Airworthiness Directives; Boeing Model 747 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-70-AD; Amendment 39-10045; AD 97-12-03]

RIN 2120-AA64

Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes two existing airworthiness

directives (AD) that are applicable to certain Boeing Model 747 series

airplanes. One of those AD's currently requires inspections for

cracking, corrosion, and fracturing of the lower horizontal clevis of

the strut midspar fittings, and replacement of discrepant parts with

new or serviceable parts, or repair, if necessary. That AD also

requires inspection for removal of broken sealant of the clevis and the

fasteners, and various follow-on actions. It also provides for optional

terminating actions for the inspections. The other AD currently

requires inspection for cracking of certain fastener holes of the upper

and lower horizontal clevis legs. This amendment continues to require

inspections to detect cracking, corrosion, and fracturing of the lower

horizontal clevis; and adds corresponding inspections of the upper

horizontal clevis, and replacement of discrepant parts with new parts,

or rework, if necessary. This amendment also removes certain optional

terminating actions. This amendment is prompted by reports of cracking

of the lower and upper leg of the horizontal clevis of the midspar

fitting. The actions specified in this AD are intended to detect and

correct cracking and fracturing of the clevis, which could result in

drooping of the strut at the strut-to-wing interface, and consequent

separation of the engine and strut from the airplane.

DATES: Effective June 24, 1997.

The incorporation by reference of Boeing Alert Service Bulletin

747-54A2179, Revision 1, dated November 27, 1996, as listed in the

regulations, is approved by the Director of the Federal Register as of

June 24, 1997.

The incorporation by reference of the following publications listed

in the regulations was approved by the Director of the Federal Register

as of the specified dates:

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Approval date and Federal

Referenced service bulletin and date Register citation

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747-54A2157, January 12, 1995............. July 28, 1995 (60 FR 33333,

June 28, 1995).

747-54A2158, November 30, 1994............ July 28, 1995 (60 FR 33336,

July 28, 1995).

747-54A2159, November 3, 1994............. June 21, 1995 (60 FR 27008,

May 22, 1995).

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The incorporation by reference of certain other publications listed

in the regulations also was approved previously by the Director of the

Federal Register as of January 22, 1997 (60 FR 66201, December 12,

1996).

Comments for inclusion in the Rules Docket must be received on or

before August 8, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 97-NM-70-AD, 1601 Lind Avenue, SW., Renton,

Washington 98055-4056.

The service information referenced in this AD 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; or at

the Office of the Federal Register, 800 North Capitol Street, NW.,

suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Tamara Dow, Aerospace Engineer,

Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,

1601 Lind Avenue, SW., Renton, Washington; telephone (425) 227-2771;

fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: On January 13, 1988, the FAA issued AD 87-

04-13 R1, amendment 39-5836 (53 FR 2005, January 26, 1988), applicable

to certain Boeing Model 747 series airplanes. That AD revised an

existing AD to require inspection for cracking, and repair or

replacement, as necessary, of the horizontal clevis of the pylon

midspar attach fitting. That action was prompted by reports of cracking

and corrosion in the fastener holes of the

[[Page 31332]]

midspar attach fitting of the engine pylon. The actions required by

that AD are intended to detect and correct such cracking/corrosion of

the attach fitting, which could cause possible separation of the pylon

and engine from the wing.

In addition, on November 25, 1996, the FAA issued AD 96-25-01,

amendment 39-9842 (61 FR 66201, December 17, 1996), applicable to

certain Boeing Model 747 series airplanes, to require inspections to

detect broken sealant common to the lower horizontal clevis of the

inboard and outboard strut midspar fittings and of the fasteners, and

various follow-on actions. That action also requires inspections to

detect cracking, corrosion, and fracturing of the lower horizontal

clevis, and replacement of discrepant parts with new or serviceable

parts, or repair, if necessary. That action also provides for optional

terminating actions for the repetitive inspections. That action was

prompted by reports of fatigue cracking, stress corrosion cracking, and

fracturing of the horizontal clevis of the inboard midspar fitting of

the number three strut. The actions required by that AD are intended to

detect and correct such cracking and fracturing, which could result in

drooping of the strut at the strut-to-wing interface, and consequent

separation of the engine and strut from the airplane.

Other Relevant Rulemaking

The FAA has previously issued several other AD's that address

cracking in the midspar fitting clevis on Boeing Model 747 series

airplanes:

1. AD 90-06-06, amendment 39-6490 (55 FR 8374, March 7, 1990):

Among various other actions, this AD requires structural modification,

among various other actions, in accordance with Boeing Document No. D6-

35999, dated March 31, 1989. The FAA has approved an alternative method

of compliance that extends the compliance time threshold to a maximum

of three years after the airplane reaches 20,000 total flight cycles,

or until the mandated strut/wing modification is accomplished,

whichever occurs first. Additionally, ultrasonic inspections to detect

cracking of the fastener holes are required at intervals not to exceed

1,000 flight cycles in accordance with Boeing Service Bulletin 747-54-

2118, dated July 26, 1986. If cracking or corrosion is detected during

those inspections, rework or replacement of the midspar fitting with a

new or serviceable part is required, in accordance with that service

bulletin.

