AD 98-15-25 Airworthiness Directives; Eurocopter Deutschland GmbH Model EC 135 Helicopters

Models named: EC 135. Read the applicability below — it usually turns on serial or part numbers too.

Model EC 135 helicopters, certificated in any category. Note 1: This AD applies to each helicopter 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 helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must use the authority provided in paragraph (d) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any helicopter from the applicability of this AD.

Required as indicated, unless accomplished previously. To detect loose tail rotor drive shaft bearing (bearing) attachment bolts, or cracked bearing supports, which could result in loss of drive to the tail rotor and subsequent loss of control of the helicopter, accomplish the following: (a) Before further flight, conduct a tail rotor drive shaft vibration survey and install a Fenestron Shaft Retrofit Kit L 535M3002 882. Note 2: Procedures and limits for the vibration survey are provided in Eurocopter Deutschland document D/TA 13/98 Revision 01. (b) Before further flight, and thereafter at intervals not to exceed 15 hours time-in-service (TIS), at each bearing support: (1) Inspect each bearing attaching lock plate that was installed with the Fenestron Shaft Retrofit Kit L 535M3002 882 for bent-open tabs. (2) Inspect for broken or missing slippage marks that may indicate looseness or rotation of attaching hardware. (3) If a lock plate tab is bent open on bearing supports A, B, or C (shown in Figure 1), or if slippage marks are broken or missing, contact the Manager, Rotorcraft Standards Staff, FAA, telephone (817) 222-5110, fax (817) 222-5961. [[Page 59208]] [GRAPHIC] [TIFF OMITTED] TR03NO98.028 (c) Before further flight, and thereafter at intervals not to exceed 3 hours TIS, using a 6-power or higher magnifying glass and a bright light, visually inspect bearing supports B and C as shown in Figure 1, from the bend radius to the attaching screws and rivets connecting the bearing supports to the tailboom. If a crack is found, replace the bearing support with an airworthy bearing support. (d) 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. 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. (e) Special flight permits will not be issued. (f) This amendment becomes effective on November 18, 1998, to all persons except those persons to whom it was made immediately effective by Priority Letter AD 98-15-25, issued July 17, 1998, which contained the requirements of this amendment. Note 4: The subject of this AD is addressed in Luftfahrt- Bundesamt (Federal Republic of Germany) AD 1998-033/6, dated July 9, 1988. Issued in Fort Worth, Texas, on October 27, 1998. Eric Bries, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 98-29375 Filed 11-2-98; 8:45 am] BILLING CODE 4910-13-P