AD 95-08-12 ACTIVE

This amendment adopts a new airworthiness directive (AD), applicable to Eurocopter Deutschland GmbH (ECD) Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters, that requires a modification of the latches on the transmission and engine cowling access doors. This amendment is prompted by five occurrences of an engine or transmission cowling access door becoming loose in flight. The actions specified by this AD are intended to prevent the transmission and engine cowling access doors from opening in flight, being struck by the main rotor blade, and subsequently, separating from the helicopter and being ingested by the main rotor or tail rotor system resulting in a loss of control of the helicopter.

Final rule

95-08-12 EUROCOPTER DEUTSCHLAND GmbH (ECD): Amendment 39-9201. Docket No. 94-SW-06-AD.

Applicability: Model MBB-BK 117 A-1, A-3, A-4, B-1, B-2, and C-1 helicopters, serial numbers 7001 through 7201, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent the transmission and engine cowling access doors from opening in flight, being struck by the main rotor blade, and subsequently, separating from the helicopter and being ingested by the main rotor or tail rotor system resulting in a loss of control of the helicopter, accomplish the following:

(a) Within the next 150 hours time-in-service, remove the left-hand and right-hand transmission and engine cowlings without removing the transmission and engine cowling access doors that are installed on the transmission and engine cowlings, and modify the access door latches, cowlings, fire walls, and fuselage in accordance with the Work Procedure contained in the Accomplishment Instructions of MBB-Helicopters Alert Service Bulletin ASB-MBB-BK 117-20-104, Revision 1, dated December 8, 1989.

(b) 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, 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: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff.

(c) 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.

(d) The modification shall be done in accordance with MBB-Helicopters Alert Service Bulletin ASB-MBB-BK 117-20-104, Revision 1, dated December 8, 1989. 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.

(e) This amendment becomes effective on May 23, 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 Deutschland GmbH (ECD) Model MBB-BK 117 helicopters was published in the Federal Register on September 13, 1994 (59 FR 46946). That action proposed to require replacing the current latches with those having positive locks, relocating certain latches, and installing additional locks on the transmission and engine cowling access doors within the next 150 hours time-in-service.

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

One commenter states that some of the language in the AD should be changed. Specifically, the commenter believes that the words "access door becoming loose in flight" and "resulting in loss of control of the helicopter", which were used to describe theunsafe condition, are misleading. According to the commenter, use of proper locking procedures will prevent the doors from becoming loose in flight. Also, there have not been any incidents in which there has been a loss of control of the helicopter. The FAA does not concur. The FAA has determined that the current latches can become worn and loose and subsequently fail, even if properly latched. Thus far, loose cowling doors have only caused damage to main rotor blades. However, the FAA has determined that main rotor blade damage as well as other resultant damage from loose cowling doors could result in loss of control of the helicopter.

After a careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed, except that the words "cowlings, fire walls, and fuselage" were added to paragraph (a) of the AD to clarify that, in addition to modifying the transmission and engine cowlings, the appropriate mating components also needed to be installed on the cowlings, firewalls, and fuselage. Additionally, the helicopter models were listed to avoid confusion regarding the applicability of the rule. Finally, the FAA has revised the proposed estimated average labor rate from $55 per work hour to an estimated average labor rate of $60 per work hour in the preamble portion of this final rule. This revision will increase the estimated total cost of the AD from $390,474 to $418,824. 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 126 helicopters of U.S. registry will be affected by this AD, that it will take approximately 45 work hours per helicopter to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts will cost approximately $624 per helicopter. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $418,824.

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 for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

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

The service information referenced in this AD may be obtained from American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005. This information may be examined 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.

Mr. Richard Monschke, Aerospace Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5116, fax (817) 222-5961.