[Federal Register Volume 64, Number 234 (Tuesday, December 7, 1999)]
[Proposed Rules]
[Pages 68297-68300]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-31680]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NM-73-AD]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 727 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to all Boeing Model 727 series
airplanes. This proposal would require a one-time
[[Page 68298]]
detailed visual inspection of the fuselage skin and bonded doubler area
above the forward entry doorway to detect fatigue cracking or the
existence of certain repairs, and follow-on corrective actions, if
necessary. This action also would require a preventive modification or
full-sized repair doubler, as applicable. This proposal is prompted by
reports of fatigue cracking in the fuselage skin and bonded doublers in
the forward and aft corners above the forward entry doorway. The
actions specified by the proposed AD are intended to prevent such
fatigue cracking of the fuselage skin and bonded doubler, which could
result in reduced structural integrity and consequent loss of cabin
pressurization.
DATES: Comments must be received by January 21, 2000.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-114,
Attention: Rules Docket No. 99-NM-73-AD, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056. Comments may be inspected at this location
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal
holidays.
The service information referenced in the proposed rule 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.
FOR FURTHER INFORMATION CONTACT: Walter Sippel, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2774; fax (425) 227-1181.
SUPPLEMENTARY INFORMATION:
Comments Invited
Interested persons are invited to participate in the making of the
proposed 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 above. All
communications received on or before the closing date for comments,
specified above, will be considered before taking action on the
proposed rule. The proposals contained in this notice may be changed in
light of the comments received.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with
the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 99-NM-73-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules
Docket No. 99-NM-73-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On February 18, 1994, the FAA issued AD 94-05-04, amendment 39-8842
(59 FR 13442, March 22, 1994), applicable to certain Boeing Model 727
series airplanes, to require incorporation of certain structural
modifications. That action was prompted by an evaluation by the Model
727 Structures Working Group, comprised of aircraft operators,
manufacturers, and the FAA. This Working Group evaluated Boeing service
bulletins that must be included as part of the ``Aging Airplane
Structural Modification Program.'' The actions specified by that AD are
intended to prevent degradation in the structural capabilities of the
affected airplanes. Those actions also reflect the FAA's decision that
long-term continued operational safety should be assured by actual
modification of the airframe rather than repetitive inspections.
Since the issuance of AD 94-05-04, the FAA has determined that
additional action (specified by Boeing Service Bulletin 727-53-0186,
Revision 1, dated May 21, 1992) is required to include certain
airplanes that are excluded in the applicability of that AD. Because AD
94-05-04 only requires modification of the airplane structure if no
cracking is detected in the fuselage skin and bonded doubler area above
the forward entry doorway, some airplanes do not have the full-sized
repair doubler installed. In addition, there is no mandatory
requirement to inspect airplanes on which the half- or full-sized
repair doubler has been installed to repair any crack that exceeds 2.5
inches or is located in the bear strap. Such conditions, if not
corrected, could result in a degradation in the structural capabilities
of the affected airplanes. In light of this, the FAA has determined
that corrective action is required for airplanes on which only a half-
sized repair doubler has been accomplished, or on which either a half-
or full-size repair doubler is found and any crack exceeds 2.5 inches
or is located in the bear strap. Accomplishment of the inspection and
corrective actions required by this AD is intended to ensure the
structural integrity of such airplanes, and to reduce the extent of
crack propagation (i.e., not to exceed 2.5 inches) in the fuselage skin
and bonded doublers above the upper area of the doorway. Such action
also reflects the FAA's decision that long-term continued operational
safety would be better assured by modification of the airframe, rather
than by repetitive inspections.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Service Bulletin 727-53-
0186, Revision 1, dated May 21, 1992, which describes procedures for
repetitive close (detailed) visual inspections to detect cracking of
the fuselage skin and bonded doubler area above the forward entry
doorway. Among other things, this service bulletin also describes
procedures for the accomplishment of either a preventive modification
(fabricating and installing a preventive modification doubler) or a
full-sized repair doubler of the upper area of the doorway skin.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to
exist or develop on other products of this same type design, the
proposed AD would require accomplishment of the actions specified in
the service bulletin described previously, except as discussed below.