The FAA has approved Boeing Alert Service Bulletin 747-54A2179,

Revision 1, dated November 27, 1996, as an alternative method of

compliance for the requirements specified in AD 90-06-06, which

references Boeing Service Bulletin 747-54-2118 as the appropriate

source of service information.

2. AD 95-10-16, amendment 39-9233 (60 FR 27008, May 5, 1995): For

airplanes equipped with Pratt & Whitney Model JT9D engines (excluding

Model JT9D-70 engines), that AD requires modification of the nacelle

strut and wing structure, and inspections of the adjacent structure

that has not been replaced by the modification, in accordance with

Boeing Alert Service Bulletin 747-54A2159, dated November 3, 1994. As a

condition to extend the compliance time from 32 to 56 months, AD 95-10-

16 also requires repetitive ultrasonic inspections to detect cracking

of the aft-most two fastener holes in both strut midspar fittings on

the inboard and outboard nacelle struts, or modification of the aft-

most two fastener holes as described in Boeing Service Bulletin 747-54-

2118.

The FAA has approved the inspections of the upper and lower

horizontal legs of the strut midspar fittings and compliance times for

those inspections specified in Boeing Alert Service Bulletin 747-

54A2179, Revision 1, dated November 29, 1996, as an alternative to

those actions specified in paragraphs (a)(2)(ii)(a) and (a)(2)(iv)(a)

of AD 95-10-16.

Since the issuance of that AD, Boeing Alert Service Bulletin 747-

54A2159, Revision 1, dated June 1, 1995, and Revision 2, dated March

14, 1996, have been approved as alternative methods of compliance with

that AD.

3. AD 95-13-05, amendment 39-9285 (60 FR 33333, June 28, 1995): For

airplanes equipped with Rolls Royce Model RB211 series engines, that AD

requires modification of the strut/wing in accordance with Boeing Alert

Service Bulletin 747-54A2157, dated January 12, 1995.

Since the issuance of that AD, Boeing Alert Service Bulletin 747-

54A2157, Revision 1, dated August 3, 1995, and Revision 2, dated

November 14, 1996, have been approved as alternative methods of

compliance with the AD.

4. AD 95-13-07, amendment 39-9287 (60 FR 33336, July 28, 1995): For

airplanes equipped with General Electric Model CF6-45 or -50 series

engines, that AD requires modification of the strut/wing in accordance

with Boeing Alert Service Bulletin 747-54A2158, dated November 30,

1994.

Since issuance of that AD, Boeing Alert Service Bulletin 747-

54A2158, Revision 1, dated August 17, 1995, and Revision 2, dated

August 15, 1996, have been approved as alternative methods of

compliance with that AD.

Actions Since Issuance of AD 87-04-13 R1 and AD 96-25-01

Since the issuance of AD 96-25-01, the FAA has received reports

indicating that cracking was found of the lower and upper leg of the

horizontal clevis of the midspar fitting on Boeing Model 747 series

airplanes. The cracking was detected during inspections that were

conducted in accordance with AD 96-25-01.

One operator reported that a midspar fitting at the number three

pylon was cracked at the fourth row of fasteners from the aft end on

the upper leg of the horizontal clevis of the midspar fitting. This

operator also reported a crack on the lower leg of the midspar fitting

at the number two pylon at the second row from the aft end.

Metallurgical analysis accomplished on the midspar fitting at the

number three pylon indicates that the cause of the cracking was stress

corrosion.

The FAA also received another report indicating that cracking was

detected on the upper leg of the horizontal clevis of the midspar

fitting at the second row of fasteners from the aft end at the number

three pylon. In addition, this report indicated that cracking was also

detected on that same airplane at the number 3 pylon at the second row

from the aft end of the lower leg. The report also indicated that

terminating action specified Boeing Service Bulletin 747-54-2118, dated

July 25, 1986, had been accomplished on the affected airplane; this

service bulletin was referenced in AD 96-25-01 as the appropriate

source of service information.

Cracking or fracturing of the lower or upper horizontal clevis of

the inboard and outboard strut midspar fittings, if not detected and

corrected in a timely manner, could result in drooping of the strut at

the strut-to-wing interface, and consequent separation of the engine

and strut from the airplane.

Explanation of New Relevant Service Information

Since the issuance of AD 87-04-13 R1 and AD 96-25-01, the FAA has

reviewed and approved Boeing Alert Service Bulletin 747-54A2179,

Revision 1, dated November 27, 1996. This alert service bulletin

describes procedures for the following:

1. Removing sealant common to the lower and upper horizontal legs

of the clevis of the outboard (for certain airplanes) and the inboard

(for all airplanes) midspar fittings, and cleaning the midspar

fittings.

