[Federal Register Volume 61, Number 243 (Tuesday, December 17, 1996)]
[Rules and Regulations]
[Pages 66201-66206]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-30685]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-NM-249-AD; Amendment 39-9842; AD 96-25-01]
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 adopts a new airworthiness directive (AD) that
is applicable to certain Boeing Model 747 series airplanes. This action
requires 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. This 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. This action also
provides for optional terminating action for the inspections. This
amendment is 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 specified in
this 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.
DATES: Effective January 22, 1997.
The incorporation by reference of certain publications, as listed
in the regulations, is approved by the Director of the Federal Register
as of January 22, 1997.
The incorporation by reference of certain other publications listed
in the regulations was approved previously by the Director of the
Federal Register as follows:
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Referenced publication and date Approval date and Federal Register citation
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Boeing Alert Service Bulletin 747- July 28, 1995 (60 FR 33333, June 28, 1995).
54A2157, January 12, 1995.
Boeing Alert Service Bulletin 747- July 28, 1995 (60 FR 33336, July 28, 1995).
54A2158, November 30, 1994.
Boeing Alert Service Bulletin 747- June 21, 1995 (60 FR 27008, May 22, 1995).
54A2159, November 3, 1994.
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Comments for inclusion in the Rules Docket must be received on or
before February 18, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-249-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,
[[Page 66202]]
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington 98056-4056; telephone (206)
227-2771; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: The FAA has received a report indicating
that a complete fracture of the lower horizontal clevis of the inboard
midspar fitting across the second row of fasteners from the aft end of
the fitting on the number 3 strut had occurred on a Boeing Model 747-
200 series airplane equipped with Pratt & Whitney JT9D-7 series
engines. Metallurgical analysis revealed that the fracture consisted of
three separate cracks that were caused by fatigue from multiple origins
on the corroded bore surface of the fitting holes. The final fracture
of the fitting was the result of ductile separation.
The terminating action specified in AD 87-04-13 R1, amendment 39-
5836 (53 FR 2005, January 26, 1988) had been accomplished on this
airplane in accordance with Boeing Service Bulletin 747-54-2118,
Revision 4, dated May 11, 1989. That terminating action consisted of an
eddy current inspection of all the hole locations and oversizing only
the aft two holes of the horizontal clevis for both midspar fittings.
When the fracture was detected, the airplane had accumulated 7,070
flight hours and 1,966 flight cycles (77,823 total flight hours and
18,858 total flight cycles) since the accomplishment of the terminating
action.
Additionally, the FAA has received a report indicating that fatigue
and stress corrosion cracking in the lower horizontal clevis common to
the second row of fasteners from the aft end of the inboard midspar
fitting of the number 3 strut had occurred on a Boeing Model 747-300
series airplane equipped with Pratt & Whitney JT9D-7R4G2 series
engines. The length of the crack was 0.67 inch; this crack was found
during an inspection of the aft row common to the horizontal clevis in
accordance with Boeing Service Bulletin 747-54-2118, Revision 4, dated
May 11, 1989. When the crack was detected, the airplane had accumulated
46,118 total flight hours and 5,485 total flight cycles.
Cracking and fracturing in the midspar fitting clevis, if not
detected and corrected in a timely manner, could result in a fractured
fitting and drooping of the strut at the strut-to-wing interface, and
consequent separation of the engine and strut from the airplane.
Additionally, the FAA has received a report indicating that broken
sealant of the fasteners has been detected. The existing sealant was
removed in order to visually inspect the fittings. Investigation
revealed loose fasteners, corrosion of the fastener holes, and surface
corrosion of the fitting.