Differences Between the Service Information and the Proposed AD
Operators should note that the service bulletin recommends a visual
inspection for cracks ``at 40,000 cycles'' for airplanes that have not
yet accumulated 40,000 total flight cycles, and an inspection ``within
3,000 flight cycles'' for airplanes that have accumulated more than
40,000 total flight cycles. The service bulletin also recommends a
repetitive inspection interval of 3,000 flight cycles, and
accomplishment of either a preventive
[[Page 68299]]
modification or a full-sized repair doubler prior to the accumulation
of 60,000 total flight cycles. However, paragraph (a) of this proposed
AD requires accomplishment of a one-time detailed visual inspection and
either the preventive modification or full-sized repair doubler ``prior
to the accumulation of 60,000 total flight cycles.'' This proposed AD
does not require repetitive inspections prior to modification or
repair. The FAA points out that cracks in the fuselage skin and bonded
doubler area above the forward entry doorway have not been found to be
a safety factor prior to the accumulation of 60,000 total flight
cycles. Therefore, the FAA considers that accomplishment of the actions
required by paragraph (a) of this proposed AD would provide an adequate
level of operational safety.
Operators also should note that the service bulletin specifies
three repair options, which include a procedure for installing a half-
sized repair doubler in the forward corner or aft area of the doorway
skin. However, this proposed AD requires installing a full-sized repair
doubler rather than a half-sized repair doubler.
Operators also should note that the service bulletin specifies
contacting the manufacturer if any repair was previously accomplished
for cracking that exceeded 2.5 inches, or if a crack was repaired in
the bear strap. However, this proposed AD requires that such repairs be
accomplished in accordance with a method approved by the FAA, 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 FAA to make such
findings.
Operators also should note that, although the service bulletin
specifies a ``close visual inspection,'' this proposed AD requires a
``detailed visual inspection.''
Other Relevant Rulemaking
Accomplishment of certain actions required by this proposed AD
would constitute terminating action for the requirements specified in
paragraph (a) of AD 94-05-04 with respect to the modification specified
in Boeing Service Bulletin 727-53-0186, dated April 27, 1989. This
service bulletin is one of many service bulletins referenced in Boeing
Document D6-54860, Revision G, Appendix A.3, dated March 5, 1993. All
other service bulletins referenced in that document still apply.
Cost Impact
There are approximately 1,429 airplanes of the affected design in
the worldwide fleet. The FAA estimates that 887 airplanes of U.S.
registry would be affected by this proposed AD.
The FAA estimates that it would take approximately 1 work hour per
airplane to accomplish the inspection of the fuselage skin and bonded
doubler area, and that the average labor rate is $60 per work hour.
Based on these figures, the cost impact of the proposed AD on U.S.
operators is estimated to be $53,220, or $60 per airplane.
The FAA estimates that it would take approximately 27 work hours
per airplane to accomplish the preventive modification or full-sized
repair doubler, and that the average labor rate is $60 per work hour.
Required parts would cost approximately $979 per airplane. Based on
these figures, the cost impact of the proposed AD on U.S. operators is
estimated to be $2,305,313, or $2,599 per airplane.
The cost impact figures discussed above are based on assumptions
that no operator has yet accomplished any of the proposed 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 proposed herein would 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
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this proposed
regulation (1) is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under the DOT
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979);
and (3) if promulgated, 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 copy of the draft
regulatory evaluation prepared for this action is contained in the
Rules Docket. A copy of it may be obtained by contacting the Rules
Docket at the location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Safety.
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration proposes to amend
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:
Boeing: Docket 99-NM-73-AD.
Applicability: All Model 727 series airplanes, 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 fatigue cracking of the fuselage skin and bonded
doubler area above the forward entry doorway, which could result in
reduced structural integrity and consequent loss of cabin
pressurization, accomplish the following:
Detailed Visual Inspection
(a) Prior to the accumulation of 60,000 total flight cycles, or
within 3,000 flight cycles after the effective date of this AD,
whichever occurs later: Perform a one-time detailed visual
inspection of the fuselage skin and bonded doubler area above the
forward entry doorway to detect fatigue cracking or the existence of
a previous repair, in accordance with Boeing Service Bulletin 727-
53-0186, Revision 1, dated May 21, 1992.
