38118 Federal Register / Vol. 63, No. 135 /Wednesday, July 15, 1998 / Proposed Rules

Note 3: Information concerning the

existence of approved alternative methods of

compliance with this AD, if any, may be

obtained from the Seattle ACO.

(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.

Issued in Renton, Washington, on July 8,

1998.

S.R. Miller,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 98–18779 Filed 7–14–98; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97–NM–296–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 747 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 series

airplanes. This proposal would require

repetitive inspections to detect cracks in

the edge frame web and doubler of the

number 1 main entry door cutout; and

repair, if necessary. This proposed AD

also provides for optional terminating

action for the repetitive inspections.

This proposal is prompted by reports

indicating that fatigue cracks were

found in the edge frame web and

doubler at the door stop number 1 of the

number 1 main entry door cutout. The

actions specified by the proposed AD

are intended to detect and correct such

fatigue cracking, which could result in

rapid decompression of the airplane.

DATES: Comments must be received by

August 31, 1998.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No.97–NM–

296–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: Bob

Breneman, Aerospace Engineer,

Airframe Branch, ANM–120S, FAA,

Transport Airplane Directorate, Seattle

Aircraft Certification Office, 1601 Lind

Avenue, SW., Renton, Washington

98055–4056; telephone (425) 227–2776;

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 97–NM–296–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.

97–NM–296–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The FAA has received reports

indicating that, while replacing the

inner chord of the frame on Boeing

Model 747 series airplanes, cracks were

found in the edge frame web and

doubler of the number 1 main entry

door cutout at station 488, between

stringers 25 and 26 (door stop number

1). The edge frame web in each incident

was almost completely severed. These

airplanes had accumulated as few as

18,502 total flight cycles. In addition,

the FAA has received a report indicating

that, during fatigue testing on a Boeing

Model 747SR test article, cracking

occurred in the edge frame web at

27,500 total pressure cycles and in the

inner chord at 30,750 total pressure

cycles. The cause of such cracking in all

incidents has been attributed to fatigue.

This condition, if not detected and

corrected, could result in rapid

decompression of the airplane.

Explanation of Relevant Service

Information

The FAA has reviewed and approved

Boeing Alert Service Bulletin 747–

53A2414, dated August 7, 1997. This

alert service bulletin describes

procedures for repetitive high frequency

eddy current (HFEC) inspections to

detect cracks in both the aft side of the

edge frame web along the lower edge of

the backup structure attachment at the

stop fitting number 1, and the forward

side of the doubler at the lower edge of

door stop number 1 of the number 1

main entry door cutout; and repair, if

necessary.

The alert service bulletin specifies

that operators of Group 1 airplanes are

to perform those inspections of the

subject areas on both the left and right

sides of the airplane; whereas, operators

of Group 2 airplanes are to perform

those inspections of the subject areas on

the left side only of the airplane. Group

1 airplanes are those Model 747 series

airplanes that have a number 1 main

entry door on both the left and right

sides of the airplane. Group 2 airplanes

are those Model 747 series airplanes

that only have a number 1 main entry

door on the left side of the airplane.

This alert service bulletin also

describes procedures for a preventative

modification of the edge frame web and

doubler, which involves trimming the

lower portion of the subject web;

removing the trimmed web and the

doubler; and installing a new web,

doubler, and splice plate. For airplanes

on which the inner chord of the edge

frame is not being replaced concurrently

with the repair specified in the alert

service bulletin, the procedures also

include an open hole HFEC inspection

of the inner chord of the edge frame.

Accomplishment of the preventative

modification would eliminate the need

for the repetitive inspections.

Accomplishment of the actions

specified in the alert service bulletin is
Federal Register / Vol. 63, No. 135 /Wednesday, July 15, 1998 / Proposed Rules 38119

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

inspections and repair, if necessary,

specified in the alert service bulletin

described previously. The proposed AD

also provides for optional terminating

action, which, if accomplished, would

terminate the repetitive inspections.

The FAA considers three criteria for

those situations where repetitive

inspections of a crack-prone area, such

as in this proposed AD, may be

permitted to continue indefinitely, even

though a positive fix to the problem

exists: (1) the area is easily accessible,

(2) the cracking is easily detectable, and

(3) the consequences of the cracking are

not likely to be catastrophic. In

consideration of the cracking that may

occur at the edge frame web and doubler

at station 488, the FAA has determined

that the circumstances warranting

continual repetitive inspections meet

these three criteria.

Cost Impact

There are approximately 685

airplanes of the affected design in the

worldwide fleet. The FAA estimates that

211 airplanes of U.S. registry would be

affected by this proposed AD, and that

the average labor rate is $60 per work

hour.

The FAA estimates that 191 airplanes

are equipped with a number 1 main

entry door on both the left and right

sides (Group 1 airplanes), that it would

take approximately 2 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

inspection proposed by this AD on U.S.

operators of these airplanes is estimated

to be $22,920, or $120 per airplane, per

inspection cycle.

The FAA estimates that 20 airplanes

are equipped with a number 1 main

entry door on the left side only (Group

2 airplanes), that it would take

approximately 1 work hour 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 inspection proposed

by this AD on U.S. operators of these

airplanes is estimated to be $1,200, or

$60 per airplane, per inspection cycle.

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 AD were not adopted.

