[Federal Register Volume 60, Number 138 (Wednesday, July 19, 1995)]
[Rules and Regulations]
[Pages 36976-36981]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-15849]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-28-AD; Amendment 39-9292; AD 95-13-12]
Airworthiness Directives; Boeing Model 767 Series Airplanes
Equipped With General Electric CF6-80C2 Series Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to certain Boeing Model 767 series airplanes, that
currently requires tests, inspections, and adjustments of the thrust
reverser system. This amendment adds requirements for installation of a
terminating modification, and repetitive operational checks of the
electro-mechanical brake and the cone brake of the center drive unit
following accomplishment of the modification. This amendment also
removes airplanes equipped with Rolls-Royce RB211-524 series engines
from the applicability of the existing AD. This amendment is prompted
by the identification of a modification that ensures that the level of
safety inherent in the original type design of the thrust reverser
system is further enhanced. The actions specified by this AD are
intended to prevent possible discrepancies that exist in the current
thrust reverser control system, which could result in inadvertent
deployment of a thrust reverser during flight.
DATES: Effective August 18, 1995.
The incorporation by reference of certain publications, as listed
in the regulations, is approved by the Director of the Federal Register
as of August 18, 1995.
The incorporation by reference of Boeing Service Bulletin 767-78-
0047, dated August 22, 1991, as listed in the regulations, was approved
previously by the Director of the Federal Register as of October 15,
1991 (56 FR 51638, October 15, 1991).
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: Lanny Pinkstaff, Aerospace Engineer,
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate,
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton,
Washington 98055-4056; telephone (206) 227-2684; fax (206) 227-1181.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) by superseding AD 91-22-02,
amendment 39-8062 (56 FR 51638, October 15, 1991), which is applicable
to Boeing Model 767 series airplanes equipped with General Electric
CF6-80C2 series engines, was published in the Federal Register on
January 6, 1995 (60 FR 2036). The action proposed to require tests,
inspections, and adjustments of the thrust reverser system;
installation of a terminating modification; and repetitive operational
checks of the electro-mechanical brake and the cone brake of the center
drive unit following accomplishment of the modification. The action
also proposed to remove airplanes equipped with Rolls-Royce RB211-524
series engines from the applicability of the existing AD.
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.
One commenter requests that the proposed compliance time for
installation of the terminating modification be extended from 3 to 5
years to be consistent with similar rules that are applicable to Boeing
Model 767-200 and 757 series airplanes. The FAA does not concur with
the commenter's request to extend the compliance time. In developing an
appropriate compliance time for installation of the terminating
modification on the affected airplanes, the FAA considered operator
fleet sizes, as well as availability of parts. The commenter is one of
two U.S. operators of the affected airplanes. In its comments to the
proposed rule, this commenter indicates that the 3-year compliance time
presents no problem. The other U.S. operator of these airplanes
indicates that it has already modified its entire fleet. Further, the
manufacturer has advised that an ample number of required parts will be
available for modification of the U.S. fleet within the proposed
compliance period. Based on this information, the FAA finds that a
compliance time of 3 years would not impose any undue economic burden
on any operator. However, the FAA would consider a request for an
adjustment of the compliance time, in accordance with the provisions of
paragraph (f) of this AD, provided that adequate justification is
presented to support such a request.
One commenter requests that the work hour estimate specified in the
proposal for installation of the terminating modification be increased
from 786 to 880 work hours. Based on its experience, the commenter
states that 880 work hours represents the actual time required for
accomplishment of the terminating modification. The FAA does not concur
with the commenter's request to increase the work hour estimate. The
appropriate number of work hours necessary to accomplish the required
modification, specified as 786 in the economic impact information,
below, was provided to the FAA by the manufacturer based on the best
data available to date. That estimate represents the time for direct
labor only and is based on the assumption that the modification will be
performed by an experienced maintenance crew. However, in light of crew
experience, some variability in the estimated number of work hours is
likely to exist from operator to operator.
