Federal Register / Vol. 63, No. 139 /Tuesday, July 21, 1998 / Proposed Rules 39045

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95–NM–275–AD]

RIN 2120–AA64

Airworthiness Directives; Airbus Model

A310 Series Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Supplemental notice of

proposed rulemaking; reopening of

comment period.

SUMMARY: This document revises an

earlier proposed airworthiness directive

(AD), applicable to all Airbus Model

A310 series airplanes, that would have

required various inspections to detect

fatigue cracks at certain locations on the

fuselage, horizontal stabilizer, and

wings and tail, and repair or

modification, if necessary; and

installation of doublers. That proposal

was prompted by results of full-scale

fatigue testing of a ModelA310 series

airplane, which revealed fatigue cracks

at those locations. This new action

revises the proposed rule by adding new

inspections and reducing certain

inspection intervals. The actions

specified by this new proposed AD are

intended to prevent reduced structural

integrity of the fuselage, horizontal

stabilizer, and wings.

DATES: Comments must be received by

August 17, 1998.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Transport

Airplane Directorate, ANM–114,

Attention: Rules Docket No. 95–NM–

275–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

Airbus Industrie, 1 Rond Point Maurice

Bellonte, 31707 Blagnac Cedex, France.

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

LindAvenue, 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.

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 95–NM–275–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.

95–NM–275–AD, 1601 Lind Avenue,

SW., Renton, Washington 98055–4056.

Discussion

A proposal to amend part 39 of the

Federal Aviation Regulations (14 CFR

part 39) to add an airworthiness

directive (AD), applicable to all Airbus

Model A310 series airplanes, was

published as a notice of proposed

rulemaking (NPRM) in the Federal

Register on January 11, 1996 (61 FR

1017). That NPRM would have required

various inspections to detect fatigue

cracks at certain locations on the

fuselage, horizontal stabilizer, and

wings and tail, and repair or

modification, if necessary; and

installation of doublers. That NPRM was

prompted by results of full-scale fatigue

testing of a Model A310 series airplane,

which revealed fatigue cracks at those

locations. That condition, if not

corrected, could result in reduced

structural integrity of the fuselage,

horizontal stabilizer, and wings.

Disposition of Comments

Due consideration has been given to

the comments received in response to

the NPRM.

Request to Cite Revised Service

Information

Airbus requests that the FAA revise

the proposal to reference later revisions

of certain service bulletins, and French

airworthiness directive 92–106–

132(B)R4, dated June 5, 1996. In

addition, Airbus indicates that two

additional inspection tasks have been

added in Revision 4 of the French

airworthiness directive. These tasks are

described in two Airbus service

bulletins:

• Airbus Service Bulletin A310–57–

2064, dated August 24, 1995, which

describes procedures for repetitive eddy

current inspections to detect cracking of

the corner angle fitting and the vertical

tee fitting at left and right frame 40, and

corrective actions, if necessary.

• Airbus Service Bulletin A310–57–

2038, Revision 2, dated January 4, 1996,

which describes procedures for

repetitive high frequency eddy current

or X-ray inspections to detect cracking

of the stringer runouts inboard and

outboard of rib 14 at stringers 6, 7, 8,

and 9.

In addition, Airbus issued the

following service bulletin revisions,

which are essentially the same as the

previous issues of the service bulletins,

except as specified below:

• Service Bulletin A310–53–2014,

Revision 5, dated June 9, 1992; as

revised by Service Bulletin Change

Notices 5.A., dated September 29, 1992,

and 5.B., dated February 5, 1996; which

specifies a reduced inspection

threshold, and updates the reference to

the appropriate French airworthiness

directive.

• Service Bulletin A310–53–2059,

Revision 1, dated January 4, 1996,

which specifies appropriate grace

periods for the specified compliance

time for accomplishment of the

recommended inspections, and updates

the reference to the appropriate French

airworthiness directive.

• Service Bulletin A310–57–2002,

Revision 2, dated January 4, 1996,

which provides a grace period for the

specified compliance time for

accomplishment of the recommended

inspection.

• Service Bulletin A310–57–2006,

Revision 3, dated May 2, 1996, which

revises the effectivity listing of the

service bulletin.

• Service Bulletin A310–57–2032,

Revision 3, dated January 4, 1996,

which revises the effectivity listing of

the service bulletin.
39046 Federal Register / Vol. 63, No. 139 /Tuesday, July 21, 1998 / Proposed Rules

• Service Bulletin A310–57–2037,

Revision 3, dated January 4, 1996,

which contains minor editorial changes.

• Service Bulletin A310–57–2046,

Revision 4, dated October 16, 1996; as

revised by Service Bulletin Change

Notice 4A, dated October 16, 1996;

which changes the inspection

technique, reduces the repetitive

inspection intervals, and revises the

effectivity listing of the service bulletin.

• Service Bulletin A310–57–2047,

Revision 2, dated January 22, 1997,

which revises the effectivity listing of

the service bulletin.

