3518 Federal Register / Vol. 66, No. 10 / Tuesday, January 16, 2001 / Proposed Rules

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 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

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:

Saab Aircraft AB: Docket 2000–NM–178–AD.

Applicability: Model SAAB 2000 series

airplanes, certificated in any category, serial

numbers –003 through –063 inclusive.

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 (c) 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 fuel leakage and reduced

structural integrity of the wings due to

fatigue cracking, accomplish the following:

Modification

(a) Except as required by paragraph (b) of

this AD: Prior to the accumulation of 13,000

total flight cycles, accomplish the

modification of the rear spar on both wings

[including applicable nondestructive test

inspections to detect discrepancies

(including cracking, scratches, or other

damage, and incorrect hole size) and cold

working of fastener holes] in accordance with

Saab Service Bulletin 2000–57–037, dated

April 13, 2000.

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.’’

Repair

(b) If any discrepancy is found during any

inspection required by paragraph (a) of this

AD, prior to further flight, repair in

accordance with a method approved by the

Manager, International Branch, ANM–116,

FAA, Transport Airplane Directorate, or the

Luftfartsverket (LFV) (or its delegated agent).

For a repair method to be approved by the

Manager, International Branch, ANM–116, as

required by this paragraph, the Manager’s

approval letter must specifically reference

this AD.

Methods of Compliance

(c) 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. Operators

shall submit their requests through an

appropriate FAA Principal Maintenance

Inspector, who may add comments and who

will then send the requests and comments to

the Manager, International Branch, ANM–

116.

Note 3: 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

(d) 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.

Note 4: The subject of this AD is addressed

in Swedish airworthiness directive 1–157,

dated April 13, 2000.

Issued in Renton, Washington, on January

9, 2001.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 01–1237 Filed 1–12–01; 8:45 am]

BILLING CODE 4910–13–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000–NM–290–AD]

RIN 2120–AA64

Airworthiness Directives; Fokker

Model F.28 Mark 0070 and Mark 0100

Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes the

supersedure of an existing airworthiness

directive (AD), applicable to all Fokker

Model F.28 Mark 0070 and Mark 0100

series airplanes, that currently requires

revising the Airplane Flight Manual

(AFM) to provide the flightcrew with

instructions not to arm the liftdumper

system prior to commanding the landing

gear to extend. For Model F.28 Mark

0100 series airplanes, the existing AD

also requires modification of the

grounds of the shielding of the

wheelspeed sensor wiring of the main

landing gear (MLG) and installation of

new electrical grounds for the

wheelspeed sensor channel of the antiskid control box of the MLG. The

proposed AD would remove the

previous revision of the AFM and

would require a new limitation and a

new warning. This proposal is

prompted by issuance of mandatory

continuing airworthiness information by

Federal Register / Vol. 66, No. 10 / Tuesday, January 16, 2001 / Proposed Rules 3519

a foreign civil airworthiness authority.

The actions specified by the proposed

AD are intended to prevent inadvertent

deployment of the liftdumpers during

approach for landing or reduced brake

pressure during low speed taxiing, and

consequent reduced controllability and

performance of the airplane.

DATES: Comments must be received by

February 15, 2001.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 2000–NM–

290–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 be

submitted via fax to (425) 227–1232.

Comments may also be sent via the

Internet using the following address: 9-

anm-nprmcomment@faa.gov. Comments

sent via fax or the Internet must contain

‘‘Docket No. 2000–NM–290–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

Fokker Services B.V., P.O. Box 231,

2150 AE Nieuw Vennep, the

Netherlands. 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,

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 action 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 action

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 2000–NM–290–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.

2000–NM–290–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

On September 21, 1999, the FAA

issued AD 99–20–07, amendment 39–

11337 (64 FR 52219, September 28,

1999), applicable to all Fokker Model

F.28 Mark 0070 and Mark 0100 series

airplanes, to require revising the

Airplane Flight Manual (AFM) to

provide the flightcrew with instructions

not to arm the liftdumper system prior

to commanding the landing gear to

extend. For Model F.28 Mark 0100

series airplanes, the existing AD also

requires modification of the grounds of

the shielding of the wheelspeed sensor

wiring of the main landing gear (MLG)

and installation of new electrical

grounds for the wheelspeed sensor

channel of the anti-skid control box of

the MLG. That action was prompted by

issuance of mandatory continuing

airworthiness information by a foreign

civil airworthiness authority. The

requirements of that AD are intended to

prevent electromagnetic interference

generated by electrical wiring that runs

parallel to the wheelspeed sensor

wiring, which could result in

inadvertent deployment of the

liftdumpers during approach for landing

or reduced brake pressure during low

speed taxiing, and consequent reduced

controllability and performance of the

airplane.