[[Page 31333]]

2. Performing detailed visual borescope inspections or alternative

ultrasonic/detailed visual inspections to detect cracking, corrosion,

and/or fracturing of the lower horizontal legs of the clevis of the

strut midspar fittings, and repair, if necessary.

3. Performing ultrasonic and detailed visual inspections to detect

cracking, corrosion, and/or fracturing of the upper horizontal leg of

the strut midspar fittings, and repair, if necessary.

4. Reworking only the discrepant areas or hole.

5. Reworking all fastener holes, or replacing the midspar fitting

with new fittings, as applicable, if any discrepancy is detected; this

eliminates the need for repetitive inspections.

Additionally, for all airplanes, the service bulletin references

replacement of the midspar fittings, which involves modification of the

strut/wing in accordance with the following Boeing service bulletins,

as applicable. Accomplishment of this modification eliminates the need

for repetitive inspections.

1. Boeing Alert Service Bulletin 747-54A2157, dated January 12,

1995; Revision 1, dated August 3, 1995; or Revision 2, dated November

14, 1996 (for airplanes equipped with Rolls Royce RB211 engines);

2. Boeing Alert Service Bulletin 747-54-A2158, dated November 30,

1994; Revision 1, dated August 17, 1995; or Revision 2, dated August

15, 1996 (for airplanes equipped with General Electric CFC-45/-50 or

Pratt & Whitney JT9D-70 engines); and

3. Boeing Service Bulletin 747-54A2159, dated November 3, 1994;

Revision 1, dated June 1, 1995; or Revision 2, dated March 14, 1996

(for airplanes equipped with Pratt & Whitney engines).

Explanation of Requirements of Rule

Since an unsafe condition has been identified that is likely to

exist or develop on other airplanes of this same type design, this AD

supersedes AD 87-04-13 R1 and AD 96-25-01, as follows:

First, this AD requires removal of certain sealant common to the

lower and upper horizontal legs of the outboard (for certain airplanes)

and the inboard (for all airplanes) midspar fittings, and cleaning the

midspar fittings.

This AD continues to require repetitive detailed visual borescope

inspections to detect cracking, corrosion, and fracturing of the lower

horizontal clevis of the inboard and outboard strut midspar fittings.

Replacement of discrepant fittings with new fittings is also required,

or rework, as applicable. This AD adds ultrasonic/detailed visual

inspections as an alternative method of accomplishing those

inspections.

This AD adds repetitive ultrasonic/detailed visual inspections of

the upper horizontal clevis of the inboard and outboard strut midspar

fittings, and replacement of discrepant fittings with new fittings, or

rework, if necessary.

For airplanes on which any cracking, corrosion, or fracturing is

detected that is outside certain limits, this AD requires

accomplishment of the strut/wing modification, replacement of the

midspar fittings of the strut with new fittings, or repair in

accordance with a method approved by the FAA, as applicable.

Accomplishment of the strut/wing modification constitutes

terminating action for the repetitive inspection requirements of this

AD.

Certain actions are required to be accomplished in accordance with

Boeing Alert Service Bulletin 747-A2179, Revision 1, dated November 27,

1996, described previously. Certain other actions are required to be

accomplished in accordance with a method approved by the FAA.

Difference Between This AD and the Alert Service Bulletin

Operators should note that, while the alert service bulletin

advises operators to contact the manufacturer if the damaged area is

beyond the specified limits, this AD requires operators to repair any

such damage in accordance with a method approved by the FAA, Transport

Airplane Directorate.

Operators also should note that airplanes on which reworking of the

upper and lower horizontal clevis of the midspar fittings has been

accomplished in accordance with Boeing Service Bulletin 747-54-2118,

dated July 25, 1986, have not been included in the effectivity of the

alert service bulletin. However, the FAA has determined that, in light

of the recent reports of cracking, the rework is not sufficient to

provide adequate assurance of permanent correction of the unsafe

condition addressed by this action. Therefore, the FAA has removed the

provision for reworking from AD 96-25-01 as an optional terminating

action for the repetitive inspection requirements of this AD.

Additionally, Boeing Alert Service Bulletin 747-54A2179, Revision

1, dated November 27, 1996, describes the replacement of the midspar

fittings of the strut as an optional method of eliminating the

repetitive inspections. The alert service bulletin also references

replacement of the midspar fittings of the strut in accordance with

either the alert service bulletin or Boeing Service Bulletin 747-54-

2118, Revision 4, dated May 11, 1989, as an optional terminating

action, which eliminates the need for repetitive inspections.

However, the FAA has determined that, in light of the recent

reports of cracking discussed previously, neither the replacement nor

the rework is sufficient to provide adequate assurance of permanent

correction of the unsafe condition. Therefore, the FAA also has removed

those optional terminating actions from this AD.

