39828 Federal Register / Vol. 65, No. 125 / Wednesday, June 28, 2000 / Proposed Rules

information specified in Airbus Temporary

Revision (TR) 4.03.00/09, TR 4.03.00/10, and

TR 4.03.00/12 (for Model A330 series

airplanes); or TR 4.03.00/20 (for Model A340

series airplanes); all dated July 23, 1999; as

applicable.

Note 2: The AFM revision required by

paragraph (a) of this AD may be

accomplished by inserting a copy of the

applicable TR into the applicable section of

the AFM. When the temporary revisions

required by paragraph (a) of this AD have

been incorporated into the general revisions

of the AFM, the general revisions may be

inserted into the AFM, provided that the

information contained in the general

revisions is identical to that specified in the

temporary revisions.

Inspections

(b) Within 1,000 flight hours after the

effective date of this AD, perform a detailed

visual inspection of the trim transfer fuel line

in the vicinity of the aft pressure bulkhead

located between frame (FR) 77 and FR86 to

detect any discrepancy (including

deformation, dents, kinks, and broken rivets

of the fuel pipe and pipe clamp, support

bracket, and shroud) in accordance with the

Accomplishment Instructions of Airbus

Service Bulletin A330–28–3060, Revision 02

(for Model A330 series airplanes), or A340–

28–4077, Revision 02 (for Model A340 series

airplanes), both dated May 27, 1999, as

applicable. Repeat the inspection thereafter

at intervals not to exceed 1,000 flight hours

until the modification required by paragraph

(c) of this AD has been accomplished.

Note 3: Inspections accomplished prior to

the effective date of this AD in accordance

with Operator Information Telex/Flight

Operations Telex (OIT/FOT) 999.0142/98,

dated December 23, 1998, are considered

acceptable for compliance with the INITIAL

detailed visual inspection required by

paragraph (b) of this AD.

Corrective Actions

(1) If any discrepancy is detected during

any inspection required by paragraph (b) of

this AD, prior to further flight, accomplish

applicable corrective actions [including

replacement of any damaged components

and deactivation of the trim fuel pipe

isolation valve and auxiliary power unit

(APU) isolation valve] in accordance with the

Accomplishment Instructions and Figure 2 of

the applicable service bulletin.

Replacement of Pipe Shroud and Pipe

(2) If the isolation valves of the trim fuel

pipe and APU are deactivated in accordance

with the FAA-approved Master Minimum

Equipment List during accomplishment of

the corrective actions required by paragraph

(b)(1) of this AD: Within 10 days after

deactivation, replace the pipe shroud and

pipe, as applicable, and reactivate the valves,

in accordance with the applicable service

bulletin.

Terminating Action

(c) Within 18 months after the effective

date of this AD, modify the air release valve

(ARV) in the trim tank system (including

cleaning and lubricating certain components,

installing two additional pressure relief

valves, and installing the adapter and ARV)

in accordance with the Accomplishment

Instructions of Airbus Service Bulletin A330–

28–3063 or A340–28–4079, both dated

October 6, 1999, as applicable.

Accomplishment of such modification

constitutes terminating action for the AFM

revisions and the repetitive inspections

required by this AD.

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,

International Branch, ANM–116, 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, International Branch,

ANM–116.

Note 4: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the International Branch,

ANM–116.

Special Flight Permits

(e) Special flight permits may be issued in

accordance with §§ 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 5: The subject of this AD is addressed

in French airworthiness directives 1999–

046–091(B), Revision 4 (for Model A330

series airplanes), and 1999–045–111(B),

Revision 4 (for Model A340 series airplanes),

both dated December 15, 1999.

Issued in Renton, Washington, on June 22,

2000.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 00–16360 Filed 6–27–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99–NM–326–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 747–400 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

adoption of a new airworthiness

directive (AD) that is applicable to

certain Boeing Model 747–400 series

airplanes. This proposal would require

repetitive inspections to detect fatigue

cracking of the longeron splice fittings

at stringer 11 on the left and right sides

at body station 2598, and various

follow-on actions. This action is

necessary to detect and correct fatigue

cracking of the longeron splice fittings

and subsequent damage to adjacent

structure. Such damage could result in

the inability of the structure to carry

horizontal stabilizer flight loads, and

consequent reduced controllability of

the horizontal stabilizer. This action is

intended to address the identified

unsafe condition.

DATES: Comments must be received by

August 14, 2000.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 99–NM–

326–AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055–4056.

