66-30-03 DORNIER: Amdt. 39-320 Part 39 Federal Register December 16, 1966. Applies to All Model DO 28 B-1 Airplanes.
Compliance required as indicated.
To detect cracks of the horizontal stabilizer spar in fuselage attachment brackets, accomplish the following:
(a) Within the next 10 hours' time in service after the effective date of the AD, unless already accomplished within the last 90 hours' time in service before the effective date of this AD and thereafter at intervals as specified below, visually inspect the welded hinge brackets P/N 28.315-01 H01 on the stabilizer front spars for cracks in the base plate in the area of the upper and lower spar flanges, using a lamp, mirror and at least a three-powered glass.
(b) If no cracks are found as a result of the inspection required by (a), the bracket is considered serviceable and the inspection must be repeated at intervals not to exceed 100 hours' time in service since the last inspection.
(c) If cracks ofless than 1/2 inch in length are found, the inspection must be repeated at intervals not to exceed 10 hours' time in service, up to a maximum of 100 hours' time in service since the initial inspection. Upon accumulation of 100 hours' time in service since initial inspection, replace bracket P/N 28.315-01 H01 with new bracket P/N 28.315-01 H03 or FAA- approved equivalent.
(d) If cracks greater than 1/2 inch in length are found, prior to next flight, replace bracket P/N 28.315-01 H01 with new bracket P/N 28.315-01 H03 or FAA-approved equivalent.
(e) The repetitive inspections required by (a), (b), and (c) may be discontinued after new replacement bracket P/N 28.315-01 H03 is installed.
(Dornier Technical Bulletin No. 28-44 dated October 11, 1966, pertains to this subject.)
This directive effective December 26, 1966.