Airworthiness Directives; Bell Helicopter Textron, Inc. Model 214B, 214B-1, and 214ST Helicopters

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-SW-29-AD]

Airworthiness Directives; Bell Helicopter Textron, Inc. Model

214B, 214B-1, and 214ST 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

airworthiness directive (AD), applicable to Bell Helicopter Textron,

Inc. (BHTI) Model 214B, 214B-1, and 214ST helicopters, that currently

establishes a retirement life of 60,000 high-power events for the main

rotor trunnion (trunnion). This proposal would require changing the

method of calculating retirement life for the trunnion from high power

events to a maximum accumulated Retirement Index Number (RIN). This

proposal is prompted by fatigue analyses and tests that show certain

trunnions fail sooner than originally anticipated because of the

unanticipated higher number of lifts or takeoffs (torque events)

performed with those trunnions 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 trunnion,

which could result in loss of the main rotor and subsequent loss of

control of the helicopter.

DATES: Comments must be received by February 10, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Rules Docket No. 94-SW-29-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., Attention: 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-SW-29-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 65368]]

94-SW-29-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Discussion

On July 20, 1994, the FAA issued AD 94-15-14, Amendment 39-8985 (59

FR 40798, August 10, 1994), to require changing the method of

calculating the retirement life for the trunnion, part number (P/N)

214-010-230-101, from flight hours to high-power events calculated

using the number of takeoffs and external load lifts. That action was

prompted by fatigue analyses and tests that show certain trunnions fail

sooner than originally anticipated because of the unanticipated high

number of lifts and takeoffs (torque events) performed with those

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

operating conditions. The requirements of that AD are intended to

prevent fatigue failure of the trunnion, which could result in loss of

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

Since the issuance of that AD, BHTI has issued BHTI Information

Letter GEN-94-54, dated April 15, 1994, Subject: Retirement Index

Number (RIN) For Cycle Lifed Components, which introduces a different

method of accounting for fatigue damage on components that have

shortened service lives as a result of frequent torque events.

Additionally, BHTI has issued BHTI Alert Service Bulletin (ASB) 214-94-

55, which is applicable to the Model 214B helicopters, and ASB 214ST-

94-70, which is applicable to the Model 214ST helicopters, both of

which are dated November 7, 1994 and describe procedures for converting

flight hours and total number of torque events into a RIN for the

trunnion, P/N 214-010-230-101. Although ASB 214-94-55 does not state

that it applies to Model 214B-1 helicopters, this was an oversight by

the manufacturer. That ASB was intended to apply to both Model 214B and

214B-1 helicopters.

Since an unsafe condition has been identified that is likely to

exist or develop on other BHTI Model 214B, 214B-1, and 214ST

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

94-15-14 to 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 for the trunnion of 120,000

at which the trunnion must be removed from service.

The FAA estimates that 8 helicopters of U.S. registry would be

affected by this proposed AD, and that it would take: (1) 10 work hours

to replace the affected trunnion 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); and (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 $11,000. Based on these

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

estimated to be $17,360 for the first year and $16,520 for each

subsequent year. These costs assume replacement of the trunnion in one

helicopter each year, creation and maintenance of the records for all

the fleet the first year, and creation of one helicopter'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 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing Amendment 39-8985 (59 FR

40798, August 10, 1994), and by adding a new airworthiness directive

(AD), to read as follows:

Bell Helicopter Textron, Inc. (BHTI): Docket No. 94-SW-29-AD.

Supersedes AD 94-15-14, Amendment 39-8985.

Applicability: Model 214B, 214B-1, and 214ST helicopters, with

main rotor trunnion (trunnion), part number (P/N) 214-010-230-101,

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 within 25 hours time-in-service (TIS) after

the effective date of this AD, unless accomplished previously.

To prevent fatigue failure of the trunnion, which could result

in loss of the main rotor and subsequent loss of control of the

helicopter, accomplish the following:

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

the trunnion, P/N 214-040-230-101.

(b) Determine and record on a component history card or

equivalent record the accumulated Retirement Index Number (RIN) to-

date on the trunnion by multiplying the accumulated high-power event

total to-date by 2 or as follows:

(1) For Model 214B, multiply the flight hour total to-date by 24

(round up any resulting fraction to the next higher whole number),

or

(2) For Model 214ST, multiply the factored flight hour total to-

date by 24 (round up any resulting fraction to the next higher whole

number).

Note 2: BHTI Alert Service Bulletin (ASB) No. 214-94-55, which

is applicable to Model 214B and 214 B-1 helicopters, and ASB No.

214ST-94-70, which is applicable to Model 214ST helicopters, both

dated November 7, 1994, pertain to this AD.

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

during each operation thereafter, maintain a count of the number and

type of external load lifts and the number of takeoffs performed

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

RIN on the component history card as follows:

[[Page 65369]]

(1) For the Model 214B and 214B-1 helicopters,

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

(ii) Increase the RIN by 1 for each external lift, or increase

the RIN by 2 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.

(2) For the Model 214ST helicopters,

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

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

operation, 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 trunnion, P/N 214-010-230-101, from service on or

before attaining an accumulated RIN of 120,000. The trunnion is no

longer retired based upon flight hours. This AD revises the

Airworthiness Limitation section of the maintenance manual by

establishing a new retirement life for the trunnion of 120,000 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.

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 4, 1996.

Eric Briese,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 96-31523 Filed 12-11-96; 8:45 am]

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