Determination of Rule's Effective Date

Since a situation exists that requires the immediate adoption of

this regulation, it is found that notice and opportunity for prior

public comment hereon are impracticable, and that good cause exists for

making this amendment effective in less than 30 days.

Comments Invited

Although this action is in the form of a final rule that involves

requirements affecting flight safety and, thus, was not preceded by

notice and an opportunity for public comment, comments are invited on

this rule. Interested persons are invited to comment on this 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 under the caption ``ADDRESSES.''

All communications received on or before the closing date for comments

will be considered, and this rule may be amended in light of the

comments received. Factual information that supports the commenter's

ideas and suggestions is extremely helpful in evaluating the

effectiveness of the AD action and determining whether additional

rulemaking action would be needed.

Comments are specifically invited on the overall regulatory,

economic, environmental, and energy aspects of the rule that might

suggest a need to modify the 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 that

summarizes each FAA-public contact concerned with the substance of this

AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments

submitted in response to this rule must submit a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket Number 97-NM-70-AD.'' The

[[Page 31334]]

postcard will be date stamped and returned to the commenter.

Regulatory Impact

The regulations adopted herein will 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 final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

The FAA has determined that this regulation is an emergency

regulation that must be issued immediately to correct an unsafe

condition in aircraft, and that it is not a ``significant regulatory

action'' under Executive Order 12866. It has been determined further

that this action involves an emergency regulation under DOT Regulatory

Policies and Procedures (44 FR 11034, February 26, 1979). If it is

determined that this emergency regulation otherwise would be

significant under DOT Regulatory Policies and Procedures, a final

regulatory evaluation will be prepared and placed in the Rules Docket.

A copy of it, if filed, may be obtained from the Rules Docket at the

location provided under the caption ``ADDRESSES.''

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends part 39 of

the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing amendment 39-5836 (53 FR

2005, January 26, 1988) and amendment 39-9842 (61 FR 66201, December

17, 1996), and by adding a new airworthiness directive (AD),

amendment 39-10045, to read as follows:

97-12-03 Boeing: Amendment 39-10045. Docket 97-NM-70-AD. Supersedes

AD 87-04-13 R1, amendment 39-5836; and AD 96-25-01, amendment 39-

9842.

Applicability: Model 747 series airplanes as listed in Boeing

Alert Service Bulletin 747-54A2179, Revision 1, dated November 27,

1996; certificated in any category, except for airplanes on which

the strut/wing modification has been accomplished in accordance with

the following Boeing alert service bulletins:

1. Boeing Alert Service Bulletin 747-54A2157, dated January 12,

1995; Revision 1, dated August 3, 1995; or Revision 2, dated

November 14, 1996;

2. Boeing Alert Service Bulletin 747-54A2158, dated November 30,

1994; Revision 1, dated August 17, 1995; or Revision 2, dated August

15, 1996; or

3. Boeing Alert Service Bulletin 747-54A2159, dated November 3,

1994; Revision 1, dated June 1, 1995; or Revision 2, dated March 14,

1996.

Note 1: This AD applies to each airplane identified in the

preceding applicability provision, regardless of whether it has been

otherwise 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 (n) 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 drooping of the strut at the strut-to-wing interface,

and consequent separation of the engine and strut from the airplane

due to cracking or fracturing of the midspar fitting clevis,

accomplish the following:

Restatement of Requirements of AD 96-25-01

(a) For all airplanes: Except as provided by paragraph (d) of

this AD, perform a detailed visual borescope inspection to detect

cracking, corrosion, and/or fracturing of the lower horizontal

clevis of both midspar fittings of the inboard struts, in accordance

with Boeing Alert Service Bulletin 747-54A2179, dated June 27, 1996,

or Revision 1, dated November 27, 1996, at the time specified in

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

applicable.

(1) For airplanes identified as Group 1 or Group 6 in the alert

service bulletin: Perform the initial inspection at the time

specified in paragraph (a)(1)(i) or (a)(1)(ii), as applicable.

Thereafter, repeat this inspection at intervals not to exceed every

150 flight cycles, or every 3 months, whichever occurs first. (i)

Within 150 flight cycles or 60 days after January 2, 1997 (the

effective date of AD 96-25-01, amendment 39-9842), whichever occurs

first. Or

(ii) For airplanes on which terminating action has been

accomplished within 500 flight cycles prior to January 2, 1997, in

accordance with Boeing Service Bulletin 747-54-2118, Revision 1,

dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3,

dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform

the initial inspection within 500 flight cycles or 12 months after

January 2, 1997, whichever occurs first.

(2) For airplanes identified as Group 2 or Group 4 in the alert

service bulletin: Perform the initial inspection at the time

specified in paragraph (a)(2)(i) or (a)(2)(ii) of this AD, as

applicable. Thereafter, repeat this inspection at intervals not to

exceed every 300 flight cycles or 6 months, whichever occurs first.