• Service Bulletin A310–57–2050,

dated April 23, 1990; as revised by

Service Bulletin Change Notices 0.A.,

dated September 29, 1992, and 0.B.,

dated January 6, 1995; which adds a

reference to the appropriate French

airworthiness directive.

The Direction Ge ́ne ́rale de l’Aviation

Civile (DGAC), which is the

airworthiness authority for France,

classified these service bulletins as

mandatory, and issued French

airworthiness directive 92–106–

132(B)R4, dated June 5, 1996, in order

to ensure the continued airworthiness of

these airplanes in France.

The FAA concurs with the

commenter’s request to cite the

additional and revised service bulletins,

and has revised this supplemental

NPRM to provide these references.

Additionally, the cost impact

information, below, has been revised to

reflect any additional costs to operators

and to update the number of affected

U.S.-registered airplanes.

Request to Substantiate Need for

Accomplishment of Service Bulletins

One commenter questions whether

each of the service bulletins cited in the

NPRM individually satisfies the unsafe

condition requirements of part 39 of the

Federal Aviation Regulations (14 CFR

part 39). The commenter points out that

Airbus Service Bulletin A310–53–2014

indicates that the existence of a ‘‘crack

does not affect aircraft safety because its

propagation ... could entail expensive

repair.’’

The commenter further states that the

supplementary comments (of the

proposed rule) describe how the DGAC

allows either a visual or eddy current

inspection to detect cracks that measure

0.078 inch, but since the FAA has

concluded that a 0.078-inch crack will

not likely be found by visual means, the

FAA proposes that only an eddy current

inspection be used for the affected

structure. The commenter states that

this restriction goes beyond what is

specified by the DGAC and should be

substantiated. The commenter states

that it suspects that the DGAC is well

aware that a 0.078-inch crack would not

be found by a visual inspection, but has

concluded that a crack of that size on

the affected structure does not render

the airplane unsafe and that visual

inspections are appropriate for the

inspection interval provided.

The commenter suggests that if the

justification for this proposed AD is

based upon the DGAC recommendation,

then the FAA’s departure from the

DGAC’s recommendation should be

coordinated with the DGAC before the

FAA adopts this proposed AD.

The FAA infers that the commenter is

requesting substantiation that

accomplishment of all of the service

bulletins referenced in the proposed AD

is necessary in order to address an

unsafe condition. The FAA also infers

that the example cited regarding visual

versus eddy current inspections is in

reference to Airbus Service Bulletin

A310–57–2039, dated September 24,

1990.

The wing, fuselage, and empennage

structure is primary structure of the

airplane that contributes significantly to

carrying flight, ground, and

pressurization loads. As in much of

commercial aircraft structure, the failure

of a single part is usually not

catastrophic, and safe flight could likely

continue for some time with any single

part cracked or broken. However, if

certain parts (as referenced in the

service bulletins) were to fail, the

residual strength of the surrounding

aircraft structure would be reduced and

could cause failure or initiate/accelerate

cracking of other structural members.

Therefore, in consonance with the

DGAC, the FAA finds that

accomplishment of the referenced

service bulletins, as required by this

supplemental NPRM, is necessary in

order to adequately address the

identified unsafe condition.

However, the FAA has reconsidered

its position concerning the use of visual

inspection techniques, specifically for

accomplishment of the actions specified

in Airbus Service Bulletin A310–57–

2039 and A310–57–2050. The FAA

finds that a visual inspection also will

adequately detect cracking. Operators

should note, however, that by the time

cracking has progressed to the point of

being visually detectable, repairs would

likely be complicated and expensive.

Since definitive repairs beyond a certain

crack length are not provided in the

service bulletins, an FAA-approved

repair would be required to be

accomplished for such cracking. The

FAA has revised paragraphs (l) and (p)

of this supplemental NPRM to add a

visual inspection method as an option

for accomplishment of the referenced

service bulletins.

Reformatting of the Supplemental

NPRM

Operators should note that the FAA

has revised the text of paragraphs (a)

through (q) of the original NPRM for the

sake of brevity and to reduce the

complexity of the requirements

specified in those paragraphs.

Conclusion

Since certain changes explained

previously expand the scope of the

originally proposed rule, the FAA has

determined that it is necessary to reopen

the comment period to provide

additional opportunity for public

comment.

This airplane model is manufactured

in France and is type certificated for

operation in the United States under the

provisions of Section 21.29 of the

Federal Aviation Regulations and the

applicable bilateral airworthiness

agreement. Pursuant to this bilateral

airworthiness agreement, the DGAC has

kept the FAA informed of the situation

described above. The FAA has

examined the findings of the DGAC,

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 supplemental NPRM would

require accomplishment of the actions

specified in the service bulletins

described previously, except as

discussed below.

