Airworthiness Directives; Bell Helicopter Textron, Inc. Model 205A-1 and 205B Helicopters

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-21-AD; Amendment 39-11011; AD 98-11-14]

RIN 2120-AA64

Airworthiness Directives; Bell Helicopter Textron, Inc. Model

205A-1 and 205B Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment

adopting Airworthiness Directive (AD) 98-11-14 which was sent

previously to all known U.S. owners and operators of Bell Helicopter

Textron, Inc. (BHTI) Model 205A-1 and 205B helicopters by individual

letters. This AD requires inspecting the trunnion assembly or tail

rotor flapping stop (flapping stop), whichever is applicable,

installing a trunnion assembly or flapping stop, if necessary; and

replacing the tail rotor yoke (yoke). This amendment is prompted by an

accident involving a BHTI Model 205A-1 helicopter in which the yoke

failed during flight. This condition, if not corrected, could lead to

failure of the yoke, loss of the tail rotor, and subsequent loss of

control of the helicopter.

DATES: Effective February 10, 1999, to all persons except those persons

to whom it was made immediately effective by Priority Letter AD 98-11-

14, issued on May 19, 1998, which contained the requirements of this

amendment.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of February 10, 1999.

Comments for inclusion in the Rules Docket must be received on or

before March 29, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Office of the Regional Counsel, Southwest Region,

Attention: Rules Docket No. 98-SW-21-AD, 2601 Meacham Blvd., Room 663,

Fort Worth, Texas 76137.

The applicable service information may be obtained from Bell

Helicopter Textron, Inc., P.O. Box 482, Fort Worth, Texas 76101,

telephone (817) 280-3391, fax (817) 280-6466. This information may be

examined at the FAA, Office of the Regional Counsel, Southwest

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Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas; or at the

Office of the Federal Register, 800 North Capitol Street, NW., suite

700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Harry Edmiston, Aerospace Engineer,

FAA, Rotorcraft Certification Office, Rotorcraft Directorate, 2601

Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5158, fax

(817) 222-5783.

SUPPLEMENTARY INFORMATION: On May 19, 1998, the FAA issued Priority

Letter AD 98-11-14, applicable to BHTI Model 205A-1 and 205B

helicopters, which requires, before further flight, reviewing

historical records of the helicopter and yoke assembly to detect any

usage or event that may have imposed an excessive bending load on the

yoke. If such usage or event occurred, before further flight, the

priority letter AD requires replacing the yoke assembly with an

airworthy yoke assembly that has zero-hours time-in-service (TIS) or

that has passed an x-ray diffraction inspection in accordance with

BHTI's service bulletins, as well as installing an airworthy trunnion

assembly or an airworthy flapping stop, depending on which part-

numbered yoke assembly is installed. If no such usage or event has

occurred, the yoke must be replaced within 180 calendar days.

Thereafter, at intervals not to exceed 25 hours TIS, or before further

flight after any incident that may have imposed an excessive bending

load on the yoke, this AD requires inspecting the trunnion assembly or

the flapping stop, whichever is applicable, for yielding. If yielding

is detected, replacing the yoke assembly and trunnion assembly or

flapping stop, whichever is applicable, is required. That action was

prompted by an accident involving a BHTI Model 205A-1 helicopter in

which the yoke failed during flight. Investigation of the accident

revealed that the yoke assembly service life may be reduced due to

unforeseen static and dynamic loading of the tail rotor. This

condition, if not corrected, could lead to failure of the yoke, loss of

the tail rotor, and subsequent loss of control of the helicopter.

The FAA has reviewed Bell Helicopter Textron, Inc. Alert Service

Bulletin (ASB) No. 205-96-68, Revision A, dated May 18, 1998, which

specifies inspecting the yoke and trunnion assemblies, and replacing

certain trunnion assemblies; and ASB 205-96-69 and ASB 205B-96-25, both

dated September 3, 1996, which specify inspecting the yoke assembly and

installing a flapping stop.