Should an operator of Group 1

airplanes elect to accomplish the

optional terminating action that would

be provided by this AD action, it would

take approximately 40 work hours to

accomplish it, at an average labor rate of

$60 per work hour. Based on these

figures, the cost impact of the optional

terminating action would be $2,400 per

airplane.

Should an operator of Group 2

airplanes elect to accomplish the

optional terminating action that would

be provided by this AD action, it would

take approximately 20 work hours to

accomplish it, at an average labor rate of

$60 per work hour. Based on these

figures, the cost impact of the optional

terminating action would be $1,200 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

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.

§ 39.13 [Amended]

2. Section 39.13 is amended by

adding the following new airworthiness

directive:

Boeing: Docket 97–NM–296–AD.

Applicability: Model 747 series airplanes,

line numbers 1 through 685 inclusive,

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 cracks in the

edge frame web and doubler of the number

1 main entry door cutout, which could result

in rapid decompression of the airplane,

accomplish the following:

(a) Perform a high frequency eddy current

(HFEC) (pencil probe eddy current)

inspection to detect cracks in both the aft

side of the lower edge frame web and the

forward side of the edge frame web doubler

at station 488, between stringers 25 and 26

(door stop number 1), of the number 1 main

entry door cutout; in accordance with Boeing

Alert Service Bulletin 747–53A2414, dated

August 7, 1997; at the time specified in

paragraph (a)(1), (a)(2), (a)(3), or (a)(4) of this

AD, as applicable. For Group 1 airplanes (as

identified in the alert service bulletin), the

inspection shall be accomplished on both the

left and right sides of the airplane. For Group

2 airplanes (as identified in the alert service

bulletin), the inspection shall be

accomplished only on the left side of the

airplane.

(1) For airplanes that have accumulated

less than 16,000 total flight cycles as of the

effective date of this AD: Inspect prior to the

accumulation of 16,000 total flight cycles, or

within 1,500 flight cycles after the effective

date of this AD, whichever occurs later.

(2) For airplanes that have accumulated

16,000 or more total flight cycles but less

than 20,000 total flight cycles as of the

effective date of this AD: Inspect prior to the

accumulation of 21,000 total flight cycles, or

within 1,500 flight cycles after the effective

date of this AD, whichever occurs first.

(3) For airplanes that have accumulated

20,000 or more total flight cycles but less

than 25,000 total flight cycles as of the
38120 Federal Register / Vol. 63, No. 135 /Wednesday, July 15, 1998 / Proposed Rules

effective date of this AD: Inspect prior to the

accumulation of 25,500 total flight cycles, or

within 1,000 flight cycles after the effective

date of this AD, whichever occurs first.

(4) For airplanes that have accumulated

25,000 or more total flight cycles as of the

effective date of this AD: Inspect within 500

flight cycles after the effective date of this

AD.

(b) If no crack is detected during any

inspection required by paragraph (a) of this

AD, repeat the HFEC inspection thereafter at

intervals not to exceed 3,000 flight cycles.

(c) If any crack is detected during any

inspection required by paragraph (a) of this

AD, prior to further flight, repair in

accordance with Boeing Alert Service

Bulletin 747–53A2414, dated August 7, 1997.

Note 2: The alert service bulletin

emphasizes the importance of performing an

open hole HFEC inspection of the inner

chord of the frame within 6.0 inches of the

web or doubler crack (as applicable), if the

inner chord of the frame is not replaced

concurrently with the web and doubler

repair.

(d) Accomplishment of the repair or

preventative modification specified in Boeing

Alert Service Bulletin 747–53A2414, dated

August 7, 1997, constitutes terminating

action for the repetitive inspection

requirements of this AD for that repaired/

modified edge frame web and doubler.

(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

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.

(f) 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 July 8,

1998.

S.R. Miller,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 98–18778 Filed 7–14–98; 8:45 am]

BILLING CODE 4910–13–U

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97–NM–51–AD]

RIN 2120–AA64

Airworthiness Directives; Boeing

Model 767 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 767 series

airplanes. This proposal would require

detailed visual inspections to detect

corrosion or chrome plating cracks on

the fuse pins, load distribution plates,

and bushings of the outboard support of

the main landing gear (MLG) beam. This

proposal also would require either

installation of the existing fuse pins and

repetitive inspections; or installation of

newer-type fuse pins, which would

constitute terminating action for the

repetitive inspections. This proposal is

prompted by a report indicating that

corrosion was found on a fuse pin in the

outboard support of the MLG beam. The

actions specified by the proposed AD

are intended to detect and correct such

corrosion and cracking, which could

result in the failure of a fuse pin and,

consequently, lead to collapse of the

MLG.

DATES: Comments must be received by

August 31, 1998.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 97–NM–

51–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,

Seattle Aircraft Certification Office,

1601 Lind Avenue, SW., Renton,

Washington; 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 97–NM–51–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.

97–NM–51–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

The FAA has received a report of

corrosion on a fuse pin in the outboard

support of the main landing gear (MLG)

beam on a Boeing Model 767 series

airplane. At the time the corrosion was

detected, the airplane had accumulated

23,637 total flight hours and 5,652 total

flight cycles. Investigation revealed that

the chrome plating on the fuse pin did

not have a sufficient bond to the base

metal, which allowed the chrome plate

to crack and peel from the base metal.

This cracking in the chrome plate

allowed moisture to accumulate in the

subject area and, consequently, caused

corrosion on the base metal of the fuse

pin. Such cracking and corrosion, if not

detected and corrected, could result in