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

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-SW-20-AD]

Airworthiness Directives; Bell Helicopter Textron, Inc. Model 412

and 412EP 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 Bell Helicopter Textron, Inc.

(BHTI) Model 412 and 412EP helicopters. This proposal would require

creation of a component history card using a Retirement Index Number

(RIN) system; would establish a system for tracking increases to the

accumulated RIN; and would establish a maximum accumulated RIN for

certain main rotor masts (masts) and main rotor spline plates (spline

plates). This proposal is prompted by fatigue analyses and tests that

show certain masts and spline plates fail earlier than originally

anticipated because of an unanticipated high number of takeoffs and

external load lifts utilizing high power settings, in addition to the

time-in-service (TIS) accrued under normal operating conditions. The

actions specified by the proposed AD are intended to prevent fatigue

failure of the mast or spline plate, which could result in failure of

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

DATES: Comments must be received by January 21, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Rules Docket No. 94-SW-20-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., Product Support

Department, P.O. Box 482, Fort Worth, Texas, 76101.

FOR FURTHER INFORMATION CONTACT: Mr. Uday Garadi, Aerospace Engineer,

FAA, Rotorcraft Certification Office, Rotorcraft Directorate, Fort

Worth, Texas 76193-0170, telephone (817) 222-5157, 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. 94-SW-20-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.

[[Page 59035]]

94-SW-20-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

This notice proposes the adoption of a new AD that is applicable to

BHTI Model 412 and 412EP helicopters. This proposal would require,

within the next 100 hours TIS, creation of a component history card

using a RIN system for certain masts and spline plates used on the

Model 412 and 412EP helicopters; would establish a system for tracking

increases to the accumulated RIN; and would establish a retirement life

of 80,000 RIN for certain helicopter masts and spline plates, and a

retirement life of 60,000 RIN for certain other helicopter masts and

spline. Fatigue analyses and tests by the manufacturer show that

certain masts and spline plates fail earlier than originally

anticipated because of an unanticipated high number of takeoffs and

external load lifts utilizing high power settings in addition to the

TIS accrued under normal operating conditions. This condition, if not

corrected, could result in fatigue failure of the mast or spline plate,

which could result in failure of the main rotor system and subsequent

loss of control of the helicopter.

The FAA has reviewed BHTI Alert Service Bulletin (ASB) No. 412-94-

81, Revision B, dated March 4, 1996, which describes procedures for

creation of a component history card within the next 100 hours TIS for

Model 412 and 412EP helicopters. The ASB also describes utilizing

either a retirement life of 10,000 hours TIS or a maximum accumulated

RIN of 80,000, whichever occurs first, for the BHTI Model 412

helicopter mast and spline plate; and a retirement life of 10,000 hours

TIS or a maximum accumulated RIN of 60,000, whichever occurs first, for

the BHTI Model 412EP helicopter mast and spline plate.

Since an unsafe condition has been identified that is likely to

exist or develop on other BHTI Model 412 and 412EP helicopters of the

same type design, the proposed AD would require creation of a component

history card using a RIN system for certain masts and spline plates,

establishing a system for tracking increases to the accumulated RIN,

and establishing a retirement life of 80,000 RIN for certain helicopter

masts and spline plates, and a retirement life of 60,000 RIN for

certain other helicopter masts and spline plates. Spline plates and

masts used on Model 412EP helicopters will be vibro-etched with

``412HP''. This identifier does not indicate FAA approval or

certification of a Model 412HP helicopter.

The FAA estimates that 294 helicopters of U.S. registry would be

affected by this proposed AD, and that it would take (1) 8 work hours

per helicopter to replace the mast and 10 work hours per helicopter to

replace the spline plate; (2) 2 work hours per helicopter to create the

component history card or equivalent record (record); (3) 10 work hours

per helicopter to maintain the record each year, and that the average

labor rate is $60 per work hour. Required parts would cost

approximately $21,635 per mast and $5,675 per spline plate. Based on

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

operators for the first year is estimated to be $1,602,790, and each

subsequent year to be $1,573,390. These costs assume replacement of the

mast and spline plate in one-sixth of the fleet each year, creation and

maintenance of the records for all the fleet the first year, and

creation of one-sixth of the fleet's records and maintenance of the

records for all the fleet each subsequent year.

