[Federal Register Volume 65, Number 114 (Tuesday, June 13, 2000)]
[Rules and Regulations]
[Pages 37022-37025]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-14436]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NM-208-AD; Amendment 39-11777; AD 2000-11-28]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 747-400 and 767-200 and -
300 Series Airplanes Powered by Pratt & Whitney Model PW4000 Series
Engines
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 747-400 and 767-200 and -300 series
airplanes, that requires repetitive inspections to detect damage and
wear of the auxiliary track assembly of the thrust reverser, and
corrective actions, if necessary. This amendment also requires eventual
repair of the auxiliary track assembly, or replacement of the slider
and liner or the entire assembly, with new, improved parts, which, when
accomplished, would terminate the repetitive inspections. This
amendment is prompted by reports of damage and wear to the auxiliary
track assembly. The actions specified by this AD are intended to
prevent a slider disengaging from the auxiliary track assembly, which
could lead to separation of a portion of the thrust reverser from the
airplane during flight, possible impact of separated portions on
airplane structure, and consequent possible rapid decompression of the
airplane, reduced controllability of the airplane, or reduced
structural integrity of the fuselage.
DATES: Effective July 18, 2000.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 18, 2000.
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: Sulmo Mariano, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate,
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (425) 227-2686; 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 747-400 and
767-200 and -300 series airplanes was published in the Federal Register
on October 19, 1999 (64 FR 56276). That action proposed to require
repetitive inspections to detect damage and wear of the auxiliary track
assembly of the thrust reverser, and corrective actions, if necessary.
That action also proposed to require eventual replacement of the liner
and slider, or the entire assembly, with new, improved parts, which,
when accomplished, would terminate the repetitive inspections.
Comments
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter supports the proposed rule.
Request To Revise Certain Requirements in the Proposed AD
Several commenters indicate that they disagree with the proposed
replacement of the auxiliary track beam assembly, including
installation of a new slider and liner, regardless of the amount of
wear and/or damage to the track beam. The commenters request that
repair of the track beam be allowed when the damage is within the
allowable limits specified in the referenced service information. One
commenter states that replacement of the track beam fitting is required
only when the wear or damage is beyond repairable limits, as specified
in Boeing Service Bulletin 747-78A2164, Revision 2, and Boeing Service
Bulletin 767-78A0079, Revision 2. The commenter notes that replacement
of the track beam fitting in and of itself does nothing to address the
root cause of the excessive wear; however, the new design slider
fitting and track liner do address and correct the root cause. A second
commenter states that the service bulletins specify replacement of the
track beam assembly if the track beam has any discrepancy AND the
measurement of the gap is greater than 0.45 inch. If the track beam has
any discrepancy and the gap measurement is less than 0.45 inch, only
the slider and liner should be replaced. Another commenter states that
replacement of the track beam assembly is necessary only when damage
cannot be repaired by means of replacement of the liner, slider, and/or
retainer bar.
The FAA concurs with the commenters' requests. The FAA has
coordinated this issue with the manufacturer, and has determined that
if the damage to the track beam assembly is not beyond the repairable
limits specified in the referenced service bulletins, a repair that
involves replacement of the slider and liner and installation of a
retainer bar, in lieu of replacement of the track beam assembly, is
acceptable. Therefore, paragraphs (a) and (c) of this AD have been
revised to specify measuring the auxiliary track beam dimensions in
accordance with the Accomplishment Instructions of the referenced
service bulletins, and to allow repair if the measurement is within the
allowable limits.
Request To Revise Cost Impact Information
One commenter states that the total number of U.S.-registered Model
747-400 series airplanes affected by the proposed AD should be higher
than the 12 airplanes shown in the cost impact section. The commenter
indicates that it has 10 affected airplanes in its fleet and assumes
that other operators also have Model 747-400 series airplanes that are
affected by the proposal.
The FAA concurs. The referenced service bulletin specifies a total
of 36 Model 747-400 series airplanes of U.S.-registry that are powered
by Pratt & Whitney PW4000 series engines. In light of this information,
the FAA has revised the cost impact information, below, to specify that
36 Model 747-400 series airplanes of U.S. registry will be affected by
this AD.
