AD 95-21-12

This amendment adopts a new airworthiness directive (AD), applicable to Eurocopter Deutschland GmbH (ECD) (Eurocopter) Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters, that requires initial and repetitive inspections of the main rotor (M/R) blade upper and lower surfaces for bulging. This amendment is prompted by two reported incidents in which a balance weight became detached from inside the M/R blade structure and migrated toward the tip of the M/R blade. The actions specified by this AD are intended to detect movement of a balance weight and to prevent severe vibrations and a subsequent precautionary landing.

Final rule

95-21-12 EUROCOPTER DEUTSCHLAND GmbH (ECD): Amendment 39-9399. Docket No. 94-SW-19-AD.

Applicability: Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 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.

Compliance: Required as indicated, unless accomplished previously.

To detect movement of a balance weight and to prevent severe vibrations and a subsequent precautionary landing, accomplish the following:

(a) Within the next 5 hours time-in-service (TIS) after the effective date of this AD, and thereafter, at intervals not to exceed 50 hours TIS, visually inspect the upper and lower surfaces of the main rotor blades (blades) in the area of the outboard lead balance weight in the marked inspection area for signs of bulging, in accordance with Paragraph 2.A. of the Accomplishment Instructions of Eurocopter Deutschland GmbH (ECD) Alert Service Bulletin ASB-MBB-BK 117-10-108, Revision 1, dated October 14, 1994.

(b) If a marked inspection area is not visible, mark the area in accordance with Paragraph 2.A. of the Accomplishment Instructions of Eurocopter Deutschland GmbH (ECD) Alert Service Bulletin ASB-MBB-BK 117-10-108, Revision 1, dated October 14, 1994, and then inspect in accordance with paragraph (a) of this AD.

(c) If bulging exceeds 1 mm (0.040 inch) in height, remove the blade and replace it with an airworthy blade in accordance with the applicable maintenance manual.

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used when approved by the Manager, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff. 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 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 inspection and replacement, if necessary, shall be done in accordance with Eurocopter Deutschland GmbH (ECD) Alert Service Bulletin ASB-MBB-BK 117-10-108, Revision 1, dated October 14, 1994. 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. Copies may be inspected at the FAA, Office of the Assistant Chief Counsel, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) This amendment becomes effective on November 20, 1995.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to Eurocopter Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters was published in the Federal Register on February 13, 1995 (60 FR 8205). That action proposed to require initial and repetitive inspections of the M/R blade upper and lower surfaces for bulging.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed, except for editorial changes and adding explanatory Note 1, relating to the scope of the applicability statement when modifications, alterations, or repairs have been made in the area subject to the requirements of the AD. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

The FAA estimates that 125 helicopters of U.S. registry will be affected by this AD, that it will take approximately one-half work hour per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $3,750.

The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action(1) is not a " significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation forpart 39 continues to read as follows:
Authority: 49 USC 106(g), 40101, 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: