Airworthiness Directives; Eurocopter Deutschland GmbH (ECD) Model MBB-BK 117 Series Helicopters

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-SW-06-AD]

Airworthiness Directives; Eurocopter Deutschland GmbH (ECD) Model

MBB-BK 117 Series Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness

directive (AD) that is applicable to Eurocopter Deutschland GmbH (ECD)

Model MBB-BK 117 series helicopters. This proposal would require a

modification of the latches on the transmission and engine cowlings

access doors. This proposal is prompted by five occurrences of an

engine or transmission cowling access door becoming loose in flight.

The actions specified by the proposed 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.

DATES: Comments must be received by November 14, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Office of the Assistant Chief Counsel, Attention:

Rules Docket No. 94-SW-06-AD, 2601 Meacham Blvd., Room 663, Fort Worth,

Texas 76137-4298. Comments may be inspected at this location between

9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal

holidays.

The service information referenced in the proposed rule 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.

FOR FURTHER INFORMATION CONTACT: Mr. Samuel E. Brodie, Aerospace

Engineer, Rotorcraft Standards Staff, FAA, Rotorcraft Directorate, 2601

Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5116, fax

(817) 222-5961.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the

proposed rule by submitting such written data, views, or arguments as

they may desire. Communications should identify the Rules Docket number

and be submitted in triplicate to the address specified above. All

communications received on or before the closing date for comments,

specified above, will be considered before taking action on the

proposed rule. The proposals contained in this notice may be changed in

light of the comments received.

Comments are specifically invited on the overall regulatory,

economic, environmental, and energy aspects of the proposed rule. All

comments submitted will be available, both before and after the closing

date for comments, in the Rules Docket for examination by interested

persons. A report summarizing each FAA-public contact concerned with

the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments

submitted in response to this notice must submit a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket Number 94-SW-06-AD.'' The postcard will be date stamped and

returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request

to the FAA, Office of the Assistant Chief Counsel, Attention: Rules

Docket No. 94-SW-06-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas

76137-4298.

Discussion

This notice proposes the adoption of a new airworthiness directive

(AD), that is applicable to Eurocopter Deutschland GmbH (ECD) Model

MBB-BK 117 series helicopters, serial numbers (S/N) 7001 through 7201.

Since 1986, there have been five reports of the engine or transmission

cowling access doors opening in flight which, in several cases,

resulted in damage to the main rotor blades.

The FAA has reviewed and approved MBB-Helicopters Alert Service

Bulletin ASB-MBB-BK 117-20-104, Revision 1, dated December 8, 1989,

that describes procedures for removing and modifying various latches of

the access doors of the transmission and engine cowlings, installing

new locks, and providing the cowlings, firewalls, and fuselage with

appropriate mating components. Transmission and engine cowlings that

open in flight can damage the rotor systems and, therefore, create an

unsafe condition.

Since an unsafe condition has been identified that is likely to

exist or develop on other ECD Model MBB-BK 117 helicopters of the same

type design, the proposed AD would 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. The actions

would be required to be accomplished in accordance with the service

bulletin described previously.

The FAA estimates that 126 helicopters of U.S. registry would be

affected by this proposed AD, that it would take approximately 45 work

hours per helicopter to accomplish the proposed actions, and that the

average labor rate is $55 per work hour. Required parts would cost

approximately $624 per helicopter. Based on these figures, the total

cost impact of the proposed AD on U.S. operators is estimated to be

$390,474.

The regulations proposed herein would 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

proposal would not have sufficient federalism implications to warrant

the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this proposed

regulation (1) is not a ``significant regulatory action'' under

Executive Order 12866; (2) is not a ``significant rule'' under the DOT

Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);

and (3) if promulgated, 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 copy of the draft

regulatory evaluation prepared for this action is contained in the

Rules Docket. A copy of it may be obtained by contacting the Rules

Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration proposes to amend

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.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding a new airworthiness directive

to read as follows:

Eurocopter Deutschland GMBH (ECD): Docket No. 94-SW-06-AD.

Applicability: Model MBB-BK 117 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 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 Regulation (14

CFR 21.197 and 21.199) to operate the helicopter to a location where

the requirements of this AD can be accomplished.

Issued in Fort Worth, Texas, on September 6, 1994.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 94-22626 Filed 9-12-94; 8:45 am]

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