Differences Between This Supplemental

NPRM and the Service Bulletins

Operators should note that, unlike the

procedures described in Airbus Service

Bulletins A310–57–2002, Revision 2,

dated January 4, 1996; A310–57–2006,

Revision 3, dated May 2, 1996; A310–

57–2032, Revision 3, dated January 4,

1996; and A310–57–2037, Revision 3,

dated January 4, 1996; this

supplemental NPRM would not permit

further flight if cracks are detected in

the wing skins. The FAA has

determined that, because of the safety

implications and consequences

associated with such cracking, any wing

skin that is found to be cracked must be

repaired or modified prior to further

flight.
Federal Register / Vol. 63, No. 139 /Tuesday, July 21, 1998 / Proposed Rules 39047

Additionally, operators should note

that, although certain service bulletins

specify that the manufacturer may be

contacted for disposition of certain

repair conditions, this supplemental

NPRM would require the repair of those

conditions to be accomplished in

accordance with a method approved by

either the FAA or the DGAC (or its

delegated agent). In light of the type of

repairs that would be required to

address the identified unsafe condition,

and in consonance with existing

bilateral airworthiness agreements, the

FAA has determined that, for this

supplemental NPRM, repairs approved

by either the FAA or the DGAC (or its

delegated agent) would be acceptable for

compliance with this supplemental

NPRM.

Cost Impact

The FAA estimates that 36 airplanes

of U.S. registry would be affected by this

AD. Approximate work hours to

accomplish the proposed actions and

costs for required parts are listed in the

following table. The average labor rate is

$60 per work hour.

A310

Service bulletin No. Work hours Parts cost/Airplane Cost/Airplane No. of U.S. airplanes Number modified

53–2014 ...... 78 $12,121 $16,801 7 5

53–2016 ...... 317 14,282 33,302 12 5

53–2054 ...... 11 N/A 660 8 0

53–2057 ...... 12 N/A 720 13 0

53–2059 ...... 13 N/A 780 17 0

53–2074 ...... 232 N/A 13,920 17 0

55–2002 ...... 715 34,100 77,000 7 6

55–2004 ...... 16 N/A 960 11 0

57–2002 ...... 8 N/A 480 6 0

57–2006 ...... 52 N/A 3,120 2 0

57–2032 ...... 5 N/A 300 6 0

57–2037 ...... 2 N/A 120 6 0

57–2039 ...... 3 N/A 180 15 0

57–2046 ...... 172 N/A 10,320 33 0

57–2047 ...... 82 N/A 4,920 24 0

57–2050 ...... 24 N/A 1,440 20 0

57–2064 ...... 8 N/A 480 26 0

57–2038 ...... 6 N/A 360 0 0

Based on these figures, the cost

impact of the AD on U.S. operators is

estimated to be $1,845,591. However,

the FAA has been advised that a certain

number of U.S.-registered airplanes

already have been modified in

accordance with the requirements of

this AD. (The numbers of U.S.-registered

airplanes that have already been

modified are listed under the heading,

‘‘Number Modified,’’ in the table above.)

Therefore, the future economic cost

impact of this rule on U.S. operators is

now $1,133,076.

The FAA recognizes that the

obligation to maintain aircraft in an

airworthy condition is vital, but

sometimes expensive. Because AD’s

require specific actions to address

specific unsafe conditions, they appear

to impose costs that would not

otherwise be borne by operators.

However, because of the general

obligation of operators to maintain

aircraft in an airworthy condition, this

appearance is deceptive. Attributing

those costs solely to the issuance of this

supplemental NPRM is unrealistic

because, in the interest of maintaining

safe aircraft, prudent operators would

accomplish the required actions even if

they were not required to do so by the

supplemental NPRM.

A full cost-benefit analysis has not

been accomplished for this

supplemental NPRM. As a matter of

law, in order to be airworthy, an aircraft

must conform to its type design and be

in a condition for safe operation. The

type design is approved only after the

FAA makes a determination that it

complies with all applicable

airworthiness requirements. In adopting

and maintaining those requirements, the

FAA has already made the

determination that they establish a level

of safety that is cost-beneficial. When

the FAA, as in this supplemental

NPRM, makes a finding of an unsafe

condition, this means that the original

cost-beneficial level of safety is no

longer being achieved and that the

proposed actions are necessary to

restore that level of safety. Because this

level of safety has already been

determined to be cost-beneficial, a full

cost-benefit analysis for this

supplemental NPRM would be

redundant and unnecessary.

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
39048 Federal Register / Vol. 63, No. 139 /Tuesday, July 21, 1998 / Proposed Rules

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:

Airbus Industrie: Docket 95–NM–275–AD.

Applicability: All Model A310 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 (u) 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 reduced structural integrity of

the fuselage, horizontal stabilizer, and wings,

accomplish the following:

(a) For airplanes listed in Airbus Service

Bulletin A310–53–2014, Revision 5, dated

June 9, 1992, as revised by Service Bulletin

Change Notices 5.A., dated September 29,

1992, and 5.B., dated February 5, 1996: Prior

to the accumulation of 12,000 total flight

cycles, or within 500 flight cycles after the

effective date of this AD, whichever occurs

later, perform an eddy current inspection to

detect cracks on the fuselage center section

doublers at frame 40, and install new

doublers, in accordance with Airbus Service

Bulletin A310–53–2014, Revision 5, dated

June 9, 1992, as revised by Service Bulletin

Change Notices 5.A., dated September 29,

1992, and 5.B., dated February 5, 1996.

