[Federal Register Volume 64, Number 168 (Tuesday, August 31, 1999)]
[Rules and Regulations]
[Pages 47365-47368]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-22193]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-77-AD; Amendment 39-11269; AD 99-18-03]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 747 series airplanes. This action 
requires repetitive inspections and tests of the thrust reverser 
control and indication system on each engine, and corrective actions, 
if necessary; installation of a terminating modification; and 
repetitive operational checks of that installation, and repair, if 
necessary. This amendment is prompted by the results of a safety 
review, which revealed that in-flight deployment of a thrust reverser 
could result in significant reduction in airplane controllability. The 
actions specified in this AD are intended to ensure the integrity of 
the fail-safe features of the thrust reverser system by preventing 
possible failure modes, which could result in inadvertent deployment of 
a thrust reverser during flight, and consequent reduced controllability 
of the airplane.

DATES: Effective September 15, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of September 15, 1999.
    Comments for inclusion in the Rules Docket must be received on or 
before November 1, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-77-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056.
    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 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.

FOR FURTHER INFORMATION CONTACT: Ed Hormel, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (206) 227-2681; fax (206) 227-1181.

SUPPLEMENTARY INFORMATION: On May 26, 1991, a Boeing Model 767-300ER 
series airplane was involved in an accident as a result of an 
uncommanded in-flight deployment of a thrust reverser. Following that 
accident, a study was conducted to evaluate the potential effects of an 
uncommanded thrust reverser deployment throughout the flight regime of 
the Boeing Model 747 series airplane. The study included a re-
evaluation of the thrust reverser control system fault analysis and 
airplane controllability. The results of the evaluation indicated that, 
in the event of thrust reverser deployment during high-speed climb 
using high engine power, these airplanes also could experience control 
problems. This condition, if not corrected, could result in possible 
failure modes in the thrust reverser control system, inadvertent 
deployment of a thrust reverser during flight, and consequent reduced 
controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-78A2148, dated June 1, 1995, and Boeing Service Bulletin 747-
78A2148, Revision 1, dated July 20, 1995, which describe procedures for 
certain repetitive inspections and tests of the thrust reverser system, 
and corrective actions, if necessary. The inspections and tests include 
inspection of the thrust reverser control microswitch; a test of the 
thrust reverser indication system; an integrity check of the number 
three gear box lock and air motor brake; an inspection of the thrust 
reverser wire bundle; and an operational test of the thrust reverser. 
The corrective actions include, among other things:
     Adjustment, or replacement and adjustment, of any 
microswitch which fails to perform its intended function during 
movement of the respective forward or reverse thrust lever.
     Replacement of the number 3 gearbox lock or deactivation 
of the thrust reverser on any engine if the thrust reverser translating 
cowl moves when the number 3 gearbox lock should be engaged.
     Replacement of the air motor on any engine if the thrust 
reverser translating cowl moves when the air motor brake should be 
engaged.
     Replacement of worn or damaged wire clamps and wiring if 
chafing or other damage is detected.
    The FAA also has reviewed and approved Boeing Service Bulletin 747-
78-2136, dated May 11, 1995, which describes procedures for 
installation of provisional wiring:
     Between the P8 panel aisle stand and relay panels P252 and 
P253;
     Between the P6 overhead panel and relay panels P252 and 
P253;
     Between relay panels P252 and P253;
     Between relay panels P252 and P253 and wing/body 
disconnect area;
     Between left wing/body disconnect area and strut No. 1 and 
2; and
     Between right wing/body disconnect area and strut No. 3 
and 4.
    This service bulletin references the Boeing Standard Wiring 
Practices Manual, which describes wire installation procedures, and the 
Boeing 747 Airplane Maintenance Manual (AMM) as additional sources of 
service information for accomplishment of this modification.
    In addition, the FAA has reviewed and approved Boeing Service 
Bulletin 747-78-2156, dated October 31, 1996, which describes 
procedures for installation of the following:
     Four additional microswitches and associated wiring in the 
aisle stand P8 panel;
     Four circuit breakers and associated wiring changes in the 
P6 panel;
     New relay panels P252 and P253; and
     Left and right wing/body disconnect panel and associated 
wiring.
    Boeing Service Bulletin 747-78-2156 references Boeing Service 
Bulletin 747-78-2136; and the following Rolls-Royce Service Bulletins:
     RB.211-71-B545, Revision 2, dated August 8, 1997, and 
RB.211-71-B551, Revision 1, dated March 20, 1998, which describe 
procedures for the installation of provisions on the engines to 
accommodate the installation of an additional thrust reverser locking 
gearbox; and
     RB.211-78-B552, dated June 21, 1996, which describes 
procedures for installation of an additional thrust reverser locking 
gearbox.
    Accomplishment of Boeing Service Bulletin 747-78-2156 requires 
prior or

