[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.
[[Page 7823]]
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.
BILLING CODE 4910-13-U
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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]
BILLING CODE 4910-13-C
