[Federal Register Volume 65, Number 149 (Wednesday, August 2, 2000)]
[Rules and Regulations]
[Pages 47252-47255]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-18661]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-79-AD; Amendment 39-11833; AD 2000-15-04]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-200 and -300 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 747-200 and -300 series 
airplanes, that currently requires various inspections and functional 
tests to detect discrepancies of the thrust reverser control and 
indication system, and correction of any discrepancy found. This 
amendment requires installation of a terminating modification, and 
repetitive functional tests of that installation, and repair, if 
necessary. This amendment is prompted by the results of a safety review 
of the thrust reverser systems on Model 747 series airplanes. The 
actions specified by this AD are intended to ensure the integrity of 
the fail safe features of the thrust reverser system by preventing 
possible failure modes in the thrust reverser control system that can 
result in inadvertent deployment of a thrust reverser during flight.

DATES: Effective September 6, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 6, 2000.
    The incorporation by reference of Boeing Service Bulletin 747-
78A2166, Revision 1, dated October 9, 1997, as listed in the 
regulations, was approved previously by the Director of the Federal 
Register as of August 25, 1999 (64 FR 39003, July 21, 1999).
    The incorporation by reference of Boeing Alert Service Bulletin 
747-78A2130, dated May 26, 1994, as listed in the regulations, was 
approved previously by the Director of the Federal Register as of April 
13, 1995 (60 FR 13623, March 14, 1995).

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: Larry Reising, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-2683; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 99-15-08, 
amendment 39-11227 (64 FR 39003, July 21, 1999), which is applicable to 
certain Boeing Model 747-200 and -300 series airplanes, was published 
in the Federal Register on December 28, 1999 (64 FR 72575). The action 
proposed to continue to require various inspections and functional 
tests to detect discrepancies of the thrust reverser control and 
indication system and correction of any discrepancy found, and 
installation of a terminating modification, repetitive functional tests 
of that installation, and repair, if necessary.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comment received.

Request to Remove Running Torque Check From Functional Test 
Procedures

    One commenter, the airplane manufacturer, requests that the running 
torque check of the thrust reverser system be removed from the 
functional test procedures contained in Appendix 1 of the proposed 
rule. The commenter states no justification for its request.
    The FAA concurs with the commenter's request. The FAA finds that 
the running torque check of the

[[Page 47253]]

thrust reverser system is not directly related to the integrity of the 
cone brake or the actuation system lock. The running torque check is 
used to determine whether the thrust reverser is able to translate 
smoothly when commanded to deploy or stow. This check is described in 
Boeing 747 Airplane Maintenance Manual 78-31-00 ``Thrust Reverser 
System--Adjustment/Test'' and is performed when the angle gearbox and 
ballscrew actuator, the rotary flexible drive shaft, or the center 
drive unit is replaced. The FAA recognizes that it is appropriate to 
perform the running torque check when these components are replaced and 
finds that it is not necessary to perform this check as part of the 
functional test specified in Appendix 1. Therefore, the running torque 
check of the thrust reverser system has not been included in Appendix 1 
of this final rule.

Conclusion

    After careful review of the available data, including the comment 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the change previously 
described. This change will neither increase the economic burden on any 
operator nor increase the scope of the AD.