[[Page 47366]]

concurrent accomplishment of Boeing Service Bulletin 747-78-2136; and 
Rolls-Royce Service Bulletins RB.211-71-B545, Revision 2; RB.211-71-
B551, Revision 1; and RB.211-78-B552, and eliminates the need for the 
repetitive inspections and tests specified in Boeing Alert Service 
Bulletin 747-78A2148, and Boeing Service Bulletin 747-78A2148, Revision 
1.

Explanation of Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design, this AD is 
being issued to prevent possible failure modes that can result in 
inadvertent deployment of a thrust reverser during flight and 
consequent reduced controllability of the airplane. This AD requires 
repetitive inspections and tests of the thrust reverser system, and 
corrective actions, if necessary; installation of a terminating 
modification; and repetitive operational checks of the gearbox locks 
and the air motor brake following accomplishment of the installation, 
and repair, if necessary. The actions are required to be accomplished 
in accordance with the service bulletins described previously, except 
as discussed below.
    This AD also includes a provision for deactivation of one thrust 
reverser in accordance with Section 78-1 of Boeing Document D6-33391, 
``Boeing 747-100/-200/-300/SP Dispatch Deviations Procedures Guide,'' 
Revision 22, dated January 30, 1998. No more than one reverser on any 
airplane may be deactivated under the provisions of this document.
    This AD also requires repetitive operational checks of the gearbox 
locks and the air motor brake following accomplishment of Boeing 
Service Bulletin 747-78-2156. Those checks are required to be performed 
in accordance with the procedures described in Chapter 78-30-00, 
Section 5, of the FAA-approved Boeing 747 Airplane Maintenance Manual 
(AMM).

Differences Between Service Bulletins and This AD

    Operators should note that, although Boeing Alert Service Bulletin 
747-78A2148 and Boeing Service Bulletin 747-78A2148, Revision 1, 
recommend accomplishing the initial inspection at the next convenient 
maintenance period, the FAA has determined that such a compliance time 
would not address the identified unsafe condition in a timely manner. 
In developing an appropriate compliance time for this AD, the FAA 
considered not only the manufacturer's recommendation, but the degree 
of urgency associated with addressing the subject unsafe condition, the 
average utilization of the affected fleet, and the time necessary to 
perform the inspections (6 hours per engine). In light of all of these 
factors, the FAA finds a 90-day compliance time for the initial 
inspection to be warranted, in that it represents an appropriate 
interval of time allowable for affected airplanes to continue to 
operate without compromising safety.
    Operators also should note that, although Boeing Service Bulletin 
747-78-2156 does not specify any compliance time for accomplishment of 
the modification, the FAA has determined that this does not address the 
identified unsafe condition in a timely manner, as described above. The 
FAA finds a 36-month compliance time for accomplishment of the 
modification is warranted, in that it represents an appropriate 
interval of time allowable for affected airplanes to continue to 
operate without compromising safety.

Cost Impact

    None of the Model 747 series airplanes affected by this action are 
on the U.S. Register. All airplanes included in the applicability of 
this rule currently are operated by non-U.S. operators under foreign 
registry; therefore, they are not directly affected by this AD action. 
However, the FAA considers that this rule is necessary to ensure that 
the unsafe condition is addressed in the event that any of these 
subject airplanes are imported and placed on the U.S. Register in the 
future.
    Should an affected airplane be imported and placed on the U.S. 
Register in the future:
    It would require approximately 24 work hours (6 work hours per 
engine) to accomplish the required inspections and tests, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of the inspections and tests required by this AD would be 
approximately $1,440 per airplane, per inspection/test cycle.
    It would require approximately 392 work hours to accomplish the 
required installation of provisional wiring, at an average labor rate 
of $60 per work hour. Required parts would cost approximately $22,298 
per airplane. Based on these figures, the cost impact of this 
modification required by this AD would be approximately $45,818 per 
airplane.
    It would require approximately 306 work hours to accomplish the 
required installation of the locking gearbox, at an average labor rate 
of $60 per work hour. Required parts would be provided by the 
manufacturer at no cost to the operators. Based on these figures, the 
cost impact of the installation required by this AD would be 
approximately $18,360 per airplane.
    It would require approximately 2 work hours to accomplish the 
required operational check, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of the operational check 
required by this AD would be approximately $120 per airplane, per 
check.