Since Issuance of Previous Rule

Since the issuance of AD 99–20–07,

the Rijksluchtvaartdienst (RLD), which

is the airworthiness authority for the

Netherlands, reports another

inadvertent deployment of the

liftdumpers that occurred on a Fokker

Model F.28 Mark 0100 series airplane.

The pilot’s report indicated that the

flightcrew had armed the liftdumpers

just after making the landing gear

DOWN selection, whereupon the

liftdumpers extended almost

instantaneously. The RLD has issued

Dutch airworthiness directive 1998–

042/2, dated February 29, 2000, to

ensure the continued airworthiness of

these airplanes in the Netherlands. The

Dutch airworthiness directive advises

the flight crew not to arm the

liftdumpers before the landing gear is

down and locked.

FAA’s Conclusions

These airplane models are

manufactured in the Netherlands 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 RLD has

kept the FAA informed of the situation

described above. The FAA has

examined the findings of the RLD,

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

supersede AD 99–20–07 to require

revising the AFM by removing the

previous revision which instructed the

flightcrew not to arm the liftdumper

system prior to commanding the landing

gear to extend and by inserting a new

limitation and a new warning not to arm

the liftdumpers before the landing gear

is down and locked in position. For

Model F.28 Mark 0100 series airplanes,

the proposed AD would continue to

require modification of the grounds of

the shielding of the wheelspeed sensor

wiring of the MGL and installation of

new electrical grounds for the

wheelspeed sensor channel of the antiskid control box of the landing gear.

3520 Federal Register / Vol. 66, No. 10 / Tuesday, January 16, 2001 / Proposed Rules

Cost Impact

There are approximately 123

airplanes of U.S. registry that would be

affected by this proposed AD.

The modifications that are currently

required by AD 99–20–07 take

approximately 33 work hours per

airplane to accomplish, at an average

labor rate of $60 per work hour.

Required parts cost approximately $755

to $1,236 per airplane. Based on these

figures, the cost impact of the currently

required actions on U.S. operators is

estimated to be between $336,405 and

$395,568, or between $2,735 and $3,216

per airplane.

The revision to the AFM that is

proposed in this AD would take

approximately 1 work hour per airplane

to accomplish, at an average labor rate

of $60 per work hour. Based on these

figures, the cost impact of the proposed

requirements of this AD on U.S.

operators is estimated to be $7,380, or

$60 per airplane.

The cost impact figures discussed

above are based on assumptions that no

operator has yet accomplished any of

the current or 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 a substantial direct

effect 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,

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

removing amendment 39–11337 (64 FR

52219, September 28, 1999), and by

adding a new airworthiness directive

(AD), to read as follows:

Fokker Services B.V.: Docket 2000–NM–290–

AD. Supersedes AD 99–20–07,

Amendment 39–11337.

Applicability: All Fokker Model F.28 Mark

0070 and Mark 0100 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 (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 inadvertent deployment of the

liftdumper systems during the approach for

landing or reduced brake pressure during low

speed taxiing, and consequent reduced

controllability and performance of the

airplane, accomplish the following:

Restatement of Certain Requirements of AD

99–20–07

Corrective Actions

(a) For Model F.28 Mark 0100 series

airplanes having serial numbers as listed in

Fokker Service Bulletin SBF100–32–067,

Revision 1, dated July 6, 1998: Within 6

months after November 2, 1999 (the effective

date of AD 99–20–07, amendment 39–11337),

modify the grounds of the shielding of the

wheelspeed sensor wiring of the main

landing gear (MLG) in accordance with part

1, 2, 3, or 4 of the Accomplishment

Instructions of the service bulletin, as

applicable.

Note 2: Modifications accomplished prior

to November 2, 1999, in accordance with

Fokker Service Bulletin SBF100–32–067,

dated March 12, 1993, are considered

acceptable for compliance with the

requirements of paragraph (a) of this AD.

(b) For Model F.28 Mark 0100 series

airplanes having serial numbers as listed in

Fokker Service Bulletin SBF100–32–037,

Revision 2, dated December 4, 1998: Within

12 months after November 2, 1999, install

new electrical grounds for the wheelspeed

sensor channel of the anti-skid control box of

the MLG in accordance with part 1, 2, or 3

of the Accomplishment Instructions of the

service bulletin, as applicable.

