97-21-01 R1 MT-PROPELLER ENTWICKLUNG GMBH: Amendment 39-11206. Docket 97-ANE-36-AD. Revises AD 97-21-01, Amendment 39-10154.
Applicability: MT-Propeller Entwicklung GMBH Model MTV-3-B-C/L250-21 propellers. These propellers are installed on but not limited to Sukhoi 29 aircraft.
Note 1: This airworthiness directive (AD) applies to each propeller identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For propellers that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
Compliance: Required as indicated, unless accomplished previously.
To prevent propeller hub cracks, which could result in propeller blade separation and possible loss of control of the airplane, accomplish the following:
(a) Within 50 hours time-in-service (TIS) after the effective date of this AD, accomplish the following:
(1) Perform an initial dye penetrant or eddy current inspection of propeller hub, part number (P/N) B-050 or A-909-A, in accordance with paragraph (a) of MT-Propeller Entwicklung GMBH Service Bulletin (SB) No. 12C, dated March 4, 1998. The dye penetrant inspection may be done on-wing, but the eddy current inspection must be performed in an FAA-approved propeller repair station.
(2) If the propeller hub is found to be cracked, prior to further flight, remove the existing propeller hub and replace with a serviceable propeller hub.
(3) Rework propeller hubs, P/N B-050, by chamfering the hub bore to 0.08 inch x 45 degrees (for further information, see Detail Y of MT-Propeller Entwicklung GMBH SB No. 12C, dated March 4, 1998). Mark hubs that have been reworked in accordance with AD 97-21-01, or this revised AD, with the letters SB12C using a metal impression stamp (1/8 inch round bottom characters) above the propeller hub serial number and part number, located in the transition area between propeller blades 1 and 2 and the pitch change cylinder.
(b) Thereafter, perform dye penetrant or eddy current inspections, in accordance with paragraph (a) of MT-Propeller Entwicklung GMBH SB No. 12C, dated March 4, 1998. The dye penetrant inspection may be done on-wing, but the eddy current inspection must be performed in an FAA-approved propeller repair station:
(1) For propellers with hubs, P/N B-050, inspect at intervals not to exceed 50 hours TIS, or 6 months since last inspection, whichever occurs first.
(2) For propellers with hubs, P/N A-909-A, inspect at intervals not to exceed 200 hours TIS, or 12 months since last inspection, whichever occurs first.
(3) If the propeller hub is found to be cracked, prior to further flight, remove the existing propeller hub and replace with a serviceable propeller hub.
(c) 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. Operators shall submit their requests through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Boston Aircraft Certification Office.
Note 2: 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.
(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the inspection requirements of this AD can be accomplished.
(e) The actions required by this AD shall be accomplished in accordance with the following MT-Propeller Entwicklung GMBH SB:
Document No.
Pages
Date
12C
1-3
March 4, 1998
Total pages: 3.
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 MT- Propeller Entwicklung GMBH, Airport Straubing-Wallmuhle, D-94348 Atting, Germany; telephone (0 94 29) 84 33, fax (0 94 29) 84 32, Internet: "propeller@aol.com". Copies may be inspected at the FAA, New England Region, Office of the Regional 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.
(f) This amendment becomes effective on August 27, 1999.