Other Relevant Rulemaking
The FAA has previously issued several other AD's that address
cracking in the midspar fitting clevis on Boeing 747 series airplanes:
1. AD 87-04-13 R1, amendment 39-5836: Requires an ultrasonic
inspection to detect cracking of the aft-most two fastener holes of the
upper and lower horizontal clevis legs in accordance with Boeing
Service Bulletin 747-54-2118, dated July 25, 1986. In addition, that AD
also provided for rework or replacement of the pylon midspar fitting,
which would eliminate the need for the repetitive ultrasonic
inspections. Since the issuance of that AD, Boeing Service Bulletin
747-54-2118, Revision 1, dated May 21, 1987; Revision 2, dated April
21, 1988; Revision 3, dated September 29, 1988; and Revision 4, dated
May 11, 1989; have been approved as alternative methods of compliance
with that AD.
2. AD 90-06-06, amendment 39-6490 (55 FR 8374, March 7, 1990):
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 the service bulletin. 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
Boeing Service Bulletin 747-54-2118, dated July 26, 1986.
3. 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 inspection 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.
Since the issuance of that AD, Boeing Alert Service Bulletin, Revision
1, dated June 1, 1995; and Revision 2, dated March 14, 1996; have been
approved as an alternative method of compliance with that AD.
4. 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.
5. 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.
Explanation of New Relevant Service Information
The FAA has reviewed and approved Boeing Alert Service Bulletin
747-54A2179, dated June 27, 1996, which describes procedures for
repetitive ultrasonic inspections to detect cracking, corrosion, and
fracturing of the upper horizontal clevis of both midspar fittings on
the inboard and outboard struts, and repetitive detailed visual
(borescope) inspections to detect cracking, corrosion, and fracturing
of the lower horizontal clevis. The alert service bulletin also
describes replacement of discrepant parts with new or serviceable
parts, if necessary, or rework of parts where no discrepancies are
detected. The alert service bulletin specifies that, for certain
airplanes, these inspections need only be accomplished on the inboard
strut.
For airplanes on which any cracking, corrosion, or fracturing is
detected, the replacement referenced in the alert service bulletin
involves modification of the strut/wing in accordance with the
following Boeing service bulletins, as applicable:
[[Page 66203]]
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).
As an alternative to accomplishing the strut/wing modification, the
alert service bulletin references 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; as additional sources of service information for
replacement of the midspar fittings with new parts.
Accomplishment of either the strut/wing modification or replacement
of the midspar fittings eliminates the need for the repetitive
inspections.
For airplanes on which no discrepancies are detected, Boeing Alert
Service Bulletin 747-54A2179 describes procedures for rework of the
upper and the lower horizontal clevis of the midspar fittings of the
inboard and outboard struts, which, if accomplished on all the fastener
holes, eliminates the need for the repetitive inspections. The alert
service bulletin recommends that, for certain airplanes, only rework of
the inboard strut need be accomplished. The rework consists of
performing an eddy current inspection in accordance with the 747 Non-
Destructive Testing (NDT) Manual D6-7170 (Part 6, Subject 51-00-00,
Figure 19) to detect cracking of all 10 to 14 fastener hole locations
(depending on fitting design), and repair, if necessary; oversizing all
fastener holes and applying one coat of BMS 10-11 Type 1 primer;
allowing the primer to dry; applying BMS 5-95 sealant in the holes and
on the shank of the oversized fasteners; and installing the oversized
fasteners wet. The alert service bulletin references Boeing Service
Bulletin 747-54-2118, Revision 4, dated May 11, 1989, as an additional
source of service information for the accomplishment of this rework. In
addition, 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; and Revision 4, dated May 11,
1989; specify certain rework limitations of the midspar fittings.
Explanation of the Requirements of the Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other Boeing Model 747 series airplanes of the same
type design, this AD is being issued to detect and correct fatigue
cracking, stress corrosion cracking, and fracturing of the inboard or
outboard fittings of the midspar fitting 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.
This AD requires visual inspections to detect broken sealant of the
fasteners and various follow-on actions (visual inspection to detect
corrosion and loose fasteners, and repair, if necessary); removal of
the existing sealant; and, after the accomplishment of certain
inspections required by this AD, application of specific sealant or
corrosion inhibitive compound to all areas where the sealant was
disturbed or removed.