One commenter indicates that a re-identification table provided in
Revision 3 of General Electric Service Bulletin 78-135 contains
numerous part number errors that should be corrected before a final
rule is issued. (The General Electric service bulletin is referenced in
``NOTE 2'' of the proposal as an additional source of service
information for installation of the terminating modification.) The FAA
infers from the commenter's statement that it requests that issuance of
the final rule be delayed until General Electric releases a revised
service bulletin containing correct part numbers. The FAA does not
concur. The FAA has been unable to confirm the future date of issuance
of Revision 4 of the General Electric service bulletin. In
[[Page 36977]]
light of the degree of urgency associated with the unsafe condition
addressed by this AD, and since the General Electric service bulletin
is only a secondary reference, the FAA does not consider that delaying
this action until after the release of a revised service bulletin is
warranted. Further, paragraph (f) of the final rule provides affected
operators the opportunity to request an alternative method of
compliance or adjustment of the compliance time if data are presented
to justify such a request.
The FAA has been advised that the terminating modification required
by this AD has been accomplished on certain U.S.-registered airplanes.
The economic impact information, below, has been revised accordingly.
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 as proposed.
There are approximately 135 Boeing Model 767 series airplanes
equipped with General Electric CF6-80C2 series engines in the worldwide
fleet. The FAA estimates that 39 airplanes of U.S. registry will be
affected by this AD.
The tests, inspections, and adjustments that were required
previously by AD 91-22-02, and retained in this AD, take approximately
30 work hours per airplane to accomplish, at an average labor rate of
$60 per work hour. Based on these figures, the total cost impact on
U.S. operators of the currently required tests, inspections, and
adjustments that are retained in this AD is estimated to be $70,200, or
$1,800 per airplane, per inspection cycle.
The terminating modification required by this AD will take
approximately 786 work hours per airplane to accomplish, at an average
labor rate of $60 per work hour. Required parts will be provided by the
manufacturer at no cost to the operator. The repetitive operational
checks required by this AD will take approximately 2 work hours per
airplane to accomplish, at an average labor rate of $60 per work hour.
Based on these figures, the total cost impact on U.S. operators of the
terminating modification and repetitive operational checks required by
this AD is estimated to be $1,843,920, or $47,280 per airplane.
The FAA has been advised that the terminating modification has been
accomplished in accordance with the requirements of this AD on 11 U.S.-
registered airplanes. Therefore, the future economic cost impact of
this rule on U.S. operators is now only $1,325,160.
The number of required work hours for each requirement of this AD,
as indicated above, is presented as if the accomplishment of the
actions were to be conducted as ``stand alone'' actions. However, in
actual practice, these actions for the most part will be accomplished
coincidentally or in combination with normally scheduled airplane
inspections and other maintenance program tasks. Therefore, the actual
number of necessary additional work hours will be minimal in many
instances. Additionally, any costs associated with special airplane
scheduling will be minimal.
The FAA recognizes that the required modification would necessitate
a large number of work hours to accomplish. However, the 3-year
compliance time specified in paragraph (c) of this AD should allow
ample time for terminating modification to be accomplished
coincidentally with scheduled major airplane inspection and maintenance
activities, thereby minimizing the costs associated with special
airplane scheduling. 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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-8062 (56 FR
51638, October 15, 1991), and by adding a new airworthiness directive
(AD), amendment 39-9292, to read as follows:
95-13-12 Boeing: Amendment 39-9292. Docket 94-NM-28-AD. Supersedes
AD 91-22-02, Amendment 39-8062.
Applicability: Model 767 series airplanes equipped with General
Electric CF6-80C2 series engines, 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 use the authority
provided in paragraph (f) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously. -
To ensure the integrity of the fail-safe features of the thrust
reverser system, accomplish the following:
(a) Within 30 days after October 15, 1991 (the effective date of
AD 91-22-02, amendment 39-8062), perform tests, inspections, and
adjustments of the thrust reverser system in accordance with Boeing
Service Bulletin 767-78-0047, dated August 22, 1991; Revision 1,
dated March 26, 1992; Revision 2, dated January 21, 1993; or
Revision 3, dated July 28, 1994. After the effective date of this
AD, those actions shall be accomplished only in accordance with
Revision 3 of the service bulletin.
(1) Except as provided by paragraph (a)(2) of this AD, repeat
all tests and inspections thereafter at intervals not to exceed
3,000 flight hours until the modification required by paragraph (c)
of this AD is accomplished.
