[Federal Register Volume 64, Number 34 (Monday, February 22, 1999)]
[Rules and Regulations]
[Pages 8500-8502]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-3935]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-NM-148-AD; Amendment 39-11048; AD 99-04-23]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 737 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to certain Boeing Model 737 series airplanes, that requires
repetitive ultrasonic inspections to detect broken bolts that attach
the terminal support fittings to the upper part of the Body Station
1088 bulkhead, and corrective actions, if necessary. This amendment
also requires eventual replacement of the existing bolts with new,
improved bolts, which, when accomplished, terminates the repetitive
inspection requirements of this AD. This amendment is prompted by
reports that bolts that attach the terminal support fittings to the
upper part of the bulkhead were found broken. The actions specified by
this AD are intended to prevent such broken bolts, which could result
in reduced structural integrity of the vertical fin installation and
possible loss of the vertical fin.
DATES: Effective March 29, 1999.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 29, 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
[[Page 8501]]
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: Rick Kawaguchi, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-1153; 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 737 series
airplanes was published in the Federal Register on July 15, 1998 (63 FR
38116). That action proposed to require repetitive ultrasonic
inspections to detect broken bolts that attach the terminal support
fittings to the upper part of the Body Station 1088 bulkhead, and
corrective actions, if necessary. That action also proposed to require
eventual replacement of the existing bolts with new, improved bolts,
which, when accomplished, would terminate the requirements of the AD.
Comments Received
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Several commenters support the proposed rule.
Request to Revise Applicability of the AD
One commenter requests that the applicability of the proposed AD be
revised to list the affected airplanes by specific model number. The
commenter states that the proposed applicability could cause undue
confusion because the next generation (737-600/-700/-800) series
airplanes will start over with line number 001, and the proposal does
not apply to these next generation airplanes.
The FAA concurs with the commenter's request. The FAA has verified
that the cumulative line numbering of the next generation airplanes
(737-600/-700/-800) will be reset to begin with line number 001.
Additionally, the Model 737-400 and -500 series airplanes begin with
line number 1486 and have a design change implemented that specifies
installation of the Inconel bolts; therefore, those airplanes are not
subject to the identified unsafe condition. The applicability section
of the final rule has been revised to specify Model 737-100, -200 and -
300 series airplanes only, line numbers 1 through 1485.
Conclusion
After careful review of the available data, including the comments
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the change previously
described. The FAA has determined that this change will neither
increase the economic burden on any operator nor increase the scope of
the AD.
Cost Impact
There are approximately 1,485 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 630 airplanes of U.S.
registry will be affected by this AD.
It will take approximately 3 work hours per airplane to accomplish
the required inspection, at an average labor rate of $60 per work hour.
Based on these figures, the cost impact of the inspection required by
this AD on U.S. operators is estimated to be $113,400, or $180 per
airplane, per inspection cycle.
It will take approximately 9 work hours per airplane to accomplish
the required replacement, at an average labor rate of $60 per work
hour. Required parts will cost approximately $471 per airplane. Based
on these figures, the cost impact of the replacement required by this
AD on U.S. operators is estimated to be $636,930, or $1,011 per
airplane.
The cost impact figures discussed above are 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.
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:
99-04-23 Boeing: Amendment 39-11048. Docket 98-NM-148-AD.
Applicability: Model 737-100, -200, and -300 series airplanes,
line numbers 1 through 1485 inclusive; certificated in any category.
Note 1: This AD applies to each airplane identified in the
preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the
requirements of this AD. For airplanes that have been modified,
altered, or repaired so that the performance of the requirements of
this AD is affected, the owner/operator must request approval for an
alternative method of compliance in accordance with paragraph (c) 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 broken bolts that attach the terminal support
fittings to the upper part of the Body Station (BS) 1088 bulkhead,
which could result in reduced structural integrity of the vertical
fin installation and possible loss of the vertical fin, accomplish
the following:
(a) Within 18 months after the effective date of this AD,
perform an ultrasonic inspection to detect broken bolts that attach
the terminal support fittings to the upper part of the BS 1088
bulkhead, in accordance with Boeing Service Bulletin 737-53-1107,
Revision 3, dated August 26, 1993; as revised
[[Page 8502]]
by Notice of Status Change 737-53-1107 NSC 3, dated June 9, 1994,
and Notice of Status Change 737-53-1107 NSC 4, dated September 22,
1994; or Boeing Service Bulletin 737-53-1107, Revision 4, dated
February 8, 1996.