This AD also requires repetitive visual inspections to detect
cracking, corrosion, and fracturing of the lower horizontal clevis of
the inboard and outboard strut midspar fittings, and replacement of
discrepant parts with new parts, if necessary, or rework, as
applicable. For certain airplanes, this AD requires that these
inspections be accomplished only on the inboard strut. This action also
provides for optional terminating action, which, if accomplished,
constitutes terminating action for the repetitive inspections.
Certain repairs are required to be accomplished in accordance with
a method approved by the FAA. Other actions are required to be
accomplished in accordance with the alert service bulletin described
previously.
Difference Between This AD and the Alert Service Bulletin
Operators should note that while Boeing Alert Service Bulletin 747-
54A2179 describes rework procedures for airplanes on which no corrosion
or cracking is detected, this AD specifies that rework may be
accomplished on airplanes on which corrosion or cracking is within
acceptable limits as specified by Figures 3 through 7 (inclusive) of
Boeing Service Bulletin 747-54-2118.
Operators should also note that, unlike the alert service bulletin,
this AD requires visual inspections to detect broken sealant of the
fasteners and various follow-on actions, if necessary (visual
inspection to detect corrosion and loose fasteners, and repair, if
necessary); removal of the existing sealant; and, after the
accomplishment of certain inspections required by this AD, application
of specific sealant or corrosion inhibitive compound to all areas where
the sealant was disturbed or removed.
Operators should note that this AD does not require initial or
repetitive ultrasonic inspections of airplanes to detect cracking and
fracturing of the upper horizontal clevis of both midspar fittings on
the inboard and outboard struts, as described in the alert service
bulletin.
Interim Action
The FAA finds that, while repetitive ultrasonic inspections to
detect cracking and fracturing of the upper horizontal clevis will
positively address the unsafe condition addressed by this AD, the
planned compliance time for the initial inspection is sufficiently long
so that notice and public comment will be practicable. The FAA is,
therefore, currently considering additional rulemaking to propose
accomplishment of these ultrasonic inspections.
Additionally, the manufacturer has advised that it is currently
developing Revision 1 of Boeing Service Bulletin 747-54A2179, which
will describe rework procedures if cracking or corrosion is detected,
and an alternative ultrasonic/detailed visual inspection of the lower
horizontal leg. Based on the results of a final review and approval of
Revision 1 of the service bulletin, the FAA may also consider approving
Revision 1 of the service bulletin as an alternative method of
compliance for the requirements of 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
[[Page 66204]]
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 96-NM-249-AD.'' The 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 adding the following new
airworthiness directive:
96-25-01 Boeing: Amendment 39-9842. Docket 96-NM-249-AD.
Applicability: Model 747 series airplanes having line positions
1 through 886; equipped with Pratt & Whitney JT9D-3, -7, and -70
series engines, General Electric CF6-45/-50 series engines, or Rolls
Royce RB211 series engines; certificated in any category.
Note 1: Except as described in Note 2 of this AD, 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 (h) 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.
Note 2: This AD does not apply to any airplane on which the
strut midspar fittings have been modified in accordance with Boeing
Service Bulletin 747-54-2118, which was originally released on July
25, 1986. In addition, this AD does not apply to any airplane on
which the strut/wing modification has been accomplished in
accordance with the following Boeing 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.
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:
(a) For all airplanes: Prior to the accomplishment of each
inspection required by paragraphs (b), (c), (d), and (e) of this AD,
perform a visual inspection to detect any broken sealant common to
the lower horizontal clevis of the inboard (for all airplanes) and
the outboard (for Group 1 airplanes identified in Boeing Alert
Service Bulletin 747-54A2179, dated June 27, 1996) midspar fittings,
and of the fasteners, in accordance with normal maintenance
practices.
