Airworthiness Directives; Mitsubishi Model YS-11 and YS-11A Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-300-AD]

RIN 2120-AA64

Airworthiness Directives; Mitsubishi Model YS-11 and YS-11A

Series Airplanes

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 all Mitsubishi Model YS-11 and YS-

11A series airplanes. This proposal would require repetitive removal of

the spinner; repetitive detailed visual inspections of the propeller

hub to detect fatigue cracking; and replacement of a propeller hub with

a new propeller hub, if necessary. This proposal is prompted by

issuance of mandatory continuing airworthiness information by a foreign

civil airworthiness authority. The actions specified by the proposed AD

are intended to detect and correct fatigue cracking of the propeller

hub, which could cause the loss of the propeller.

DATES: Comments must be received by September 30, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-114,

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Attention: Rules Docket No. 98-NM-300-AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056. 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 Nihon Aeroplane Manufacturing, Toranomon Daiichi,

Kotohire-Cho, Shiba, Minato-Ku, Tokyo, Japan. This information may be

examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue,

SW., Renton, Washington; or at the FAA, Transport Airplane Directorate,

Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard,

Lakewood, California.

FOR FURTHER INFORMATION CONTACT: Jon Mowery, Aerospace Engineer,

Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, Los

Angeles Aircraft Certification Office, 3960 Paramount Boulevard,

Lakewood, California 90712-4137; telephone (562) 627-5322; fax (562)

627-5210.

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 shall 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 Number 98-NM-300-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, Transport Airplane Directorate, ANM-114, Attention: Rules

Docket No. 98-NM-300-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

The Japan Civil Aviation Bureau (JCAB), which is the airworthiness

authority for Japan, notified the FAA that an unsafe condition may

exist on all Mitsubishi YS-11 and YS-11A series airplanes. The JCAB

advises that cracking has been found on propeller hubs. This cracking

has been attributed to material fatigue. This condition, if not

corrected, could result in the loss of the propeller.

The JCAB has issued Japanese airworthiness directive TCD-4667-97,

dated October 13, 1997, which describes procedures for repetitive

removal of the spinner; repetitive detailed visual inspections to

detect fatigue cracking of the propeller hub; and replacement of

cracked propeller hubs with new propeller hubs, if necessary. The JCAB

classified these actions as mandatory in order to assure the continued

airworthiness of these airplanes in Japan.

FAA's Conclusions

These airplane models are manufactured in Japan and are type

certificated for operation in the United States under the provisions of

section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and

the applicable bilateral airworthiness agreement. Pursuant to this

bilateral airworthiness agreement, the JCAB has kept the FAA informed

of the situation described above. The FAA has examined the findings of

the JCAB, reviewed all available information, and determined that AD

action is necessary for products of this type design that are

certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to

exist or develop on other airplanes of the same type design registered

in the United States, the proposed AD would require accomplishment of

the actions specified in the Japanese airworthiness directive described

previously.

Differences Between Proposed Rule and Foreign Airworthiness

Directive

The proposed AD would differ from the parallel Japanese

airworthiness directive in that it would require accomplishment of the

inspection within 25 flight hours or 30 days after the effective date

of this AD, whichever occurs first. The parallel Japanese airworthiness

directive requires accomplishment of the inspection prior to further

flight, unless an inspection was performed within 25 flight hours

before the effective date of the Japanese airworthiness directive. In

developing an appropriate compliance time for this AD, the FAA

considered not only the safety implications, but the Japanese

airworthiness authority's requirements, the availability of required

parts, and the practical aspect of accomplishing the inspection within

an interval of time that parallels normal scheduled maintenance for

affected operators. The FAA also considered the fact that the Japanese

airworthiness directive (containing the procedures for accomplishing

the required actions) has been available to all operators of Mitsubishi

Model YS-11 and YS-11A series airplanes since October 1997. Therefore,

U.S. operators have had ample time since then to consider initiating

those actions, which this proposed AD ultimately mandates.

Cost Impact

The FAA estimates that 25 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 32 work

hours per airplane to accomplish the proposed inspection, and that the

average labor rate is $60 per work hour. Based on these figures, the

cost impact of the proposed AD on U.S. operators is estimated to be

$48,000, or $1,920 per airplane, per inspection cycle.

The cost impact figure discussed above is based on assumptions that

no operator has yet accomplished any of the proposed requirements of

this AD action, and that no operator would accomplish those actions in

the future if this AD were not adopted.

Regulatory Impact

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

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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 adding the following new

airworthiness directive:

Mitsubish Heavy Industries, Ltd.: Docket 98-NM-300-AD.

Applicability: All Model YS-11 and YS-11A series airplanes,

certificated in any category.

Note 1: This AD applies to each airplane 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 airplanes that have been modified,

altered, or repaired so that the performance of the requirements of

this AD is affected, the owner/operator must request approval for an

alternative method of compliance in accordance with paragraph (b) of

this AD. The request should include an assessment of the effect of

the modification, alteration, or repair on the unsafe condition

addressed by this AD; and, if the unsafe condition has not been

eliminated, the request should include specific proposed actions to

address it.

Compliance: Required as indicated, unless accomplished

previously.

To detect and correct fatigue cracking of the propeller hub,

which could cause the loss of the propeller, accomplish the

following:

Inspection and Replacement

(a) Within 25 flight hours or 30 days after the effective date

of this AD, whichever occurs first, remove the spinner and perform a

detailed visual inspection for cracking of the propeller hub in the

crack area shown in Figure 1 of this AD.

Note 2: For the purposes of this AD, a detailed visual

inspection is defined as: ``An intensive visual examination of a

specific structural area, system, installation, or assembly to

detect damage, failure, or irregularity. Available lighting is

normally supplemented with a direct source of good lighting at

intensity deemed appropriate by the inspector. Inspection aids such

as mirror, magnifying lenses, etc., may be used. Surface cleaning

and elaborate access procedures may be required.''

(1) If no crack is found, repeat the actions required by

paragraph (a) of this AD thereafter at intervals not to exceed 25

flight hours.

(2) If any crack is detected, prior to further flight, replace

the hub with a new hub. Repeat the actions required by paragraph (a)

of this AD thereafter at intervals not to exceed 25 flight hours.

Alternative Methods of Compliance

(b) 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, Los Angeles Aircraft Certification

Office (ACO), FAA, Transport Airplane Directorate. Operators shall

submit their requests through an appropriate FAA Principal

Maintenance Inspector, who may add comments and then send it to the

Manager, Los Angeles ACO.

Note 3: Information concerning the existence of approved

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

obtained from the Los Angeles ACO.

Special Flight Permits

(c) Special flight permits may be issued for non-revenue bearing

flights with essential crew only in accordance with sections 21.197

and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and

21.199) to operate the airplane to a location where the requirements

of this AD can be accomplished.

Note 4: The subject of this AD is addressed in Japanese

airworthiness directive TCD-4667-97, dated October 13, 1997.

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Issued in Renton, Washington, on August 24, 1999.

Vi L. Lipski,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-22528 Filed 8-30-99; 8:45 am]

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