AD 94-06-05 ACTIVE

94-06-05 HAMILTON STANDARD: Amendment 39-8853. Docket 94-ANE-09.
Applicability: Hamilton Standard Model 14RF-9, 14RF-19, and 14RF-21 propellers, installed on but not limited to Embraer EMB-120 series, Construcciones Aeronauticas, SA (CASA) CN-235 series, and SAAB-SCANIA SF340 series aircraft.

Compliance: Required as indicated, unless accomplished previously.

To prevent propeller hub cracking and loss of engine oil, and possible loss of a propeller blade or hub, accomplish the following:

(a) Within 30 days after the effective date of this airworthiness directive (AD), perform an initial torque check of the propeller hub retaining nuts, as follows:

(1) For Hamilton Standard Model 14RF-9 propellers, in accordance with Temporary Revision (TR) No. 61-6, dated March 15, 1993, to Hamilton Standard Maintenance Manual (MM) P5186.

(2) For Hamilton Standard Model 14RF-19 propellers, in accordance with TR No. 61-6, dated April 8, 1993, to Hamilton Standard MM P5199.

(3) For Hamilton Standard Model 14RF-21 propellers, in accordance with TR No. 61-4, dated March 15, 1993, to Hamilton Standard MM P5189.

(b) If propeller hub retaining nuts are found not to meet the acceptance criteria in accordance with the applicable TR to the Hamilton Standard MM's during the initial torque check in accordance with paragraph (a), and during the repetitive torque checks performed in accordance with paragraph (e) of this AD, remove the propeller hub from service and inspect for cracks in accordance with the applicable TR's listed in paragraph (a) of this AD. Remove propeller hubs with crack indications and replace with serviceable propeller hubs prior to further flight.

(c) If the initial propeller hub retaining nut torque check is acceptable in accordance with the applicable TR listed in paragraph (a) of this AD, support the propeller with an appropriate lifting fixture and loosen all the propeller hub retaining nuts. Tighten the propeller hub retaining nuts as follows:

(1) For Hamilton Standard Model 14RF-9 propellers, in accordance with TR No. 61-7, dated July 27, 1993, to Hamilton Standard MM P5186.

(2) For Hamilton Standard Model 14RF-19 propellers, in accordance with TR No. 61-7, dated July 27, 1993, to Hamilton Standard MM P5199.

(3) For Hamilton Standard Model 14RF-21 propellers, in accordance with TR No. 61-5, dated July 27, 1993, to Hamilton Standard MM P5189.

(d) Make a one-time entry into propeller maintenance records to record:

(1) that the initial torque check was performed;

(2) the propeller hub retaining nuts were loosened and tightened in accordance with paragraph (c) of this AD; and

(3) the torque values.

(e) Thereafter, perform repetitive torque checks at intervals not to exceed 500 hours time in service since the last inspection, in accordance with the applicable TR to the Hamilton Standard MM's listed in paragraph (a) of this AD.

(f) Install all propellersafter the effective date of this AD using the propeller hub retaining nut tightening procedure defined in the applicable TR to the Hamilton Standard MM's listed in paragraph (c) of this AD. Record the torque values in accordance with paragraph (d) of this AD.

(g) Visually inspect and investigate all external propeller oil leakage at the next line check, or within 70 hours TIS after the effective date of this AD, whichever occurs first. If the leakage is found to be caused by other than a leak in the blade seal, the pressure relief valve, or actuator assembly, the propeller must be removed from service and replaced with a serviceable propeller prior to further flight.

(h) Thereafter, visually inspect and investigate all external propeller oil leakage at intervals not to exceed 70 hours TIS since the last inspection, or at the next line check, whichever occurs first. If the leakage is found to be caused by other than a leak in the blade seal, the pressure relief valve, or actuator assembly, the propeller must be removed from service and replaced with a serviceable propeller prior to further flight.

(i) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Boston Aircraft Certification Office. The request should be forwarded through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Boston Aircraft Certification Office. NOTE: Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the Boston Aircraft Certification Office.

(j) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the aircraft to a location where the requirements of this AD can be accomplished.

(k) The torque checks, retightening, and installation procedures shall be done in accordance with the following service documents:

Document No.
Pages
Date
TR No. 61-6 to Hamilton
Standard MM P5186
1-8
March 15, 1993
Total pages: 8.

TR No. 61-7 to Hamilton
Standard MM P5186
1-9
July 27, 1993
Total pages: 9.

TR No. 61-6 to Hamilton
Standard MM P5199
1-6
April 8, 1993
Total pages: 6.

TR No. 61-7 to Hamilton
Standard MM P5199
1-7
July 27, 1993
Total pages: 7.

TR No. 61-4 to Hamilton
Standard MM P5189
1-8
March 15, 1993
Total pages: 8.

TR No. 61-5 to Hamilton
Standard MM P5189
1-7
July 27, 1993
Total pages: 7.

This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Hamilton Standard, One Hamilton Road, Windsor Locks, CT 06096-1010. Copies may be inspected at the FAA, New England Region, Office of the Assistant Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(l) This amendment becomes effective on March 29, 1994.