Identify the hole and the inspection purpose

Fastener holes can be locations of stress concentration and fatigue damage. Eddy current examination may help investigate surface or near-surface discontinuities in conductive material, but the technique depends on the hole geometry, material and accessible surfaces. It does not establish the condition of every part of a bolted connection.

When discussing eddy current testing, provide hole dimensions, material information, drawings and the suspected damage location. Explain whether the objective is targeted investigation or a defined set of holes in a maintenance scope. Do not assume a probe used on a weld can provide the required hole coverage.

Coordinate dismantling before inspection

An installed fastener can obstruct the bore and affect signals. Where bore examination requires removal, that work needs an agreed dismantling sequence, competent personnel and the owner's controls for supporting and isolating the assembly. The inspector should not be left to improvise how a load-bearing connection is opened.

Record fastener and hole identities before parts are separated. Keep track of orientation and component pairing. If only the accessible mouth of a hole can be examined, state that restriction; it is not interchangeable with a scan of the bore through its full accessible depth.

Discuss probe and reference suitability

Diameter, depth, countersinks, threads, nearby edges and layered assemblies influence probe access and signal response. Conductivity, permeability, surface damage and lift-off can also affect interpretation. A suitable reference or calibration arrangement should represent the relevant material and geometry under the selected procedure.

Cleaning should remove interfering contamination without changing the feature under investigation. Coatings or residues inside a hole may introduce variable lift-off. Agree what preparation is needed, and record any ovality, burrs or wear that may complicate the examination rather than interpreting every response as cracking.

Keep findings tied to hole coordinates

A useful result identifies the hole, examined depth or region, orientation reference and indication location. Save the relevant signal evidence where the scope calls for it. State limitations such as restricted probe travel, inaccessible layers or a reference that does not represent part of the geometry.

An eddy current response is not automatically a crack or a rejectable condition. Verification may involve repeat examination, another suitable surface method or engineering review. If the geometry prevents reliable sizing, report that fact instead of turning signal amplitude into an unsupported physical crack dimension.

Plan the follow-up interface

For example, an investigation of a row of holes could use numbered locations on a drawing and a clock-position convention viewed from a stated side. That arrangement lets a reviewer request confirmation at one hole without confusing it with its neighbour. It is a planning example, not a completed client result.

Keep reassembly requirements and the disposition of findings separate from the NDT record. The responsible engineer or owner determines the next action using the relevant evidence and requirements. A no-indication result does not resolve fastener preload, joint design or load capacity, which are different questions.