Airworthiness Directives; Bell Helicopter Textron, Inc. Model 214ST Helicopters

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-SW-28-AD]

Airworthiness Directives; Bell Helicopter Textron, Inc. Model

214ST Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: This document proposes the adoption of a new airworthiness

directive (AD) that is applicable to Bell Helicopter Textron, Inc.

(BHTI) Model 214ST 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 the pillow block

bearing bolts (bearing bolts). This proposal is prompted by fatigue

analyses and tests that show certain bearing bolts fail sooner than

originally anticipated because of the unanticipated high number of

takeoffs and external load lifts utilizing high-power settings in

addition to the time-in-service (TIS) accrued under other operating

conditions. The actions specified by the proposed AD are intended to

prevent fatigue failure of the bearing bolts, which could result in

failure of the main rotor system and subsequent loss of control of the

helicopter.

DATES: Comments must be received by February 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-28-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. Charles Harrison, Aerospace

Engineer, FAA, Rotorcraft Certification Office, Rotorcraft Directorate,

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. 94-SW28-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-28-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas

76137.

[[Page 67504]]

Discussion

This notice proposes the adoption of a new airworthiness directive

(AD) that is applicable to BHTI Model 214ST helicopters. This proposal

would require, within the next 25 hours TIS after the effective date of

this AD, creation of a component history card using the RIN system for

certain bearing bolts on the Model 214ST helicopters; a system for

tracking increases to the accumulated RIN; and would establish a

maximum accumulated RIN of 17,000 for the Model 214ST helicopter

bearing bolts. Fatigue analyses and tests by the manufacturer show that

certain bearing bolts fail sooner than originally anticipated because

of the unanticipated high number of takeoffs and external load lifts

utilizing high-power settings in addition to the TIS accrued under

other operating conditions. This condition, if not corrected, could

result in fatigue failure of the bearing bolts, 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. 214ST-

94-69, dated November 7, 1994, which describes procedures for creation

of a component history card within the next 25 hours TIS for Model

214ST helicopters. The ASB also describes the retirement life as 17,000

RIN for the bearing bolts installed on the Model 214ST helicopters.

Since an unsafe condition has been identified that is likely to

exist or develop on other BHTI Model 214ST helicopters of the same type

design, the proposed AD would require creation of a component history

card using the RIN system; a system for tracking increases to the

accumulated RIN; and would establish a maximum accumulated RIN of

17,000 for the Model 214ST helicopter bearing bolts.

The FAA estimates that 6 helicopters of U.S. registry would be

affected by this proposed AD, and that it would take (1) 24 work hours

per helicopter to replace the affected bearing bolts due to the new

method of determining the retirement life required by this AD; (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 $2,000 per

helicopter. Based on these figures, the total cost impact of the

proposed AD on U.S. operators for the first year is estimated to be

$7,760 and each subsequent year to be $7,160. These costs assume

replacement of the bearing bolts 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-28-AD.

Applicability: All Model 214ST helicopters with pillow block

bearing bolts (bearing bolts), part number (P/N) 20-057-12-48D or -

50D, 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 25 hours time-in-service (TIS) after

the effective date of this AD, unless accomplished previously.

To prevent fatigue failure of the bearing bolts, 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

the bearing bolts, P/N 20-057-12-48D or -50D.

(b) To determine the accumulated RIN to date on parts in

service, multiply the factored flight hour total to date by 13.6

(round-off the result to the next higher whole number). Record on

the component history card the accumulated Retirement Index Number

(RIN).

Note 2: Bell Helicopter Textron, Inc. Alert Service Bulletin

214ST-94-69, dated November 7, 1994, pertains to this AD.

(c) After compliance with paragraphs (a) and (b) of this AD,

during each operation thereafter, maintain a count of each takeoff

and external load lift performed, and at the end of each day's

operations, increase the accumulated RIN on the component history

cards as follows:

(1) Increase the RIN by 2 for each takeoff.

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

increase the RIN by 4 for each external load lift 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.

(d) Remove the bearing bolts from service on or before attaining

an accumulated RIN of 17,000. If any of the four bearing bolts are

replaced based on condition, then all four bolts must be replaced at

that time. The bolts are no longer retired based upon flight hours.

This AD revises the Airworthiness Limitations section of the

maintenance manual by establishing a new retirement life for the

bearing bolts of 17,000 RIN.

(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,

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 Certification

Office.

[[Page 67505]]

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 December 9, 1996.

Eric Bries,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 96-32434 Filed 12-20-96; 8:45 am]

BILLING CODE 4910-13-U