Apparatus and method for eddy current inspection of structures

A probe apparatus for eddy current inspection of a tapered, annular cavity of a structure of an air vehicle, the probe apparatus comprising:

• a connector end configured to connect to a rotating scanner device;
• and,
• a sensor end connected to the connector end via a body portion, the sensor end comprising:
• three foot portions, each foot portion comprising a mounting element attached to a base element;
• two eddy current elements comprising a reference eddy current coil attached to the mounting element of one foot portion and a test eddy current coil attached to the mounting element of another foot portion;
• a positioning mechanism comprising three positioning arm elements, each positioning arm element attached to each respective foot portion, the positioning mechanism configured to position the two eddy current elements against cavity walls of the tapered, annular cavity of the structure of the air vehicle to be inspected with the probe apparatus, when the probe apparatus is positioned within the tapered, annular cavity;
• and,
• an aligning mechanism comprising three pivot joint mechanisms, each pivot joint mechanism attached to each respective foot portion, the aligning mechanism coupled to the positioning mechanism, the aligning mechanism configured to align the two eddy current elements in a perpendicular position with respect to the cavity walls of the tapered, annular cavity, when the probe apparatus is positioned within the tapered, annular cavity.

A differential method of performing an eddy current inspection of an annular cavity of a structure, the method comprising the steps of:

• attaching a rotating scanner device to a connector end of a probe apparatus, the probe apparatus comprising a sensor end comprising:
• two or more eddy current elements comprising at least one reference eddy current coil and at least one test eddy current coil;
• a positioning mechanism;
• an aligning mechanism coupled to the positioning mechanism;
• and
• three or more foot portions, each foot portion attached to the positioning mechanism and attached to the aligning mechanism, and each foot portion comprising a mounting element and a base element, the mounting element having a first side attached to one eddy current element and having a second side attached to the base element:
• inserting the probe apparatus into the annular cavity of the structure to be inspected and rotating the probe apparatus with the rotating scanner device;
• positioning with the positioning mechanism the two or more eddy current elements against cavity walls of the annular cavity to be inspected with the probe apparatus;
• aligning with the aligning mechanism the two or more eddy current elements, so that each of the two or more eddy current elements is in a perpendicular position with respect to the cavity walls of the annular cavity to be inspected with the probe apparatus;
• and,
• emitting and receiving signals to and from the two or more eddy current elements and the rotating scanner device to obtain data providing an indication of structural health of the structure.