(1) If no broken bolt is found, repeat the ultrasonic inspection
thereafter at intervals not to exceed 18 months.
(2) If any broken bolt is found, prior to further flight,
perform the actions specified in paragraph (b) of this AD.
(b) Prior to the accumulation of 20 years since date of
manufacture of the airplane, or within 18 months after the effective
date of this AD, whichever occurs later, remove all 16 H-11 steel
alloy bolts that attach the terminal support fittings to the upper
part of the bulkhead, and perform an eddy current inspection to
detect cracking or corrosion of the bolt holes, in accordance with
Figure 2 of Boeing Service Bulletin 737-53-1107, Revision 3, dated
August 26, 1993; as revised by Notice of Status Change 737-53-1107
NSC 3, dated June 9, 1994, and Notice of Status Change 737-53-1107
NSC 4, dated September 22, 1994; or Boeing Service Bulletin 737-53-
1107, Revision 4, dated February 8, 1996.
(1) If no cracking or corrosion is found, prior to further
flight, oversize all 16 bolt holes and install new Inconel bolts, in
accordance with Figure 2 of the service bulletin. Accomplishment of
this installation constitutes terminating action for the repetitive
inspection requirements of this AD.
(2) If any corrosion is found, prior to further flight, oversize
the bolt hole within the limits specified in Figure 2, Step 4, of
the service bulletin, and install a new Inconel bolt, in accordance
with Figure 2 of the service bulletin. Accomplishment of the
installation for all 16 bolt holes constitutes terminating action
for the repetitive inspection requirements of this AD. If corrosion
does not clean up within the limits specified in Figure 2, Step 4,
of the service bulletin, prior to further flight, repair in
accordance with a method approved by the Manager, Seattle Aircraft
Certification Office (ACO), FAA, Transport Airplane Directorate.
(3) If any cracking is found, prior to further flight, oversize
the bolt hole within the limits specified in Figure 2, Step 5, of
the service bulletin, and perform another eddy current inspection to
ensure cracks have been removed, in accordance with Figure 2 of the
service bulletin.
(i) If, after oversizing, no cracking is found, prior to further
flight, oversize the bolt hole again, and install a new Inconel
bolt, in accordance with Figure 2 of the service bulletin.
Accomplishment of the installation for all 16 bolt holes constitutes
terminating action for the repetitive inspection requirements of
this AD.
(ii) If, after oversizing, any cracking is found, prior to
further flight, repair in accordance with a method approved by the
Manager, Seattle ACO.
Note 2: Replacement of all H-11 steel alloy bolts accomplished
prior to the effective date of this AD, in accordance with Boeing
Service Bulletin 737-53-1107, dated October 15, 1987; Revision 1,
dated June 22, 1989; or Revision 2, dated September 10, 1992; is
considered acceptable for compliance with the applicable actions
specified in paragraph (b) of this AD.
(c) 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.
(d) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where
the requirements of this AD can be accomplished.
(e) Except as provided by paragraphs (b)(2) and (b)(3)(ii) of
this AD, the actions shall be done in accordance with Boeing Service
Bulletin 737-53-1107, Revision 3, dated August 26, 1993; as revised
by Notice of Status Change 737-53-1107 NSC 3, dated June 9, 1994,
and Notice of Status Change 737-53-1107 NSC 4, dated September 22,
1994; or Boeing Service Bulletin 737-53-1107, Revision 4, dated
February 8, 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.
(f) This amendment becomes effective on March 29, 1999.
Issued in Renton, Washington, on February 11, 1999.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-3935 Filed 2-19-99; 8:45 am]
BILLING CODE 4910-13-U