Cost Impact

    There are approximately 9 Model 747-200 and -300 series airplanes 
of the affected design in the worldwide fleet. The FAA estimates that 2 
airplanes of U.S. registry will be affected by this AD.
    The actions originally required by AD 95-06-01, and retained in 
this AD, take approximately 33 work hours per airplane to accomplish, 
at an average labor rate of $60 per work hour. Based on these figures, 
the cost impact of the currently required actions on U.S. operators is 
estimated to be $3,960, or $1,980 per airplane, per inspection/test 
cycle.
    The other actions (repeating the functional test of the cone brake 
required by AD 95-06-01 at reduced intervals) that are currently 
required by AD 99-15-08, and retained in this AD, do not add any 
additional economic burden on affected operators.
    The bracket installation required by this new AD takes 
approximately 64 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 operators. Based on these figures, the 
cost impact of the bracket installation required by this AD on U.S. 
operators is estimated to be $7,680, or $3,840 per airplane.
    The actuation system lock installation required by this new AD 
takes approximately 16 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 operators. Based on 
these figures, the cost impact of the lock installation required by 
this AD on U.S. operators is estimated to be $1,920, or $960 per 
airplane.
    The functional test required by this new AD takes approximately 2 
work hours per airplane to accomplish, at an average labor rate of $60 
per work hour. Based on these figures, the cost impact of the 
functional test required by this AD on U.S. operators is estimated to 
be $240, or $120 per airplane, per test cycle.
    The wiring modifications required by this new AD take approximately 
833 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 operators. Based on these figures, the cost impact of 
these modifications required by this AD on U.S. operators is estimated 
to be $99,960, or $49,980 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the requirements of this 
AD action, and that no operator would accomplish those actions in the 
future if this AD were not adopted.

Regulatory Impact

    The regulations adopted herein will not have 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 removing amendment 39-11227 (64 FR 
39003, July 21, 1999), and by adding a new airworthiness directive 
(AD), amendment 39-11833, to read as follows:

2000-15-04 Boeing: Amendment 39-11833. Docket 99-NM-79-AD. 
Supersedes AD 99-15-08, Amendment 39-11227.

    Applicability: Model 747-200 and -300 series airplanes equipped 
with General Electric Model CF6-80C2 series engines with Power 
Management Control engine controls, 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 (h)(1) 
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 ensure the integrity of the fail safe features of the thrust 
reverser system by preventing possible failure modes in the thrust 
reverser control system that can result in inadvertent deployment of 
a thrust reverser during flight, accomplish the following:

RESTATEMENT OF THE ORIGINAL REQUIREMENTS OF AD 95-06-01:

Repetitive Tests and Inspections

    (a) Within 90 days after April 13, 1995 (the effective date of 
AD 95-06-01, amendment 39-9171), perform tests of the position 
switch module and the cone brake of the center drive unit (CDU) on 
each thrust reverser, and perform an inspection to detect

[[Page 47254]]

damage to the bullnose seal on the translating sleeve on each thrust 
reverser, in accordance with paragraphs III.A. through III.C. of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
78A2130, dated May 26, 1994. Repeat the tests and inspection 
thereafter at intervals not to exceed 1,000 hours time-in-service 
until the functional test required by paragraph (d) of this AD is 
accomplished.
    (b) Within 9 months after April 13, 1995, perform inspections 
and functional tests of the thrust reverser control and indication 
system in accordance with paragraphs III.D. through III.F., III.H., 
and III.I. of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-78A2130, dated May 26, 1994. Repeat these 
inspections and functional tests thereafter at intervals not to 
exceed 18 months.

Corrective Action

    (c) If any of the inspections and/or functional tests required 
by paragraphs (a) and (b) of this AD cannot be successfully 
performed, or if any discrepancy is found during those inspections 
and/or functional tests, accomplish either paragraph (c)(1) or 
(c)(2) of this AD.
    (1) Prior to further flight, correct the discrepancy found, in 
accordance with Boeing Alert Service Bulletin 747-78A2130, dated May 
26, 1994. Or
    (2) The airplane may be operated in accordance with the 
provisions and limitations specified in an operator's FAA-approved 
Minimum Equipment List (MEL), provided that no more than one thrust 
reverser on the airplane is inoperative.

