[Federal Register Volume 64, Number 168 (Tuesday, August 31, 1999)]
[Rules and Regulations]
[Pages 47377-47382]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-22397]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-03-AD; Amendment 39-11271; AD 99-18-05]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 727 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 all Boeing Model 727 series airplanes, that requires
repetitive inspections to detect cracks in the forward flange of the
vertical beam of the aft pressure bulkhead at certain buttock lines,
and installation of a splice repair, if necessary. The amendment also
requires installation of a preventative modification on the vertical
beam of the door frame in certain cases. This amendment is prompted by
reports of fatigue cracks found in the vertical beam web and forward
flange of the aft pressure bulkhead. The actions specified by this AD
are intended to detect and correct
[[Page 47378]]
such fatigue cracking, which could result in the inability of the
subject vertical beam to withstand the fail-safe loads, and consequent
loss of cabin pressurization.
DATES: Effective October 5, 1999.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of October 5, 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: Walter Sippel, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue, SW., Renton, Washington; telephone (425) 227-2774;
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 all Boeing Model 727 series
airplanes was published in the Federal Register on July 18, 1997 (62 FR
38493). That action proposed to require repetitive inspections to
detect cracks in the forward flange of the vertical beam of the aft
pressure bulkhead at certain buttock lines, and installation of a
splice repair, if necessary. That action also proposed to require
installation of a preventative modification on the vertical beam of the
door frames in certain cases.
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.
Two commenters support the proposed rule.
Request to Correct Service Information
One commenter states that the last sentence under the heading
``Explanation of Relevant Service Information'' of the proposed AD
incorrectly references Boeing Service Bulletin 727-53-0055 as ``an
additional source of service information for identical procedures to
repair and modify the affected area.'' The commenter adds that Boeing
Service Bulletin 727-53-0055 specifies a splice installation only if
cracks are beyond repair/modification limits, whereas Boeing Service
Bulletin 727-53-0210, dated April 1, 1993, specifies a splice repair
and modification any time cracks are found.
The FAA does not concur that the reference to Boeing Service
Bulletin 727-53-0055 is incorrect in the proposed AD. Although Boeing
Service Bulletins 727-53-0055 and 727-53-0210 specify an inspection of
the vertical beam at different locations, both service bulletins
specify the same procedures for accomplishing the preventative
modification and the splice repair. In light of this, the FAA considers
that the reference to Boeing Service Bulletin 727-53-0055 is correct.
However, the ``Explanation of Relevant Service Information'' does not
reappear in the final rule; therefore, no change to the final rule is
necessary in this regard.
Requests to Revise the Cost Estimate
Three commenters request that the cost estimate in the proposed AD
be revised.
One commenter estimates that access to the affected area and
removal and installation of the lavatories and walls would require 80
hours for a fleet cost of $389,000 for the inspection, total out-of-
service costs of $1,285,380, additional inspection costs of $728,382
because of a disruption of normal ``C'' checks, and an inspection-only
cost of $2,402,762. The commenter adds that the proposed AD requires
inspections within 1,500 flight cycles, which would not allow the
airplane to be scheduled into normal ``C'' checks and would necessitate
its removal from service for approximately 90 days.
Another commenter estimates approximately 10 hours for the
inspections. This estimate is based on 4 hours to gain access to the
inspection area, 2 hours to accomplish the inspection, and 4 hours to
close up the inspection area, with a cost per airplane of approximately
$600 and a fleet cost of $632,400.
Another commenter estimates 200 hours (two mechanics for 5 working
days) to remove/replace the lavatories and perform the inspections. The
commenter states that, because the proposed initial inspection interval
of 1,500 flight cycles is 500 flight cycles less than its current ``C''
check interval, 25 percent of its Model 727 fleet would need to be
removed from service on a ``special route'' basis and flown to a
maintenance base to accomplish the inspection. The commenter adds that
this schedule disruption and the downtime added to routine ``C'' check
visits would severely impact operations and result in unnecessary
expense and burden.