Note 3: Installations accomplished prior to

November 2, 1999, in accordance with

Fokker Service Bulletin SBF100–32–037,

dated November 12, 1990, or Revision 1,

dated November 16, 1998, are considered

acceptable for compliance with the

requirements of paragraph (b) of this AD.

New Actions Required by This AD

Revision of the Airplane Flight Manual

(c) Within 10 days after the effective date

of this AD, revise the Limitations and Normal

Procedures sections of the FAA-approved

Airplane Flight Manual (AFM) in accordance

with paragraphs (c)(1), (c)(2), (c)(3) and (c)(4)

of this AD. This may be accomplished by

inserting a copy of this AD into the

appropriate sections of the AFM.

(1) Remove the following information from

the Limitations section:

‘‘LIFTDUMPER SYSTEM—DO NOT ARM

THE LIFTDUMPER SYSTEM BEFORE

LANDING GEAR DOWN SELECTION.’’

(2) Add the following information to the

Limitations section in the Miscellaneous

Limitations sub-section:

‘‘FLIGHT CONTROLS—NORMAL

OPERATION OF LIFTDUMPERS: DO NOT

ARM THE LIFTDUMPER SYSTEM BEFORE

LANDING GEAR IS DOWN AND LOCKED.’’

(3) Remove the following information from

Section 5—Normal Procedures, sub-section

Approach and Landing, after the subject

Approach:

‘‘BEFORE LANDING—WARNING: DO

NOT ARM THE LIFTDUMPER SYSTEM

BEFORE LANDING GEAR DOWN

SELECTION. Selecting Landing Gear DOWN

after arming the liftdumper system may

result in inadvertent deployment of the

liftdumpers, because the liftdumper arming

test may be partially ineffective.’’

(4) Add the following information to

Section 5—Normal Procedures, sub-section

Approach and Landing, after the subject

Approach:

‘‘BEFORE LANDING— WARNING: DO

NOT ARM THE LIFTDUMPER SYSTEM

BEFORE LANDING GEAR IS DOWN AND

LOCKED.’’

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, Transport

Airplane Directorate, FAA. 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

Federal Register / Vol. 66, No. 10 / Tuesday, January 16, 2001 / Proposed Rules 3521

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 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 5: The subject of this AD is addressed

in Dutch airworthiness directive 1998–042/2,

dated February 29, 2000.

Issued in Renton, Washington, on January

9, 2001.

Donald L. Riggin,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 01–1236 Filed 1–12–01; 8:45 am]

BILLING CODE 4910–13–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000–NM–303–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 777–200 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 777–200 series

airplanes. This proposal would require

repetitive detailed visual and ultrasonic

inspections of the lower flange of the

flaperon inboard support to find

cracking, and corrective actions, if

necessary. This proposal also would

require a modification, which would

terminate the repetitive inspections.

This action is necessary to prevent

fracture of the inboard support

structure, which could result in an inflight loss of the inboard flaperon,

structural damage, and consequent

reduced controllability of the airplane.

This action is intended to address the

identified unsafe condition.

DATES: Comments must be received by

March 2, 2001.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 2000–NM–

303–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-anm-nprmcomment@faa.gov.

Comments sent via fax or the Internet

must contain ‘‘Docket No. 2000–NM–

303–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,

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, 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 action 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 action

must submit a self-addressed, stamped

postcard on which the following

statement is made: ‘‘Comments to

Docket Number 2000–NM–303–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.

2000–NM–303–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

Flight testing of certain Boeing Model

777–200 series airplanes showed that

high engine thrust conditions during

takeoff cause tremendous cyclic loads

on the support structure of the inboard

flaperon. Based on engineering analysis,

fatigue cracks of the support structure

could develop at approximately 4,000

flight cycles. Such fatigue cracking

could result in fracture of the inboard

support structure, in-flight loss of the

inboard flaperon, significant damage to

the surrounding structure, and

consequent reduced controllability of

the airplane.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Boeing Alert Service Bulletin 777–

57A0036, dated June 24, 1999, which

describes procedures for detailed visual

and ultrasonic inspections of the lower

flange of the flaperon inboard support to

find cracking, and corrective actions if

cracking is found. The corrective actions

consist of accomplishment of the

terminating action in Part 2 of the

service bulletin. The terminating action

includes, but is not limited to, a high

frequency eddy current inspection to

find cracks of the aft holes that attach

the failsafe strap to the lower flange,

oversizing of the holes if cracks are

found, and installation of a failsafe

strap. Accomplishment of the actions

specified in the 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