AD 68-07-04

68-07-04 PIPER AIRCRAFT: Amdt. 39-576 as amended by Amendment 39-1324 is further amended by Amendment 39-1426. Applies to Piper PA-23-250 airplanes Serial Nos. 27- 2505 and up having engine mount part number 31215.

Compliance required as indicated.

a. With airplanes having engine mount date stamped prior to 26 May 1965, within the next 50 hours in service after the effective date of this AD unless already accomplished within the last 50 hours in service and thereafter at intervals not to exceed 100 hours in service from the last inspection visually inspect the mount for cracks in the following areas:

(i) The lower forward lateral tube

(ii) The three-tube horizontal diagonal truss in and around the three welded junctures with the lower forward lateral fore and aft tube, and

(iii) The lower left horizontal fore and aft tube.

b. With airplanes having engine mounts date stamped 26 May 1965 and after, and having 1000 or more hours in service, within the next 50 hours in service after the effective date of this AD, unless already accomplished within the last 50 hours in service, and thereafter at intervals not to exceed 100 hours in service from the last inspection visually inspect the engine mount tubes forward of the firewall for cracks. c. If cracks are found accomplish either of the following,

(i) Replace the engine mount prior to further flight with a new mount part number 31215. After installation of new mount continue repetitive inspection of this mount after 1000 hours as described in paragraph b.

(ii) Repair the engine mount prior to further flight in accordance with FAR 43. Conduct a magnetic particle, or equivalent method, inspection of the entire mount for cracks prior to approval of the repaired engine mount. Continue visual inspections of the mount within 100 hours in service and thereafter not to exceed 100 hours in service from the last inspection.

NOTE: On engine mounts date-stamped prior to 26 May 1965, a pictorial description of the affected areas can be found in Piper Service Letter No. 462. The engine mount is date- stamped on either of the two diamond-shaped gusset plates located near the upper firewall attachment points.

Amendment 39-576 was effective April 11, 1968.

Amendment 39-1324 was effective November 2, 1971.

This Amendment 39-1426 is effective April 11, 1972.