(i) Within 150 flight cycles or 60 days after January 2, 1997,

whichever occurs first. Or

(ii) For airplanes on which terminating action has been

accomplished within 1,000 flight cycles prior to January 2, 1997, in

accordance with Boeing Service Bulletin 747-54-2118, Revision 1,

dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3,

dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform

the initial inspection within 1,000 flight cycles or 12 months after

January 2, 1997, whichever occurs first.

(3) For airplanes identified as Group 3 in the alert service

bulletin: Perform the initial inspection at the time specified in

paragraph (a)(3)(i) or (a)(3)(ii) of this AD, as applicable.

Thereafter, repeat this inspection at intervals not to exceed every

350 flight cycles or 6 months, whichever occurs first.

(i) Within 150 flight cycles or 60 days after January 2, 1997,

whichever occurs first. Or

(ii) For airplanes on which terminating action has been

accomplished within 1,000 flight cycles prior to January 2, 1997, in

accordance with Boeing Service Bulletin 747-54-2118, Revision 1,

dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3,

dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform

the initial inspection within 1,000 flight cycles or 12 months after

January 2, 1997, whichever occurs first.

(4) For airplanes identified as Group 5 in the alert service

bulletin: Perform the initial inspection at the time specified in

paragraph (a)(4)(i) or (a)(4)(ii) of this AD, as applicable.

Thereafter, repeat the inspection at intervals not to exceed every

300 flight cycles or 6 months, whichever occurs first.

(i) Within 150 flight cycles or 60 days after January 2, 1997,

whichever occurs first.

(ii) For airplanes on which terminating action has been

accomplished within 800 flight cycles prior to January 2, 1997, in

accordance with Boeing Service Bulletin 747-54-2118, Revision 1,

dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3,

dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform

the initial inspection within 800 flight cycles or 12 months after

January 2, 1997, whichever occurs first.

(b) For airplanes identified as Group 1 in Boeing Alert Service

Bulletin 747-54A2179, dated June 27, 1996, or Revision 1, dated

November 27, 1996: Except as provided by paragraph (e) of this AD,

perform a detailed visual borescope inspection to detect cracking,

corrosion, and/or fracturing of the lower horizontal clevis of both

midspar fittings of the outboard struts, in accordance with Boeing

Alert Service Bulletin 747-54A2179, dated June 27, 1996, or Revision

1, dated November 27, 1996, at the time specified in paragraph

(b)(1) or (b)(2) of this

[[Page 31335]]

AD, as applicable. Thereafter, repeat the inspection at intervals

not to exceed every 300 flight cycles or 6 months, whichever occurs

first.

(1) Within 200 flight cycles or 60 days after January 2, 1997,

whichever occurs first. Or

(2) For airplanes on which the terminating action has been

accomplished within the last 1,000 flight cycles prior to January 2,

1997, in accordance with Boeing Service Bulletin 747-54-2118,

Revision 1, dated May 21, 1987; Revision 2, dated April 21, 1988;

Revision 3, dated September 29, 1988; or Revision 4, dated May 11,

1989: Perform the inspection within 1,000 flight cycles or 12 months

after January 2, 1997, whichever occurs first.

New Requirements of this AD

(c) For all airplanes: After the effective date of this AD,

prior to the accomplishment of each inspection required by paragraph

(a), (b), (d), or (e), of this AD, remove the sealant common to the

lower leg of the horizontal clevis of the inboard (for all

airplanes) midspar fittings, and the outboard (for Groups 1 and 6

airplanes) and clean the midspar fittings, in accordance with Boeing

Alert Service Bulletin 747-54A2179, Revision 1, dated November 27,

1996. Prior to further flight following accomplishment of these

actions, apply corrosion inhibitive compound BMS 3-23 to any area

where the original sealant was removed or disturbed, in accordance

with Boeing Standard Operational Procedures (BSOP) 20-41-05 for

Model 747 series airplanes.

(d) Accomplishment of the actions specified in this paragraph is

an alternative to compliance with paragraph (a) of this AD. Perform

an ultrasonic/detailed visual inspection to detect cracking,

corrosion, and/or fracturing of the lower horizontal clevis of both

midspar fittings of the inboard struts, in accordance with Boeing

Alert Service Bulletin 747-54A2179, Revision 1, dated November 27,

1996, at the time specified in paragraph (d)(1), (d)(2), (d)(3), or

(d)(4) as applicable.

(1) For airplanes identified as Group 1 or 6 in the alert

service bulletin: Perform the inspections at the time specified in

paragraph (d)(1)(i) or (d)(1)(ii) of this AD. Thereafter, repeat the

inspections at intervals not to exceed every 1,000 flight cycles or

18 months, whichever occurs first.

(i) Within 150 flight cycles or 3 months after accomplishing the

last inspection required by paragraph (b) of AD 96-25-01 or

paragraph (a) of this AD.