Request for Credit for Previously Accomplished Work
One commenter requests credit for prior accomplishment of work done
in
[[Page 37023]]
accordance with Boeing Service Bulletin 747-78A2164, dated June 19,
1997, including Revision 1, dated February 5, 1998; and 767-78A0079,
dated June 19, 1997, including Revision 1, dated February 5, 1998;
which were previously issued revisions of the service bulletins
referenced in the proposed rule as the appropriate sources of service
information for accomplishment of the actions in the proposal. The
commenter states that it incorporated the inspection and terminating
actions described in the above service bulletins on two-thirds of its
fleet beginning in June 1997. Additionally, the commenter states that
the proposed rule requires different terminating action than the
original and Revision 1 of the service bulletins specify.
The FAA partially concurs with the commenter's request. The FAA has
determined that there are significant differences between Revision 2 of
the service bulletins and the original issue. The accomplishment
instructions in Revision 2 provide more detailed information about how
to perform the inspections, and are more specific regarding the extent
of damage permitted before accomplishing repair work. Therefore, the
FAA cannot give credit for work accomplished in accordance with the
original issue of the service bulletin. However, for any procedure
which an operator has accomplished previously, the operator may request
approval of an alternative method of compliance in accordance with the
provisions of paragraph (d) of this AD.
Revision 1 of the service bulletin is essentially identical to
Revision 2, which was cited in the proposed AD as the appropriate
source of service information for accomplishment of the required
actions. Revision 2 simply changes the recommended repetitive
inspection interval for detection of no wear or damage. Therefore, this
final rule has been revised to add a new NOTE 4 to include Revision 1
of the referenced service bulletins as an additional source of service
information for accomplishment of the actions.
Request To Extend Compliance Time and Revise Proposed Inspection
One commenter states that the results of a survey of operators of
Model 747 and 767 series airplanes powered by Pratt & Whitney PW4000
series engines, which was conducted by the manufacturer in January
1998, revealed that the most significant wear occurs on the lower
auxiliary track assembly. The commenter recommends that the inspection
only pertain to that assembly. The commenter also requests that the FAA
extend the grace period for inspection of the upper and lower auxiliary
track assemblies from 90 days to 18 months for the reason stated
previously.
The FAA does not concur with the commenter's requests. In
developing an appropriate compliance time for this action, the FAA
considered not only the degree of urgency associated with addressing
the subject unsafe condition, but accomplishment of the required
inspection within an interval of time that parallels normal scheduled
maintenance for the majority of affected operators. However, under the
provisions of paragraph (d) of the final rule, the FAA may approve
requests for adjustments to the compliance time if data are submitted
to substantiate that such an adjustment would provide an acceptable
level of safety.
In addition, the inspection required by paragraph (a) of the final
rule is required to be accomplished in accordance with the inspection
procedures specified in Boeing Service Bulletin 747-78A2164, Revision
2, dated December 3, 1998; or Boeing Service Bulletin 767-78A0079,
Revision 2, dated December 3, 1998; as applicable. Inspection of only
the lower auxiliary track assembly is inadequate, in light of the fact
that service experience accumulated over time has shown that excessive
wear and damage are present in both the upper and lower auxiliary track
assemblies. Therefore, no change to the final rule is necessary in this
regard.
Other Related Service Information
One commenter recommends that the FAA include the actions specified
in Boeing Service Bulletins 767-78-0005, 767-78-0037, and 767-78-0039
in the proposed rule as additional requirements. These service
bulletins describe the replacement of the aluminum auxiliary slider
fittings of the original design with new design steel fittings, on
Model 767 series airplanes powered by General Electric CF6-80A and
Pratt & Whitney JT9D-7R4D series engines. The commenter states that
cracking of the aluminum fittings due to fatigue loading could result
in breakage of the slider and subsequent separation of a portion of the
thrust reverser from the airplane, which could lead to an unsafe
condition similar to that addressed in the proposed AD.
The FAA does not concur with the commenter's recommendation. The
FAA has determined that since the suggested changes would alter the
actions currently required by this AD, additional rulemaking would be
required. The FAA finds that to delay this action would be
inappropriate in light of the identified unsafe condition. However, the
FAA will discuss this issue with the manufacturer at a later date;
therefore, no change to the final rule is necessary.
