Subcontracted penetrant inspection and a critical task at 02:00
An EASA Part-145 organisation holds a line maintenance approval for the Airbus A320 family and Boeing 737 NG at its main base. During an overnight transit check on an A320, a technician finds a crack indication at a wing spar fitting. The type certificate holder's structural repair manual requires fluorescent penetrant inspection of the fastener holes before a repair can be designed. The organisation employs no NDT staff at this station. The shift manager proposes to use a local NDT company which holds EN ISO 9712 Level 2 certification for penetrant testing but is not approved under Part-145 and has no quality system recognised by the competent authority; the company would issue its report under its own letterhead. The repair that follows has been designated by the operator as a critical maintenance task, and only one licensed engineer is on duty after 02:00.
1. Can the Part-145 use the local NDT company? What conditions apply and who remains responsible?
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Specialised services of this kind - NDT, welding, heat treatment, calibration, plating - may be provided by an organisation that does not itself hold a Part-145 approval, but only inside a controlled arrangement. The Part-145 must:
- Have the arrangement covered by its MOE and procedures, and, where the rule or the competent authority requires it, have the provider accepted or notified;
- Audit the provider's competence and quality arrangements rather than merely accepting a certificate;
- Ensure the inspection is performed to the approved data (the SRM procedure or an approved repair scheme) by qualified Level 2 or Level 3 personnel under a recognised scheme such as EN 4179 or EN ISO 9712, with the certification scope actually covering penetrant testing of the relevant material and geometry;
- Maintain traceability of the report into its own work pack, with the results evaluated against the acceptance criteria in the approved data.
The Part-145 remains responsible for the airworthiness of the work performed under its control; the subcontractor's report is evidence, not a release. What is not acceptable is using an unassessed company because it is 02:00 and convenient. If the procedures do not yet cover subcontracting of NDT, they must be amended and accepted before the work is done; alternatively the aircraft is moved to an organisation approved for the task.
2. Who issues the certificate of release to service once the inspection and repair are complete, and what must it reference?
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The CRS is issued by the Part-145 that performed and controlled the maintenance, by certifying staff authorised for that aircraft type and task - here B1.1 staff authorised on the A320. It is not issued by the NDT company, which is not Part-145 approved for the aircraft and cannot release it.
Before signing, the certifying staff must confirm that: the NDT report is acceptable (correct method, correct procedure, qualified signatory, results evaluated against the limits in the repair scheme); the repair was carried out in accordance with approved data; any independent inspection required for the critical task has been completed and separately recorded; and any functional test or re-protection (sealant, corrosion protection) has been completed.
The CRS must identify the maintenance data used (SRM reference and repair scheme number), the date, the certifying staff and the organisation, and state that the work was carried out in accordance with the approved data. If the repair is major, the approved design data must be referenced and the repair entered in the aircraft logbook. Loose reference to 'repair carried out' without the data reference breaks the traceability the airworthiness review will later depend on.
3. How must the critical task and the shift handover be managed given the staffing?
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The critical-task designation triggers an independent inspection: a second person, not involved in the work, competent and authorised for it, who physically verifies the completed task against the maintenance data and signs separately. The MOE must contain the list of critical maintenance tasks and the procedure, and the task card must have distinct 'performed by' and 'inspected by' blocks.
After 02:00 with one licensed engineer, the task cannot be completed and released. The options are: stop before the critical step; call in another authorised inspector; or defer, if the item is deferrable under the operator's procedures - which a structural repair normally is not. Releasing on a single signature, or asking a colleague to sign an inspection they did not perform, is a falsification of the maintenance record, not a shortcut.
Handover is a recognised human-factors risk point. The incoming shift must receive written and verbal handover identifying exactly what is open, what has been inspected, by whom, and what has not, and must not sign for work done by the outgoing shift. The organisation should also review why the task was scheduled onto a single-person shift, and record the event through its error-capturing and human-factors processes rather than treating it as an individual failing.