[Federal Register Volume 63, Number 178 (Tuesday, September 15, 1998)]
[Rules and Regulations]
[Pages 49269-49272]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-24247]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-47-AD; Amdt. 39-10739; AD 98-18-23]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to certain Boeing Model 747
[[Page 49270]]
series airplanes, that currently requires repetitive high frequency
eddy current (HFEC) inspections to detect cracking on all surfaces of
the upper recesses in certain latch support fittings of the cargo
doorway, and replacement of cracked fittings with new fittings. The
existing AD also provides for optional terminating action for the
repetitive inspections. This amendment requires accomplishment of the
previously optional terminating action. This amendment is prompted by
reports indicating that the repetitive inspections required by the
existing AD may not detect cracked fittings in a timely manner. The
actions specified by this AD are intended to prevent the cargo door
from opening while the airplane is in flight, which could result in
rapid decompression of the airplane.
DATES: Effective October 20, 1998.
The incorporation by reference of Boeing Alert Service Bulletin
747-53A2377, dated December 10, 1992, and Boeing Service Bulletin 747-
53A2377, Revision 2, dated October 6, 1994, as listed in the
regulations, is approved by the Director of the Federal Register as of
October 20, 1998.
The incorporation by reference of Boeing Service Bulletin 747-
53A2377, Revision 1, dated January 28, 1993, as listed in the
regulations, was approved previously by the Director of the Federal
Register as of March 11, 1993 (58 FR 11190, February 24, 1993).
ADDRESSES: The service information referenced in this AD may be
obtained from Boeing Commercial Airplane Group, PO 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: Bob Breneman, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2776; fax (425) 227-1181.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 93-02-16,
amendment 39-8500 (58 FR 11190, February 24, 1993), which is applicable
to certain Boeing Model 747 series airplanes, was published in the
Federal Register on December 11, 1997 (62 FR 65233). The action
proposed to continue to require repetitive high frequency eddy current
inspections to detect cracking on all surfaces of the upper recesses in
certain latch support fittings of the cargo doorway, and replacement of
cracked fittings with new fittings. The action also proposed to require
accomplishment of the previously optional terminating action.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Support for the Rule
Several commenters support the proposed rule.
Request To Revise Cost Estimate
One commenter requests that the cost estimate for the proposed rule
be increased to $4,500 per installation to reflect replacement of two
truss fittings associated with each latch support fitting. The
commenter notes that certain truss fittings [(the subject of AD 79-17-
02 R2, amendment 39-3867 (45 FR 52357, August 7, 1980)] and certain
latch support fittings (the subject of this AD) are made of the same
7079-T6 material. The commenter reports that it intends to replace the
truss fittings at the same time it replaces the latch support fittings.
The FAA does not concur that the estimated cost of replacement of
the latch support fittings should be increased to $4,500 per
installation. This AD does not require replacement of any truss
fittings that are attached to the latch support fittings. Although AD
79-17-02 R2 requires that the truss fittings be inspected, it does not
require replacement because of the fail-safe design that incorporates
two truss fittings for each latch support fitting. While the FAA
acknowledges that it would be prudent for operators to replace those
truss fittings at the same time the latch support fittings are
replaced, this AD does not require replacement of any truss fittings.
No change to the cost estimate of the final rule is necessary.
Request To Reduce Compliance Times
One commenter (the Civil Aviation Authority (CAA), which is the
airworthiness authority for the United Kingdom) requests that the
compliance time for the proposed actions be reduced. Specifically, the
CAA suggests that the inspections be performed at 3-month intervals and
the latch support fittings replaced within 12 months. In support of its
recommendation, the commenter refers to a report of an 8-inch crack
found in a latch support fitting on a Boeing Model 747 series airplane.
The fitting had been inspected twice in a 6-month period; no crack had
been found during the first inspection. The commenter suggests that,
based on the reported incident, such reduced compliance times would be
more realistic.
The FAA does not concur with the request to reduce the compliance
times. The FAA finds that the proposed 18-month replacement threshold
will provide an acceptable level of safety because of the fail-safe
capability resulting from multiple latch support fittings. In addition,
the 18-month compliance time will allow for the fittings to be replaced
during scheduled maintenance at regular maintenance bases, thereby
minimizing the impact on affected operators. The FAA recognizes the
CAA's jurisdiction and authority to require accomplishment within its
suggested inspection interval and replacement threshold on affected
airplanes within the United Kingdom.
Comment Concerning Availability of Materials
One commenter states that the 18-month replacement threshold
required by this AD should not present a scheduling problem provided
that materials are available from the manufacturer.
At this time, the FAA is not aware of any scheduling difficulties
that may delay operators' acquisition of the required materials for
timely compliance with this AD.
Change to the Rule
Operators should note that new paragraph (b) of the final rule has
been revised to include an additional source of service information for
accomplishment of the replacement. This change allows operators to
replace the support fittings in accordance with Boeing Service Bulletin
747-53A2377, Revision 1, dated January 28, 1993, in addition to the
other cited versions of alert service bulletin.