Comments may be inspected at this

location between 9 a.m. and 3 p.m.,

Monday through Friday, except Federal

holidays. Comments may be submitted

via fax to (425) 227–1232. Comments

may also be sent via the Internet using

the following address: 9-anmnprmcomment@faa.gov. Comments sent

via fax or the Internet must contain

‘‘Docket No. 99–NM–326–AD’’ in the

subject line and need not be submitted

in triplicate. Comments sent via the

Internet as attached electronic files must

be formatted in Microsoft Word 97 for

Windows or ASCII text.

The service information referenced in

the proposed rule may be obtained from

Boeing Commercial Airplane Group, PO

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: Rick

Kawaguchi, Aerospace Engineer,

Airframe Branch, ANM–120S, FAA,

Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (425) 227–1153;

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

Federal Register / Vol. 65, No. 125 / Wednesday, June 28, 2000 / Proposed Rules 39829

considered before taking action on the

proposed rule. The proposals contained

in this notice may be changed in light

of the comments received.

Submit comments using the following

format:

• Organize comments issue-by-issue.

For example, discuss a request to

change the compliance time and a

request to change the service bulletin

reference as two separate issues.

• For each issue, state what specific

change to the proposed AD is being

requested.

• Include justification (e.g., reasons or

data) for each request.

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–326–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–326–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The FAA has received reports

indicating that fatigue cracking was

detected on the longeron splice fittings

at stringer 11 on certain Boeing Model

747–100, –200, –300, 747SR and 747SP

series airplanes. On three airplanes with

flight cycles ranging from 16,867 to

27,146, and with flight hours ranging

from 30,198 to 62,783, the splice fitting

cracks that were detected measured up

to 1.5 inches long. The longeron splice

fittings on Model 747–400 series

airplanes affected by this proposal are

identical to those on which the fatigue

cracking was detected. Such fatigue

cracking, and subsequent damage to

adjacent structure, could result in the

inability of the structure to carry

horizontal stabilizer flight loads, and

consequent reduced controllability of

the horizontal stabilizer.

Related Rulemaking

This proposed AD is related to AD

2000–10–23, amendment 39–11748 (65

FR 34061, June 30, 2000), which is

applicable to certain Boeing Model 747–

100, –200, –300, 747SR, and 747SP

series airplanes. That AD requires

repetitive inspections to detect cracking

of the longeron splice fittings at stringer

11, on the left and right sides at body

station 2598, and replacement of any

cracked fitting with a new fitting. This

NPRM proposes similar actions for

Boeing Model 747–400 series airplanes.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Boeing Alert Service Bulletin 747–

53A2419, dated December 17, 1998,

which describes procedures for

repetitive detailed visual inspections to

detect cracking of the longeron splice

fittings at stringer 11, on the left and

right sides at body station 2598. If no

cracking is detected, follow-on actions

include rework of the fittings or

replacement of the fittings with new

fittings, and repetitive inspections to

detect cracking. If any cracking is

detected, the corrective action is to be

accomplished prior to further flight. The

corrective action includes replacement

of all four longeron splice fittings on the

affected side, and repetitive detailed

visual inspections to detect cracking.

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 repair or

replacement conditions, this AD

requires the repair or replacement 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.

Operators also should note that the

alert service bulletin specifies that the

corrective actions required by this

proposed AD may be accomplished in

accordance with ‘‘an operator’s

equivalent procedure.’’ However, this

proposed AD requires that an

‘‘operator’s equivalent procedure’’ may

be used only in accordance with the

procedures specified in the operator’s

maintenance manual.

This proposed AD would mandate

rework or replacement of all four

longeron splice fittings on the

applicable side of the airplane if any of

the four fittings on that side are

reworked or replaced. The alert service

bulletin provides for that action as

recommended.

Cost Impact

There are approximately 490

airplanes of the affected design in the

worldwide fleet. The FAA estimates that

59 airplanes of U.S. registry would be

affected by this proposed AD.

It would take approximately 2 work

hours (1 hour per each side) per

airplane to accomplish the proposed

inspection, at an average labor rate of

$60 per work hour. Based on these

figures, the cost impact of the proposed

inspection on U.S. operators is

estimated to be $7,080, or $120 per

airplane, per inspection cycle.

It would take approximately 12 work

hours (6 hours per each side) per

airplane to accomplish the proposed

rework or replacement, at an average

labor rate of $60 per work hour.

Required parts would cost between $731

and $7,906 per airplane. Based on these

figures, the cost impact of the proposed

rework or replacement on U.S. operators

is estimated to be between $1,451 and

$8,626 per airplane.