Since the unsafe condition described is likely to exist or develop

on other BHTI Model 205A-1 and 205B helicopters of the same type

design, the FAA issued Priority Letter AD 98-11-14 to prevent failure

of the yoke, loss of the tail rotor, and subsequent loss of control of

the helicopter. The AD requires, before further flight, reviewing

historical records of the helicopter and yoke assembly to detect any

usage or event that may have imposed an excessive bending load on the

yoke. If such usage or event occurred, this AD requires, before further

flight, replacing the yoke assembly with an airworthy yoke assembly

that has zero-hours TIS, or that has passed an x-ray diffraction

inspection in accordance with Bell Helicopter Textron, Inc. Alert

Service Bulletin (ASB) 205-96-68, Revision A, dated May 18, 1998, or

ASB 205-96-69 or ASB 205B-96-25, both dated September 3, 1996,

whichever is applicable, as well as installing an airworthy trunnion

assembly or an airworthy flapping stop, depending on which part-

numbered yoke assembly is installed. If no such usage or event has

occurred, the yoke must be replaced within 180 calendar days.

Thereafter, at intervals not to exceed 25 hours TIS, or before further

flight after any incident that may have imposed an excessive bending

load on the yoke, this AD requires inspecting the trunnion assembly or

the flapping stop, whichever is applicable, for yielding. If yielding

is detected, replacing the yoke assembly and trunnion assembly or

flapping stop, whichever is applicable, is required. The actions are

required to be accomplished in accordance with the service bulletins

described previously. The short compliance time involved is required

because the previously described critical unsafe condition can

adversely affect both the controllability and structural integrity of

the helicopter. Therefore, the previously-stated actions are required

prior to further flight, and this AD must be issued immediately.

Since it was found that immediate corrective action was required,

notice and opportunity for prior public comment thereon were

impracticable and contrary to the public interest, and good cause

existed to make the AD effective immediately by individual letters

issued on May 19, 1998 to all known U.S. owners and operators of BHTI

Model 205A-1 and 205B helicopters. These conditions still exist, and

the AD is hereby published in the Federal Register as an amendment to

section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to

make it effective to all persons.

The FAA estimates that 495 helicopters of U.S. registry will be

affected by this AD; that it will take approximately 9 work hours per

helicopter to conduct the inspections, install the trunnion assembly or

flapping stops, and replace the yoke; and that the average labor rate

is $60 per work hour. Required parts will cost approximately $1,028 for

a trunnion assembly or $936 for the flapping stops and $6,637 for the

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

the AD on U.S. operators is estimated to be $4,061,475 to replace both

the trunnion assembly and the yoke in the entire fleet.

Comments Invited

Although this action is in the form of a final rule that involves

requirements affecting flight safety and, thus, was not preceded by

notice and an opportunity for public comment, comments are invited on

this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All

communications received on or before the closing date for comments will

be considered, and this rule may be amended in light of the comments

received. Factual information that supports the commenter's ideas and

suggestions is extremely helpful in evaluating the effectiveness of the

AD action and determining whether additional rulemaking action would be

needed.

Comments are specifically invited on the overall regulatory,

economic, environmental, and energy aspects of the rule that might

suggest a need to modify the 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 that

summarizes each FAA-public contact concerned with the substance of this

AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments

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

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

to Docket No. 98-SW-21-AD.'' The postcard will be date stamped and

returned to the commenter.

The regulations adopted herein will not have substantial direct

effects on the States, on the relationship between the

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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 final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

The FAA has determined that this regulation is an emergency

regulation that must be issued immediately to correct an unsafe

condition in aircraft, and that it is not a ``significant regulatory

action'' under Executive Order 12866. It has been determined further

that this action involves an emergency regulation under DOT Regulatory

Policies and Procedures (44 FR 11034, February 26, 1979). If it is

determined that this emergency regulation otherwise would be

significant under DOT Regulatory Policies and Procedures, a final

regulatory evaluation will be prepared and placed in the Rules Docket.

A copy of it, if filed, may be obtained from the Rules Docket at the

location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends 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 adding a new airworthiness directive

to read as follows:

98-11-14 Bell Helicopter Textron, Inc.: Amendment 39-11011. Docket

No. 98-SW-21-AD.