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 200 Boeing Model 747 series airplanes of
the affected design in the worldwide fleet.
[[Page 49271]]
The FAA estimates that 115 airplanes of U.S. registry will be affected
by this AD.
The inspections that currently are required by AD 93-02-16, and
retained in this AD, take approximately 31 work hours per airplane, per
inspection cycle, to accomplish, at an average labor rate of $60 per
work hour. Based on these figures, the cost impact of the currently
required inspections on U.S. operators is estimated to be $213,900, or
$1,860 per airplane, per inspection cycle.
The new action (replacement of the latch support fittings) that is
required by this AD will take approximately 1,019 work hours per
airplane to accomplish, at an average labor rate of $60 per work hour.
Required parts will cost approximately $20,917 per airplane ($12,888
for all aft door fittings; $8,029 for all forward door fittings). Based
on these figures, the cost impact of the new replacement requirements
of this AD on U.S. operators is estimated to be $9,436,555, or $82,057
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 removing amendment 39-8500 (58 FR
11190, February 24, 1993), and by adding a new airworthiness directive
(AD), amendment 39-10739, to read as follows:
98-18-23 Boeing: Amendment 39-10739. Docket 97-NM-47-AD. Supersedes
AD 93-02-16, Amendment 39-8500.
Applicability: Model 747 series airplanes, line numbers 1
through 200 inclusive; having 7079-T6 aluminum latch support
fittings; 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 (d) 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 the cargo door from opening while the airplane is in
flight, which could result in rapid decompression of the airplane,
accomplish the following:
Restatement of the Requirements of this AD 93-02-16
(a) Within 60 days after March 11, 1993 (the effective date of
AD 93-02-16, amendment 39-8500), perform a high frequency eddy
current (HFEC) inspection to detect cracking on all surfaces of the
upper recess in each 7079-T6 aluminum latch support fitting of the
cargo doorway, in accordance with Boeing Service Bulletin 747-
53A2377, Revision 1, dated January 28, 1993, or Revision 2, dated
October 6, 1994. After the effective date of this AD, only Revision
2 of the service bulletin shall be used.
Note 2: Boeing Service Bulletin 747-53A2377, Revision 2, dated
October 6, 1994, references Boeing Service Bulletin 747-53-2200,
Revision 1, dated November 16, 1979, as an additional source of
service information for the replacement of these fittings.
(1) If any cracking is found on any fitting, prior to further
flight, replace the cracked fitting with a new 7075-T73 aluminum
latch support fitting in accordance with Boeing Service Bulletin
747-53A2377, Revision 1, dated January 28, 1993, or Revision 2,
dated October 6, 1994. After the effective date of this AD, only
Revision 2 of the service bulletin shall be used.
(2) If no cracking is found on any fitting, repeat the HFEC
inspection thereafter at intervals not to exceed 18 months until the
requirements of paragraph (b) of this AD are accomplished.
New Requirements of This AD
(b) Within 18 months after the effective date of this AD,
replace all 7079-T6 aluminum latch support fittings with new 7075-
T73 fittings, in accordance with Boeing Alert Service Bulletin 747-
53A2377, dated December 10, 1992, Boeing Service Bulletin 747-
53A2377, Revision 1, dated January 28, 1993, or Boeing Service
Bulletin 747-53A2377, Revision 2, dated October 6, 1994. Replacement
of all latch support fittings constitutes terminating action for the
inspection requirements of this AD.
(c) As of the effective date of this AD, no operator shall
install any 7079-T6 aluminum latch support fitting of the cargo door
on any airplane.
(d) 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 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Seattle ACO.
(e) 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.
(f) The actions shall be done in accordance with Boeing Alert
Service Bulletin 747-53A2377, dated December 10, 1992; Boeing
Service Bulletin 747-53A2377, Revision 1, dated January 28, 1993; or
Boeing Service Bulletin 747-53A2377, Revision 2, dated October 6,
1994.
(1) The incorporation by reference of Boeing Alert Service
Bulletin 747-53A2377, dated December 10, 1992, and Boeing Service
Bulletin 747-53A2377, Revision 2, dated October 6, 1994, is approved
by the Director of the Federal Register, in accordance with 5 U.S.C.
552(a) and 1 CFR part 51.
(2) The incorporation by reference of Boeing Service Bulletin
747-53A2377, Revision 1, dated January 28, 1993, was approved
previously by the Director of the Federal Register as of March 11,
1993 (58 FR 11190, February 24, 1993).
(3) Copies may be obtained from Boeing Commercial Airplane
Group, P.O. Box 3707,
[[Page 49272]]
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.
(g) This amendment becomes effective on October 20, 1998.
Issued in Renton, Washington, on August 28, 1998.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 98-24247 Filed 9-14-98; 8:45 am]
BILLING CODE 4910-13-P