(ii) For airplanes on which terminating action has been

accomplished within 500 flight cycles after January 2, 1997, in

accordance with Boeing Service Bulletin 747-54-2118, Revision 1,

dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3,

dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform

the initial inspection within 500 flight cycles or 12 months after

January 2, 1997, whichever occurs first.

(2) For airplanes identified as Group 2 or 4 in the alert

service bulletin: Perform the inspection at the time specified in

paragraph (d)(2)(i) or (d)(2)(ii) of this AD, as applicable.

Thereafter, repeat this inspection at intervals not to exceed every

1,500 flight cycles or 18 months, whichever occurs first.

(i) Within 300 flight cycles or 6 months after accomplishing the

last inspection required by paragraph (b) of AD 96-25-01 or

paragraph (a) of this AD. Or

(ii) For airplanes on which terminating action has been

accomplished within 1,000 flight cycles after January 2, 1997, in

accordance with Boeing Service Bulletin 747-54-2118, Revision 1,

dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3,

dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform

the initial inspection within 1,000 flight cycles or 12 months after

January 2, 1997, whichever occurs first.

(3) For airplanes identified as Group 3 in the alert service

bulletin: Perform the inspection at the time specified in paragraph

(d)(3)(i) or (d)(3)(ii) of this AD, as applicable. Thereafter,

repeat the inspection at intervals not to exceed every 2,500 flight

cycles or 18 months, whichever occurs first.

(i) Within 350 flight cycles or 6 months after accomplishing the

last inspection required by paragraph (b) of AD 96-25-01 or

paragraph (a) of this AD. Or

(ii) For airplanes on which terminating action has been

accomplished within 1,000 flight cycles after January 2, 1997, in

accordance with Boeing Service Bulletin 747-54-2118, Revision 1,

dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3,

dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform

the initial inspection within 1,000 flight cycles or 12 months after

January 2, 1997, whichever occurs first.

(4) For airplanes identified as Group 5 in the alert service

bulletin: Perform the inspection at the time specified in paragraph

(d)(4)(i) or (d)(4)(ii) of this AD, as applicable. Thereafter,

repeat the inspection at intervals not to exceed every 1,500 flight

cycles or 18 months, whichever occurs first.

(i) Within 300 flight cycles or 6 months after accomplishing the

last inspection required by paragraph (b) of AD 96-25-01 or

paragraph (a) of this AD. Or

(ii) For airplanes on which terminating action has been

accomplished within 800 flight cycles after January 2, 1997, in

accordance with Boeing Service Bulletin 747-54-2118, Revision 1,

dated May 21, 1987; Revision 2, dated April 21, 1988; Revision 3,

dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform

the initial inspection within 800 flight cycles or 12 months after

January 2, 1997, whichever occurs first.

(e) For airplanes identified as Group 1 in Boeing Alert Service

Bulletin 747-54A2179, Revision 1, dated November 27, 1996:

Accomplishment of the actions specified in this paragraph is an

alternative to compliance with paragraph (b) of this AD. Perform an

ultrasonic/detailed visual inspection to detect cracking, corrosion,

and/or fracturing of the lower horizontal clevis of both midspar

fittings of the outboard struts, in accordance with Boeing Alert

Service Bulletin 747-54A2179, Revision 1, dated November 27, 1996,

at the time specified in paragraph (e)(1) or (e)(2) of this AD, as

applicable. Thereafter, repeat the inspection at intervals not to

exceed every 2,000 flight cycles or 18 months, whichever occurs

first.

(1) Within 300 flight cycles or 6 months after accomplishing the

last inspection required by paragraph (c) of AD 96-25-01 or

paragraph (b) of this AD. Or

(2) For airplanes on which terminating action has been

accomplished within 1,000 flight cycles after January 2, 1997, in

accordance with Boeing Service Bulletin 747-54-2118, Revision 1,

dated May 21, 1987; Revision 2, dated April 21, 1988; evision 3,

dated September 29, 1988; or Revision 4, dated May 11, 1989: Perform

the inspection within 1,000 flight cycles or 12 months after January

2, 1997, whichever occurs first.

(f) For all airplanes: After the effective date of this AD,

prior to the accomplishment of each inspection required by

paragraphs (g), (h), or (i), of this AD, remove the sealant of the

upper horizontal leg surface and clean the midspar fittings in

accordance with Boeing Alert Service Bulletin 747-54A2179, Revision

1, dated November 27, 1996. Prior to further flight following

accomplishment of these actions: Restore the sealant of the upper

horizontal leg surface in accordance with the alert service

bulletin.