Except as provided by paragraph (t) of this

AD, if any discrepancy is found, prior to

further flight, perform follow-on corrective

actions, as applicable, in accordance with the

service bulletin.

(b) For airplanes listed in Airbus Service

Bulletin A310–53–2016, Revision 5, dated

December 7, 1992: Prior to the accumulation

of 12,000 total flight cycles, or within 1,000

flight cycles after the effective date of this

AD, whichever occurs later, perform a

defectoscope or rototest inspection to detect

cracks in the area of frame 47 and frame 54,

and install new doublers, in accordance with

Airbus Service Bulletin A310–53–2016,

Revision 5, dated December 7, 1992. Except

as provided by paragraph (t) of this AD, if

any discrepancy is found, prior to further

flight, perform follow-on corrective actions,

as applicable, in accordance with the service

bulletin.

(c) For airplanes listed in Airbus Service

Bulletin A310–53–2054, Revision 2, dated

May 22, 1990: Prior to the accumulation of

12,000 total flight cycles, or within 1,000

flight cycles after the effective date of this

AD, whichever occurs later, and thereafter at

intervals not to exceed 3,000 flight cycles,

perform a visual inspection to detect cracks

on frame 46 between the left- and right-hand

sides of stringers 21 and 22 on the forward

and aft faces in accordance with Airbus

Service Bulletin A310–53–2054, Revision 2,

dated May 22, 1990. If any crack is found,

prior to further flight, repair in accordance

with Airbus Service Bulletin A310–53–2054,

Revision 2, dated May 22, 1990.

(1) Accomplishment of the repair required

by paragraph (c) of this AD, or modification

of the reinforcement angle runout in

accordance with Airbus Service Bulletin

A310–53–2019, Revision 2, dated May 22,

1990, terminates the repetitive inspection

requirements of paragraph (c) of this AD.

(2) Accomplishment of paragraph (c) of

this AD terminates the requirements of AD

91–13–01, amendment 39–7032.

(d) For airplanes listed in Airbus Service

Bulletin A310–53–2057, Revision 1, dated

April 30, 1992: Perform a visual inspection

to detect cracks at the T-section connecting

frame 50A to the beam between the left- and

right-hand sides of frames 50 and 51, in

accordance with Airbus Service Bulletin

A310–53–2057, Revision 1, dated April 30,

1992. Perform the inspection at the time

specified in paragraph (d)(1) or (d)(2) of this

AD, as applicable. If any crack is found, prior

to further flight, accomplish Airbus

Modifications No. 4853 and No. 5273 in

accordance with Airbus Service Bulletin

A310–53–2057, Revision 1, dated April 30,

1992. Accomplishment of these

modifications terminates the requirements of

this paragraph.

(1) For the airplane having manufacturer’s

serial number (MSN) 191: Prior to the

accumulation of 24,000 total flight cycles, or

within 1,000 flight cycles after the effective

date of this AD, whichever occurs later; and

thereafter at intervals not to exceed 6,000

flight cycles.

(2) For airplanes other than the airplane

identified in paragraph (d)(1) of this AD:

Prior to the accumulation of 12,000 total

flight cycles, or within 1,000 flight cycles

after the effective date of this AD, whichever

occurs later; and thereafter at intervals not to

exceed 6,000 flight cycles.

(e) For airplanes listed in Airbus Service

Bulletin A310–53–2059, Revision 1, dated

January 4, 1996: Perform a visual inspection

to detect cracks in the lower milled side

panel at the lap joint with the upper side

panel at frame 47 and stringer 22, left- and

right-hand sides, in accordance with Airbus

Service Bulletin A310–53–2059, Revision 1,

dated January 4, 1996. Perform the inspection

at the time specified in paragraph (e)(1) or

(e)(2) of this AD, as applicable. Except as

provided by paragraph (t) of this AD, if any

crack is found, prior to further flight, repair

in accordance with the service bulletin.

Thereafter, repeat the inspections at intervals

not to exceed 9,000 flight cycles, or

accomplish Airbus Modification 5997

(Airbus Service Bulletin A310–53–2058).

Accomplishment of either the repair or

Airbus Modification 5997 constitutes

terminating action for the repetitive

inspections required by this paragraph.

(1) For Model A310–200 series airplanes,

accomplish the inspection at the time

specified in paragraph (e)(1)(i) or (e)(1)(ii) of

this AD, as applicable.

(i) For airplanes that have accumulated less

than 20,000 total flight cycles as of the

effective date of this AD: Prior to the

accumulation of 18,000 total flight cycles, or

within 2,000 flight cycles after the effective

date of this AD, whichever occurs later.

