[Federal Register Volume 64, Number 31 (Wednesday, February 17, 1999)]
[Proposed Rules]
[Pages 7822-7827]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-3736]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-323-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757-200, -200PF, and -
200CB Series Airplanes Powered by Rolls-Royce RB211-535C/E4/E4B 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 757-200, -
200PF, and -200CB series airplanes. This proposal would require 
modification of the engine thrust control cable installation, and 
repetitive inspections to detect certain discrepancies of the cables, 
pulleys, pulley brackets, and cable travel; and repair, if necessary. 
This proposal is prompted by reports of failure of certain engine 
thrust control cables. The actions specified by the proposed AD are 
intended to prevent such failures, which could result in a severe 
asymmetric thrust condition during landing, and consequent reduced 
controllability of the airplane.

DATES: Comments must be received by April 5, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-323-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule 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.

FOR FURTHER INFORMATION CONTACT: Kathrine Rask, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-1547; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 98-NM-323-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 98-NM-323-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    In 1985, the FAA received a report indicating that a Boeing Model 
747-100 series airplane had experienced a thrust control `B' cable 
failure following application of reverse thrust during landing. This 
failure caused engine number 1 to advance to full forward thrust with 
engine numbers 2, 3, and 4 in full reverse thrust. The airplane exited 
the runway and eventually slid to a stop with consequent hull damage.
    In April 1997, during a review of the certification plan for Boeing 
Model 757-300 series airplanes, Boeing informed the FAA that the thrust 
control cable installation on Boeing Model 757-200, -200PF, and -200CB 
series airplanes, equipped with Rolls Royce engines, is similar to the 
thrust control cable installation on the Boeing Model 747-100 series 
airplane, and that a similar failure could result in subsequent runway 
departure. Such a failure mode was examined during the type 
certification of the Boeing Model 757-200 series airplane and, at that 
time, the consensus was that the airplane would be controllable 
following a thrust control `B' cable failure. The 1985 report and 
subsequent testing of a Model 757-200 series airplane contradicted this 
assumption.
    The FAA recently has received a report of uncommanded advancement 
of the right thrust lever on a Boeing Model 757-200 series airplane 
during flight. Subsequently, the engine power began steadily 
increasing. In order to reduce the engine power, the flight crew set 
the lever to the idle stop position; however, the engine power 
continued to increase. The flight crew then used the cut-off lever to 
stop the engine as it approached the maximum speed. After the airplane 
landed, a close visual inspection revealed that the thrust control 
cable had broken due to continuous chafing against the adjacent wire 
bundle that supplies power to the right window heater. Such failure of 
a thrust control cable could result in a severe asymmetric thrust 
condition during landing, and consequent reduced controllability of the 
airplane.

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Explanation of Relevant Service Information

    The FAA has reviewed and approved the following service bulletins:
     Boeing Service Bulletin 757-76-1, dated May 18, 1984, 
which describes procedures for removal of the guide bracket of the 
engine thrust control cable that is located on the front spar of the 
right wing.
     Boeing Service Bulletin 757-76-0005, dated May 5, 1988, 
which describes procedures for replacement of sections of the engine 
thrust control cables with smaller diameter cables, and removal of the 
engine cable breakaway stop assemblies.
     Boeing Alert Service Bulletin 757-30A0018, Revision 1, 
dated September 17, 1998, which describes procedures for installation 
of a support bracket assembly between the window heat wire bundle and 
the engine thrust control cable, and adjustment of the wire bundle, if 
necessary, to maintain necessary clearance.
    Accomplishment of the actions specified in the service bulletins 
described previously, and the repetitive inspection mandated by this 
AD, is intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require modification of the engine thrust control 
cable installation and repetitive inspections to detect certain 
discrepancies of the cables, pulleys, pulley brackets, and cable 
travel; and repair, if necessary. The actions would be required to be 
accomplished in accordance with the procedure included in paragraph (a) 
of this AD, the service bulletins described previously, and the 
airplane maintenance manual.