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 254 airplanes of the affected design in the
worldwide fleet. The FAA estimates that 36 Model 747-400 series
airplanes and 46 Model 767-200 and -300 series airplanes of U.S.
registry will be affected by this AD.
It will take approximately 4 work hours per engine to accomplish
the required repetitive inspections, at an average labor rate of $60
per work hour. Based on these figures, the cost impact of the AD on
U.S. operators of Model 747-400 series airplanes (4 engines per
airplane) is estimated to be $34,560, or $960 per airplane, per
inspection cycle. The cost impact of the AD on U.S. operators of Model
767 series airplanes (2 engines per airplane) is estimated to be
$22,080, or $480 per airplane, per inspection cycle.
Should an operator be required to accomplish the replacement of the
auxiliary track assembly, it would take approximately 220 work hours
per auxiliary track assembly to accomplish the replacement, at an
average labor rate of $60 per work hour. Required parts would cost
approximately $30,090. Based on these figures, the cost impact of this
replacement is estimated to be $43,290 per assembly. There are four
auxiliary track assemblies per engine.
Should an operator be required to accomplish the replacement of the
liner and slider, it would take approximately 8 work hours per
auxiliary track assembly to accomplish the replacement, at an average
labor rate of $60 per work hour. Required parts would be provided at no
cost by the airplane manufacturer. Based on these figures, the cost
impact of this replacement is estimated to be $480 per assembly. There
are four auxiliary track assemblies per engine.
The cost impact figures discussed above are based on assumptions
that no
[[Page 37024]]
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 adopted herein will not have a substantial direct
effect 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, it
is determined that this final rule does not have federalism
implications under Executive Order 13132.
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:
2000-11-28 Boeing: Amendment 39-11777. Docket 99-NM-208-AD.
Applicability: Model 747-400 series airplanes powered by Pratt &
Whitney PW4000 series engines, line numbers 696 through 1100
inclusive; and Model 767-200 and -300 series airplanes powered by
Pratt & Whitney PW4000 series engines, line numbers 1 through 646
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 (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 a slider disengaging from the auxiliary track
assembly, which could lead to separation of a portion of the thrust
reverser from the airplane during flight, possible impact of
separated portions on airplane structure, and consequent possible
rapid decompression of the airplane, reduced controllability of the
airplane, or reduced structural integrity of the fuselage,
accomplish the following:
Initial Inspection
(a) Prior to the accumulation of 3,000 total flight cycles, or
within 90 days after the effective date of this AD, whichever occurs
later, perform a detailed visual inspection of the upper and lower
auxiliary track assemblies on each thrust reverser half of each
engine to detect missing segments of the track lip; to detect signs
that the slider has disengaged from the track; to detect cracks,
gouges, and wear of the liner; and measure the auxiliary track beam
dimensions; in accordance with the Accomplishment Instructions of
Boeing Service Bulletin 747-78A2164, Revision 2, dated December 3,
1998 (for Model 747-400 series airplanes); or Boeing Service
Bulletin 767-78A0079, Revision 2, dated December 3, 1998 (for Model
767 series airplanes); as applicable.
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
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/Corrective Actions
(1) If no discrepancy is detected, repeat the detailed visual
inspection thereafter at intervals not to exceed 3,000 flight cycles
or 7,000 flight hours, whichever occurs earlier, until paragraph (b)
or (c), as applicable, has been accomplished.
(2) If the auxiliary track lip has a missing segment of 3 inches
or longer, or longitudinal cracks at the base of the lip, or other
indications that the slider has disengaged from the track in the
forward 4 inches, prior to further flight, repair in accordance with
Part A of the Accomplishment Instructions of the applicable service
bulletin. Repeat the detailed visual inspection thereafter at the
applicable intervals specified in Part A of the Accomplishment
Instructions of the applicable service bulletin, until paragraph (c)
of this AD has been accomplished.
(3) If the auxiliary track lip has a missing segment of 3 inches
or longer, or longitudinal cracks at the base of the lip, or other
indications that the slider has disengaged from the track AFT of the
forward four inches, accomplish paragraphs (a)(3)(i) or (a)(3)(ii)
of this AD.
(i) Prior to further flight, repair in accordance with Part B of
the Accomplishment Instructions of the applicable service bulletin.
