Airworthiness Directives; Robinson Helicopter Company Model R44 Series Helicopters

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-SW-11-AD; Amendment 39-9013; AD 94-17-18]

Airworthiness Directives; Robinson Helicopter Company Model R44

Series Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that

is applicable to Robinson Helicopter Company (RHC) Model R44 series

helicopters. This action requires removal and replacement of specific

components of the cyclic control system. This amendment is prompted by

an accident involving an R44 in which the probable cause was determined

to be fatigue failure of the cyclic stick assembly. The actions

specified in this AD are intended to prevent failure of the cyclic

stick assembly and loss of control of the helicopter.

DATES: Effective September 9, 1994.

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

before October 24, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Rules Docket No. 94-SW-11-AD, 2601 Meacham Blvd., Room 663, Fort Worth,

Texas 76137.

FOR FURTHER INFORMATION CONTACT: Ms. Lirio Liu, Aerospace Engineer, Los

Angeles Aircraft Certification Office, ANM-123L, 3229 E. Spring Street,

Long Beach, California 90806-2425, telephone (310) 988-5229, fax (310)

988-5210.

SUPPLEMENTARY INFORMATION: This amendment adopts a new airworthiness

directive (AD) that is applicable to RHC Model R44 series helicopters.

On July 31, 1993, a RHC Model R44 crashed shortly after takeoff. The

helicopter had accumulated 174 hours time-in-service at the time of the

accident. The National Transportation Safety Board (NTSB) determined

the probable cause for the accident as fatigue failure of the cyclic

stick assembly. After reviewing the NTSB report, the FAA finds it

necessary to take action to remove the cyclic control system involved

in this accident from eligibility for further flight. Of the six Model

R44 series helicopters in the field, five have been modified to

incorporate a revised FAA-approved cyclic control system design. The

sixth helicopter, serial number (S/N) 0011, has not been modified. The

cyclic control system controls the attitude of the helicopter. If it

fails, the operator loses the ability to control inputs to the rotor.

This condition, if not corrected, could result in failure of the cyclic

stick assembly and loss of control of the helicopter.

Since an unsafe condition has been identified that is likely to

exist or develop on other RHC Model R44 series helicopters of the same

type design, this AD is being issued to prevent failure of the cyclic

stick assembly and loss of control of the helicopter.

The FAA has found that the original cyclic control system design

fully meets existing FAA design standards, but has limited damage

tolerance characteristics and does not display slow crack growth

properties. When initial damage or a flaw is introduced, the cyclic

stick assembly can fail due to fatigue prior to its retirement time of

4,000 hours time-in-service. This AD requires immediate removal and

replacement of specific components of the cyclic control system in

accordance with the applicable maintenance manual.

Since a situation exists that requires the immediate adoption of

this regulation, it is found that notice and opportunity for prior

public comment hereon are impracticable, and that good cause exists for

making this amendment effective in less than 30 days.

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. 94-SW-11-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 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, 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. App. 1354(a), 1421 and 1423; 49 U.S.C.

106(g); and 14 CFR 11.89.

Sec. 39.13 [Amended]

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

to read as follows:

AD 94-17-18 Robinson Helicopter Company: Amendment 39-9013. Docket

No. 94-SW-11-AD.

Applicability: Model R44 series helicopters, certificated in any

category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent failure of the cyclic stick assembly and loss of

control of the helicopter, accomplish the following:

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

remove the following cyclic control system parts and replace with

the corresponding replacement parts in accordance with the

applicable maintenance manual:

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Remove part

Nos. Replace with part Nos.

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A205-3 A205-5 Revision J or higher.

C175-1 C175-2 Revision H or higher.

C176-1 C176-2 Revision B or higher.

C177-1 C177-2 Revision F or higher.

C319-1 C319-3 Revision I or higher.

C320-1 C320-1 Revision L or higher.

C958-4 C958-5 Revision E or higher.

A101-4 D173-1 Revision A or higher.

C338-1 C338-4 Revision C or higher.

A211-2 C211-3 Revision I or higher.

A137-1 A137-2 Revision C or higher.

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(b) An alternative method of compliance or adjustment of the

compliance time that provides an acceptable level of safety may be

used when approved by the Manager, Los Angeles Aircraft

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, Los Angeles Aircraft Certification

Office.

Note: Information concerning the existence of approved

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

obtained from the Los Angeles Aircraft Certification Office.

(c) Special flight permits will not be issued.

(d) This amendment becomes effective on September 9, 1994.

Issued in Fort Worth, Texas, on August 18, 1994.

Larry M. Kelly,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 94-20753 Filed 8-24-94; 8:45 am]

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