Introduction
The vast majority of components which are fitted to aircraft today are considered to be on condition, this means that the component may remain fitted to the aircraft until an imminent failure is detected.
However even components which are on condition are typically subject to configuration control – which means the component which is fitted must correspond to the aircraft data. Essentially it is only when the dash no (of the part No is incremented is there likely to be a configuration issue.
The important thing is to ensure the component status is clearly identified on the incoming documentation – Form 1 or 8130-3 or equivalent
Certain Components which are fitted to the aircraft have a life which can be described in Flying Hours FH, Cycles CYC or Calendar Time CAL. The technical records for these “life limited components” form part of the Continuing Airworthiness Records and are of critical importance to the integrity of the technical records.
Note also that when these components are removed serviceable they are considered to be “part life” and we should ensure that we track and officially recorded this information.
In Addition, Components are subject to various Airworthiness Directives AD’s Modifications and Service Bulletins. It may also be that Part No of the component changes after modification. For example, a component part No 1234-02 changes and becomes a 1234-03.
Alternatively, the modification data plate may be altered to record that mod 1 (for example has been accomplished)
Life Limited Parts – Traceability
To enable the traceability of LLP it is required to have details of the part “Back to Birth” in terms of Fitment & and Certifiable Hrs, Cyc or Landings. Not only from a regulatory compliance point of view but in terms of the obligations under a lease agreement.
There are no industry templates to support Back to Birth evidence so it is up to the organisation Incoming Inspection to satisfy this element – Discuss!
Retention Period For Component Technical Records (Not LLP)
The requirements that apply to a service life-limited component (see definition in AMC M.A.305) are basically stated in M.A.305 (e) and (h).
All detailed maintenance records of a maintenance action (e.g. a restoration) must be kept until another maintenance action equivalent in scope (another restoration) is done, but never less than 36 months. Keep in mind that:
- a service life limited component log card must be kept with all the relevant information, so the action should be recorded there, and
- the records showing compliance with other requirements stated in M.A.305, e.g. an airworthiness directive, or any other information that could be affecting the configuration of the aircraft, must be retained too.
So clearly we can see that the EASA regulations do not support an effective component management process as “preferred” by many stakeholders within the industry. The challenge becomes to accept that Hrs / Cycs & Lndgs are NOT going to be available for ALL components. (They must be for LLP of course)
14 CFR Part 43.10 titled “Disposition of life-limited aircraft parts.”
Life-limited Part means any part for which a mandatory replacement limit is specified in the type design, the Instructions for Continued Airworthiness, or the maintenance manual.
A life-limited part is designated as such during the certification process. The key word in the definition is “mandatory.” That is a mandatory replacement limit as opposed to a recommended replacement limit.
Life status means the accumulated cycles, hours, or any other mandatory replacement limit of a life-limited part.
The second term defined in the new rule is “life status.” The “life status” is simply where the part is in its life cycle or timeline or how much of the limit is used up.
The mandatory replacement times for a part come initially from the type certificate. The type certificate for an aircraft, engine, or propeller either calls out the mandatory replacement limit for parts specifically within the content of the type certificate or it may refer to another document that calls out the limitations.
Best Practice
a) Each time a part is removed from an aircraft the life status must be recorded or updated in the record keeping system. The system may be computer or paper-based and must include the part number, serial number, and current life status of the part.
b) Life-limited parts can be removed and segregated from all other parts as long as a system is in place to record the part number, serial numbers, and life status of the part and the parts are stored in a physical location unmistakably separate from parts that are eligible for installation on an aircraft, engine, or propeller.
c) Life-limited parts are generally serialized, but not always. For example, the wing bolts on a Raytheon King Air B200 are limited to 15 years but they are not serialized or marked in any special way.
d) Part Life LLP should be accepted into the system with addition acceptance by the Engineering Technical Services and or Quality Assurance Dept.
Next Steps
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