English to French Tech/Engineering Aerospace / Aviation / Space

(a) With the tap test hammer, hit the outside surface of the stringers and front spinner shell continuously with a light constant force, and listen for changes in sound which can show damage below the surface.
NOTE: In the tap test, you hit the outside surface of the spinner and stringers with a hammer made specifically for the test. Changes in sound may indicate structural damage below the spinner surface.
NOTE: The tap tester must hear sounds in the frequency range of 3000 to 8000 hertz (hz) at 30 decibels (db) or lower in the better ear. Once a year, a tap tester must have a hearing examination.
CAUTION: SOME CHANGES IN SOUND ARE THE RESULT OF SUDDEN CHANGES IN SHELL THICKNESS OR A MATERIAL DIFFERENCE. THIS IS USUAL AND IS NOT A SEPARATION, VOID, OR EMPTY SPACE.
(b) During the tap test, use the tap test hammer at locations approximately 6.4 mm apart.
(c) If the tap test is done on the wing, the area must not have too much noise because the accuracy of the test is related to the sound levels and the differences in them. The tap test area must have a nominal intensity of 72 decibels with a maximum intensity of 75 decibels.
(d) If the tap test shows possible damage to the stringers or front spinner shell, make a mark to show the unsatisfactory area.
(e) If there is evidence of debonding in the stingers or the front spinner shell, the front spinner must be replaced.