(1) If no broken sealant is detected, prior to further flight,
remove the existing sealant in accordance with normal maintenance
practices, and perform the inspections required by paragraph, (b),
(c), (d), and/or (e) of this AD, as applicable, at the times
specified in the applicable paragraph. Thereafter, prior to further
flight following completion of each inspection required by paragraph
(b), (c), (d), and/or (e) of this AD; reapply sealant to any area
where the existing sealant was removed or disturbed, in accordance
with Boeing 747 Maintenance Manual 51-31-01, or apply corrosion
inhibitive compound BMS 3-23 in accordance with Boeing 747 BSOP 20-
41-05.
(2) If any broken sealant is detected, prior to further flight,
remove the existing sealant and perform a visual inspection of the
fitting to detect corrosion of the fitting and check for loose
fasteners by attempting to rotate them or move them upward with
finger pressure.
(i) If no corrosion or loose fastener is detected, perform the
inspections required by paragraph (b), (c), (d), and/or (e) of this
AD, as applicable, at the times specified in the applicable
paragraph. Thereafter, prior to further flight following completion
of each inspection required by paragraph (b), (c), (d), and/or (e)
of this AD: Reapply sealant to any area where the existing sealant
was removed or disturbed, in accordance with Boeing 747 Maintenance
Manual 51-31-01, or apply corrosion inhibitive compound BMS 3-23 in
accordance with Boeing 747 BSOP 20-41-05.
(ii) If any corrosion or loose fastener is detected, prior to
further flight, repair in accordance with a method approved by the
Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport
Airplane Directorate.
(b) For all airplanes: Perform a detailed visual borescope
inspection to detect cracking, corrosion, and 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, at the time specified in paragraph
(b)(1), (b)(2), or (b)(3), as applicable.
(1) For Groups 1 and 6 airplanes, as identified in the alert
service bulletin: Perform the inspection at the time specified in
paragraph (b)(1)(i) or (b)(1)(ii), as applicable.
(i) Within 150 flight cycles or 60 days after the effective date
of this AD, whichever occurs first. Or
[[Page 66205]]
(ii) If terminating action has been accomplished 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; within the last 500
flight cycles prior to the effective date of this AD: Perform the
inspection required by this paragraph within 500 flight cycles or 12
months after the effective date of this AD, whichever occur first.
(2) For Group 2, 3, and 4 airplanes, as identified in the alert
service bulletin: Perform the inspection at the time specified in
paragraph (b)(2)(i) or (b)(2)(ii), as applicable.
(i) Within 150 flight cycles or 60 days after the effective date
of this AD, whichever occurs first. Or
(ii) If terminating action has been accomplished 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; within the last 1000
flight cycles prior to the effective date of this AD: Perform the
inspection within 1000 flight cycles or 12 months after the
effective date of this AD, whichever occurs first.
(3) For Group 5 airplanes, as identified in the alert service
bulletin: Perform the inspection at the time specified in paragraph
(b)(3)(i) or (b)(3)(ii), as applicable.
(i) Within 150 flight cycles or 60 days after the effective date
of this AD, whichever occurs first. Or
(ii) If terminating action has been accomplished 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; within the last 800
flight cycles prior to the effective date of this AD: Perform the
inspection within 800 flight cycles or 12 months after the effective
date of this AD, whichever occurs first.
(c) For Group 1 airplanes, as identified in Boeing Alert Service
Bulletin 747-54A2179: Perform a detailed visual borescope inspection
to detect cracking, corrosion, and 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, at the time specified in paragraph (c)(1) or (c)(2)
of this AD, as applicable.
(1) Within 200 flight cycles or 60 days after the effective date
of this AD, whichever occurs first. Or
(2) If terminating action has been accomplished 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; within the last 1,000
flight cycles prior to the effective date of this AD: Perform the
inspection within 1,000 flight cycles or 12 months after the
effective date of this AD, whichever occurs first.
(d) For all airplanes: Repeat the inspections of the inboard
struts, as specified in paragraph (b) of this AD, at the time
specified in paragraph (d)(1) or (d)(2), as applicable, until the
terminating action specified in paragraph (f) or (g) of this AD, as
applicable, has been accomplished.