(ii) For airplanes that have accumulated

20,000 or more total flight cycles as of the

effective date of this AD: Within 1,000 flight

cycles after the effective date of this AD.

(2) For Model A310–300 series airplanes,

accomplish the inspection at the time

specified in paragraph (e)(2)(i) or (e)(2)(ii) of

this AD, as applicable.

(i) For airplanes that have accumulated less

than 19,700 total flight cycles as of the

effective date of this AD: Prior to the

accumulation of 18,000 total flight cycles, or

within 1,700 flight cycles after the effective

date of this AD, whichever occurs later.

(ii) For airplanes that have accumulated

19,700 or more total flight cycles as of the

effective date of this AD: Within 850 flight

cycles after the effective date of this AD.

(f) For airplanes listed in Airbus Service

Bulletin A310–55–2002, Revision 4, dated

April 28, 1989: Prior to the accumulation of

12,000 total flight cycles, or within 1,000

flight cycles after the effective date of this

AD, whichever occurs later, perform an eddy

current inspection to detect cracks on the

upper integral part adjacent to the rear attach

fittings on the horizontal stabilizer, and

modify the horizontal stabilizer, in

accordance with Airbus Service Bulletin

A310–55–2002, Revision 4, dated April 28,

1989. Except as provided by paragraph (t) of

this AD, if any discrepancy is found, prior to

further flight, perform follow-on corrective

actions, as applicable, in accordance with the

service bulletin.

(g) For airplanes listed in Airbus Service

Bulletin A310–55–2004, Revision 2, dated

February 7, 1991: Perform a high frequency

eddy current rototest inspection to detect

cracks at specified fastener holes in the top

skin chordwise splice along the contour of

the steel doubler between ribs 3 and 4 on the

left- and right-hand center and side boxes on

the horizontal stabilizer in accordance with

Airbus Service Bulletin A310–55–2004,

Revision 2, dated February 7, 1991, at the

time specified in paragraph (g)(1) or (g)(2) of

this AD, as applicable. Except as provided by

paragraph (t) of this AD, if any discrepancy

is found, prior to further flight, perform

follow-on corrective actions, as applicable, in

accordance with the service bulletin.

(1) For airplanes on which Airbus

Modification A310–4933 (Airbus Service

Bulletin A310–55–2002) was accomplished

prior to the accumulation of 6,000 total flight

cycles on the airplane; or for airplanes having

MSN 311 through 414 inclusive, on which

Airbus Modification A310–4933 was

accomplished during production: Prior to the
Federal Register / Vol. 63, No. 139 /Tuesday, July 21, 1998 / Proposed Rules 39049

accumulation of 18,000 total flight cycles, or

within 1,000 flight cycles after the effective

date of this AD, whichever occurs later; and

thereafter at intervals not to exceed 12,000

flight cycles.

(2) For airplanes on which Airbus

Modification A310–4933 (Airbus Service

Bulletin A310–55–2002) was accomplished

upon or after the accumulation of 6,000 total

flight cycles: Prior to the accumulation of

12,000 flight cycles since the modification, or

within 1,000 flight cycles after the effective

date of this AD, whichever occurs later; and

thereafter at intervals not to exceed 12,000

flight cycles.

(h) For airplanes listed in Airbus Service

Bulletin A310–57–2002, Revision 2, dated

January 4, 1996: Prior to the accumulation of

12,000 total flight cycles, or within 1,000

flight cycles after the effective date of this

AD, whichever occurs later; and thereafter at

intervals not to exceed 3,000 flight cycles;

perform a detailed visual inspection to detect

cracks in the external surface of the wing

lower skin around the landing access panel

holes of the leading edge, in accordance with

Airbus Service Bulletin A310–57–2002,

Revision 1, dated July 2, 1992. If any

discrepancy is found, prior to further flight,

repair in accordance with a method approved

by either the Manager, International Branch,

ANM–116, FAA, Transport Airplane

Directorate, or the Direction Ge ́ne ́rale de

l’Aviation Civile (DGAC) (or its delegated

agent). Accomplishment of Airbus

Modification 5101 (Airbus Service Bulletin

A310–57–2003) terminates the repetitive

inspection requirements of paragraph (h) of

this AD.

(i) For airplanes listed in Airbus Service

Bulletin A310–57–2006, Revision 3, dated

May 2, 1996: Prior to the accumulation of

6,000 total flight cycles, or within 1,000 flight

cycles after the effective date of this AD,

whichever occurs later; and thereafter at

intervals not to exceed 3,000 flight cycles;

perform an eddy current inspection to detect

cracks in the holes around the overwing

refueling aperture at ribs 13–14, in

accordance with Airbus Service Bulletin

A310–57–2006, Revision 3, dated May 2,

1996. Except as provided by paragraph (t) of

this AD, if any discrepancy is found, prior to

further flight, perform follow-on corrective

actions, as applicable, in accordance with the

service bulletin. Accomplishment of Airbus

Modification 5891H5128 (Airbus Service

Bulletin A310–57–2020) terminates the

repetitive inspection requirements of

paragraph (i) of this AD.

