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

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: Supplemental notice of proposed rulemaking; reopening of

comment period.

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SUMMARY: This document revises an earlier proposed airworthiness

directive (AD), applicable to certain Boeing Model 757-200, -200PF, and

-200CB series airplanes, that would have required 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. That proposal was prompted

by reports of failure of certain engine thrust control cables. This new

action would revise the proposed rule by extending the compliance time

for certain actions, revising certain inspection procedures, and adding

a requirement for a one-time inspection to determine the part number of

thrust control cable pulleys and replacement of existing pulleys with

new pulleys, if necessary. The actions specified by this new proposed

AD are intended to prevent failure of certain engine thrust control

cables, which could result in a severe asymmetric thrust condition

during landing, and consequent reduced controllability of the airplane.

DATES: Comments must be received by October 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

A proposal to amend part 39 of the Federal Aviation Regulations (14

CFR part 39) to add an airworthiness directive (AD), applicable to

certain Boeing Model 757-200, -200PF, and -200CB series airplanes, was

published as a notice of proposed rulemaking (NPRM) in the Federal

Register on February 17, 1999 (64 FR 7822). That NPRM would have

required 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. That NPRM was prompted by reports of failure of certain

engine thrust control cables. That condition, if not corrected, could

result in a severe asymmetric thrust condition during landing, and

consequent reduced controllability of the airplane.

Actions Since Issuance of Previous Proposal

Due consideration has been given to the comments received in

response to the NPRM. Certain of these comments and the information

they provided have led the FAA to consider making certain significant

changes to the proposal. These comments and the changes prompted by

them are explained below.

Request to Extend Compliance Time

One commenter requests that the compliance time for the thrust

control cable inspection [specified in paragraph (a) of the NPRM] be

extended from 18 months or 6,000 flight hours after the effective date

of this AD (whichever occurs first) to 24 months or 6,000 flight hours

after the effective date of this AD (whichever occurs first). The

commenter states that, for some operators, 6,000 flight hours would not

closely correspond to 18 months.

The FAA concurs with the commenter's request to extend the

compliance time somewhat. The FAA's intent is that the inspection

specified in the proposal be performed during a regularly scheduled

maintenance visit,

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when the airplane is at a base where special equipment and trained

personnel are readily available, if necessary. The FAA has determined

that an interval of 24 months better corresponds to operators' normal

maintenance schedules than an interval of 18 months. The FAA does not

consider that such an extension of the compliance time to 24 months

would adversely affect safety. Therefore, as the commenter requests,

paragraph (a) of this supplemental NPRM has been revised accordingly.

Similarly, the repetitive interval for the inspection specified in

paragraph (a) of this supplemental NPRM has been revised from the

earlier of 18 months or 6,000 flight hours to the earlier of 24 months

or 6,000 flight hours, and paragraphs (c) and (d) of this supplemental

NPRM [i.e., paragraphs (b) and (c) of the original NPRM] have been

revised to incorporate a compliance time of 24 months or 6,000 flight

hours after the effective date of this AD, whichever occurs first.

Request To Revise Inspection Procedure

Two commenters request that the ``Thrust Control Cable Inspection

Procedure,'' specified in paragraph (a) and described in Appendix 1 of

the proposal, be revised to focus on minimizing the possibility of

failure of an engine thrust control cable. One of the commenters

suggests that the procedure be revised to eliminate all steps that

don't contribute to the intent of the AD. The same commenter also

suggests that the inspection procedure would be enhanced by adding an

inspection of the cable joints.

The FAA concurs with the commenters' request, and the ``Thrust

Control Cable Inspection Procedure'' specified in Appendix 1 of this

supplemental NPRM has been revised accordingly.

Request To Add Requirement for Pulley Replacement

One commenter, the airplane manufacturer, suggests that the intent

of the proposed AD would be enhanced by inclusion of a requirement for

replacement of existing phenolic thrust control cable pulleys in the

struts with aluminum pulleys. The commenter states that phenolic

pulleys have seized due to delamination and loss of bearing

lubrication, which would result in chafing of the engine thrust control

cables. The commenter notes that this replacement is described in

Boeing Service Letter 757-SL-76-004-A, dated July 21, 1997.

The FAA concurs with the commenter's request. Therefore, a new

paragraph (b) has been added to this supplemental NPRM, which would

require, for airplanes having line numbers 1 through 636 inclusive, a

one-time inspection of the thrust control cable pulleys in the struts

to determine the part number of the pulleys, and replacement of

phenolic pulleys with new aluminum pulleys. Such replacement would be

required to be accomplished in accordance with the Boeing 757 Airplane

Maintenance Manual. A new Note 2 also has been added to this

supplemental NPRM to provide references for the location of the pulleys

to be inspected in accordance with paragraph (b) of this proposed AD.

Request To Revise Cost Impact

One commenter, the airplane manufacturer, requests that the ``Cost

Impact'' section of the proposal be revised to remove the statement

that the manufacturer will provide certain parts at no cost to the

operators. The FAA concurs with the commenter's request and has revised

the Cost Impact section of this supplemental NPRM in accordance with

new cost data provided by the manufacturer.

Explanation of Additional Change to the Original NPRM

The Cost Impact section in this supplemental NPRM has been revised

to increase the number of affected airplanes in the worldwide fleet as

well as on the U.S. Register from the numbers stated in the original

NPRM. Since the issuance of the NPRM, more airplanes have been

delivered by the manufacturer; thus the number of affected airplanes

has increased. No change to the applicability statement of the AD has

been made or is necessary.