Determination of Rule's Effective Date

    Since this AD action does not affect any airplane that is currently 
on the U.S. register, it has no adverse economic impact and imposes no 
additional burden on any person. Therefore, prior notice and public 
procedures hereon are unnecessary and the amendment may be made 
effective in less than 30 days after publication in the Federal 
Register.

Comments Invited

    Although this action is in the form of a final rule and was not 
preceded by notice and opportunity for public comment, comments are 
invited on this rule. Interested persons are invited to comment on this 
rule by submitting such written data, views, or arguments as they may 
desire. Communications shall identify the Rules Docket number and be 
submitted in triplicate to the address specified under the caption 
ADDRESSES. All communications received on or before the closing date 
for comments will be considered, and this rule may be amended in light 
of the comments received. Factual information that supports the 
commenter's ideas and suggestions is extremely helpful in evaluating 
the effectiveness of the AD action and determining whether additional 
rulemaking action would be needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-77-AD.'' The postcard will be date stamped and 
returned to the commenter.

[[Page 47367]]

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:

99-18-03 Boeing: Amendment 39-11269. Docket 99-NM-77-AD.

    Applicability: Model 747-100B, -200, -300, and SP series 
airplanes, equipped with Rolls Royce RB211-524B2, C2, and D4 
engines; certificated in any category, as listed in the following 
service bulletins:
     Boeing Alert Service Bulletin 747-78A2148, dated June 
1, 1995;
     Boeing Service Bulletin 747-78A2148, Revision 1, dated 
July 20, 1995;
     Boeing Service Bulletin 747-78-2136, dated May 11, 
1995; and
     Boeing Service Bulletin 747-78-2156, dated October 31, 
1996.

    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 (f) 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 inadvertent deployment of a thrust reverser during 
flight and consequent reduced controllability of the airplane, 
accomplish the following:

Repetitive Inspections and Tests

    (a) Within 90 days after the effective date of this AD: Perform 
the applicable inspections and tests of the thrust reverser control 
and indication system on each engine, in accordance with Part III.A. 
through III.G. of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 747-78A2148, dated June 1, 1995, or Boeing Service 
Bulletin 747-78A2148, Revision 1, dated July 20, 1995. Repeat the 
applicable inspections and tests thereafter at intervals not to 
exceed 18 months, until accomplishment of paragraph (c) of this AD.

Corrective Actions

    (b) If any inspection or test required by paragraph (a) of this 
AD cannot be successfully performed as specified in the service 
bulletin, or if any discrepancy is detected during any inspection or 
test, accomplish paragraphs (b)(1) and (b)(2) of this AD.
    (1) Prior to further flight, deactivate the associated thrust 
reverser in accordance with Section 78-1 of Boeing Document D6-
33391, ``Boeing 747-100/-200/-300/SP Dispatch Deviations Procedures 
Guide,'' Revision 22, dated January 30, 1998. No more than one 
reverser on any airplane may be deactivated under the provisions of 
this paragraph.

    Note 2: The airplane may be operated in accordance with the 
provisions and limitations specified in the operator's FAA-approved 
Master Minimum Equipment List (MMEL), provided that no more than one 
thrust reverser on the airplane is inoperative.

    (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 Alert Service Bulletin 747-78A2148, dated 
June 1, 1995, or Boeing Service Bulletin 767-78A2148, Revision 1, 
dated July 20, 1995. Additionally, the inspections and tests 
required by paragraph (a) of this AD must be successfully 
accomplished as specified in the service bulletin; once this is 
accomplished, the thrust reverser must then be reactivated.