RESTATEMENT OF REQUIREMENTS OF AD 99-15-08:

Repetitive Tests/Terminating Action

    (d) Within 1,000 hours time-in-service after the most recent 
test of the CDU cone brake performed in accordance with paragraph 
(a) of this AD, or within 650 hours time-in-service after August 25, 
1999 (the effective date of AD 99-15-08, amendment 39-11227), 
whichever occurs first: Perform a functional test to detect 
discrepancies of the CDU cone brake on each thrust reverser, in 
accordance with Boeing Service Bulletin 747-78A2166, Revision 1, 
dated October 9, 1997, or paragraph III.B. of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-78A2130, dated May 
26, 1994. Repeat the functional test thereafter at the interval 
specified in paragraph (d)(1) or (d)(2) of this AD, as applicable. 
Accomplishment of such functional test constitutes terminating 
action for the repetitive test of the CDU cone brake required by 
paragraph (a) of this AD; the position switch module tests and the 
bullnose seal inspections continue to be required as specified in 
paragraph (a) of this AD.
    (1) For airplanes equipped with thrust reversers NOT modified in 
accordance with Boeing Service Bulletin 747-78-2144, Revision 1, 
dated April 11, 1996: Repeat the functional test at intervals not to 
exceed 650 hours time-in-service.
    (2) For airplanes equipped with thrust reversers modified in 
accordance with Boeing Service Bulletin 747-78-2144, Revision 1, 
dated April 11, 1996: Repeat the functional test at intervals not to 
exceed 1,000 hours time-in-service.

Corrective Action

    (e) If any functional test required by paragraph (d) of this AD 
cannot be successfully performed, or if any discrepancy is found 
during any functional test required by paragraph (d) of this AD, 
accomplish either paragraph (e)(1) or (e)(2) of this AD.
    (1) Prior to further flight, correct the discrepancy found, in 
accordance with Boeing Service Bulletin 747-78A2166, Revision 1, 
dated October 9, 1997, or paragraph III.B. of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 747-78A2130, dated May 
26, 1994. Or
    (2) The airplane may be operated in accordance with the 
provisions and limitations specified in the operator's FAA-approved 
MEL, provided that no more than one thrust reverser on the airplane 
is inoperative.

NEW REQUIREMENTS OF THIS AD:

Terminating Action

    (f) Accomplish the requirements of paragraphs (f)(1) and (f)(2) 
of this AD at the times specified in those paragraphs. 
Accomplishment of the actions required by paragraph (f)(1) of this 
AD constitutes terminating action for the requirements of paragraphs 
(a), (b), (d), and (e) of this AD.
    (1) Within 36 months after the effective date of this AD, 
accomplish the requirements of paragraphs (f)(1)(i) and (f)(1)(ii) 
of this AD.
    (i) Install an actuation system lock bracket and fastening 
hardware to each thrust reverser in accordance with the 
Accomplishment Instructions of Lockheed Martin Service Bulletin 78-
1007, Revision 1, dated March 18, 1997, or Middle River Aircraft 
Systems Service Bulletin 78-1007, Revision 2, dated March 10, 1998.
    (ii) Install an actuation system lock (also called an electro-
mechanical lock or electro-mechanical brake) on each thrust reverser 
in accordance with the Accomplishment Instructions of Lockheed 
Martin Service Bulletin 78-1020, Revision 2, dated March 20, 1997, 
or Middle River Aircraft Systems Service Bulletin 78-1020, Revision 
3, dated March 16, 1998.
    (2) Prior to or concurrent with the accomplishment of the 
requirements of paragraph (f)(1)(ii) of this AD, perform the thrust 
reverser wiring modifications of the wings, strut, and fuselage, in 
accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 747-78-2144, Revision 1, dated April 11, 1996.

Repetitive Tests

    (g) Within 1,000 hours time-in-service after accomplishment of 
paragraph (f) of this AD, or within 1,000 hours time-in-service 
after the effective date of this AD, whichever occurs later: Perform 
a functional test to detect discrepancies of the CDU cone brake and 
actuation system lock on each thrust reverser, in accordance with 
Appendix 1 of this AD. Prior to further flight, correct any 
discrepancy detected and repeat the functional test of that repair, 
in accordance with the procedures described in the Boeing 747 
Maintenance Manual. Repeat the functional tests thereafter at 
intervals not to exceed 1,000 hours time-in-service.