(2) Repeat the check of the grounding wire for the Directional
Pilot Valve (DPV) of the thrust reverser in accordance with the
service bulletin at intervals not to exceed 1,500 flight hours, and
whenever maintenance action is taken that would disturb the DPV
grounding
[[Page 36978]]
circuit, until the modification required by paragraph (c) of this AD is
accomplished.
(b) If any of the tests and/or inspections required by paragraph
(a) of this AD cannot be successfully performed, or if those tests
and/or inspections result in findings that are unacceptable in
accordance with Boeing Service Bulletin 767-78-0047, dated August
22, 1991; Revision 1, dated March 26, 1992; Revision 2, dated
January 21, 1993; or Revision 3, dated July 28, 1994; accomplish
paragraphs (b)(1) and (b)(2) of this AD. After the effective date of
this AD, the actions required by paragraphs (b)(1) and (b)(2) shall
be accomplished only in accordance with Revision 3 of the service
bulletin.
(1) Prior to further flight, deactivate the associated thrust
reverser in accordance with Section 78-31-1 of Boeing Document
D630T002, ``Boeing 767 Dispatch Deviation Guide,'' Revision 9, dated
May 1, 1991; or Revision 10, dated September 1, 1992. After the
effective date of this AD, this action shall be accomplished only in
accordance with Revision 10 of the Boeing document. No more than one
reverser on any airplane may be deactivated under the provisions of
this paragraph.
(2) Within 10 days after deactivation of any thrust reverser in
accordance with this paragraph, the thrust reverser must be repaired
in accordance with Boeing Service Bulletin 767-78-0047, dated August
22, 1991; Revision 1, dated March 26, 1992; Revision 2, dated
January 21, 1993; or Revision 3, dated July 28, 1994. After the
effective date of this AD, the repair shall be accomplished only in
accordance with Revision 3 of the service bulletin. Additionally,
the tests and/or inspections required by paragraph (a) of this AD
must be successfully accomplished; once this is accomplished, the
thrust reverser must then be reactivated.
(c) Within 3 years after the effective date of this AD, install
a third locking system on the left- and right-hand engine thrust
reversers in accordance with Boeing Service Bulletin 767-78-0063,
Revision 2, dated April 28, 1994.
Note 2: The Boeing service bulletin references General Electric
Service Bulletin 78-135 as an additional source of service
information for accomplishment of the third locking system on the
thrust reversers. However, the Boeing service bulletin does not
specify the appropriate revision level for the General Electric
service bulletin. The appropriate revision level for the General
Electric service bulletin to be used in conjunction with the Boeing
service bulletin is Revision 3, dated August 2, 1994.
(d) Within 4,000 flight hours after accomplishing the
modification required by paragraph (c) of this AD, or within 4,000
flight hours after the effective date of this AD, whichever occurs
later; and thereafter at intervals not to exceed 4,000 flight hours;
perform operational checks of the electro-mechanical brake and the
cone brake of the center drive unit in accordance with Appendix 1
(including Figure 1) of this AD.
(e) Accomplishment of the modification and periodic operational
checks required by paragraphs (c) and (d) of this AD constitutes
terminating action for the tests, inspections, and adjustments
required by paragraph (a) of this AD.
(f) 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.
(g) 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.
(h) Certain actions shall be done in accordance with the
following Boeing service bulletins, which contain the specified
effective pages:
----------------------------------------------------------------------------------------------------------------
Revision level
Service bulletin referenced and date- Page No. shown on page- Date shown on page
----------------------------------------------------------------------------------------------------------------
767-78-0047, Revision 1, March 26, 1-33-............................ 1-............. March 26, 1992.
1992.
767-78-0047, Revision 2, January 21, 1-2, 4, 12-13, 20-32............. 2.............. January 21, 1993.
1993 -.
3, 5, 10-11, 14-15, 17-19 -...... 1-............. March 26, 1992.
6-9, 16-......................... Original-...... August 22, 1991.
767-78-0047, Revision 3, July 28, 1-32-............................ 3-............. July 28, 1994.
1994..
767-78-0063, Revision 2, April 28, 1-292-........................... 2-............. April 28, 1994.