The FAA does not concur with the commenters' requests to revise the
cost estimate in the AD. The FAA based its estimate on the cost
estimate recommended in Boeing Service Bulletin 727-53-0210, dated
April 1, 1993; as revised by Notice of Status Change 727-53-0210 NSC 1,
dated June 17, 1993; and Notice of Status Change 727-53-0210 NSC 2,
dated September 21, 1995. In that service bulletin, the time for
removal and installation of lavatories is not included in the estimate
because those times vary significantly based on the type of lavatories
installed and whether lavatory galleys are installed (freighters have
neither), and whether or not other inspections are being accomplished.
The FAA recognizes that, in accomplishing the requirements of any
AD, operators may incur ``incidental'' costs in addition to the
``direct'' costs. The cost analysis in AD rulemaking actions, however,
typically does not include incidental costs, such as the time required
to gain access and close up; planning time; or time necessitated by
other administrative actions. Because incidental costs may vary
significantly from operator to operator, they are almost impossible to
calculate.
In addition, where safety considerations allow, the FAA attempts to
impose compliance times that generally coincide with operators'
maintenance schedules. However, because operators' schedules vary
substantially, the FAA is unable to accommodate every operator's
optimal scheduling in each AD. Each AD does allow individual operators
to obtain approval for extensions of compliance times, based on a
showing that the extension will not affect safety adversely. Therefore,
the FAA does not consider it appropriate to attribute to the AD, the
costs associated with the type of special scheduling that might
otherwise be required. Furthermore, because the FAA generally attempts
to impose compliance times that coincide with operators' scheduled
maintenance, the FAA considers it inappropriate to attribute the cost
associated with aircraft ``downtime'' to the cost of the AD, because,
normally, compliance with the AD will not necessitate any additional
downtime beyond that of a regularly scheduled maintenance hold. Even
if, in some cases, additional downtime is necessary for some airplanes,
the FAA does not possess sufficient information to evaluate the number
of airplanes that may be so affected or the amount of additional
downtime that may be
[[Page 47379]]
required. No change to the final rule is necessary in this regard.
Request to Revise Compliance Time
One commenter requests revising Note 2 [following paragraph (a)(2)
of the proposed AD]. The commenter states that Note 2 does not agree
with the service bulletin. The commenter considers that if the splice
repair has been accomplished, the inspection threshold should be 20,000
flight cycles since installation of the splice repair; whereas, if the
splice repair has not been accomplished, the threshold should be 20,000
flight cycles from time of delivery.
The FAA agrees with the commenter's remark that Note 2 of the
proposed AD does not correspond with the service bulletin, and has
removed the note from this final rule. In reviewing this comment, the
FAA notes that the compliance time specified in the proposed AD differs
from the service bulletin. However, the FAA's intent was that the
compliance times coincide with the service bulletin.
Further, the FAA notes that the splice repair or the preventative
modification may have been installed independently on the left and
right vertical beams. In such cases, in order to allow those beams to
be inspected independently, the FAA has revised the final rule to
specify compliance times from the time of installation of the splice
repair or preventative modification of the vertical beams. The
compliance times in paragraphs (a)(1) and (a)(2) of this AD have been
revised to coincide with the service bulletin, as follows:
For any vertical beam on which neither the preventative
modification nor the splice repair have been accomplished, paragraph
(a)(1) of this AD requires an inspection prior to the accumulation of
20,000 total flight cycles, or within 1,500 flight cycles after the
effective date of this AD, whichever occurs later.
For any vertical beam on which the preventative
modification has not been accomplished and the splice repair has been
accomplished, paragraph (a)(2) of this AD requires an inspection prior
to the accumulation of 20,000 flight cycles since installation of the
splice repair, or within 1,500 flight cycles after the effective date
of this AD, whichever occurs later.
Request to Extend Compliance Time for Inspections
One commenter requests an inspection interval of 4,000 flight
cycles, with repeat inspections every 4,000 flight cycles if the
preventative modification has not been accomplished. The commenter
states that the 4,000 flight cycle limit would allow the operator to
remove the lavatories, accomplish the inspection, and install the
preventative modification during scheduled corrosion (R-check) visits.