(j) For airplanes listed in Airbus Service

Bulletin A310–57–2032, Revision 3, dated

January 4, 1996: Prior to the accumulation of

12,000 total flight cycles, or within 1,000

flight cycles after the effective date of this

AD, whichever occurs later; and thereafter at

intervals not to exceed 4,500 flight cycles;

perform a detailed visual inspection to detect

cracks around the bolts in the wing top skin

upper surface of the front spar between rib

7 and rib 28, in accordance with Airbus

Service Bulletin A310–57–2032, Revision 3,

dated January 4, 1996. If any discrepancy is

found, prior to further flight, repair in

accordance with a method approved by the

Manager, International Branch, ANM–116, or

the DGAC (or its delegated agent).

Accomplishment of Airbus Modification

5026H0878 (Airbus Service Bulletin A310–

57–2005) terminates the repetitive inspection

requirements of paragraph (j) of this AD.

(k) For airplanes listed in Airbus Service

Bulletin A310–57–2037, Revision 3, dated

January 4, 1996: Prior to the accumulation of

12,000 total flight cycles, or within 1,000

flight cycles after the effective date of this

AD, whichever occurs later; and thereafter at

intervals not to exceed 3,000 flight cycles;

perform a high frequency eddy current

inspection to detect cracks around the

attachment bolt heads for the shroud panel

landing on the bottom skin aft of the rear

spar, forward of access door 575CB/675CB, in

accordance with Airbus Service Bulletin

A310–57–2037, Revision 3, dated January 4,

1996. If any discrepancy is found, prior to

further flight, repair in accordance with a

method approved by the Manager,

International Branch, ANM–116, or the

DGAC (or its delegated agent).

Accomplishment of Airbus Modification

5106H0894 (Airbus Service Bulletin A310–

57–2004) terminates the repetitive inspection

requirements of paragraph (k) of this AD.

(l) For airplanes listed in Airbus Service

Bulletin A310–57–2039, dated September 24,

1990: Perform either an eddy current or

visual inspection to detect cracks on the left

and right vertical posts, numbers 1 through

5 inclusive, in the wing center box at frame

40/41, in accordance with Airbus Service

Bulletin A310–57–2039, dated September 24,

1990. Perform the inspection at the time

specified in paragraph (l)(1) or (l)(2) of this

AD, as applicable. Except as provided by

paragraph (t) of this AD, if any crack is

found, prior to further flight, accomplish the

modification specified in Airbus Service

Bulletin A310–57–2041, dated September 24,

1990, in accordance with Airbus Service

Bulletin A310–57–2039, dated September 24,

1990.

(1) For airplanes on which Airbus

Modification 7541/S7973 (reference Airbus

Service Bulletin A310–57–2041) has not been

accomplished: Inspect prior to the

accumulation of 21,000 total flight cycles, or

within 1,000 flight cycles after the effective

date of this AD, whichever occurs later; and

thereafter at intervals not to exceed 4,200

flight cycles (for a visual inspection), or 7,500

flight cycles (for an eddy current inspection).

(2) For airplanes on which Airbus

Modification 7541/S7973 (reference Airbus

Service Bulletin A310–57–2041) has been

accomplished: Inspect at the time specified

in the graph contained in Note 1 of paragraph

1.A.(2) of Airbus Service Bulletin A310–57–

2039, dated September 24, 1990, or within

1,000 flight cycles after the effective date of

this AD, whichever occurs later; and

thereafter at intervals not to exceed 5,000

flight cycles (for a visual inspection), or 8,600

flight cycles (for an eddy current inspection).

(m) For Model A310–200 series airplanes

on which Airbus Modification 7925H1113

has not been accomplished: Prior to the

accumulation of 12,000 total flight cycles, or

within 1,000 flight cycles after the effective

date of this AD, whichever occurs later,

perform an ultrasonic inspection to detect

cracks in certain bolt holes where the main

landing gear forward pick-up fitting is

attached to the rear spar, in accordance with

Airbus Service Bulletin A310–57–2046,

Revision 4, dated October 16, 1996

(including Appendix 1, Revision 3, dated

October 17, 1995), as revised by Service

Bulletin Change Notice 4A, dated October 16,

1996. Accomplishment of paragraph (m) of

this AD terminates the requirements of AD

91–06–18, amendment 39–6940.

(1) If no crack is found, accomplish either

paragraph (m)(1)(i) or (m)(1)(ii) of this AD in

accordance with the service bulletin at the

time specified in that paragraph.

(i) Repeat the inspection of the bolt/stud

holes thereafter at intervals not to exceed

3,500 flight cycles. Or

(ii) Prior to further flight, accomplish

Airbus Modification 7925H1113; and, prior

to the accumulation of 18,000 flight cycles

after accomplishment of Airbus Modification

7925H1113, perform the inspection required

by paragraph (m) of this AD. Repeat the

inspection thereafter at intervals not to

exceed 11,600 flight cycles.

