[Federal Register Volume 64, Number 26 (Tuesday, February 9, 1999)]
[Rules and Regulations]
[Pages 6189-6191]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-2723]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-144-AD; Amendment 39-11025; AD 99-04-01]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Boeing Model 747 series airplanes, that requires
repetitive inspections of the outboard nacelle struts to detect fatigue
cracking of the strut skin and spring beam support fittings, and to
detect cracked or loose fasteners of the support fittings; and
corrective actions, if necessary. This amendment also provides for
optional terminating action for the repetitive inspection requirements.
This amendment is prompted by reports indicating that several cracked
or broken spring beam support fittings were found on the outboard
nacelle struts. The actions specified by this AD are intended to detect
and correct such fatigue cracking and loose fasteners, which could
result in failure of the outboard nacelle struts and consequent
separation of the engine.
DATES: Effective March 16, 1999.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 16, 1999.
ADDRESSES: 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 Federal
Aviation Administration (FAA), Transport Airplane Directorate, Rules
Docket, 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 L. Anderson, Aerospace
Engineer, Airframe Branch, ANM-120S, FAA, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056; telephone (425) 227-2771; fax (425) 227-
1181.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to certain Boeing Model 747 series
airplanes was published in the Federal Register on November 24, 1998
(63 FR 64913). That action proposed to require repetitive inspections
of the outboard nacelle struts to detect fatigue cracking of the strut
skin and spring beam support fittings, and to detect cracked or loose
fasteners of the support fittings; and corrective actions, if
necessary. That action also proposed to provide for optional
terminating action for the repetitive inspection requirements.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the single comment received.
The commenter supports the proposed AD.
Conclusion
After careful review of the available data, including the comment
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule as proposed.
Cost Impact
There are approximately 145 Model 747 series airplanes of the
affected design in the worldwide fleet. The FAA estimates that 9
airplanes of U.S. registry will be affected by this AD, that it will
take approximately 16 work hours per airplane to accomplish the
required inspection, and that the average labor rate is $60 per work
hour. Based on these figures, the cost impact
[[Page 6190]]
of the AD on U.S. operators is estimated to be $8,640, or $960 per
airplane, per inspection cycle.
The cost impact figure discussed above is based on assumptions that
no operator has yet accomplished any of the requirements of this AD
action, and that no operator would accomplish those actions in the
future if this AD were not adopted.
Should an operator elect to accomplish the fastener hole inspection
and modification, it would take approximately 20 work hours (excluding
removal of the strut and spring beam) to accomplish it, at an average
labor rate of $60 per hour. Based on these figures, the cost impact of
this optional terminating action is estimated to be $1,200 per strut.
Should an operator elect to accomplish the replacement of the
spring beam support fittings with new support fittings, it would take
approximately 108 work hours (excluding removal of the strut and spring
beam) to accomplish it, at an average labor rate of $60 per hour. Based
on these figures, the cost impact of this optional terminating action
is estimated to be $6,480 per support fitting.
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.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it 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:
99-04-01 Boeing: Amendment 39-11025. Docket 98-NM-144-AD.
Applicability: Model 747 series airplanes, line numbers 202
through 886 inclusive, equipped with General Electric Model CF6-45/
50 and Pratt & Whitney Model JT9D-70 series engines; on which the
strut/wing modification has not been accomplished in accordance with
AD 95-13-07, amendment 39-9287; certificated in any category.
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 (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.
Compliance: Required as indicated, unless accomplished
previously.
To detect and correct fatigue cracking of the strut skin and
spring beam support fittings on the outboard nacelle struts, and
cracked or loose fasteners of the support fittings, which could
result in failure of the outboard nacelle struts and consequent
separation of the engine, accomplish the following:
(a) Prior to the accumulation of 13,000 total flight cycles, or
within 6 months after the effective date of this AD, whichever
occurs later, perform a detailed visual inspection of the outboard
nacelle struts, as specified by paragraphs (a)(1), (a)(2), (a)(3),
and (a)(4) of this AD, in accordance with Boeing Alert Service
Bulletin 747-54A2172, dated February 23, 1995, or Boeing Service
Bulletin 747-54A2172, Revision 1, dated January 4, 1996.
(1) Inspect the spring beam support fittings to detect cracks of
the support fittings.
(2) Inspect the spring beam support fittings at the fasteners,
using a borescope to detect cracks of the support fittings.
(3) Inspect the fasteners of the outer spring beam support
fittings to detect cracked or loose fasteners.
(4) Inspect the strut skin to detect cracks.