Corrective Action
(1) If no crack or repair is detected, prior to further flight,
perform the preventive modification in accordance with the service
bulletin. No further action is required by this AD.
(2) If any crack but no repair is detected, prior to further
flight, accomplish the actions required by paragraph (a)(2)(i),
(a)(2)(ii), or (a)(2)(iii), as applicable.
(i) If any crack is less than or equal to 2.5 inches, perform
the full-sized repair doubler in accordance with Boeing Service
Bulletin
[[Page 68300]]
727-53-0186, Revision 1, dated May 21, 1992. Accomplishment of this
action constitutes terminating action for the requirements of this
AD.
(ii) If any crack exceeds 2.5 inches, 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
(DER) who has been authorized by the Manager, Seattle ACO, to make
such findings. For a repair method to be approved by the Manager,
Seattle ACO, or the Boeing DER, as required by this paragraph, the
approval letter must specifically reference this AD.
(iii) If any crack in the bear strap is detected, 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 DER who has been authorized by
the Manager, Seattle ACO, to make such findings. For a repair method
to be approved by the Manager, Seattle ACO, or the Boeing DER, as
required by this paragraph, the approval letter must specifically
reference this AD.
(3) If any repair is found, accomplish paragraph (a)(3)(i),
(a)(3)(ii), or (a)(3)(iii), of this AD, as applicable.
(i) If a full-sized repair doubler is found, as specified by
Boeing Service Bulletin 727-53-0186, dated April 27, 1989, or
Revision 1, dated May 21, 1992, and any crack is less than or equal
to 2.5 inches, no further action is required by this AD.
(ii) If a half-sized repair doubler is found, as specified by
Boeing Service Bulletin 727-53-0186, dated April 27, 1989, or
Revision 1, dated May 21, 1992, and any crack is less than or equal
to 2.5 inches and is not in the bear strap: Prior to further flight,
perform the full-sized repair doubler in accordance with Boeing
Service Bulletin 727-53-0186, Revision 1, dated May 21, 1992. No
further action is required by this AD.
(iii) If a half-sized or full-sized repair doubler is found, as
specified by the service bulletin, and any crack exceeds 2.5 inches
or is located in the bear strap: 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 DER who has been authorized by
the Manager, Seattle ACO, to make such findings. For a repair method
to be approved by the Manager, Seattle ACO, or the Boeing DER, as
required by this paragraph, the approval letter must specifically
reference this AD.
Note 2: For the purposes of this AD, a detailed visual
inspection is defined as: ``An intensive visual examination of a
specific structural area, system, installation, or assembly to
detect damage, failure, or irregularity. Available lighting is
normally supplemented with a direct source of good lighting at an
intensity deemed appropriate by the inspector. Inspection aids such
as mirrors, magnifying lenses, etc. may be used. Surface cleaning
and elaborate access procedures may be required.''
Terminating Action for AD 94-05-04
(b) Accomplishment of the requirements of this AD constitutes
terminating action for the requirements of paragraph (a) of AD 94-
05-04, amendment 39-8842 (which are required to be accomplished in
accordance with Appendices A.3, B.3, and C.3 of Boeing Document
Number D6-54860, ``Aging Airplane Service Bulletin Structural
Modification and Inspection Program--Model 727,'' Revision G, dated
March 5, 1993), with respect to the modification specified in Boeing
Service Bulletin 727-53-0186, dated April 27, 1989. All other
service bulletins referenced in Boeing Document Number D6-54860
still apply.
Alternative Methods of Compliance
(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, 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.
Special Flight Permits
(d) Special flight permits may be issued in accordance with
Secs. 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.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 99-31680 Filed 12-6-99; 8:45 am]
BILLING CODE 4910-13-U
