AD 99-11-11 Airworthiness Directives; Eurocopter France Model SA-365N, N1, N2, N3, and SA-366G1 Helicopters

Models named: SA-365N, N1, N2, N3. Read the applicability below — it usually turns on serial or part numbers too.

Model SA-365N, N1, N2, and N3 helicopters, serial numbers up to and including 6538, and SA-366G1 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 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 (d) 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 cracks in the main gearbox (MGB) planetary gear shaft (shaft), which could lead to failure of the MGB and subsequent loss of control of the helicopter, accomplish the following: (a) Within 25 hours time-in-service, install a MGB shaft vibration level monitoring unit (VLMU), in accordance with paragraph B. of the Accomplishment Instructions of either Eurocopter AS 365 Service Bulletin No. 31.00.03, applicable to Model SA-365N, N1, N2, and N3 helicopters; or Eurocopter SA 366 Service Bulletin No. 31.01, applicable to Model SA-366G1 helicopters, both dated June 23, 1998 (SB's). (b) Before further flight, accomplish the following: (1) Insert paragraphs 2D1), 2D2), and 2D3) of the SB's into the applicable Rotorcraft Flight Manual post-start normal procedures section. (2) Insert the following statement in the Emergency Procedures section of the applicable Rotorcraft Flight Manual: ``If vertical vibrations at approximately 4/rev frequency are detected, reduce power, land as soon as practicable, and perform a VLMU vibration level check.'' (3) Insert the following statement into the Limitations section of the applicable Rotorcraft Flight Manual: ``If the VLMU becomes inoperative, it must be returned to service within 30 calendar days or the helicopter must be grounded until such repairs are made.'' (c) If the VLMU becomes inoperative, inspect the MGB magnetic plug; it must be inspected before every flight and inspect the MGB oil filter each day in which flights are conducted or at intervals not to exceed 12 hours time-in-service, whichever occurs first. When metallic particles are found on either the magnetic plug or the oil filter element, conduct drive system ground vibration measurements before further flight. (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, Rotorcraft Directorate, FAA. Operators shall submit their requests through a FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Standards Staff. Note 2: 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 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 helicopter to a location where the requirements of this AD can be accomplished. (f) The actions shall be done in accordance with the Eurocopter AS 365 Service Bulletin No. 31.00.03, or Eurocopter SA 366 Service Bulletin No. 31.01, both dated June 23, 1998, as applicable. 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 American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972) 641-3460, fax (972) 641-3527. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. (g) This amendment becomes effective on June 10, 1999. Note 3: The subject of this AD is addressed in Direction Generale de L'Aviation Civile (France) AD 98-324-045(A), applicable to Model SA-365N helicopters, and AD 98-323-023(A), applicable to Model SA-366 helicopters, both dated August 12, 1998. Issued in Fort Worth, Texas, on May 18, 1999. Mark R. Schilling, Acting Manager, Rotorcraft Directorate, Aircraft Certification Service. [FR Doc. 99-13320 Filed 5-25-99; 8:45 am] BILLING CODE 4910-13-U