Note 2: Airbus Service Bulletin A310–57–

2046, Revision 4, dated October 16, 1996

(including Appendix 1, Revision 3, dated

October 17, 1995), as revised by Service

Bulletin Change Notice 4A, dated October 16,

1996, references Airbus Service Bulletin

A310–57–2049 and Repair Instruction R571–

49305 as additional sources of service

information for accomplishment of Airbus

Modification 7925H1113.

(2) If any crack is found, prior to further

flight, repair in accordance with a method

approved by the Manager, International

Branch, ANM–116, or the DGAC (or its

delegated agent).

(n) For Model A310–300 series airplanes

on which Airbus Modification 7925H1113

has not been accomplished: Prior to the

accumulation of 9,000 flight cycles, or within

1,000 flight cycles after the effective date of

this AD, whichever occurs later, perform an

ultrasonic inspection to detect cracks in

certain bolt holes where the main landing

gear forward pick-up fitting is attached to the

rear spar, in accordance with Airbus Service

Bulletin A310–57–2046, Revision 4, dated

October 16, 1996 (including Appendix 1,

Revision 3, dated October 17, 1995), as

revised by Service Bulletin Change Notice

4A, dated October 16, 1996. Accomplishment

of paragraph (n) of this AD terminates the

requirements of AD 91–06–18, amendment

39–6940.

(1) If no crack is found, accomplish either

paragraph (n)(1)(i) or (n)(1)(ii) of this AD in

accordance with the service bulletin at the

time specified in that paragraph.

(i) Repeat the inspection of the bolt/stud

holes thereafter at intervals not to exceed

3,100 flight cycles. Or

(ii) Prior to further flight, accomplish

Airbus Modification 7925H1113; and, prior

to the accumulation of 18,000 flight cycles

after accomplishment of Airbus Modification

7925H1113, perform the inspection required

by paragraph (n) of this AD. Repeat the

inspection thereafter at intervals not to

exceed 11,600 flight cycles.

Note 3: Airbus Service Bulletin A310–57–

2046, Revision 4, dated October 16, 1996

(including Appendix 1, Revision 3, dated
39050 Federal Register / Vol. 63, No. 139 /Tuesday, July 21, 1998 / Proposed Rules

October 17, 1995), as revised by Service

Bulletin Change Notice 4A, dated October 16,

1996, references Airbus Service Bulletin

A310–57–2049 and Repair Instruction R571–

49305 as additional sources of service

information for accomplishment of Airbus

Modification 7925H1113.

(2) If any crack is found, prior to further

flight, repair in accordance with a method

approved by the Manager, International

Branch, ANM–116, or the DGAC (or its

delegated agent).

(o) For airplanes listed in Airbus Service

Bulletin A310–57–2047, Revision 2, dated

January 22, 1997: Perform a rotating probe

inspection to detect cracks in the fastener

holes on the left-and right-hand sides of the

rear spar internal angle and tee fitting, in

accordance with Airbus Service Bulletin

A310–57–2047, Revision 2, dated January 22,

1997, at the applicable time specified in Note

2 of paragraph 1.A.(2) of the service bulletin,

or within 1,000 flight cycles after the

effective date of this AD, whichever occurs

later; and thereafter at the intervals specified

in Note 2 of paragraph 1.A.(2) of the service

bulletin. Except as provided by paragraph (t)

of this AD, if any discrepancy is found, prior

to further flight, perform follow-on corrective

actions in accordance with the service

bulletin.

(p) For airplanes listed in Airbus Service

Bulletin A310–57–2050, dated April 23,

1990, as revised by Service Bulletin Change

Notices 0.A., dated September 29, 1992, and

0.B., dated January 6, 1995: Perform a visual

or rotating probe inspection to detect cracks

in the drain holes on the lower skin panel in

the center wing box between frames 42 and

46, in accordance with Airbus Service

Bulletin A310–57–2050, dated April 23,

1990, as revised by Service Bulletin Change

Notices 0.A., dated September 29, 1992, and

0.B., dated January 6, 1995, at the applicable

time specified in Note 1 of paragraph 1.A.(2)

of the service bulletin, or within 1,000 flight

cycles after the effective date of this AD,

whichever occurs later; and thereafter at

intervals not to exceed those specified in

Note 1 of paragraph 1.A.(2) of the service

bulletin. Except as provided by paragraph (t)

of this AD, if any discrepancy is found, prior

to further flight, perform follow-on corrective

actions in accordance with the service

bulletin. Accomplishment of Airbus

Modification number 6130S6815 (Airbus

Service Bulletin A310–57–2048), constitutes

terminating action for the repetitive

inspections required by paragraph (p) of this

AD.

(q) For airplanes listed in Airbus Service

Bulletin A310–53–2074, Revision 1, dated

February 20, 1995: Perform visual and eddy

current inspections to detect damaged

sealant, corrosion, and cracks in accordance

with Airbus Service Bulletin A310–53–2074,

Revision 1, dated February 20, 1995.

