68-02-01: Crankshaft Front End

68-02-01 BRISTOL SIDDELEY: Amendment 39-542. Applies to deHavilland Model Gipsy Queen Series 70 Engines with Crankshafts with Modifications 1399 (R.155), 1609 (R.259), 2289 (R.155 and R.259), 2931 (R.563 and R.564), or Repair Schemes R.155 and R.259 incorporated. Compliance required as indicated, unless already accomplished. To prevent failure of the crankshaft front end that could result in loss of the propeller, accomplish the following: (a) Within the next 400 hours' time in service after the effective date of this AD and thereafter at intervals not to exceed 400 hours' time in service from the last inspection, visually inspect the crankshaft for cracks, in accordance with Bristol Siddeley Technical News Sheet (TNS) G.Q. 70 No. 105, dated August 14, 1967, or later ARB-approved issue, or an FAA-approved equivalent. (b) If cracks are found during the inspections required by paragraph (a), replace cracked crankshaft before further flight with an uncracked crankshaft, or incorporate Gipsy Modification 2925 (R.550). If Gipsy Modification 2925 (R.550) is not incorporated, inspect the replacement crankshaft in accordance with paragraph (a). (c) If no cracks are found during the inspections required by paragraph (a), incorporate Modification 2925 (R.550), or an FAA-approved equivalent, at next overhaul. (d) The repetitive inspections required by paragraph (a) may be discontinued after the incorporation of Gipsy Modification 2925 (R.550). This amendment becomes effective February 16, 1968.