2 states that engines on which Rolls‑Royce modification 1946 has been incorporated via Service Bulletin Da72‑533 are not affected by this AD. The exclusion is not automatic; it depends on the modification being sufficiently recorded in the engine’s maintenance records. Operators without documented incorporation of mod 1946 cannot presume exemption. Failure to verify records is a common operational gotcha.

• The AD does not reproduce the SB technical detail. The AD requires compliance with Rolls‑Royce SB Da73‑A87 Revision 3 dated 19 November 2007. The AD does not include thresholds, numerical limits, nor the precise calibration technique. A frequent operational mistake is to assume the AD itself contains the technical steps. In practice, operators must obtain the referenced SB and follow it exactly.

• Timing and intervals are defined by the SB, not the AD. The Compliance section requires action “after the effective date this AD at the thresholds and within the time intervals and limits as indicated in Rolls‑Royce SB Da73‑A87 Revision 3.” That means the AD’s timing obligations are not self‑executing; they refer to the SB’s schedule. Misreading the AD as setting an independent calendar could cause mistimed checks.

• “Follow‑up actions, as necessary” can include corrective work. The Requirement calls for checks and follow‑up actions “as necessary.” The SB will define accept/reject criteria that trigger follow‑up actions; those can include repairs, adjustments, or parts replacement. Operators must plan for the possibility of additional maintenance tasks and potential part lead times.

• EASA reference may indicate parallel obligations. Note 3 refers to EASA AD 2008‑0004 dated 11 January 2008. Operators with operations in EASA jurisdictions may need to check whether parallel ADs impose different procedural or timing requirements. The AD does not reconcile any differences; it merely references the EASA AD.

• Effective date lag. The AD was signed 11 February 2008 and states it becomes effective 10 April 2008. Operators should be aware that obligations apply “after the effective date,” so planning windows exist to source the SB, schedule checks, and confirm records. However, where an SB threshold coincides with an interval prior to the effective date, the SB’s thresholds could create near‑term requirements that must be addressed once the AD is effective.

• Aircraft type note is illustrative, not limiting. Note 1 lists Fokker F27, Maryland/Fairchild F‑27 and FH‑227, and HS.748 as known installations but expressly states the list is “not limited to” those aircraft. Operators of other airframes with the listed engines should not assume their aircraft are exempt.

• The AD text lacks explicit enforcement and documentation guidance. The AD does not specify how to log compliance or how regulators will verify it. Operators should not assume informal or lax verification; they should prepare contemporaneous records in line with their usual continuing airworthiness management processes.

Each of these items is taken from the AD language. The practical upshot is that operators must check engine identity and modification history, obtain and follow SB Da73‑A87 Rev 3, plan for potential repairs, and be alert to cross‑jurisdictional ADs such as EASA AD 2008‑0004.

The AD makes compliance straightforward in principle: obtain Rolls‑Royce SB Da73‑A87 Revision 3 dated 19 November 2007, determine applicability for each engine, and perform the required burner flow calibration checks and any follow‑up actions per the SB at the thresholds and intervals the SB prescribes, after the AD’s effective date of 10 April 2008. In practice, compliance steps are:

1. Confirm applicability

   • Verify the engine model against the AD’s Applicability list. The AD names specific Dart models and indicates “all serial numbers” for those models.
   • Check the engine’s modification record to confirm whether Rolls‑Royce modification 1946 (SB Da72‑533) has been incorporated. If that modification is recorded as incorporated via SB Da72‑533, the engine is excluded from this AD per Note 2.

2. Obtain the operative service bulletin

   • Acquire Rolls‑Royce SB Da73‑A87 Revision 3 dated 19 November 2007. The AD mandates compliance with the procedures and thresholds contained in that SB. The AD does not replicate the SB’s technical content; obtaining the SB is essential.

3. Schedule and perform calibration checks

   • Using the thresholds and intervals specified in SB Da73‑A87 Rev 3, schedule the first calibration checks and subsequent recurring checks to occur “after the effective date” of the AD (10 April 2008). Ensure checks are performed by appropriately qualified maintenance personnel or an approved maintenance organisation as applicable to your operations and regulatory approvals.

4. Follow SB‑specified accept/reject criteria and take follow‑up actions

   • The Requirement includes performing “follow‑up actions, as necessary.” That phrase binds operators to the SB’s accept/reject criteria. If checks reveal burner fuel flow variations outside allowable limits, perform the corrective actions specified in the SB. Those actions may include adjustment, repair, overhaul, or replacement of parts, as detailed in the SB.

5. Document completion and maintain records

   • Although the AD text does not specify record‑keeping procedures, document the completion of checks and any follow‑up actions in the aircraft and engine technical logs and in the continuing airworthiness records consistent with your organisation’s obligations. If the operator intends to rely on an exclusion (Rolls‑Royce mod 1946), ensure that the modification and SB Da72‑533 incorporation are documented.

6. Coordinate with operations and maintenance planning

   • Anticipate downtime for checks and potential follow‑up repairs. Incorporate the checks into scheduled maintenance visits where feasible, consistent with the SB thresholds and intervals, to reduce operational disruption.

7. Consider cross‑jurisdictional obligations

   • Note 3 refers to EASA AD 2008‑0004. If operating in jurisdictions where EASA ADs apply, confirm whether any additional or differing requirements are imposed by EASA or by other national regulators, and reconcile those with the CASA AD and the SB instructions.

8. Seek technical clarification from the manufacturer where required

   • If the SB’s procedures leave operational questions (for example, ambiguous accept/reject measurement interpretation), seek clarification from Rolls‑Royce or an authorised representative. The AD requires adherence to the SB, so documented manufacturer guidance will support compliance.

9. Monitor for further regulatory or SB changes

   • The AD adopts a specific SB revision and an effective date. Subsequent revisions of the SB or new ADs could change intervals, thresholds, or methods. Maintain an active process to monitor for SB updates or amended ADs.

10. Record evidence in the event of inspection

• Prepare an auditable trail showing that checks were scheduled and performed in accordance with SB Da73‑A87 Rev 3 and that any corrective actions were executed as required. The AD itself does not specify how regulators will verify compliance, so keeping comprehensive records is prudent.

These steps reflect the AD’s operative requirements: verify applicability, follow the named SB, adhere to SB thresholds and intervals from the AD’s effective date, document the work, and manage the logistical impact of any follow‑up corrective actions. The AD does not provide technical detail of the checks; compliance therefore depends on strict adherence to Rolls‑Royce SB Da73‑A87 Revision 3 and to accurate modification and maintenance records confirming whether an exclusion (mod 1946 via SB Da72‑533) applies.