Justification of Compliance Time

    This proposed AD includes a procedure to inspect the engine thrust 
control cables, pulleys, pulley brackets, and cable travel, which is 
similar to the inspection for control cables contained in Chapter 20-
20-02 of the 757 Maintenance Manual. Although the Boeing Maintenance 
Planning Document (MPD) recommends that an inspection of the engine 
thrust control cables be conducted in accordance with Chapter 20-20-02 
at every ``2C'' check, this proposed AD requires repetitive inspections 
at intervals of 18 months or 6,000 flight hours (whichever occurs 
first), which corresponds with a ``C'' check interval. The FAA has no 
evidence that indicates that the Model 757 series airplane that 
experienced the thrust control cable failure was not adhering to those 
recommendations; therefore, the FAA has determined that the repetitive 
inspections of the thrust control cables, pulleys, pulley brackets, and 
cable travel must be done on a more frequent basis than that specified 
in the MPD.

Cost Impact

    There are approximately 450 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 228 airplanes of U.S. registry 
would be affected by this proposed AD.
    It would take approximately 3 work hours per airplane to accomplish 
the proposed inspection, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the inspection proposed by 
this AD on U.S. operators is estimated to be $41,040, or $180 per 
airplane, per inspection cycle.
    For airplanes identified in Boeing Service Bulletin 757-76-1 (8 
U.S.-registered airplanes), it would take approximately 2 work hours 
per airplane to accomplish the proposed guide bracket removal, at an 
average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators is estimated to be 
$960, or $120 per airplane.
    For airplanes identified in Boeing Service Bulletin 757-76-0005 (14 
U.S.-registered airplanes), it would take approximately 14 work hours 
per airplane to accomplish the proposed replacement, 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 proposed AD on U.S. operators is estimated to be 
$11,760, or $840 per airplane.
    For airplanes identified in Boeing Alert Service Bulletin 757-
30A0018, Revision 1 (167 U.S.-registered airplanes), it would take 
approximately 2 work hours per airplane to accomplish the proposed 
installation and adjustment, 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 
proposed AD on U.S. operators is estimated to be $20,040, or $120 per 
airplane.
    The cost impact figures discussed above are based on assumptions 
that no 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 proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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:

Boeing: Docket 98-NM-323-AD.

    Applicability: Model 757-200, -200PF, and -200CB series 
airplanes powered by Rolls-Royce RB211-535C/E4/E4B turbofan 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

[[Page 7824]]

requirements of this AD is affected, the owner/operator must request 
approval for an alternative method of compliance in accordance with 
paragraph (e) 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 engine thrust control cable failure, which could 
result in a severe asymmetric thrust condition during landing, and 
consequent reduced controllability of the airplane, accomplish the 
following:
    (a) Within 18 months or 6,000 flight hours after the effective 
date of this AD, whichever occurs first: Accomplish the ``Thrust 
Control Cable Inspection Procedure'' specified in Appendix 1 
(including Figures 1 and 2) of this AD to verify the integrity of 
the thrust control cables. Prior to further flight, repair any 
discrepancy found in accordance with the procedures described in the 
Boeing 757 Maintenance Manual. Repeat the inspection thereafter at 
intervals not to exceed 18 months or 6,000 flight hours, whichever 
occurs first.
    (b) For airplanes identified in Boeing Service Bulletin 757-76-
1, dated May 18, 1984: Within 18 months or 6,000 flight hours after 
the effective date of this AD, whichever occurs first, remove the 
guide bracket of the engine thrust control cable located on the 
front spar of the right wing in accordance with the service 
bulletin.
    (c) For airplanes identified in Boeing Service Bulletin 757-76-
0005, dated May 5, 1988: Within 18 months or 6,000 flight hours 
after the effective date of this AD, whichever occurs first, remove 
the engine thrust control cable breakaway stop assemblies, and 
replace sections of the engine thrust control cables with smaller 
diameter cables in accordance with the service bulletin.
    (d) For airplanes identified in Boeing Alert Service Bulletin 
757-30A0018, Revision 1, dated September 17, 1998: Within 60 days 
after the effective date of this AD, install a support bracket 
assembly between the window heat wire bundle and the engine thrust 
control cable; and adjust the wire bundle clearance, as necessary, 
to parallel the minimum clearance specified in the alert service 
bulletin.
    (e) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (f) 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.