(g) For all airplanes: Within 90 days after the effective date

of this AD, perform an ultrasonic/detailed visual inspection to

detect cracking, corrosion, and/or fracturing of the upper

horizontal clevis of both midspar fittings of the inboard struts, in

accordance with Boeing Alert Service Bulletin 747-54A2179, Revision

1, dated November 27, 1996. Repeat the ultrasonic/detailed visual

inspection thereafter at the time specified in paragraph (g)(1),

(g)(2), or (g)(3), as applicable.

(1) For airplanes identified as Group 1 or 6 in the alert

service bulletin: Repeat at intervals not to exceed every 1,000

flight cycles or 18 months, whichever occurs first.

(2) For airplanes identified as Group 2, 4, or 5 in the alert

service bulletin: Repeat at intervals not to exceed every 1,500

flight cycles or 18 months, whichever occurs first.

(3) For airplanes identified as Group 3 in the alert service

bulletin: Repeat at intervals not to exceed every 2,500 flight

cycles or 18 months, whichever occurs first.

(h) For airplanes identified as Group 1 in Boeing Alert Service

Bulletin 747-54A2179, Revision 1, dated November 27, 1996: Within 90

days after the effective date of this AD, perform an ultrasonic/

detailed visual inspection of the upper horizontal clevis of both

midspar fittings of the outboard strut to detect cracking,

corrosion, and/or fracturing, in accordance with the alert service

bulletin. Repeat the inspection thereafter at intervals not to

exceed every 2,000 flight cycles or 18 months, whichever occurs

first.

(i) For airplanes specified in paragraph (i)(1) or (i)(2) of

this AD: Perform the actions specified in paragraph (a), (b), (d),

(e), (f), (g), or (h) of this AD, as applicable, at the time

specified in paragraph (i)(1) or (i)(2) of this AD, as applicable.

Thereafter, perform the repetitive inspections at the time specified

in paragraph (a), (b), (d), (e), (f), (g), or (h) of this AD, as

applicable.

(1) For airplanes on which rework of all the fastener holes has

been accomplished in

[[Page 31336]]

accordance with Boeing Alert Service Bulletin 747-54A2179, dated

June 27, 1996, Revision 1, dated November 27, 1996, or Boeing

Service Bulletin 747-54-2118, dated July 25, 1986: Perform the

initial inspection at the later of the times specified in paragraphs

(i)(1)(i) and (i)(1)(ii) of this AD.

(i) Prior to the accumulation of 3,000 total landings, or within

3 years after accomplishment of the rework, whichever occurs first.

Or

(ii) Within 90 days after the effective date of this AD.

(2) For airplanes on which the midspar fittings have been

replaced in accordance with Boeing Alert Service Bulletin 747-

54A2179, Revision 1, dated November 27, 1996, or Boeing Service

Bulletin 747-54-2118, dated July 25, 1986; Revision 1, dated May 21,

1987; Revision 2, dated April 21, 1988; Revision 3, dated September

29, 1988; or Revision 4, dated May 11, 1989: Perform the initial

inspection at the later of the times specified in paragraphs

(i)(2)(i) and (i)(2)(ii) of this AD.

(i) Prior to the accumulation of 5,000 landings, or within 5

years after the fitting has been replaced, whichever occurs first.

Or

(ii) Within 90 days after the effective date of this AD.

(j) For all airplanes: If any cracking, corrosion, or fracturing

is detected during any inspection required by this AD that is

outside the limits specified in Boeing Alert Service Bulletin 757-

54A2179, Revision 1, dated November 27, 1996, and the damaged area

is within the area limits specified in the alert service bulletin,

prior to further flight, accomplish the requirements of paragraph

(j)(1) or (j)(2) of this AD.

(1) Accomplish the strut/wing modification specified in

paragraph (j)(1)(i), (j)(1)(ii), or (j)(1)(iii) of this AD, as

applicable. Following accomplishment of that action, no further

action is required by this AD.

(i) For airplanes equipped with Rolls Royce Model RB211 series

engines: Accomplish the strut/wing modification in accordance with

Boeing Alert Service Bulletin 747-54A2157, Revision 2, dated

November 14, 1996. Accomplishment of this paragraph terminates the

requirements of AD 95-13-05, amendment 39-9285.

(ii) For airplanes equipped with General Electric Model CF6-45

or -50 series engines, or Pratt & Whitney Model JT9D-70 series

engines: Accomplish the strut/wing modification in accordance with

Boeing Alert Service Bulletin 747-54A2158, Revision 2, dated August

15, 1996. Accomplishment of this paragraph terminates the

requirements of AD 95-13-07, amendment 39-9287.

(iii) For airplanes equipped with Pratt & Whitney Model JT9D

series engines (excluding Model JT9D-70 engines): Accomplish the

strut/wing modification in accordance with Boeing Alert Service

Bulletin 747-54A2159, Revision 2, dated March 14, 1996.

Accomplishment of this paragraph terminates the requirements of AD

95-10-16, amendment 39-9233.

