AD 68-10-03 ACTIVE

68-10-03 MCCAULEY: Amdt. 39-596. Applies to the following models with hub serial numbers whose first two digits are 62, 63, 64 or 65: D2A34C49, D2A34C49-A installed on Continental IO-470-S engines. D2AF34C54, D2AF34C54-A installed on Continental TSIO-470-D engines. 2AF34C55, 2AF34C55-A, 2AF34C55-8, 2AF34C55-C, 2AF34C55-D, 2AF34C55-E, 2AF34C55-F, 2AF34C55-G installed on Continental IO-470-L engines. D2AF34C60, D2AF34C60-A, D2AF34C60-B installed on Continental IO-360-A engines.

To detect and prevent formation of cracks and possible hub failure, accomplish the following on propellers with 1200 hours' or more time in service within the next 25 hours' time in service after the effective date of this AD, unless previously accomplished:

(a) Remove propeller from aircraft and disassemble. Remove hub alignment dowels and hub mounting studs from hub.

(b) Inspect dowel and stud holes and adjacent areas for cracks by penetrant method. Replace before further flight any crackedhub with an approved replacement hub or hub which has been inspected and altered according to this AD.

(c) Remove sharp corners formed where the hub mounting stud holes and hub alignment dowel pin holes intersect the inside of the propeller hub, in accordance with instructions in McCauley Service Manual or an alteration approved by the Chief, Engineering & Manufacturing Branch, Eastern Region.

Propellers with 1200 hours' or more time in service which have been inspected according to Paragraph (b) within 300 hours' time in service prior to the effective date of this AD, but which have not been modified according to Paragraph (c), need not comply with this AD until 300 hours' time in service from such previous inspection.

This amendment is effective May 11, 1968.