77-14-07 HARTZELL PROPELLERS: Amendment 39-2955. Applies to Hartzell Model EHC-A3VF- 2B/V7636N propellers used on Continental IO-520-E series engines installed on the DeHavilland (Heron) D.H. 114 series aircraft modified in accordance with STC SA1685WE.
(a) External Clamp and Blade Inspection
To detect cracks and prevent possible blade clamp and shank failures accomplish this paragraph before further flight or within 32 hours time in service from the time of previous inspection, if accomplished. Reinspect in accordance with this paragraph each 32 hours time in service thereafter:
(1) Remove spinner and inspect propeller blade shank external surface for cracks using a 10X (ten power) glass from area where blade emerges from clamp to the station 10 inches outboard of the clamp.
(2) Inspect blade clamp for cracks using a 10X (ten power) glass. Also, inspect for loose or broken bolts. Replace any cracked clamp or broken bolt with new parts before further flight.(b) Blade Shank Inspection
To detect cracks in the blade shank retention shoulder and groove and prevent possible blade failure, accomplish this paragraph before further flight or within 400 hours time in service from the time of previous inspection, if accomplished. Reinspect in accordance with this paragraph each 400 hours time in service thereafter:
(1) Remove propeller from the aircraft, disassemble blades from propeller and inspect the double retention shoulders of the blade shanks for evidence of cracks in the shoulder and groove surfaces using a 3-step dye penetrant method. If no cracks are found, reassemble in accordance with Hartzell (overhaul) Manual No. 114B, or later FAA approved revision. During reassembly insure that a complete seal and proper sealant are used in the retention area interface between blades and clamps.
(2) Upon request of the operator, subject to approval of the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Great Lakes Region, an ultrasonic or other alternate method of crack detection which does not require removal from the aircraft or disassembly of the propeller may be substituted for paragraph (b)(1) above.
In the event any cracked blade is found during inspections accomplished in accordance with paragraphs (a) or (b) above, the propeller must be replaced with a propeller which has been inspected and modified in accordance with paragraph (c) which follows:
Any propeller with a history of synchronization difficulties and/or rough operation must be replaced before further flight with a propeller inspected and modified in accordance with paragraph (c) which follows:
(c) Blade Shank Modification
To prevent the initiation of fatigue cracks induced by shot peening and the propagation of such cracks by corrosion; rework, or replace if necessary in accordance with this paragraph within the next 1200 hours or one year in service after the effective date of this AD, whichever occurs first. Reinspect and, as necessary, rework or replace in accordance with this paragraph each 1200 hours or two years thereafter, whichever occurs first:
(1) Remove propeller from the aircraft, disassemble propeller and inspect blades, clamps, and hub for cracks in accordance with applicable portions of Hartzell Bulletin No. 97A dated March 1, 1973, Bulletin No. 113B dated September 10, 1976 and Hartzell (overhaul) Manual No. 114B, or later FAA approved revisions.
(2) Return propeller blades to Hartzell Propeller, Inc., or a maintenance agency designated by it, for rework of shot peened areas and removal of any dimensional inconsistencies in accordance with processes approved by the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Great Lakes Region.
(3) Reassemble propeller in accordance with Hartzell (overhaul) Manual No. 114B or later approved revision. During reassembly insure that a complete seal and proper sealant are usedin the retention area interface between blades and clamps.
Replace before further flight any cracked or irreparable blade with a new or processed blade which conforms to paragraph (c)(2) above.
A service record (log) shall be maintained for affected propellers (blades and hub) which are inspected, repaired or replaced in accordance with this airworthiness directive. Report serial number, total time and description of any cracked blades to the Chief, Engineering and Manufacturing Branch, AGL-210, Great Lakes Region, FAA, 2300 East Devon Avenue, Des Plaines, Illinois 60018. (Reporting approved by the Bureau of the Budget under BOB No. 04-R0174).
Upon request of the operator, a Federal Aviation Administration Maintenance Inspector, subject to approval of the Chief, Engineering and Manufacturing Branch, Federal Aviation Administration, Great Lakes Region, may adjust the repetitive inspection intervals specified in this airworthiness directive, if the request contains satisfactory substantiating data to justify the adjustment for that operator.
The manufacturer's specifications and procedures identified in this directive are incorporated herein and made part hereof pursuant to 5 U.S.C. 522(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to Hartzell Propeller, Inc., 350 Washington Avenue, Piqua, Ohio 45356 These documents may also be examined at the Great Lakes Regional Office, 2300 East Devon Avenue, Des Plaines, Illinois 60018, and at FAA Headquarters, 800 Independence Avenue, S.W., Washington, D.C. 20591. A historical file of this airworthiness directive which includes incorporated material in full is maintained by the FAA at its headquarters in Washington, D.C. and at the Great Lakes Region.
This amendment becomes effective: July 14, 1977.