Applicability: Model 205A-1 helicopters, with tail rotor yoke

assembly, part number (P/N) 212-011-702-all dash numbers, or P/N

212-010-704-all dash numbers, or P/N 212-010-744-all dash numbers,

and Model 205B helicopters, with tail rotor yoke assembly, P/N 212-

011-702-all dash numbers, 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 (d) 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 tail rotor yoke (yoke), loss of the

tail rotor, and subsequent loss of control of the helicopter,

accomplish the following:

(a) Before further flight, review all historical records of the

helicopter and the tail rotor yoke assembly (yoke assembly) for any

static or dynamic incident history that could have imposed an

excessive bending load on the yoke. If such a history exists, comply

with paragraph (b) of this AD before further flight.

Note 2: Examples of excessive bending loads include exposure to

high wind gusts (such as those from rotor wash or prop blast),

improper ground handling (in which the tail rotor blade has been

used as a hand hold), improper feathering bearing removal (in which

the yoke is not properly supported when pressing out bearings), a

static ground strike of some type (such as being struck by a

vehicle), or an incident in which a damaged tail rotor blade was

replaced due to a blade strike. An overload may also occur

dynamically during a power-on or power-off sudden stoppage incident

or hard landing.

(b) Within the next 180 calendar days, remove the yoke assembly

and replace it with an airworthy yoke assembly having zero hours

time-in-service (TIS), or with an airworthy yoke assembly

(regardless of TIS) that has passed an x-ray diffraction inspection

in accordance with Bell Helicopter Textron, Inc. Alert Service

Bulletin (ASB) 205-96-68, Revision A, dated May 18, 1998, or ASB

205-96-69 or ASB 205B-96-25, both dated September 3, 1996, whichever

is applicable. When the yoke assembly is replaced, for helicopters

with a yoke assembly, P/N 212-011-702-all dash numbers, install an

airworthy tail rotor flapping stop, P/N 212-011-713-103, and for

helicopters with yoke assemblies, P/N 212-010-704-all dash numbers

or P/N 212-010-744-all dash numbers, install an airworthy trunnion

assembly, P/N 212-010-738-001. If any incident as described in

paragraph (a) of this AD occurs after the effective date of this AD

and prior to compliance with this paragraph, then compliance with

this paragraph is required before further flight.

Note 3: Yoke assemblies that have passed an x-ray diffraction

inspection at BHTI will have the letters ``FM'' vibro-etched on them

following the serial number.

(c) After accomplishing the requirements of paragraph (b) of

this AD, thereafter at intervals not to exceed 25 hours TIS, or

before further flight after any incident as described in paragraph

(a) of this AD, inspect the trunnion assembly, and replace the yoke

assembly and trunnion assembly, if required, in accordance with Part

III, Paragraph 1, of ASB 205-96-68, Revision A, dated May 18, 1998;

or inspect the flapping stop and replace the yoke assembly and

flapping stop, if required, in accordance with Part III, Paragraphs

1, 2, and 3, of ASB 205-96-69 or ASB 205B-96-25, both dated

September 3, 1996, whichever is applicable.

(d) 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. 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, Rotorcraft Directorate.

Note 4: Information concerning the existence of approved

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

obtained from the Rotorcraft Certification Office.

(e) 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.

(f) The repetitive inspections shall be done in accordance with

Bell Helicopter Textron, Inc. Alert Service Bulletin (ASB) No. 205-

96-68, Revision A, dated May 18, 1998, which specifies inspections

of the yoke and trunnion assemblies, and replacement of certain

trunnion assemblies; and ASB 205-96-69 and ASB 205B-96-25, both

dated September 3, 1996, which specify inspections of the yoke

assembly and installation of a flapping stop. This incorporation by

reference was approved by the Director of the Federal Register in

accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be

obtained from Bell Helicopter Textron, Inc., P.O. Box 482, Fort

Worth, Texas 76101, telephone (817) 280-3391, fax (817) 280-6466.

Copies may be inspected at the FAA, Office of the Regional Counsel,

Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas;

or at the Office of the Federal Register, 800 North Capitol Street,

NW., suite 700, Washington, DC.

(g) This amendment becomes effective on February 10, 1999, to

all persons except those persons to whom it was made immediately

effective by Priority Letter AD 98-11-14, issued May 19, 1998, which

contained the requirements of this amendment.

Issued in Fort Worth, Texas, on January 14, 1999.

Eric Bries,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 99-1430 Filed 1-25-99; 8:45 am]

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