Airworthiness Directives; Boeing Model 777 Series Airplanes

Proposed Rules

Federal Register

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Proposed Rules

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-346-AD]

RIN 2120-AA64

Airworthiness Directives; Boeing Model 777 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 certain Boeing 777 series

airplanes. This proposal would require a one-time inspection to detect

cracking of the fastener holes common to the upper wing skins and

trailing edge panels of both wings, and corrective actions, if

necessary. This proposal also would require coldwork of the fastener

holes and installation of new or serviceable fasteners. This proposal

is prompted by a report indicating that fatigue cracks have been found

in the upper wing skin of both wings. The actions specified by the

proposed AD are intended to prevent fatigue cracking of the upper wing

skin, which could result in reduced structural integrity of the wing.

DATES: Comments must be received by February 18, 2000.

d installation of new or serviceable fasteners. This proposal

is prompted by a report indicating that fatigue cracks have been found

in the upper wing skin of both wings. The actions specified by the

proposed AD are intended to prevent fatigue cracking of the upper wing

skin, which could result in reduced structural integrity of the wing.

DATES: Comments must be received by February 18, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 99-NM-346-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 Boeing Commercial Airplane Group, P.O. Box 3707, Seattle,

Washington 98124-2207. This information may be examined at the FAA,

Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,

Washington.

FOR FURTHER INFORMATION CONTACT: Stan Wood, Aerospace Engineer,

Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,

Washington 98055-4056; telephone (425) 227-2772; fax (425) 227-1181.

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

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 99-NM-346-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. 99-NM-346-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

The FAA has received a report indicating that fatigue cracks have

been found in the upper wing skin of both wings on a Boeing Model 777

test airplane. During fatigue testing of the airplane, two cracks were

detected at 80,813 flight cycles. Both cracks were detected at the tab

out for the outboard support fitting of the main landing gear beam. The

crack found on the left upper wing skin was 1.5 inches in length, and

the crack found in the right upper wing skin was 5.1 inches in length.

Examination of the cracked parts was inconclusive as to when the cracks

had initiated. Such fatigue cracking, if not detected and corrected,

could result in reduced structural integrity of the wing.

Explanation of Relevant Service Information

beam. The

crack found on the left upper wing skin was 1.5 inches in length, and

the crack found in the right upper wing skin was 5.1 inches in length.

Examination of the cracked parts was inconclusive as to when the cracks

had initiated. Such fatigue cracking, if not detected and corrected,

could result in reduced structural integrity of the wing.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Alert Service Bulletin

777-57A0022, dated August 26, 1999, which describes procedures for a

one-time eddy current inspection to detect cracking of the fastener

holes common to the upper wing skins and trailing edge panels of both

wings, and corrective actions, if necessary. The corrective actions

involve rework and re-inspection of the fastener hole. Additionally,

for any fastener hole that may require rework and re-inspections, the

corrective actions also involve measurement of the fastener hole

diameter and edge margin to ensure specific limits are maintained. The

alert service bulletin also describes procedures for coldwork of the

fastener holes and installation of new or serviceable fasteners.

Accomplishment of the actions specified in the alert service bulletin

is intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to

exist or develop on other products of this same type design, the

proposed AD would require accomplishment of the actions specified in

the alert service bulletin described previously, except as discussed

below.

Differences Between Proposed Rule and Alert Service Bulletin

Operators should note that, although the alert service bulletin

specifies that the manufacturer may be contacted for disposition of

certain conditions, this proposal would require the repair of those

conditions to be accomplished in

accordance with a method approved by the FAA.

Cost Impact

ubstantial 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 adding the following new

airworthiness directive:

Boeing: Docket 99-NM-346-AD.

Applicability: Model 777 series airplanes having line numbers 1

through 119 inclusive, except line numbers 94, 102, 104, and 118,

certificated in any category.

rity 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:

Boeing: Docket 99-NM-346-AD.

Applicability: Model 777 series airplanes having line numbers 1

through 119 inclusive, except line numbers 94, 102, 104, and 118,

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 (d) 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 prevent fatigue cracking of the upper wing skin, which could

result in reduced structural integrity of the wing, accomplish the

following:

Eddy Current Inspection of Fastener Holes

(a) Prior to the accumulation of 16,000 total flight cycles or

40,000 total flight hours, whichever occurs earlier, perform a one-

time eddy current inspection to detect cracking of the fastener

holes common to the upper wing skins and trailing edge panels of

both wings, in accordance with Boeing Alert Service Bulletin 777-

57A0022, dated August 26, 1999.

Rework and Re-Inspection of Fastener Hole

Prior to the accumulation of 16,000 total flight cycles or

40,000 total flight hours, whichever occurs earlier, perform a one-

time eddy current inspection to detect cracking of the fastener

holes common to the upper wing skins and trailing edge panels of

both wings, in accordance with Boeing Alert Service Bulletin 777-

57A0022, dated August 26, 1999.

Rework and Re-Inspection of Fastener Hole

(b) If any cracking is detected during the inspection required

by paragraph (a) of this AD, prior to further flight, oversize the

fastener hole and perform additional eddy current inspections to

detect cracking of the fastener holes until all cracking is no

longer detectable by means of eddy current inspection. Perform the

actions in accordance with Boeing Alert Service Bulletin 777-

57A0022, dated August 26, 1999. Prior to further flight, oversize

the fastener hole an additional \1/32\-inch minimum and measure the

starting hole diameter and edge margin of the fastener hole, in

accordance with the alert service bulletin.

(1) If the fastener hole diameter or the edge margin of any

fastener hole is not within the limits specified in the alert

service bulletin, prior to further flight, repair in accordance with

a method approved by the Manager, Seattle Aircraft Certification

Office (ACO), FAA, Transport Airplane Directorate, or a Boeing

Company Designated Engineering Representative who has been

authorized by the FAA to make such findings. For a repair method to

be approved by the Manager, Seattle ACO, as required by this

paragraph, the Manager's approval letter must specifically reference

this AD.

(2) If the fastener hole diameter and edge margin of all the

fastener holes are within the limits specified in the alert service

bulletin, prior to further flight, accomplish the requirements of

paragraph (c) of this AD.

Coldwork of Fastener Holes

od to

be approved by the Manager, Seattle ACO, as required by this

paragraph, the Manager's approval letter must specifically reference

this AD.

(2) If the fastener hole diameter and edge margin of all the

fastener holes are within the limits specified in the alert service

bulletin, prior to further flight, accomplish the requirements of

paragraph (c) of this AD.

Coldwork of Fastener Holes

(c) If no cracking is detected during the eddy current

inspection required by paragraph (a), or the fastener hole diameter

and edge margin of all the fastener holes are within the limits

required by paragraph (b) of this AD, prior to further flight,

coldwork the fastener holes and install new or serviceable

fasteners, in accordance with Boeing Alert Service Bulletin 777-

57A0022, dated August 26, 1999.

Alternative Methods of Compliance

(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, Seattle ACO. Operators shall submit

their requests through an appropriate FAA Principal Maintenance

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

Seattle ACO.

Note 2: Information concerning the existence of approved

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

obtained from the Seattle ACO.

Special Flight Permits

(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 airplane to a location where

the requirements of this AD can be accomplished.

Issued in Renton, Washington, on December 28, 1999.

D.L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 00-50 Filed 1-3-00; 8:45 am]

BILLING CODE 4910-13-U