The cost impact figures discussed

above are 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 proposed AD were not adopted. The

cost impact figures discussed in AD

rulemaking actions represent only the

time necessary to perform the specific

actions actually required by the AD.

These figures typically do not include

incidental costs, such as the time

required to gain access and close up,

planning time, or time necessitated by

other administrative actions.

Regulatory Impact

The regulations proposed herein

would not have a substantial direct

effect on the States, on the relationship

between the national Government and

the States, or on the distribution of

39830 Federal Register / Vol. 65, No. 125 / Wednesday, June 28, 2000 / Proposed Rules

power and responsibilities among the

various levels of government. Therefore,

it is determined that this proposal

would not have federalism implications

under Executive Order 13132.

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.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

Boeing: Docket 99–NM–326–AD.

Applicability: Model 747–400 series

airplanes, as listed in Boeing Alert Service

Bulletin 747–53A2419, dated December 17,

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 (e) 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 longeron splice fittings and subsequent

damage to adjacent structure, which could

result in the inability of the structure to carry

horizontal stabilizer flight loads, and

consequent reduced controllability of the

horizontal stabilizer; accomplish the

following:

Initial Detailed Visual Inspection

(a) Perform a detailed visual inspection to

detect cracking of the longeron fittings at

stringer 11, on the left and right sides at body

station 2598, at the later of the times

specified in paragraphs (a)(1) and (a)(2) of

this AD, in accordance with the

Accomplishment Instructions of Boeing Alert

Service Bulletin 747–53A2419, dated

December 17, 1998.

(1) Inspect prior to the accumulation of

17,000 total flight cycles or 63,000 total flight

hours, whichever occurs first.

(2) Inspect within 24 months after the

effective date of this AD.

Note 2: Where there are differences

between the AD and the alert service

bulletin, the AD prevails.

Note 3: 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.’’

Rework/Replacement/Repetitive Inspections

(b) If no cracking is detected during the

inspection required by paragraph (a) of this

AD, accomplish the requirements of either

paragraph (b)(1), (b)(2), or (b)(3) of this AD.

(1) Prior to further flight, rework all four

longeron splice fittings on the left and right

sides at body station 2598, in accordance

with Part 3 of the Accomplishment

Instructions of Boeing Alert Service Bulletin

747–53A2419, dated December 17, 1998.

Repeat the inspection required by paragraph

(a) of this AD one time at the later of the

times specified in paragraphs (b)(1)(i) and

(b)(1)(ii) of this AD, and thereafter at

intervals not to exceed 3,000 flight cycles or

18,000 flight hours, whichever occurs first.

(i) For airplanes on which the rework is

accomplished prior to the accumulation of

7,000 total flight cycles and prior to the

accumulation of 25,000 total flight hours:

Inspect within 20,000 flight cycles or 72,000

flight hours after rework, whichever occurs

first.

(ii) For airplanes on which the rework is

accomplished at or after the accumulation of

7,000 total flight cycles, or 25,000 total flight

hours: Inspect within 10,000 flight cycles or

36,000 flight hours after rework, whichever

occurs first.

(2) Prior to further flight, replace all four

longeron splice fittings on the left and right

sides at body station 2598 with new fittings,

in accordance with Part 2 of the

Accomplishment Instructions of Boeing Alert

Service Bulletin 747–53A2419, dated

December 17, 1998. Repeat the inspection

required by paragraph (a) of this AD one time

within 20,000 flight cycles or 72,000 flight

hours after the replacement, whichever

occurs first; and thereafter at intervals not to

exceed 3,000 flight cycles or 18,000 flight

hours, whichever occurs first.

(3) Repeat the inspection required by

paragraph (a) of this AD at intervals not to

exceed 3,000 flight cycles or 18,000 flight

hours, whichever occurs first.

Corrective Action/Repetitive Inspections

(c) If any cracking is detected during any

inspection required by paragraph (a) or (b)(3)

of this AD, prior to further flight: Replace all

four longeron splice fittings on the affected

side in accordance with Part 2 of the

Accomplishment Instructions of Boeing Alert

Service Bulletin 747–53A2419, dated

December 17, 1998. Repeat the inspection

required by paragraph (a) of this AD one time

within 20,000 flight cycles or 72,000 flight

hours after the replacement, whichever

occurs first; and thereafter at intervals not to

exceed 3,000 flight cycles or 18,000 flight

hours, whichever occurs first.

(d) If any cracking is detected during any

inspection required by paragraph (b)(1),

(b)(2), or (c) of this AD, 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 (DER) who has

been authorized by the Manager, Seattle

ACO, to make such findings. For a repair

method to be approved by the Manager,

Seattle ACO, as required by this paragraph,

the approval letter must specifically

reference this AD.