The commenter adds that these corrosion visits are of sufficient
duration to absorb the additional work without undue impact, and that
its current fleet plans include the initial inspection and installation
of the preventative modification during the same visit. The commenter
considers that the 4,000 flight cycles for the initial inspection is
justified from a technical standpoint because it has been conducting
routine intensified inspections and repairs of the aft pressure
bulkhead vertical beam at scheduled heavy maintenance visits since
1988. The commenter also states that the inspection interval of 1,500
flight cycles is 500 flight cycles less than its current ``C-check''
interval. The commenter adds that, unless the inspection intervals are
increased, 25% of its 727 fleet would be removed from service on a
``special route'' basis and flown to base maintenance. The commenter
considers that this schedule disruption and the additional downtime
added to routine C-checks would severely impact operations and result
in unnecessary expense and burden, whereas inspection intervals of
4,000 flight cycles would allow sufficient time to accomplish the work
without undue impact.
The FAA does not concur with the commenter's request to revise the
compliance times, as described. The grace period for the initial
inspection and the inspection intervals specified in this AD were
determined based on engineering analysis of crack growth rates and the
type of detection methods used. The compliance times proposed by the
commenter do not ensure that cracking will be detected in a timely
manner.
Another commenter requests that the initial inspection threshold
required by paragraph (a)(1) of the proposed AD be increased from
``18,500 total flight cycles'' to ``30,000 total flight cycles.'' The
commenter states that the two reports of cracks have both occurred at
48,000 and 48,500 flight cycles. The commenter adds that it considers
the inspection threshold of 18,500 flight cycles to be premature
because cracking did not occur before 48,000 flight cycles.
The FAA does not concur that the inspection threshold required by
paragraph (a)(1) of the final rule, should be increased to 30,000 total
flight cycles. While Boeing Service Bulletin 727-53-0210 specifies that
cracks occurred at thresholds exceeding 48,000 flight cycles, the FAA
considers that the extent of such cracking was unsafe. In developing an
appropriate compliance time for this AD, the FAA considered the degree
of urgency associated with addressing the subject unsafe condition, the
average utilization of the affected fleet, the time necessary to
perform the inspection, and the practical aspects of performing the
inspections. In consideration of these factors, the FAA finds that the
compliance time required by paragraph (a)(1) of this AD represents an
appropriate threshold for accomplishment of the inspection in a timely
manner within the fleet and still maintain an adequate level of safety.
The FAA considers that the inspections can be accomplished within an
interval of time that parallels normal scheduled maintenance for a
majority of affected operators, and within an appropriate interval to
prevent the initiation and propagation of fatigue cracking in the
vertical beam web and forward flange of the aft pressure bulkhead.
Because the objective of the proposed inspections is to detect and
correct these cracks before the extent of the cracking found on those
airplanes, the FAA has determined that the inspection threshold
specified in paragraph (a)(1) of the AD is appropriate. No change was
made to the final rule in this regard.
Request to Defer Accomplishment of Modification on Both Frames
One commenter states that operators should have the option of
``terminating the inspection'' on both frames. The FAA infers that the
commenter requests that the repair be required for cracked door frames
only, and that operators be allowed to accomplish the modification at a
time established by the operator. The FAA has determined that an
appropriate level of safety can be assured by accomplishment of both
the repair and modification on all cracked door frames prior to further
flight, as recommended by the manufacturer. Additionally, repetitive
inspections of uncracked door frames must be accomplished at the
intervals specified in this AD. Paragraphs (b) and (c) of this AD have
been revised accordingly.
Request to Change Installation Requirement for Splice Repair
One commenter requests that an operator should be allowed to
install the splice repair only (not the preventative modification) on a
cracked door frame, followed by repeat inspections beginning at 18,500
flight cycles.
The FAA does not concur that an adequate level of safety can be
ensured
[[Page 47380]]
by requiring only the splice repair and continued inspection beginning
at 18,500 flight cycles after repair of the cracked vertical beam. The
FAA points out that the commenter provided no technical justification
for accomplishing only the repair with repetitive inspections of a
cracked vertical beam; the FAA considers cracking in the forward flange
of the vertical beam of the aft pressure bulkhead to be a significant
safety issue.