(1) For Groups 1 and 6 airplanes: Repeat the inspections at the
time specified in either paragraph (d)(1)(i) or (d)(1)(ii) of this
AD, as applicable.
(i) Inspect thereafter at intervals not to exceed 150 flight
cycles or 3 months, whichever occurs first. Or
(ii) If the aft two fastener holes have been oversized, an eddy
current inspection of the remaining holes has been performed, and
fasteners have been installed wet with BMS 5-95 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: Inspect thereafter at
intervals not to exceed 150 flight cycles.
(2) For Groups 2, 3, 4, and 5 airplanes: Repeat the inspections
at the time specified in either paragraph (d)(2)(i) or (d)(2)(ii) of
this AD, as applicable.
(i) Inspect thereafter at intervals not to exceed 300 flight
cycles or 6 months, whichever occurs first. Or
(ii) If the aft two fastener holes have been oversized, an eddy
current inspection of the remaining holes has been performed, and
fasteners have been installed wet with BMS 5-95 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: Inspect thereafter at
intervals not to exceed 300 flight cycles.
(e) For Group 1 airplanes: Repeat the inspection of the outboard
struts, as required by paragraph (c) of this AD, at the times
specified in either paragraph (e)(1) or (e)(2) of this AD, as
applicable.
(1) Inspect thereafter at intervals not to exceed 300 flight
cycles or 6 months, whichever occurs first. Or
(2) If the aft two fastener holes have been oversized, an eddy
current inspection of the remaining holes has been performed, and
fasteners have been installed wet with BMS 5-95 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: Inspect thereafter at
intervals not to exceed 300 flight cycles.
(f) For all airplanes: If any cracking, corrosion, or fracturing
is detected during any inspection required by this AD, and it is
outside the limits specified in Boeing Service Bulletin 747-54-2118,
Revision 4, dated May 11, 1989: Prior to further flight, accomplish
the requirements of either paragraph (f)(1) or (f)(2) of this AD.
Following accomplishment of those actions, no further action is
required by this AD.
(1) Accomplish the strut/wing modification specified in
paragraph (f)(1)(i), (f)(1)(ii), or (f)(1)(iii) of this AD, as
applicable.
(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 also 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 also 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 also terminates the requirements of
AD 95-10-16, amendment 39-9233.
(2) Replace the midspar fittings of the strut with new or
serviceable fittings in accordance with Boeing Service Bulletin 747-
54-2118, Revision 4, dated May 11, 1989.
(g) For all airplanes: If any cracking or corrosion is detected
during any inspection required by this AD that is within the limits
specified in Boeing Service Bulletin 747-54-2118, Revision 4, dated
May 11, 1989: Prior to further flight, accomplish the requirements
of either paragraph (g)(1), (g)(2), or (g)(3) of this AD.
(1) For Group 2, 3, 4, and 5 airplanes: Rework both the upper
and lower horizontal clevis of the midspar fittings of each inboard
strut, and for Group 1 airplanes, rework both the upper and lower
horizontal clevis of the midspar fittings of each inboard and
outboard strut, 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. Accomplishment of the requirements of this paragraph
constitute terminating action for the requirements of this AD
provided that the actions specified in paragraphs (g)(1)(i),
(g)(1)(ii), (g)(1)(iii), and (g)(1)(iv) are also accomplished.
(i) The rework shall be accomplished on all holes of the
horizontal flanges;
(ii) The rework shall include an eddy current inspection of all
holes at the horizontal flanges, in accordance with Boeing Non-
Destructive Testing (NDT) Manual D6-7170 Part 6, Subject 51-00-00,
Figure 19.
(iii) All holes of the horizontal flanges shall be oversized and
insurance cut an additional 0.0312 inch, in accordance with Boeing
Service Bulletin 747-54-2118, Revision 4, dated May 11, 1989. And
(iv) One coat of BMS 10-11 Type 1 primer shall be applied to the
fastener holes, and the oversized fasteners shall be installed wet
with BMS 5-95 sealant, in accordance with Boeing Service Bulletin
747-54-2118, Revision 4, dated May 11, 1989.