Accomplish these requirements at the

applicable time specified in Table 2 of

paragraph 1.C.(4) of the service bulletin, or

within 1,000 flight cycles after the effective

date of this AD, whichever occurs later; and

thereafter at intervals not to exceed those

specified in Table 2 of paragraph 1.C.(4) of

the service bulletin, as applicable. Except as

provided by paragraph (t) of this AD, if any

discrepancy is found, prior to further flight,

perform follow-on corrective actions in

accordance with the service bulletin.

(r) For airplanes listed in Airbus Service

Bulletin A310–57–2064, dated August 24,

1995: Perform an eddy current inspection to

detect cracks of the upper corner angle fitting

and the vertical tee fitting at left and right

frame 40, in accordance with Airbus Service

Bulletin A310–57–2064, dated August 24,

1995. Perform the inspection at the time

specified in paragraph (r)(1) or (r)(2) of this

AD, as applicable. Except as provided by

paragraph (t) of this AD, if any crack is

found, prior to further flight, perform

corrective actions in accordance with the

service bulletin.

(1) For Model A310–200 series airplanes:

Prior to the accumulation of 18,000 total

flight cycles, or within 2,000 flight cycles

after the effective date of this AD, whichever

occurs later; and thereafter at intervals not to

exceed 11,000 flight cycles.

(2) For Model A310–300 series airplanes:

Prior to the accumulation of 18,000 total

flight cycles, or within 1,700 flight cycles

after the effective date of this AD, whichever

occurs later; and thereafter at intervals not to

exceed 7,700 flight cycles.

(s) For airplanes listed in Airbus Service

Bulletin A310–57–2038, Revision 2, dated

January 4, 1996: Prior to the accumulation of

12,000 total flight cycles, or within 1,500

flight cycles after the effective date of this

AD, whichever occurs later, perform a high

frequency eddy current (HFEC) or X-ray

inspection to detect cracking of the stringer

runouts inboard and outboard of rib 14 at

stringers 6, 7, 8, and 9, in accordance with

Airbus Service Bulletin A310–57–2038,

Revision 2, dated January 4, 1996. Thereafter,

repeat the inspection at intervals not to

exceed those specified in paragraph 1.B.(5) of

the service bulletin, as applicable. If any

crack is detected, prior to further flight,

repair in accordance with a method approved

by the Manager, International Branch, ANM–

116, or the DGAC (or its delegated agent).

(t) If any crack is found during any

inspection required by this AD, and the

applicable service bulletin specifies to

contact Airbus for an appropriate action Prior

to further flight, repair in accordance with a

method approved by either the Manager,

International Branch, ANM–116, or the

DGAC (or its delegated agent).

(u) 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 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.

(v) 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 French airworthiness directive 92–106–

132(B)R4, dated June 5, 1996.

Issued in Renton, Washington, on July 14,

1998.

Darrell M. Pederson,

Acting Manager, Transport Airplane

Directorate, Aircraft Certification Service.

[FR Doc. 98–19332 Filed 7–20–98; 8:45 am]

BILLING CODE 4910–13–P

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98–CE–39–AD]

RIN 2120–AA64

Airworthiness Directives; Mitsubishi

Heavy Industries, Ltd. MU–2B Series

Airplanes

AGENCY: Federal Aviation

Administration, DOT.

ACTION: Notice of proposed rulemaking

(NPRM).

SUMMARY: This document proposes to

adopt a new airworthiness directive

(AD) that would apply to certain

Mitsubishi Heavy Industries, Ltd.

(Mitsubishi) MU–2B series airplanes.

The proposed AD would require

inspecting each forward attachment

fitting bolt (total of four bolts) of the

wing tip tanks for the correct bolt and

replacing any incorrect bolt. The

proposed AD is the result of mandatory

continuing airworthiness information

(MCAI) issued by the airworthiness

authority for Japan. The actions

specified by the proposed AD are

intended to prevent the wing tip tank

from separating from the airplane

because of an incorrect bolt corroding,

which could result in loss of control of

the airplane.

DATES: Comments must be received on

or before August 25, 1998.

ADDRESSES: Submit comments in

triplicate to the Federal Aviation

Administration (FAA), Central Region,

Office of the Regional Counsel,

Attention: Rules Docket No. 98–CE–39–

AD, Room 1558, 601 E. 12th Street,

Kansas City, Missouri 64106. Comments

may be inspected at this location

between 8 a.m. and 4 p.m., Monday

through Friday, holidays excepted.

Mitsubishi MU–2 Service Bulletin

(SB) No. 225, dated September 29, 1995,

may be obtained from Mitsubishi Heavy

Industries, Ltd., Nagoya Aerospace

Systems Works, 10, OYE–CHO,

MINATO–KU, Nagoya, Japan,

telephone: NAGOYA (611) 2141,