In developing the appropriate actions (i.e., repair, modification,
and repetitive inspections) for this AD, the FAA considered not only
those safety issues but the recommendations of the manufacturer, the
availability of parts, and the practical aspect of accomplishing the
required inspections within an interval of time that parallels normal
scheduled maintenance for the majority of affected operators. The FAA
considers that the repair, modification, and repetitive inspections
required by the proposed AD are necessary to ensure the timely
detection of cracking.
To further clarify the required repetitive inspection intervals of
uncracked vertical beams and the required actions for cracked vertical
beams, paragraphs (b)(1)(i) and (b)(1)(ii) have been added, and
paragraphs (b), (b)(1), (b)(2), and (c) have been revised in the final
rule.
Requests to Clarify the Repetitive Inspection Intervals
One commenter requests that paragraph (a)(2) of the proposed AD,
which specifies repetitive inspections at intervals not to exceed 6,000
flight cycles, be divided into two sections, one for airplanes
inspected at 3,000 flight cycles and another for airplanes inspected at
6,000 flight cycles. The commenter states that, for airplanes with the
modification accomplished previously, paragraph (a)(2) requires
repetitive inspections thereafter at intervals not to exceed 6,000
flight cycles; however, paragraph (b)(2) requires such inspections at
intervals not to exceed 3,000 flight cycles. The commenter considers
that the FAA's intent was to require such inspections thereafter at
intervals not to exceed 3,000 flight cycles for airplanes that do not
have preventative modifications installed.
Another commenter states that the actions required by paragraphs
(a)(2) and (b)(2) seem to conflict. That commenter suggests changing
the wording in those paragraphs to clarify that repetitive inspections
are not to exceed 3,000 flight cycles for unmodified structure or 6,000
flight cycles for modified structure.
The FAA concurs. The FAA agrees that clarification of the number of
repetitive inspection intervals specified in paragraphs (a)(2) and
(b)(2) of the proposed AD is necessary. The FAA also agrees that it is
necessary to distinguish between the number of flight cycles required
for modified and unmodified structures in the final rule. In light of
this, the FAA has deleted the repetitive inspections specified in
paragraph (a)(2) of the proposed AD, and has specified the repetitive
inspection intervals required for modified and unmodified structures in
paragraphs (b)(1)(i) and (b)(1)(ii) of the final rule.
Request to Allow Repair/Modification During D-Check
One commenter requests that the repair and modification required by
the proposed AD be accomplished during ``D-check'' opportunities
because the actions required could exceed 200 hours and possibly 4
days.
The FAA does not concur. The FAA points out that the compliance
times specified in the AD for the repair and preventative modification
were based on the information included in Boeing Service Bulletin 727-
53-0210, and that it considers these estimates appropriate. The FAA has
determined that continued flight with unmodified structure, which has
begun to crack and is likely to continue cracking, does not provide an
acceptable level of safety. In light of these considerations, no change
has been made to the final rule in this regard.
Request to Correct Typographical Error
Two commenters request a correction to paragraph (c) of the NPRM to
delete a reference to paragraph (a)(3). The FAA agrees that paragraph
(a)(3) did not exist in the NPRM and that a reference to that paragraph
should not have been included in paragraph (c) of the NPRM. However,
the final rule now includes a paragraph (a)(3), which is appropriately
referenced in paragraph (c) of this final rule.
Request to Permit ``Industry-Accepted Shop Practices''
One commenter requests including a statement in the final rule
allowing the use of industry-accepted shop practices in lieu of
processes and finishes (e.g., primer, paint, or sealant) that are
specified by the original equipment manufacturer (OEM) and that have no
effect on the intent of the AD. The commenter states that industry-
accepted shop practices would allow operators to use equivalent methods
and types of finishes without first having to seek approval from the
FAA for an alternative method of compliance.
The FAA does not concur with the request to allow the use of
industry-accepted shop practices instead of the alternative method of
compliance required by paragraph (d) of the proposed AD. The FAA points
out that such practices could vary from operator to operator and, thus,
make it impossible to ensure the appropriate level of safety required.
