74-10-07 DETROIT DIESEL ALLISON AEROPRODUCTS: Amendment 39-1839. Applies to Detroit Diesel Allison Aeroproducts Model A6441FN-606 and -606A propellers.
Compliance required as indicated, unless already accomplished:
(a) For propeller blades and hubs, installed on an aircraft prior to the effective date of this Airworthiness Directive, that have been stripped, inspected for corrosion, and replated per Detroit Diesel Allison Overhaul Manual 1AC3 or an equivalent procedure approved by the Chief, Engineering and Manufacturing Branch, FAA, Great Lakes Region, within the preceding 27 months prior to the effective date of this AD, remove from service before 36 months since date of initial installation on an aircraft following stripping, inspecting for corrosion and replating.
(b) For propeller blades and hubs, installed on an aircraft prior to the effective date of this AD, that have been stripped, inspected for corrosion and replated per Detroit Diesel Overhaul Manual 1AC3or equivalent, but this work has not been accomplished within the preceding 27 months prior to the effective date of this AD, remove from service in accordance with the following schedule:
On the effective date of this AD, the number of months since the date of initial installation on an aircraft after being stripped, inspected for corrosion, and replated as described above:
Over 55 months - Remove from service by: 25 flight hours after effective date of this AD.
55 months - Remove from service by: May 11, 1974
53-54 months - Remove from service by: June 11, 1974
48-52 months - Remove from service by: July 11, 1974
42-47 months - Remove from service by: October 11, 1974
27-41 months - Remove from service by: January 11, 1975
(c) New propeller blades and hubs may continue in service 40 months since initial installation on aircraft. However, those in service, at the effective date of this AD, more than 31 months since initial installation on aircraft shall be removed from service at or before the time or dates specified in the schedule under paragraph (b).
(d) Propeller blades and hubs removed from service pursuant to paragraphs (a), (b), or (c), stripped, inspected for corrosion and replated as set forth above, and installed on an aircraft shall thereafter be removed from service, stripped, inspected for corrosion, and replated as described above at intervals not to exceed 36 months.
(e) Propeller blades and hubs initially installed on an aircraft on or after the effective date of this AD shall be stripped, inspected for corrosion and replated, as described above, at intervals no greater than 36 months from date of initial installation; provided however, that new propeller blades and hubs may continue in service for 40 months since initial installation.
(f) Extensions of compliance times or date may be obtained from the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Great Lakes Region, upon submission of acceptable substantiating data to support the extension.
This amendment is effective May 17, 1974, and was effective April 11, 1974, for all recipients of the telegram dated April 11, 1974, which contained this amendment.