Modification

    (c) Within 36 months after the effective date of this AD, 
install an additional locking system on the thrust reversers in 
accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 747-78-2156, dated October 31, 1996. Prior to or concurrent 
with accomplishment of Boeing Service Bulletin 747-78-2156, dated 
October 31, 1996: Accomplish Boeing Service Bulletin 747-78-2136, 
dated May 11, 1995; and Rolls-Royce Service Bulletins RB.211-71-
B545, Revision 2, dated August 8, 1997, RB.211-71-B551, Revision 1, 
dated March 20, 1998, and RB.211-78-B552, dated June 21, 1996. 
Accomplishment of these actions constitutes terminating action for 
the repetitive inspections and tests required by paragraph (a) of 
this AD.

Operational Checks

    (d) Within 3,000 flight hours after accomplishing the 
modification required by paragraph (c) of this AD, or within 1,000 
flight hours after the effective date of this AD, whichever occurs 
later: Perform operational checks of the number 2 and number 3 
gearbox locks and of the air motor brake, in accordance with the 
procedures described in Chapter 78-30-00, Section 5, of the FAA-
approved Boeing 747 Airplane Maintenance Manual (AMM).

Corrective Actions

    (e) If any operational check required by paragraph (d) of this 
AD cannot be successfully performed as specified in the procedures 
described in Chapter 78-30-00, Section 5, of the AMM, or if any 
discrepancy is detected during any operational check, accomplish 
paragraphs (e)(1) and (e)(2) of this AD. Repeat the operational 
checks thereafter at intervals not to exceed 3,000 flight hours.
    (1) Prior to further flight, deactivate the associated thrust 
reverser in accordance with Section 78-1 of Boeing Document D6-
33391, ``Boeing 747-100/-200/-300/SP Dispatch Deviations Procedures 
Guide,'' Revision 22, dated January 30, 1998. No more than one 
reverser on any airplane may be deactivated under the provisions of 
this paragraph.

    Note 3: The airplane may be operated in accordance with the 
provisions and limitations specified in the operator's FAA-approved 
MMEL, provided that no more than one thrust reverser on the airplane 
is inoperative.

    (2) Within 10 days after deactivation of any thrust reverser in 
accordance with this paragraph, the thrust reverser must be repaired 
in accordance the AMM. Additionally, the operational checks required 
by paragraph (d) of this AD must be successfully accomplished as 
specified in the AMM; once this is accomplished, the thrust reverser 
must then be reactivated.

Alternative Methods of Compliance

    (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.


[[Page 47368]]


    Note 4: 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

    (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.

Incorporation by Reference

    (h) Except as provided by paragraphs (b)(1), (d), (e), (e)(1), 
and (e)(2) of this AD, the actions shall be done in accordance with 
the applicable service bulletins, which contain the specified list 
of effective pages:

----------------------------------------------------------------------------------------------------------------
  Service bulletin referenced                                 Revision level shown
           and date                Page No. shown on page            on page              Date shown on page
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Boeing 747-78-2136, May 11,     1-161......................  Original..............  May 11, 1995.
 1995.
Boeing 747-78A2148, June 1,     1-50.......................  Original..............  June 1, 1995.
 1995.
Boeing 747-78A2148, Revision    1-50.......................  1.....................  July 20, 1995.
 1, July 20, 1995.
Boeing 747-78-2156, October     1-283......................  Original..............  October 31, 1996.
 31, 1996.
Rolls-Royce, RB.211-78-B552     1-33.......................  Original..............  June 21, 1996.
 June 21, 1996.
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                                                   Supplement
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                                1, 2.......................  Original..............  June 21, 1996.
Rolls-Royce, RB.211-71-B545,    1, 4.......................  2.....................  August 8, 1997.
 Revision 2, August 8, 1997.
                                2, 3, 5-45.................  Original..............  December 22, 1995.
----------------------------------------------------------------------------------------------------------------
                                                   Supplement
----------------------------------------------------------------------------------------------------------------
                                1, 2.......................  2.....................  August 8, 1997.
Rolls-Royce, RB.211-71-B551,    1, 5, 85...................  1.....................  March 20, 1998.
 Revision 1, March 20, 1998.
                                2-4, 6-84, 86-106..........  Original..............  June 21, 1996.
                                                   Supplement
----------------------------------------------------------------------------------------------------------------
                                1-5........................  1.....................  March 20, 1998.
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    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.
    (i) This amendment becomes effective on September 15, 1999.

    Issued in Renton, Washington, on August 19, 1999.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-22193 Filed 8-30-99; 8:45 am]
BILLING CODE 4910-13-U