In light of this, the FAA has determined that it is unacceptable to
delegate an undefined practice. This final rule requires that the
actions be accomplished in accordance with the procedures specified in
Boeing Service Bulletin 727-53-0210. An industry-accepted shop practice
may be used only if approved as an alternative method of compliance in
accordance with paragraph (d) of the final rule. No change has been
made to paragraph (d) of the final rule.
Explanation of Changes Made to the Proposal
Operators should note that the following changes were made to this
AD to clarify certain terminology:
The term ``aft fuselage bulkhead,'' which was used in the
proposed AD, has been changed to ``aft pressure bulkhead'' in the final
rule. This change was made in the Summary and throughout this AD to
correlate with the term used in Boeing Service Bulletin 727-53-0210 and
because it more accurately describes the bulkhead.
The term ``close visual inspections,'' as specified in
certain paragraphs of the proposed AD, has been changed to ``detailed
visual inspections.'' This terminology is considered to be technically
equivalent. This change was made in paragraphs (b)(1)(i), (b)(1)(ii),
(b)(2), and (c) of the final rule. In addition, Note 2 has been added
to the final rule, following paragraph (a)(3), to include the
definition of a ``detailed visual inspection.''
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 changes previously
described. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
Cost Impact
There are approximately 1,560 Model 727 series airplanes of the
affected design in the worldwide fleet. The FAA
[[Page 47381]]
estimates that 1,054 airplanes of U.S. registry will be affected by
this AD.
It will take approximately 2 work hours per airplane to accomplish
the required inspections, 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 $126,480, or
$120 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 be required to accomplish the preventative
modification, it will take approximately 100 work hours per airplane to
accomplish, at an average labor rate of $60 per work hour. The cost of
required parts could range between $910 and $1,042 per preventative
modification kit (2 kits per airplane). Based on these figures, the
cost impact of the preventative modification required by this AD on
U.S. operators is estimated to be between $7,820, and $8,084 per
airplane.
Should an operator be required to accomplish the splice repair, it
will take approximately 148 work hours per airplane to accomplish, at
an average labor rate of $60 per work hour. Required parts will cost
approximately $3,545 per airplane ($1,756 for the splice repair kit on
the left side, and $1,789 for the splice repair kit on the right side).
Based on these figures, the cost impact of the splice repair required
by this AD on U.S. operators is estimated to be $12,425 per airplane.
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:
99-18-05 Boeing: Amendment 39-11271. Docket 97-NM-03-AD.
Applicability: All Model 727 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 (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 detect and correct fatigue cracking in the forward flange of
the vertical beam of the aft pressure bulkhead, which could result
in the inability of the subject vertical beam to withstand the fail-
safe loads, and consequent loss of cabin pressurization, accomplish
the following:
Initial Inspections
(a) Perform a detailed visual inspection and a high frequency
eddy current (HFEC) inspection to detect cracks in the forward
flange of the vertical beam at left and right buttock line 17.8 from
water lines 265 through 288 inclusive, in accordance with Boeing
Service Bulletin 727-53-0210, dated April 1, 1993, as revised by
Notice of Status Change 727-53-0210 NSC 1, dated June 17, 1993, and
Notice of Status Change 727-53-0210 NSC 2, dated September 21, 1995;
at the time specified in paragraph (a)(1), (a)(2), or (a)(3) of this
AD, as applicable.
(1) For any vertical beam on which neither the preventative
modification nor the splice repair have been accomplished, as
specified in Boeing Service Bulletin 727-53-0210, dated April 1,
1993; or Boeing Service Bulletin 727-53-0055, Revision 6, dated
February 28, 1986, Revision 7, dated March 5, 1987, Revision 8,
dated December 17, 1987, or Revision 9, dated August 3, 1989:
Inspect prior to the accumulation of 20,000 total flight cycles, or
within 1,500 flight cycles after the effective date of this AD,
whichever occurs later.