(2) For Group 2, 3, 4, and 5 airplanes: Rework both the upper
and lower horizontal clevis of the midspar fittings of each inboard
strut, and for Group 1 airplanes, rework both the upper and lower
horizontal clevis of the
[[Page 66206]]
midspar fittings of each inboard and outboard strut, in accordance
with Boeing Service Bulletin 747-54-2118, dated July 25, 1986.
Accomplishment of the requirements of this paragraph constitute
terminating action for the requirements of this AD.
(3) Accomplish the rework (removal of cracking and corrosion)
specified in Boeing Service Bulletin 747-54-2118, Revision 4, dated
May 11, 1989, with the exception that eddy current inspections
specified in that service bulletin must be accomplished in
accordance with Boeing Non-Destructive Testing (NDT) Manual D6-7170
Part 6, Subject 51-00-00, Figure 19. Thereafter, repeat the
inspections specified in paragraph (d) or (e) of this AD, as
applicable, at the time required by the applicable paragraph.
(h) 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 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(i) 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.
(j) 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:
----------------------------------------------------------------------------------------------------------------
Referenced service bulletin and date Approval date and Federal 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
following Boeing service bulletins, which contain the specified
effective pages:
----------------------------------------------------------------------------------------------------------------
Revision
Service bulletin referenced and date Page No. level shown Date shown on page
on page
----------------------------------------------------------------------------------------------------------------
Alert 747-54A2179, June 27, 1996...... 1-34................... (\1\) June 27, 1996.
747-54A2157, Revision 1, August 3, 1-901.................. 1 August 3, 1995.
1995.
747-54A2157, Revision 2, November 14, 1-961.................. 2 November 14, 1996.
1996.
747-54A2158, Revision 1, August 17, 1-1,052................ 1 August 17, 1995.
1995.
747-54A2158, Revision 2, August 15, 1-1,080D2.............. August 15,
1996. 1996.
747-54A2159, Revision 1, June 1, 1995. 1-1,240................ 1 June 1, 1995.
747-54A2159, Revision 2, March 14, 1-1,298................ 2 March 14, 1996.
1996.
747-54-2118, July 25, 1986............ 1-172.................. (\1\) July 25, 1986.
Notice of Status Change, 747-54-2118 1...................... (\1\) October 5, 1986.
NSC 1, October 5, 1986.
747-54-2118, Revision 1, May 21, 1987. 1-175.................. 1 May 21, 1987.
747-54-2118, Revision 2, April 21, 1-5, 7-13, 17-21, 24, 2 April 21, 1988.
1988. 30, 31, 38, 39, 48-51,
58, 59, 61, 69-72, 84,
101, 117, 134, 151,
170.
6, 14-16, 22, 23, 26- 1 May 21, 1987.
29, 32-37, 40-47, 52-
57, 60, 62-68, 73-83,
85-100, 102-116, 118-
133, 135-150, 152-169,
171-175.
25..................... (\1\) July 25, 1986.
747-54-2118, Revision 3, September 29, 1-6, 9, 10, 12, 21, 22. 3 September 29, 1988.
1988.
7, 8, 13-20, 23, 24, 26- 1 May 21, 1987.
175.
11..................... 2 April 21, 1988.
25..................... (\1\) July 25, 1986.
747-54-2118, Revision 4, May 11, 1989. 1-12, 16, 17, 21-170, 4 May 11, 1989.
173, 174.
13, 18-20.............. 2 April 21, 1988.
14, 15................. 1 May 21, 1987.
171, 172, 175, 176..... \1\ July 25, 1986.
----------------------------------------------------------------------------------------------------------------
\1\ Original.
The incorporation by reference of those documents 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.
(k) This amendment becomes effective on January 2, 1997.
Issued in Renton, Washington, on November 25, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-30685 Filed 12-16-96; 8:45 am]
BILLING CODE 4910-13-U