(b) If no discrepancy is found during any inspection required by
paragraph (a) of this AD, perform detailed visual inspections of the
outboard nacelle struts to detect any discrepancies specified in
paragraphs (b)(1), (b)(2), (b)(3), and (b)(4) of this AD, in
accordance with Boeing Alert Service Bulletin 747-54A2172, dated
February 23, 1995; or Boeing Service Bulletin 747-54A2172, Revision
1, dated January 4, 1996. Perform the inspection at the times
specified in paragraph (c) or (d) of this AD, as applicable.
(1) Perform a detailed visual inspection, using a borescope, of
only the outer spring beam support fittings at the fasteners through
the horizontal flange to detect cracks of the support fittings.
(2) Perform a detailed visual inspection, using a borescope, of
the fasteners through the vertical flange of only the outer spring
beam support fittings to detect loose collars.
(3) Perform an external detailed visual inspection of only the
outer spring beam support fittings to detect cracked or loose
fastener heads.
(4) Perform a detailed visual inspection of the strut skin to
detect cracks.
(c) For Model 747-SR series airplanes equipped with General
Electric Model CF6-45 series engines, on which no discrepancy is
found during any inspection required by paragraph (a) of this AD:
Perform the inspection required by paragraph (b) of this AD within
1,600 flight cycles following the accomplishment of the inspection
required by paragraph (a) of this AD; and thereafter at intervals
not to exceed 1,600 flight cycles until accomplishment of the
optional terminating action specified in paragraph (g) of this AD.
(d) For Model 747 series airplanes other than those identified
in paragraph (c) of this AD, on which no discrepancy is found during
any inspection required by paragraph (a) of this AD: Perform the
inspection required by paragraph (b) of this AD within 1,000 flight
cycles following the accomplishment of the inspection required by
paragraph (a) of this AD; and thereafter at intervals not to exceed
1,000 flight cycles until accomplishment of the optional terminating
action specified in paragraph (g) of this AD.
(e) If any cracking is found in the spring beam support fittings
during any inspection required by this AD, prior to further flight,
replace the support fitting with a new support fitting, in
accordance with the Accomplishment Instructions in Part IV. of
Boeing Service Bulletin 747-54A2172, Revision 1, dated January 4,
1996. Accomplishment of this replacement constitutes terminating
action for the repetitive inspection requirements of this AD for
only the new support fitting. Continue the repetitive inspections
required by paragraph (b) of this AD for the other support fitting
locations until accomplishment of the terminating action specified
by paragraph (g)(1) or (g)(2) of this AD, as applicable.
(f) If any crack is found on the strut skin, or if any cracked
or loose fastener or collar
[[Page 6191]]
is found during any inspection required by this AD, prior to further
flight, repair in accordance with a method approved by the Manager,
Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane
Directorate; or in accordance with data meeting the type
certification basis of the airplane approved by a Boeing Company
Designated Engineering Representative who has been authorized by the
Manager, Seattle ACO, to make such findings.
(g) Accomplishment of an open-hole high frequency eddy current
(HFEC) inspection, in accordance with Boeing Alert Service Bulletin
747-54A2172, dated February 23, 1995, or Boeing Service Bulletin
747-54A2172, Revision 1, dated January 4, 1996; and either paragraph
(g)(1) or (g)(2) of this AD, as applicable; constitutes terminating
action for the requirements of this AD.
(1) If no discrepancy is found during the HFEC inspection, prior
to further flight, rework the fastener holes and install new
fasteners, in accordance with Figures 6 and 7 of Boeing Alert
Service Bulletin 747-54A2172, dated February 23, 1995, or Boeing
Service Bulletin 747-54A2172, Revision 1, dated January 4, 1996.
(2) If any cracking is found during the HFEC inspection, prior
to further flight, replace any cracked spring beam support fitting
with a new support fitting, in accordance with Part IV. of the
Accomplishment Instructions specified by Boeing Service Bulletin
747-54A2172, Revision 1, dated January 4, 1996.
(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 Aircraft Certification
Office (ACO), FAA, Transport Airplane Directorate. Operators shall
submit their requests through an appropriate FAA Principal
Maintenance Inspector, who may add comments and then send it to the
Manager, Seattle ACO.
Note 2: 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) Except as provided by paragraph (f), (g), (g)(1), and (g)(2)
of this AD, the actions shall be done in accordance with Boeing
Alert Service Bulletin 747-54A2172, dated February 23, 1995, and
Boeing Service Bulletin 747-54A2172, Revision 1, dated January 4,
1996, as applicable. 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.
(k) This amendment becomes effective on March 16, 1999.
Issued in Renton, Washington, on February 1, 1999.
Dorenda D. Baker,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-2723 Filed 2-8-99; 8:45 am]
BILLING CODE 4910-13-P