Note 4: There is no terminating action

currently available for the inspections

required by this AD.

Alternative Methods of Compliance

(e) 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 5: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

Special Flight Permit

(f) Special flight permits may be issued in

accordance with §§ 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.

Federal Register / Vol. 65, No. 125 / Wednesday, June 28, 2000 / Proposed Rules 39831

Issued in Renton, Washington, on June 22,

2000.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 00–16358 Filed 6–27–00; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99–NM–355–AD]

RIN 2120–AA64

Airworthiness Directives; British

Aerospace Model BAe 146 and Model

Avro 146–RJ Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

adoption of a new airworthiness

directive (AD) that is applicable to all

British Aerospace Model BAe 146 and

certain Model Avro 146–RJ series

airplanes. This proposal would require

inspections and torque checks of the

stringer crown fittings and bolts at Ribs

0 and 2 of the wings for discrepancies,

corrective action, if necessary; and

eventual modification of the stringer

crown fittings, which would terminate

the inspections and checks. This action

is necessary to prevent increased loads

on the upper wing skin due to looseness

of the stringer fittings and bolts at Ribs

0 and 2 of the wings, which could result

in reduced structural integrity of the

wings. This action is intended to

address the identified unsafe condition.

DATES: Comments must be received by

July 28, 2000.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 99–NM–

355–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. Comments may also

be sent via the Internet using the

following address: 9-anmnprmcomment@faa.gov. Comments sent

via the Internet must contain ‘‘Docket

No. 99–NM–355–AD’’ in the subject line

and need not be submitted in triplicate.

Comments sent via the Internet as

attached electronic files must be

formatted in Microsoft Word 97 for

Windows or ASCII text.

The service information referenced in

the proposed rule may be obtained from

British Aerospace Regional Aircraft

American Support, 13850 Mclearen

Road, Herndon, Virginia 20171. This

information may be examined at the

FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton,

Washington.

FOR FURTHER INFORMATION CONTACT:

Norman B. Martenson, Manager,

International Branch, ANM–116, FAA,

Transport Airplane Directorate, 1601

Lind Avenue, SW., Renton, Washington

98055–4056; telephone (425) 227–2110;

fax (425) 227–1149.

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.

Submit comments using the following

format:

• Organize comments issue-by-issue.

For example, discuss a request to

change the compliance time and a

request to change the service bulletin

reference as two separate issues.

• For each issue, state what specific

change to the proposed AD is being

requested.

• Include justification (e.g., reasons or

data) for each request.

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–355–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–355–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The Civil Aviation Authority (CAA),

which is the airworthiness authority for

the United Kingdom, notified the FAA

that an unsafe condition may exist on

all British Aerospace Model BAe 146

and certain Model Avro 146–RJ series

airplanes. The CAA advises that, during

in-service maintenance inspections

inside the upper part of the center and

outer wing fuel tanks at Ribs 0 and 2,

loose Jo-bolts and movement at the

stringer crown fittings have been found.

Movement in this area will cause

increased loads on the upper wing skin.

This condition, if not corrected, could

result in reduced structural integrity of

the wings.

Explanation of Relevant Service

Information

British Aerospace has issued Service

Bulletin SB.57–56, dated September 2,

1999, which describes procedures for

repetitive detailed visual inspections of

the stringers and torque checks of the Jobolts at Ribs 0 and 2 of the wings for

discrepancies. The discrepancies

include loose Jo-bolts, loose stringer

crown fittings, fretting of fittings and

stringers, and cracking or other damage

of attachments to the upper skin and

joint plates. The service bulletin also

describes procedures for modification of

all stringer crown fittings at Ribs 0 and

2 of the wings, which would eliminate

the need for the repetitive inspections.

The modification includes detailed

visual and eddy current inspections for

discrepancies (i.e., fretting, cracking,

corrosion) of the stringers, fittings, and

upper wing skin; repairs, if necessary;

and installation of oversize interference

fit radial-lock fasteners per Repair

Instruction (R.I.L. HC571H9033).

Accomplishment of the actions

specified in the service bulletin is

intended to adequately address the

identified unsafe condition. The CAA

classified this service bulletin as

mandatory and issued British

airworthiness directive 004–09–99 in

order to assure the continued

airworthiness of these airplanes in the

United Kingdom.

FAA’s Conclusions

These airplane models are

manufactured in the United Kingdom

and are type certificated for operation in

the United States under the provisions