(2) For any vertical beam on which the preventative modification
has not been accomplished and the splice repair has been
accomplished, as specified in Boeing Service Bulletin 727-53-0210,
dated April 1, 1993, or Boeing Service Bulletin 727-53-0055,
Revision 6, dated February 28, 1986, Revision 7, dated March 5,
1987, Revision 8, dated December 17, 1987, or Revision 9, dated
August 3, 1989: Inspect prior to the accumulation of 20,000 flight
cycles since installation of the splice repair, or within 1,500
flight cycles after the effective date of this AD, whichever occurs
later.
(3) For any vertical beam on which the preventative modification
has been accomplished and the splice repair has or has not been
accomplished, as specified in Boeing Service Bulletin 727-53-0210,
dated April 1, 1993, or Boeing Service Bulletin 727-53-0055,
Revision 6, dated February 28, 1986, Revision 7, dated March 5,
1987, Revision 8, dated December 17, 1987, or Revision 9, dated
August 3, 1989: Inspect prior to the accumulation of 40,000 flight
cycles since installation of the preventative modification, or
within 1,500 flight cycles after the effective date of this AD,
whichever occurs later.
Note 2: For the purposes of this AD, a detailed 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 intensity
deemed appropriate by the inspector. Inspection aids such as mirror,
magnifying lenses, etc. may be used. Surface cleaning and elaborate
access procedures may be required.''
Repetitive Inspections and Corrective Action
(b) If no crack is detected during any inspection required by
paragraph (a)(1), (a)(2), or (a)(3) of this AD, accomplish either
paragraph (b)(1) or (b)(2) of this AD, as applicable, in accordance
with Boeing Service Bulletin 727-53-0210, dated April 1, 1993, as
revised by Notice of Status Change 727-53-0210 NSC 1, dated June 17,
1993, and Notice of Status Change 727-53-0210 NSC 2, dated September
21, 1995.
(1) For any vertical beam on which the preventative modification
has not been accomplished, as specified in paragraphs (a)(1) and
(a)(2) of this AD, accomplish either paragraph (b)(1)(i) or
(b)(1)(ii) of this AD in accordance with the service bulletin.
[[Page 47382]]
(i) Prior to further flight, install the preventative
modification. Prior to the accumulation of 40,000 flight cycles
following accomplishment of a preventative modification, accomplish
the detailed visual and HFEC inspections specified in paragraph (a)
of this AD for any modified area. Repeat those inspections
thereafter at intervals not to exceed 6,000 flight cycles for that
modified area. Or
(ii) Repeat the detailed visual and HFEC inspections specified
in paragraph (a) of this AD for any unmodified area at intervals not
to exceed 3,000 flight cycles.
(2) For any vertical beam on which the preventative modification
has been accomplished, repeat the detailed visual and HFEC
inspections specified in paragraph (a) of this AD thereafter at
intervals not to exceed 6,000 flight cycles.
(c) If any crack is detected during any inspection required by
paragraph (a)(1), (a)(2), or (a)(3) of this AD, prior to further
flight, install a splice repair and preventative modification to all
cracked door frames, in accordance with Boeing Service Bulletin 727-
53-0210, dated April 1, 1993, as revised by Notice of Status Change
727-53-0210 NSC 1, dated June 17, 1993, and Notice of Status Change
727-53-0210 NSC 2, dated September 21, 1995. Prior to the
accumulation of 40,000 flight cycles following accomplishment of the
preventative modification, accomplish the detailed visual and HFEC
inspections specified in paragraph (a) of this AD. Repeat those
inspections specified in paragraph (a) for that repaired and
modified area thereafter at intervals not to exceed 6,000 flight
cycles.
Alternative Method of Compliance
(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.
Special Flight Permits
(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.
Incorporation by Reference
(f) The actions shall be done in accordance with Boeing Service
Bulletin 727-53-0210, dated April 1, 1993, as revised by Notice of
Status Change 727-53-0210 NSC 1, dated June 17, 1993, and Notice of
Status Change 727-53-0210 NSC 2, dated September 21, 1995. 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.
(g) This amendment becomes effective on October 5, 1999.
Issued in Renton, Washington, on August 23, 1999.
Vi L. Lipski,
Acting Manager,
Transport Airplane Directorate,
Aircraft Certification Service.
[FR Doc. 99-22397 Filed 8-30-99; 8:45 am]
BILLING CODE 4910-13-U