70-07-01 HAWKER SIDDELEY: Amdt. 39-960 as amended by Amendment 39-1416. Applies to Model DH 104 "Dove" airplanes.
Compliance is required as indicated.
(a) Within 25 hours' time in service after the effective date of this AD, visually inspect the tubular engine mounting structure, P/N 4EM.201A and 4EM.203A, for external evidence of internal corrosion (paint blistering, pin holes, etc.), cracks, or structural defects. (Particular attention should be given to the lower tubes and welded joints.) If any evidence of internal corrosion, cracks, or structural defects is found, before further flight comply with paragraph (c). If no evidence of internal corrosion, cracks, or structural defects is found, repeat the visual inspection within each 100 hours' time in service since the last inspection.
(b) Conduct x-ray inspections of engine mounting frames in accordance with paragraph (c) as follows:
(1) For engine mounting frames serial numbers DHB/1 and subsequent or prefixed by "DH/...", including those frames incorporating Modification PP.225, within the next 25 hours' time in service after the effective date of this AD, unless already accomplished within the last four years prior to the effective date of this AD, and thereafter at intervals not to exceed four years from the last inspection.
(2) For engine mounting frames serial number prefix "S4/DHB/..." or "BGB/DHB/..." (manufactured to the standards of Modification PP.225), within 10 years after the date of manufacture and thereafter at intervals not to exceed four years from the last inspection.
NOTE: See Hawker Siddeley Technical News Sheet Series: CT(104) No. 190, Issue 3, dated September 14, 1970, for dates of engine mount manufacture.
(c) Conduct an x-ray inspection in accordance with Hawker Siddeley Technical News Sheet Series: CT (104) No. 190, Issue 1, dated August 24, 1964, or Issue 3, dated September 14, 1970, or FAA-approved equivalent. If internal corrosion, cracks,or structural defects are found, before further flight replace or repair the engine mounting frame in accordance with de Havilland Division Factory-approved instructions or an equivalent approved by the Chief, Aircraft Certification Staff, FAA European Region. If no internal corrosion, cracks, or structural defects are found, the frame may be returned to service.
(d) Within 25 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 30 hours' time in service since the last inspection, visually inspect the engine mount pickup fittings for loose rivets and structural defects. If loose rivets or structural defects are found, before further flight replace or repair in accordance with de Havilland Division Factory-approved Instructions Technical News Sheet CT (104) No. 49, dated 2 February 1951, or an equivalent approved by the Chief, Aircraft Certification Staff, FAA European Region.
(e) Upon incorporation of Modification 524 (and repair R4W169), the 30-hour periodic inspection specified in paragraph (d) may be changed to inspections not to exceed 100- hour intervals.
(f) It is requested that notification in writing of the results, positive and negative, of all of the above required inspections be given the Chief, Engineering and Manufacturing Branch, Aeronautical Center, AC-210. (Reporting approved by the Bureau of the Budget under BOB No. 04-R0174.)
This supersedes AD 55-20-01, published in 21 F.R. 9538, and AD 65-20-02, Amendment 39-123.
Amendment 39-960 was effective upon publication in the Federal Register as to all persons except those persons to whom it was made immediately effective by the telegram dated February 3, 1970, which contained this amendment.
This Amendment 39-1416 is effective April 24, 1972.