(2) Replace the midspar fittings of the strut with new fittings

in accordance with Boeing Alert Service Bulletin 747-54A2179,

Revision 1, dated November 27, 1996. Repeat the inspections

thereafter at the intervals specified in paragraph (i)(2) of this

AD.

(k) If any cracking, corrosion, or fracturing is detected during

any inspection required by this AD that is outside the limits

specified in Boeing Alert Service Bulletin 747-54A2179, Revision 1,

dated November 27, 1996, and the damaged area is outside the area

limits specified in the alert service bulletin, prior to further

flight, accomplish the requirements of either paragraph (j)(1) or

(j)(2) of this AD, or repair in accordance with a method approved by

the Manager, Seattle ACO.

(l) For all airplanes: If any cracking, corrosion, or fracturing

is detected during any inspection required by this AD and it is

within the limits specified in Boeing Alert Service Bulletin 757-

54A2179, Revision 1, dated November 27, 1996: Prior to further

flight, accomplish the requirements of paragraph (l)(1), (l)(2),

(l)(3), or (l)(4) of this AD.

(1) Rework any discrepant area in accordance with the alert

service bulletin. Following the rework, repeat the actions required

by paragraph (a), (b), (d), (e), (f), (g), or (h) of this AD, as

applicable, at the intervals specified in those paragraphs.

(2) Rework all the fastener holes in accordance with the alert

service bulletin. Within 3,000 flight cycles or 3 years after

reworking all the fastener holes, whichever occurs first: Repeat the

actions required by paragraph (i)(1) of this AD, and accomplish the

repetitive inspections required by paragraph (i) of this AD.

(3) Replace the midspar fittings in accordance with the alert

service bulletin. Within 5,000 flight cycles or 5 years after

replacing the midspar fittings, whichever occurs first: Repeat the

actions required by paragraph (i)(2) of this AD, and accomplish the

repetitive inspections required by paragraph (i) of this AD.

(4) Accomplish the strut/wing modification specified in

paragraph (j)(1)(i), (j)(1)(ii), or (j)(1)(iii) of this AD, as

applicable. Following accomplishment of that action, no further

action is required by this AD.

(m) Accomplishment of the strut/wing modification specified in

paragraph (j)(1)(i), (j)(1)(ii), or (j)(1)(iii) of this AD

constitutes terminating action for the requirements of this AD.

(n) An alternative method of compliance or adjustment of the

compliance time that provides an acceptable level of safety may be

used if approved by the Manager, Seattle ACO. Operators shall submit

their requests through an appropriate FAA Principal Maintenance

Inspector, who may add comments and then send it to the Manager,

Seattle ACO.

Note 2: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Seattle ACO.

(o) 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.

(p) Certain actions shall be done in accordance with the Boeing

Alert Service Bulletins listed in the following table. The

incorporation by reference of those documents was approved

previously by the Director of the Federal Register, in accordance

with 5 U.S.C. 552(a) and 1 CFR part 51, as of the dates specified in

the table below:

------------------------------------------------------------------------

Approval Date and Federal

Referenced Service Bulletin and Date Register Citation

------------------------------------------------------------------------

747-54A2157, January 12, 1995............. July 28, 1995 (60 FR 33333,

June 28, 1995).

747-54A2158, November 30, 1994............ July 28, 1995 (60 FR 33336,

July 28, 1995).

747-54A2159, November 3, 1994............. June 21, 1995 (60 FR 27008,

May 22, 1995).

------------------------------------------------------------------------

Certain other actions shall be done in accordance with the Boeing

Alert Service Bulletins listed in the following table. The

incorporation by reference of those documents was approved previously

by the Director of the Federal Register on January 22, 1997 (61 FR

66201, December 12, 1996), in accordance with 5 U.S.C. 552(a) and 1 CFR

part 51:

------------------------------------------------------------------------

Revision

Referenced Service Bulletin Level Date

------------------------------------------------------------------------

747-54A2179......................... Original June 27, 1996.

747-54A2157......................... 1 Aug. 3, 1995.

747-54A2157......................... 2 Nov. 14, 1996.

747-54A2158......................... 1 Aug. 17, 1995.

747-54A2158......................... 2 Aug. 15, 1996.

747-54A2159......................... 1 June 1, 1995.

747-54A2159......................... 2 Mar. 14, 1996.

------------------------------------------------------------------------

Certain other actions shall be done in accordance with Boeing Alert

Service Bulletin 747-54A2179, Revision 1, dated November 27, 1996. This

incorporation by reference was approved by the Director of the Federal

Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies

may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707,

Seattle, Washington 98124-2207. Copies may be inspected at the FAA,

Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton,

Washington; or at the Office of the Federal Register, 800 North Capitol

Street, NW., suite 700, Washington, DC.

(q) This amendment becomes effective on June 24, 1997.

Issued in Renton, Washington, on May 30, 1997.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 97-14769 Filed 6-6-97; 8:45 am]

BILLING CODE 4910-13-U