Proving the Life of the Part: RSC Traceability, Regulation & Risk Mitigation

As aircraft component interchangeability increases, Removable Structural Components (RSCs) present unique technical and commercial challenges. RSCs—such as doors, flaps, and nacelles—can be reused across airframes, leading to lifecycle desynchronization and regulatory risk if not independently tracked. To maintain airworthiness and maximize asset value, traceability must be established and maintained throughout a component’s life, particularly when components are removed, transferred, or reinstalled. This paper outlines industry expectations, traceability models, and Avtrac’s methodology for delivering defensible RSC lifecycle documentation, referred to as a Dirty Finger Print (DFP).

Understanding RSCs & Their Significance

RSCs include structural elements that affect aircraft safety and compliance. Because these components can be moved between aircraft, they accumulate usage independently from the airframe. If this usage is not accurately recorded and validated, compliance may be jeopardized and asset valuation diminished. Airbus, EASA, and FAA all recommend or mandate component-level tracking of high-value assemblies such as flaps, stabilizers, and pylons.

Airworthiness and Compliance Considerations

RSCs are often subject to specific maintenance intervals, life limits, and repair tolerances set out in Airworthiness Directives (ADs) and Airworthiness Limitations Sections (ALS). When full service history is unavailable, operators may use conservative reconstruction approaches referenced in EASA AMC 20-20B and FAA AC 120-93, such as using fleet leader data or manufacturing dates.

Dirty Finger Print (DFP) Defined

In Avtrac's methodology, 'DFP' refers to the complete historical record of an RSC. This includes its part number (PN), serial number (SN), OEM documentation, workcards, certificates, repair records, and installation history. A validated DFP ensures the component's service life and limitations can be confidently established, audited, and marketed.

Clarification on Monte-Carlo Counting Method (MCCM)

MCCM provides a statistical means of estimating the operational life of RSCs with incomplete history. It generates multiple simulations based on known usage profiles from similar aircraft. While widely accepted in industry and referenced in OEM In-Service Information, the MCCM output must be used with caution. Regulatory authorities do not mandate specific statistical thresholds (such as the 95th percentile), and any assumptions must be fully documented.

Avtrac’s RSC Traceability Support

Avtrac delivers a comprehensive RSC traceability service including:- On-site visual inspection and documentation of each component- OEM and OCCM records cross-verification- Lifecycle analysis using certified records and/or MCCM- Compilation of RSC Status Reports with validated FH, FC, and life remainingAvtrac’s program ensures regulatory compliance, reduces lease return friction, and protects aircraft value for operators and lessors.

Conclusion

RSC traceability has become an industry priority, not just a technical task. With growing regulatory scrutiny and commercial risk, operators and lessors must implement structured, audit-ready tracking systems. Avtrac’s process ensures full lifecycle transparency and delivers value by preserving airworthiness, compliance, and financial integrity of aircraft structural components.

To learn more about Avtrac's approach to RSC management including the MCCM approach download our whitepaper Proving the Life of the Part: RSC Traceability, Regulation & Risk Mitigation