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

to read as follows:

Bell Helicopter Textron Inc.: Docket No. 94-SW-20-AD.

Applicability: Model 412 and Model 412EP helicopters with main

rotor mast (mast), part number (P/N) 412-040-101-105, -109, -117, -

121, -125, -127, or -129, and main rotor spline plate (spline plate)

P/N 412-010-167-105 or P/N 412-010-177-101, -105, -109, -113, or -

117, 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 within 100 hours time-in-service (TIS)

after the effective date of this AD, unless accomplished previously.

To prevent fatigue failure of the mast and spline plate, which

could result in failure of the main rotor system and subsequent loss

of control of the helicopter, accomplish the following:

(a) Create a component history card or an equivalent record for

each affected mast and spline plate. Record the accumulated

Retirement Index Number (RIN) on the mast and spline plate component

history card(s) as follows:

(1) If the numbers of takeoffs (at any gross weight) and

external load lift events are known, and those numbers do not

include any external load operation in which the load was picked up

at a higher elevation and released at a lower elevation, and the

difference in elevation between the pickup point and the release

point was 200 feet or greater (high power lift event), increase the

accumulated RIN by one for each takeoff and external load lift.

(2) If the numbers of takeoffs (at any gross weight) and

external load lifts are known, and the number of external load lifts

includes a high power lift event, increase the accumulated RIN by

two for each takeoff and two for each external load lift.

(3) For each hour time-in-service (TIS) for which the numbers of

takeoffs and external

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load lifts are unknown, and the number of external load lifts does

not include a high power lift event, increase the accumulated RIN by

10 for each hour TIS.

(4) For each hour TIS for which the numbers of takeoffs and

external load lifts are unknown, but the number of external load

lifts does include a high power lift event, increase the accumulated

RIN by 20 for each hour TIS.

(5) For each hour TIS for which the numbers of takeoffs and

external load lifts are unknown, and it is unknown whether the

external load lifts include any high-power lift event, increase the

accumulated RIN by 20 for each hour TIS.

(b) After compliance with paragraph (a) of this AD, during each

operation thereafter, maintain a count of each lift or takeoff

performed and at the end of each day's operations, increase the

accumulated RIN on the component history card as follows:

(1) Increase the RIN by 1 for each takeoff.

(2) Increase the RIN by 1 for each external load lift, or

increase the RIN by 2 for each external load operation in which the

load is picked up at a higher elevation and released at a lower

elevation, and the difference in elevation between the pickup point

and the release point is 200 feet or greater.

(c) Retire the mast and spline plate in accordance with the

following:

(1) For the mast, part number (P/N) 412-040-101-105, 109, -117,

or -127, used on the Model 412 helicopter upon reaching 10,000 hours

TIS or 80,000 maximum RIN, whichever occurs first.

(2) For the mast, P/N 412-040-101-121, -125, or -129, used on

the Model 412EP helicopter, upon reaching 10,000 hours TIS or 60,000

maximum RIN, whichever occurs first.

(3) For the spline plate, P/N 412-010-167-105 or P/N 412-010-

177-101, or -109, used on the Model 412 helicopter, at 10,000 hours

TIS or 80,000 maximum RIN, whichever occurs first.

(4) For the spline plate, P/N 412-010-167-105 or P/N 412-010-

177-101, -105, -113, or -117, used on the Model 412EP helicopter, at

10,000 hours TIS or 60,000 maximum RIN, whichever occurs first.

(d) For spline plate, P/N 412-010-167-105 or P/N 412-010-177-

101, -105, -113, or -117, installed on Model 412EP helicopters, at

the next scheduled teardown inspection, beside the P/N on the side

of the spline plate, vibro-etch ``412HP'' and annotate in the

component history card or equivalent record ``412HP/EP only'' to

reflect that this spline plate can only be installed on the Model

412EP helicopter, and not on any other Model 412 helicopter. Retire

the spline plates that have been vibro-etched with ``412HP'' on or

before accumulating 10,000 hours TIS or 60,000 RIN, whichever occurs

first.

Note 2: Bell Helicopter Textron, Inc. Alert Service Bulletin No.

412-94-81, Revision B, dated March 4, 1996, pertains to this

subject.

(e) 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 Certification Office,

Rotorcraft Directorate, FAA. 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 November 6, 1996.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 96-29609 Filed 11-19-96; 8:45 am]

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