Airworthiness Directives; Boeing Model 767 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-132-AD]

RIN 2120-AA64

Airworthiness Directives; Boeing Model 767 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 Model 767 series

airplanes. This proposal would require repetitive inspections of the

side load underwing fitting bushings for broken sealant or bushing

migration, and corrective action, if necessary. This proposal would

also provide optional terminating action in lieu of repetitive

inspections. This proposal is prompted by reports of migrated bushings

and corrosion on the side load fittings. The actions specified by the

proposed AD are intended to prevent corrosion in the side load

underwing fitting, which could result in cracking and consequent

reduced structural integrity of the wing strut.

DATES: Comments must be received by January 10, 2000.

[[Page 66120]]

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 99-NM-132-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: James G. Rehrl, Aerospace Engineer,

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

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

Washington 98055-4056; telephone (425) 227-2783; 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. 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-132-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-132-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

The FAA has received reports of migrated bushings on the side load

underwing fittings on Boeing Model 767 series airplanes. Where migrated

bushings were found, several cases of corrosion of the side fitting lug

bore were reported. Migration of the side load fitting bushing breaks

the moisture barrier to the fitting bore, and can cause corrosion of

the fitting bore. Bushing migration can also cause damage to the

adjacent structure when the bushing contacts the adjacent structure as

it migrates outward. This condition, if not corrected, could result in

cracking and consequent reduced structural integrity of the wing strut.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin 767-57-

0063, dated May 7, 1998, which describes procedures for repetitive

detailed visual inspections of the side load underwing fitting bushings

for broken sealant or bushing migration, and corrective action, if

necessary. The corrective action includes reworking the side load

fitting and installing a new bushing, if necessary. The service

bulletin also describes optional terminating action to rework the side

load fitting that may be accomplished in lieu of repetitive detailed

visual inspections.

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 service bulletin described previously.

This proposed AD also would provide for optional terminating action for

the repetitive inspections.

Operators should note that the FAA has determined that the

repetitive inspections proposed by this AD can be allowed to continue

in lieu of accomplishment of a terminating action. In making this

determination, the FAA considers that, in this case, long-term

continued operational safety will be adequately assured by

accomplishing the repetitive inspections to detect broken sealant or

bushing migration of the side load fitting bushing before it represents

a hazard to the airplane.

Differences Between the Proposed Rule and the Service Bulletin

Boeing Service Bulletin 767-57-0063, dated May 7, 1998, specifies

that the manufacturer may be contacted for disposition of certain

repair conditions, this proposed AD would require the repair of those

conditions to be accomplished in accordance with a method approved by

the FAA, or in accordance with data meeting the type certification

basis of the airplane approved by 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 Aircraft Certification Office (ACO), FAA, Transport Airplane

Directorate, as specified in paragraph (d) of this proposed AD, the

Manager's approval letter must specifically reference this AD.

Cost Impact

There are approximately 663 airplanes of the affected design in the

worldwide fleet. The FAA estimates that 312 airplanes of U.S. registry

would be affected by this proposed AD, that it would take approximately

4 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 $74,880, or $240 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.

Should an operator elect to accomplish the optional terminating

action rather than continue the repetitive inspections, it would take

approximately 12 work hours per airplane to accomplish the

modification, at an average labor rate of $60 per work hour.

Required parts would cost approximately $1,500 per airplane. Based

on these figures, the cost impact of this optional terminating action

is estimated to be $2,220 per airplane.

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

[[Page 66121]]

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-132-AD.

Applicability: Model 767 series airplanes, as listed in Boeing

Service Bulletin 767-57-0063, dated May 7, 1998; 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 (f) 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 corrosion in the side load underwing fitting, which

could result in cracking and consequent reduced structural integrity

of the wing strut, accomplish the following:

Initial Inspection

(a) Accomplish a detailed visual inspection of the side load

underwing fitting to detect broken sealant or bushing migration, in

accordance with Boeing Service Bulletin 767-57-0063, dated May 7,

1998, at the later of the times specified in paragraphs (a)(1) and

(a)(2) of this AD.

(1) Within 10 years since the date of manufacture, or

(2) Within 3000 cycles or 18 months after the effective date of

this AD, whichever occurs first.

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.''

Repetitive Inspections

(b) If no broken sealant or evidence of bushing migration is

detected, repeat the inspection required by paragraph (a) of this AD

thereafter at intervals not to exceed 6 years.

Corrective Action

(c) If evidence of broken sealant or bushing migration is

detected, prior to further flight, accomplish the corrective action

specified in paragraph (c)(1) or (c)(2) of this AD, except as

provided by paragraph (d) of this AD.

(1) Remove the bushing and inspect the side load fitting lug

bore for corrosion as shown in Figure 3 of Boeing Service Bulletin

767-57-0063, dated May 7, 1998, and rework as specified in Figure 3

of the service bulletin.

(2) Reseal the bushing and service the side load fitting in

accordance with Boeing Service Bulletin 767-57-0063, dated May 7,

1998. Within 3,000 flight cycles or 18 months, whichever occurs

first, remove the bushing and inspect the side load fitting lug bore

for corrosion as shown in Figure 3 of the service bulletin, and

rework as specified in Figure 3 of the service bulletin.

(d) For airplanes on which broken sealant or evidence of bushing

migration is detected: During the accomplishment of the actions

specified in paragraphs(c)(1) or (c)(2) of this AD, if damage to the

lug bore or fitting is found that is outside the limits specified in

Boeing Service Bulletin 767-57-0063, dated May 7, 1998; prior to

further flight, repair in accordance with a method approved by the

Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport

Airplane Directorate; or in accordance with data meeting the type

certification basis of the airplane approved by 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 AD, the Manager's approval

letter must specifically reference this AD.

Optional Terminating Action

(e) Accomplishment of rework of the side load fitting in

accordance with Figure 1 or Figure 3 of Boeing Service Bulletin 767-

57-0063, dated May 7, 1998, constitutes terminating action for the

requirements of this AD.

Alternative Methods of Compliance

(f) 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 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, Seattle ACO.

Note 3: 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

(g) 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 November 18, 1999.

D.L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-30631 Filed 11-23-99; 8:45 am]

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