Conclusion

Since these changes expand the scope of the originally proposed

rule, the FAA has determined that it is necessary to reopen the comment

period to provide additional opportunity for public comment.

Cost Impact

There are approximately 483 airplanes of the affected design in the

worldwide fleet. The FAA estimates that 248 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 to verify the integrity of the thrust control

cables, at an average labor rate of $60 per work hour. Based on these

figures, the cost impact of this inspection proposed by this AD on U.S.

operators is estimated to be $44,640, or $180 per airplane, per

inspection cycle.

It would take approximately 1 work hour per airplane to accomplish

the proposed inspection to determine the part number of the thrust

control cable pulleys, at an average labor rate of $60 per work hour.

Based on these figures, the cost impact of this inspection proposed by

this AD on U.S. operators is estimated to be $14,880, or $60 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 cost

approximately $1,410 per airplane. Based on these figures, the cost

impact of the proposed AD on U.S. operators is estimated to be $31,500,

or $2,250 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 cost approximately $192 per airplane. Based

on these figures, the cost impact of the proposed AD on U.S. operators

is estimated to be $52,104, or $312 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)

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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 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 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:

Inspections and Corrective Actions

(a) Within 24 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 Figure 1) 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 24 months or 6,000 flight hours, whichever

occurs first.

(b) For airplanes having line numbers 1 through 636 inclusive:

Within 24 months or 6,000 flight hours after the effective date of

this AD, whichever occurs first, perform a one-time inspection of

the 8 engine thrust control cable pulleys in the struts (4 in each

strut) to determine the part number (P/N) of each pulley. If any

pulley having P/N 65B80977-1 is installed, prior to further flight,

replace it with a pulley having P/N 255T1232-7, in accordance with

the procedures described in the Boeing 757 Airplane Maintenance

Manual.

Note 2: The location of the pulleys to be inspected in

accordance with paragraph (b) of this AD is specified in Chapters

53-11-53-04, 76-11-52-01, and 76-11-52-02 of the Boeing 757

Illustrated Parts Catalog.

Modifications

(c) For airplanes identified in Boeing Service Bulletin 757-76-

1, dated May 18, 1984: Within 24 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.

(d) For airplanes identified in Boeing Service Bulletin 757-76-

0005, dated May 5, 1988: Within 24 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.

(e) 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.

Alternative Method 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.

Note 3: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Seattle ACO.

Appendix 1.--Thrust Control Cable Inspection Procedure

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 acomplished. Issued in Renton,

Washington, on September 2, 1999.

1. General

A. Clean the cables, if necessary, for the inspection, in

accordance with Boeing 757 Maintenance Manual 12-21-31.

B. Use these procedures to verify the integrity of the thrust

control cable system. The procedures must be performed along the

entire cable run for each engine. To ensure verification of the

portions of the cables which are in contact with pulleys and

quadrants, the thrust control must be moved by operation of the

thrust and/or the reverse thrust levers to expose those portions of

the cables.

C. The first task is an inspection of the control cable wire

rope. The second task is an inspection of the control cable

fittings. The third task is an inspection of the pulleys.

Note: These three tasks may be performed concurrently at one

location of the cable system on the airplane, if desired, for

convenience.

2. Inspection of the Control Cable Wire Rope

A. Perform a detailed visual inspection to ensure that the cable

does not contact parts other than pulleys, quadrants, cable seals,

or grommets installed to control the cable routing. Look for

evidence of contact with other parts. Correct the condition if

evidence of contact is found.

Note: For the purposes of this procedure, a detailed visual

inspection is defined as: ``An intensive visual examination of a

specific structural area, system, installation, or assembly to

detect damage, failure, or irregularity. Available lighting is

normally supplemented with a direct source of good lighting at

intensity deemed appropriate by the inspector. Inspection aids such

as mirror, magnifying lenses, etc., may be used. Surface cleaning

and elaborate access procedures may be required.''

B. Perform a detailed visual inspection of the cable runs to

detect incorrect routing, kinks in the wire rope, or other damage.

Replace the cable assembly if:

(1) One cable strand had worn wires where one wire cross section

is decreased by more than 40 percent (see Figure 1),

(2) A kink is found, or

(3) Corrosion is found.

C. Perform a detailed visual inspection of the cable: To check

for broken wires, rub a cloth along the length of the cable. The

cloth catches on broken wires.

(1) Replace the 7x7 cable assembly if there are two or more

broken wires in 12 continuous inches of cable or there are three or

more broken wires anywhere in the total cable assembly.

(2) Replace the 7x19 cable assembly if there are four or more

broken wires in 12 continuous inches of cable or there are six or

more broken wires anywhere in the total cable assembly.

3. Inspection of the Control Cable Fittings

A. Perform a detailed visual inspection to ensure that the means

of locking the joints

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are intact (wire locking, cotter pins, turnbuckle clips, etc.).

Install any missing parts.

B. Perform a detailed visual inspection of the swaged portions

of swaged end fittings to detect surface cracks or corrosion.

Replace the cable assembly if cracks or corrosion are found.

C. Perform a detailed visual inspection of the unswaged portion

of the end fitting. Replace the cable assembly if a crack is

visible, if corrosion is present, or if the end fitting is bent more

than 2 degrees.

D. Perform a detailed visual inspection of the turnbuckle.

Replace the turnbuckle if a crack is visible or if corrosion is

present.

4. Inspection of Pulleys

A. Perform a detailed visual inspection to ensure that pulleys

are free to rotate. Replace pulleys which are not free to rotate.

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[GRAPHIC] [TIFF OMITTED] TP10SE99.000

Dorenda D. Baker,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-23478 Filed 9-9-99; 8:45 am]

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