Alternative Methods of Compliance

    (h)(1) 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.
    (2) Alternative methods of compliance, approved previously in 
accordance with AD 99-15-08, amendment 39-11227, are approved as 
alternative methods of compliance with the corresponding 
requirements specified in this AD.

    Note 2: 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

    (i) 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

    (j) Except as provided by paragraphs (c)(2), (e)(2), and (g) of 
this AD, the actions shall be done in accordance with Boeing Alert 
Service Bulletin 747-78A2130, dated May 26, 1994; Boeing Service 
Bulletin 747-78A2166, Revision 1, dated October 9, 1997; Lockheed 
Martin Service Bulletin 78-1007, Revision 1, dated March 18, 1997; 
Middle River Aircraft Systems Service Bulletin 78-1007, Revision 2, 
dated March 10, 1998; Lockheed Martin Service Bulletin 78-1020, 
Revision 2, dated March 20, 1997; Middle River Aircraft Systems 
Service Bulletin 78-1020, Revision 3, dated March 16, 1998; or 
Boeing Service Bulletin 747-78-2144, Revision 1, dated April 11, 
1996; as applicable.
    (1) The incorporation by reference of Lockheed Martin Service 
Bulletin 78-1007, Revision 1, dated March 18, 1997; Middle River 
Aircraft Systems Service Bulletin 78-1007, Revision 2, dated March 
10, 1998; Lockheed Martin Service Bulletin 78-1020, Revision 2, 
dated March 20, 1997; Middle River Aircraft Systems Service Bulletin 
78-1020, Revision 3, dated March 16, 1998; and Boeing Service 
Bulletin 747-78-2144, Revision 1, dated April 11, 1996; is approved 
by the Director of the Federal Register in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51. Lockheed Martin Service Bulletin 78-1007, 
Revision 1, dated March 18, 1997, contains the following list of 
effective pages:

[[Page 47255]]



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                                                              Revision level
                          Page No.                            shown on page           Date shown on page
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1, 3, 4, 22-28.............................................               1   March 18, 1997.
2, 5-21....................................................        Original   August 30, 1997.
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Lockheed Martin Service Bulletin 78-1020, Revision 2, dated March 
20, 1997, contains the following list of effective pages:

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                                                              Revision level
                          Page No.                            shown on page           Date shown on page
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1-5, 8, 12, 13, 15, 19-21, 23-36...........................               2   March 20, 1997.
6, 7, 9-11, 14, 16-18, 22, 37..............................               1   January 17, 1996.
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    (2) The incorporation by reference of Boeing Service Bulletin 
747-78A2166, Revision 1, dated October 9, 1997, was approved 
previously by the Director of the Federal Register as of August 25, 
1999 (64 FR 39003, July 21, 1999).
    (3) The incorporation by reference of Boeing Alert Service 
Bulletin 747-78A2130, dated May 26, 1994, was approved previously by 
the Director of the Federal Register as of April 13, 1995 (60 FR 
13623, March 14, 1995).
    (4) 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.

Effective Date

    (k) This amendment becomes effective on September 6, 2000.

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
    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 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.
    (i) The electro-mechanical brake system is working correctly if 
the torque is reached before you turn the wrench 450 degrees (1\1/4\ 
turns).
    (ii) 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.
    (iii) If you do not get 90 pound-inches of torque, you must 
replace the electro-mechanical brake.
    (f) Release the torque by turning the wrench in the opposite 
direction until you read zero pound-inches.
    (i) 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.
    (2) 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 100 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 lease 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) Re-install the lockout plate.
    (2) Fully retract the thrust reverser (unless already 
accomplished).
    (3) Pull down on the manual release handle on the electro-
mechanical brake until the handle fully engages the retaining clip 
(unless already accomplished).

    Note: This will lock the electro-mechanical brake.

    (4) Close the fan cowl panels.

    Issued in Renton, Washington, on July 18, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-18661 Filed 8-1-00; 8:45 am]
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