AD 99-12-01 Airworthiness Directives; Eurocopter Deutschland (Eurocopter) Model EC135 Helicopters

Model EC135 helicopter with main rotor hub shaft (shaft), part number (P/N) L623M100S 101, installed, certificated in any category. Note 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters 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.

Required as indicated, unless accomplished previously. To detect a fatigue crack in the shaft that could lead to shaft failure and subsequent loss of control of the helicopter, accomplish the following: (a) Before further flight, and thereafter, at intervals not to exceed 15 hours time-in-service (TIS), visually inspect the shaft, P/N L623M100S 101, for any crack in the area marked in Figure 1. Clean the shaft before using a bright light source to inspect for cracks. If any crack is found, replace the shaft with an airworthy shaft before further flight. (b) Within 10 hours TIS, conduct a one-time dye-penetrant inspection of the shaft using the MIL-STD-6866 or ASTM-E-1417 procedure in the area shown in Figure 1. If any crack is found, replace the shaft with an airworthy shaft before further flight. Note 2: Eurocopter EC 135 Alert Service Bulletin EC 135-62A-004, Rev. 1, dated May 7, 1999, pertains to the subject of this AD. BILLING CODE 4910-13-P [[Page 35561]] [GRAPHIC] [TIFF OMITTED] TR01JY99.039 BILLING CODE 4910-13-C [[Page 35562]] (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, Rotorcraft Standards Staff, FAA, Rotorcraft Directorate. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Standards Staff. Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff. (d) Special flight permits will not be issued. (e) This amendment becomes effective on July 16, 1999, to all persons except those persons to whom it was made immediately effective by Priority Letter AD 99-12-01, issued May 27, 1999, which contained the requirements of this amendment. Note 4: The subject of this AD is addressed in Luftfahrt- Bundesamt (Federal Republic of Germany) AD 1999-185, dated May 6, 1999. Issued in Fort Worth, Texas, on June 23, 1999. Henry A. Armstrong, Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 99-16591 Filed 6-30-99; 8:45 am] BILLING CODE 4910-13-P