Return to Service After an Unapproved Alteration
A maintenance facility installs a cabin reconfiguration on a business jet: new seat tracks, relocated cabinetry, and a revised electrical load for galley equipment. The facility holds an airframe rating but not a design approval. The work was performed to a drawing package supplied by the owner's interior designer, which shows the layout but contains no structural substantiation and no electrical load analysis. The facility's inspector signs off the installation as 'completed per drawing.' Six months later, during an annual inspection at another facility, an inspector finds that the seat track fasteners penetrate a floor beam without the required edge distance and that the galley circuit exceeds the original breaker rating. The aircraft has been flying with passengers throughout. The owner wants the new facility to 'just fix the fasteners and sign it off' so the aircraft can return to service quickly.
1. Assess the airworthiness status of the alteration and the facility's position, and determine what is required before return to service.
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The alteration was not properly approved. A layout drawing from an interior designer is not approved design data. The facility held an airframe rating but not a design approval, so it could install an approved alteration but could not create the approval. Structural substantiation for seat tracks and floor-beam attachment, and an electrical load analysis for the galley circuit, are missing. The installation therefore is an unapproved alteration, and the aircraft has been operating in that condition.
The two findings are airworthiness defects, not cosmetic issues. Fasteners penetrating a floor beam without edge distance affect structural integrity under load; an oversized galley circuit risks overload and fire. Both require design evaluation, not field correction by the same facility.
Before return to service, the operator needs: approved design data covering the structural attachment and the electrical load; a conformity inspection against that data; correction of the fasteners to the approved edge distance, with any beam damage assessed; and a revised electrical configuration with correct circuit protection. The correcting facility must hold the appropriate ratings and work to approved data. If it cannot obtain design approval, it must route the design to an approved design organization and then perform the installation to that data. A sign-off 'per drawing' is not a return-to-service basis for an unapproved alteration.
2. What records and approvals should exist, and how should the owner's request to 'just fix and sign' be answered?
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The records should include: the approved design data and its approval basis; the electrical load analysis; the structural substantiation; the conformity inspection records; the work order describing the corrective actions; and a return-to-service statement by an authorized person. If the alteration is major, the applicable approval and any operating limitations must be documented, and the aircraft's weight and balance and equipment list updated.
The owner's request should be answered directly: the facility cannot sign off an alteration it did not approve, and cannot certify conformity to data that does not exist. Fixing the fasteners without design substantiation would leave the structural question unresolved and would create a false record. The facility should explain the two paths - obtain approved data and correct to it, or remove the alteration and restore the original configuration - and let the owner choose. It should also document the as-found condition and notify the operator in writing, because the aircraft has been flying noncompliant and the operator needs to assess past flights. Speed is achievable through the approved-data route, but not by skipping it.