1994..
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This incorporation by reference of these documents was approved by
the Director of the Federal Register in accordance with 5 U.S.C. 552(a)
and 1 CFR part 51. Certain other actions shall be done in accordance
with Boeing Service Bulletin 767-78-0047, dated August 22, 1991. The
incorporation by reference of this document was approved previously by
the Director of the Federal Register in accordance with 5 U.S.C. 552(a)
and 1 CFR part 51 as of October 15, 1991 (56 FR 51638, October 15,
1991). 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.
(i) This amendment becomes effective on August 18, 1995.
Appendix 1
Thrust Reverser Electro-Mechanical Brake and CDU Cone Brake Test
1. General
A. This procedure contains steps to do two checks:
(1) A check of the holding torque of the electro-mechanical
brake
(2) A check of the holding torque of the CDU cone brake.
2. Electro-Mechanical Brake and CDU Cone Brake Torque Check (Fig.
1)
A. Prepare to do the checks:
(1) Open the fan cowl panels.
B. Do a check of the torque of the electro-mechanical brake:
(1) Do a check of the running torque of the thrust reverser
system:
(a) Manually extend the thrust reverser six inches and measure
the running torque.
(1) Make sure the torque is less than 10 pound-inches.
(2) Do a check of the electro-mechanical brake holding torque:
(a) Make sure the thrust reverser translating cowl is extended
at least one inch.
(b) Make sure the CDU lock handle is released.
(c) Pull down on the manual release handle on the electro-
mechanical brake until the handle fully engages the retaining clip.
Note: This will lock the electro-mechanical brake.
(d) With the manual drive lockout cover removed from the CDU,
install a \1/4\-inch extension tool and dial-type torque wrench into
the drive pad.
Note: You will need a 24-inch extension to provide adequate
clearance for the torque wrench.
(e) Apply 90 pound-inches of torque to the system.
(1) The electro-mechanical brake system is working correctly if
the torque is reached before you turn the wrench 450 degrees (1-\1/
4\ turns).
(2) If the flexshaft turns more than 450 degrees before you
reach the specified torque, you must replace the long flexshaft
between the CDU and the upper angle gearbox.
(3) If you do not get 90 pound-inches of torque, you must
replace the electro-mechanical brake.
[[Page 36979]]
(f) Release the torque by turning the wrench in the opposite
direction until you read zero pound-inches.
(1) If the wrench does not return to within 30 degrees of
initial starting point, you must replace the long flexshaft between
the CDU and upper angle gearbox.
(3) Fully retract the thrust reverser.
C. Do a check of the torque of the CDU cone brake:
(1) Pull up on the manual release handle to unlock the electro-
mechanical brake.
(2) Pull the manual brake release lever on the CDU to release
the cone brake.
Note: This will release the pre-load tension that may occur
during a stow cycle.
(3) Return the manual brake release lever to the locked position
to engage the cone brake.
(4) Remove the two bolts that hold the lockout plate to the CDU
and remove the lockout plate.
(5) Install a \1/4\-inch drive and a dial-type torque wrench
into the CDU drive pad.
Caution: DO NOT USE MORE THAN 130 POUND-INCHES OF TORQUE WHEN
YOU DO THIS CHECK. EXCESSIVE TORQUE WILL DAMAGE THE CDU.
(6) Turn the torque wrench to try to manually extend the
translating cowl until you get at least 15 pound-inches.
Note: The cone brake prevents movement in the extend direction
only. If you try to measure the holding torque in the retract
direction, you will get a false reading.
(a) If the torque is less than 15 pound-inches, you must replace
the CDU.
D. Return the airplane to its usual condition:
(1) Fully retract the thrust reverser.
(2) Pull down on the manual release handle on the electro-
mechanical brake until the handle fully engages the retaining clip.
Note: This will lock the electro-mechanical brake.
(3) Close the fan cowl panels.
BILLING CODE 4910-13-U
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[GRAPHIC][TIFF OMITTED]TR19JY95.000
BILLING CODE 4910-13-C
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Issued in Renton, Washington, on June 22, 1995.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-15849 Filed 7-18-95; 8:45 am]
BILLING CODE 4910-13-U