Repeat the detailed visual inspection thereafter at the applicable
intervals specified in Part B of the Accomplishment Instructions of
the applicable service bulletin, until paragraph (c) of this AD has
been accomplished.
(ii) Accomplish both paragraphs (a)(3)(ii)(A) and (a)(3)(ii)(B)
of this AD:
(A) Prior to further flight, deactivate the associated thrust
reverser in accordance with Section 78-2 of Boeing Document
D6U10151, ``Boeing 747-400 Dispatch Deviations Guide,'' Revision 11,
dated March 31, 1998 (for Model 747-400 series airplanes); or
Section 78-2 of Boeing Document D630T002, ``Boeing 767 Dispatch
Deviations Guide,'' Revision 19, dated May 14, 1999 (for Model 767
series airplanes); as applicable. No more than one thrust reverser
on any airplane may be deactivated under the provisions of the
paragraph.
Note 3: The airplane may be operated for up to 30 days in
accordance with the provisions and limitations specified in the
operator's FAA-approved Master Minimum Equipment List, provided that
no more than one thrust reverser on the airplane is inoperative.
(B) Within 30 days after deactivation of any thrust reverser in
accordance with paragraph (a)(3)(ii)(A) of this AD, the thrust
reverser must be repaired in accordance with the Accomplishment
Instructions of the applicable service bulletin; once this is
accomplished, the thrust reverser may then be reactivated. Repeat
the detailed visual inspection thereafter at the applicable
intervals specified in the Accomplishment Instructions of the
applicable service bulletin, until paragraph (c) of this AD has been
accomplished.
Terminating Action
(b) For any auxiliary track assembly on which no discrepancy is
detected during any detailed visual inspection required by paragraph
(a) of this AD: Replace the liner and slider of the auxiliary track
assembly with a new, improved liner and slider, in accordance with
Part A of the Accomplishment Instructions of Boeing Service Bulletin
747-78A2164, Revision 2, dated December 3, 1998 (for Model 747-400
series airplanes); or Boeing Service Bulletin 767-78A0079, Revision
2, dated December 3, 1998 (for Model 767 series airplanes); as
applicable; at the later of the times specified in paragraphs (b)(1)
and (b)(2) of this AD. Such action constitutes terminating action
for the requirements of this AD for that assembly.
[[Page 37025]]
(1) Within 6,000 flight cycles, 14,000 flight hours, or 5 years
after the date of the first inspection, whichever occurs earliest;
or
(2) Within 4 years after the effective date of this AD.
(c) For any auxiliary track assembly on which any discrepancy is
detected during any detailed visual inspection required by paragraph
(a) of this AD: Repair the auxiliary track assembly (replace the
slider and liner and install a retainer bar), or replace with a new,
improved assembly (including a new liner and slider), as applicable,
in accordance with the Accomplishment Instructions of Boeing Service
Bulletin 747-78A2164, Revision 2, dated December 3, 1998 (for Model
747-400 series airplanes); or Boeing Service Bulletin 767-78A0079,
Revision 2, dated December 3, 1998 (for Model 767 series airplanes);
as applicable; at the later of the times specified in paragraphs
(c)(1) and (c)(2) of this AD. Such action constitutes terminating
action for the requirements of this AD for that assembly.
(1) Within 4,500 flight cycles, 10,000 flight hours, or 3 years
after the date of the first repair, whichever occurs earliest; or
(2) Within 2 years after the effective date of this AD.
Note 4: Inspections and repairs accomplished prior to the
effective date of this AD in accordance with Boeing Service Bulletin
747-78A2164, Revision 1, or Boeing Service Bulletin 767-78A0079,
Revision 1, both dated February 5, 1998; are considered acceptable
for compliance with the applicable actions specified in this AD.
Alternative Methods 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 5: 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) Except as provided by paragraph (a)(3)(ii)(A) of this AD,
the actions shall be done in accordance with Boeing Service Bulletin
747-78A2164, Revision 2, dated December 3, 1998; or Boeing Service
Bulletin 767-78A0079, Revision 2, dated December 3, 1998; 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.
(g) This amendment becomes effective on July 18, 2000.
Issued in Renton, Washington, on June 2, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 00-14436 Filed 6-12-00; 8:45 am]
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