Appendix 1.--Thrust Control Cable Inspection Procedure

1. General

    A. Use these procedures to test the integrity of the thrust 
control cables. The procedures must be performed along the entire 
cable run for each engine.
    B. The first task is an inspection of the control cable. The 
second task is an inspection of the control cable pulley. The third 
task is an inspection of the control cable pulley bracket. The 
fourth task is an inspection of control cable travel.

2. Inspection of the Control Cables

    A. Clean the cables (if necessary) for the inspection, in 
accordance with 757 Maintenance Manual 12-12-31.
    B. Examine the cables:
    (1) To do a check for broken wires, rub a cloth along the length 
of the cable. The cloth catches broken wires.
    (2) To aid in the visual inspection, remove the tension and bend 
the cable. Broken wire ends frequently move apart from the cable 
surface. Use large bend radius to prevent kinks.

    Note: Wires break most frequently where cables go through 
fairleads or around pulleys. Examine these areas carefully.

    C. Remove the control cable from the airplane when you find one 
of these conditions:
    (1) If one cable strand has worn wires where one wire cross 
section is decreased by 40 percent or more in an area that goes over 
a pulley, through a pressure seal, or through a fairlead (see Figure 
1).
    (2) A broken wire in the area that goes over a pulley, through a 
pressure seal, or through a fairlead.

    Note: A cable assembly can have one broken wire if the broken 
wire is in a straight part of the cable assembly. The broken wire 
must not go over a pulley or through a pressure seal or fairlead. 
The cable must agree with the other specifications of this section.

    (3) Two or more broken wires.
    (4) A nick or cut.
    (5) Rust or corrosion.
    D. Lubricate the cable (if you removed the lubricant), in 
accordance with 757 Maintenance Manual 12-12-31.

    Note: Do not apply grease to CRES cables.

3. Inspection of the Control Cable Pulley

    A. Visually examine the pulleys for roughness, sharp edges, and 
unwanted material in the grooves.
    B. Visually examine the pulley wear pattern (see Figure 2).
    C. Do these steps at the same time to examine the pulley for 
wobble:
    (1) Push on the side of the pulley at the outer edge with a 2-
pound force, perpendicular to control cable travel.
    (2) Make sure the movement of the outer edge is no more than:
    (a) 0.10 inch for 8-inch diameter pulleys.
    (b) 0.09 inch for 6-inch diameter pulleys.
    (c) 0.08 inch for 5-inch diameter pulleys.
    (d) 0.07 inch for 4-inch diameter pulleys.
    (e) 0.06 inch for 3-inch diameter pulleys.
    D. Make sure the pulley bearings have lubrication and turn 
smoothly.
    E. Examine the pulley bolts for wear.
    F. Remove the pulley from the airplane when you find one of 
these conditions:
    (1) An unusual pulley wear pattern.
    (2) Too much pulley wobble.
    (3) The pulley does not turn freely and smoothly.

4. Inspection of the Control Cable Pulley Bracket

    A. Examine the brackets and the support structure for cracks or 
other damage.
    B. Replace or repair all brackets or structure that have damage.

5. Inspection of the Cable Travel

    A. Make sure the cable guides and fairleads have no worn or 
broken parts and that the parts are aligned, clean, and attached 
correctly.
    B. Make sure the deflection angle at each fairlead is not more 
than 3 degrees.
    C. Visually examine the cable runs for incorrect routing or 
twists in the cable.
    D. Make sure the cable moves freely through its full travel, and 
does not contact structure, wire bundles, or tubing.

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    Issued in Renton, Washington, on February 9, 1999.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-3736 Filed 2-16-99; 8:45 am]
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