Airworthiness Directives; Bell Helicopter Textron, Inc. Model 412 Helicopters

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 96-SW-17-AD]

Airworthiness Directives; Bell Helicopter Textron, Inc. Model 412

Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing priority

letter airworthiness directive (AD), applicable to certain Bell

Helicopter Textron, Inc. Model 412 helicopters, that currently requires

a daily inspection of certain swashplate support assemblies. It also

requires a reduction in VNE, and installation of appropriate

airspeed indicator markings and a placard. This action would require

the same actions required by the existing Priority Letter AD, but would

restrict the applicability to the Model 412 helicopters with a certain

steel main rotor control swashplate support assembly (steel swashplate

support assembly) installed. This AD also proposes to allow the

installation of an improved main rotor control swashplate assembly that

terminates the requirements of this AD. This proposal is prompted by

reported cracks and in-service failures of certain steel swashplate

support assemblies. The actions specified by the proposed AD are

intended to prevent failure of the steel swashplate support assembly

that could result in loss of main rotor control and subsequent loss of

control of the helicopter.

DATES: Comments must be received by December 24, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Rules Docket No. 96-SW-17-AD, 2601 Meacham Blvd., Room 663, Fort Worth,

Texas 76137. 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 Bell Helicopter Textron, Inc., P.O. Box 482, Fort Worth,

Texas 76101. 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. Charles Harrison, Federal Aviation

Administration, Southwest Region, Rotorcraft Certification Office, ASW-

170, Fort Worth, Texas 76193-0170, telephone (817) 222-5447, FAX (817)

222-5959.

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 No. 96-SW-17-AD.'' The postcard will be date stamped and

returned to the commenter.

[[Page 55232]]

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. 96-SW-17-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas

76137.

Discussion

On January 31, 1992, the FAA issued priority letter AD 92-03-13, to

require, before further flight and thereafter before the first flight

of each day, an inspection of the forward and aft clevis areas of the

steel swashplate support assembly, part number (P/N) 412-010-453-101.

It also requires a reduction in the maximum allowable airspeed to the

lesser of 110 knots or VNE, and further requires the installation

of appropriate airspeed indicator markings and a placard. That AD also

mandates that if a crack is found in the clevis areas of the steel

swashplate support assembly, the steel swashplate support assembly must

be removed and replaced with an airworthy part. That action was

prompted by two reported in-service failures of a swashplate support

assembly. The requirements of that AD are intended to prevent loss of

main rotor control and subsequent loss of control of the helicopter.

Since the issuance of that AD, an improved steel swashplate support

assembly, P/N 412-010-453-105, has become available. Installation of

the improved steel swashplate support assembly, P/N 412-010-453-105, or

an aluminum swashplate support assembly, P/N 412-010-443-101 or -109,

terminates the requirements of this AD. BHTI issued Alert Service

Bulletin (ASB) No. 412-92-61, dated May 14, 1992, to provide for

installation of this improved steel swashplate support assembly.

Additionally, some editorial changes have been made to the AD.

Since an unsafe condition has been identified that is likely to

exist or develop on other Bell Helicopter Textron, Inc. Model 412

helicopters of the same type design, the proposed AD would supersede

priority letter AD 92-03-13, issued January 13, 1992, to require a

daily inspection of certain steel main rotor control swashplate support

assemblies, a reduction in VNE, and installation of appropriate

airspeed markings and a placard. It also proposes an optional

installation of an improved steel main rotor control swashplate support

assembly or an aluminum swashplate support assembly, that when

installed, constitutes a terminating action for the requirements of

this AD. The actions would be required to be accomplished in accordance

with ASB No. 412-92-61, dated May 14, 1992, and ASB No. 412-92-57,

Revision A, dated January 30, 1992.

The FAA estimates that 40 helicopters of U.S. registry would be

affected by this proposed AD, that it would take 20 work hours per

helicopter to accomplish the proposed actions, and that the average

labor rate is $60 per work hour. The aluminum swashplate support

assembly, P/N 412-010-443-101 or -109 costs $4,526. The steel

swashplate support assembly, P/N 412-010-453-105, costs $9,234. Based

on these figures, the total cost impact of the proposed AD on U.S.

operators is estimated to be $417,360, if all the swashplates in the

fleet are replaced with support assemblies, P/N 412-010-453-105.

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 USC 106(g), 40113, 44701.

Sec. 39.13 [Amended]

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

(AD), to read as follows:

Bell Helicopter Textron, Inc.: Docket No. 96-SW-17-AD. Supersedes

priority letter AD 92-03-13, issued January 31, 1992, Docket No. 92-

ASW-31.

Applicability: Model 412 helicopters, with steel main rotor

control swashplate support assembly (steel swashplate support

assembly), part number (P/N) 412-010-453-101, installed,

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 (e) 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 prevent failure of the steel swashplate support

assembly that could result in loss of main rotor control and

subsequent loss of control of the helicopter, accomplish the

following:

(a) Before further flight after the effective date of this AD,

and thereafter, before the first flight of each day, visually

inspect, with an inspection mirror and a bright light, the forward

and aft clevis areas of the steel swashplate support assembly, part

number (P/N) 412-010-453-101, in accordance with Bell Helicopter

Textron, Inc. Alert Service Bulletin (ASB) 412-92-57, Revision A,

dated January 30, 1992.

(b) Before further flight after the effective date of this AD,

install a red radial arc on each airspeed indicator to prohibit

airspeeds above 110 knots. Near the pilot's airspeed indicator,

install a placard made of material that is not easily erased,

disfigured, or obscured that contains the following statement in

lettering that is 0.2 inch minimum in height: ``VNE not to

exceed 110 KIAS or VNE from the airspeed limitation placard,

whichever is less.''

Note 2: ASB No. 412-92-58, dated January 27, 1992, contains

information on the airspeed limitation.

(c) If a crack is found, before further flight, replace the

steel swashplate support assembly, P/N 412-010-453-101, with an

airworthy part.

(d) Installation of an improved steel swashplate support

assembly, P/N 412-010-453-105, or aluminum swashplate support

assembly, P/N 412-010-443-101 or -109, in

[[Page 55233]]

accordance with the Accomplishment Instructions of ASB 412-92-61,

dated May 14, 1992, constitutes a terminating action for the

requirements of this AD, and the red radial arc on each airspeed

indicator and the airspeed placard installed as a result of this AD

may be removed.

(e) An alternative method of compliance or an adjustment of the

compliance time that provides an equivalent level of safety may be

used if approved by the Manager, Rotorcraft Certification Office.

Operators shall submit their requests through an FAA principal

maintenance inspector, who may concur or comment and then send it to

the Manager, Rotorcraft Certification Office.

Note 3: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Rotorcraft Certification Office.

(f) 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.

Issued in Fort Worth, Texas, on October 17, 1996.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 96-27393 Filed 10-24-96; 8:45 am]

BILLING CODE 4910-13-U