Airworthiness Directives; Boeing Model 747 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-223-AD; Amendment 39-11186; AD 99-11-15]

RIN 2120-AA64

Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD),

applicable to certain Boeing Model 747 series airplanes, that requires

a one-time detailed visual inspection to detect improperly installed or

frayed aileron cables, and a one-time detailed visual inspection to

detect improper identification or location of the cable markers, and

corrective actions, if necessary. This amendment is prompted by a

report that an aileron cable failed, due to improper installation onto

the wrong groove of an aileron cable drum. The actions specified by

this AD are intended to detect and correct an improperly installed

aileron cable; such installation could lead to the failure of the

aileron cable, and consequent reduced lateral control capability of the

airplane.

DATES: Effective July 8, 1999.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of July 8, 1999.

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: Tamara L. Anderson, Aerospace

Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft

Certification Office, 1601 Lind Avenue, SW., Renton, Washington;

telephone (425) 227-2771; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to include an airworthiness

directive (AD) that is applicable to certain Boeing Model 747 series

airplanes was published in the Federal Register on September 8, 1998

(63 FR 47447). That action proposed to require a one-time detailed

visual inspection to detect improperly installed or frayed aileron

cables, and a one-time detailed visual inspection to detect improper

identification or location of the cable markers, and corrective

actions, 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 comments received.

Support for the Proposal

Two commenters support the proposed rule, and two commenters

offered no objection to the proposed rule.

Request To Reference Revised Service Information

One commenter requests that the FAA revise the proposed rule to add

references to Revision 1 of Boeing Service Bulletin 747-27-2367, dated

December 17, 1998, as an appropriate source of service information for

accomplishment of the actions specified by the proposal. The proposed

AD referenced only the original issue of the service bulletin, dated

June 25, 1998.

The FAA concurs with the commenter's request. The FAA has reviewed

and approved Boeing Service Bulletin 747-27-2367, Revision 1. The

instructions contained in Revision 1 of the service bulletin are

substantially similar to those in the original issue of the service

bulletin. Therefore, paragraph (a) of this final rule has been revised

to state that the inspections are to be accomplished in accordance with

either the original issue or Revision 1 of the service bulletin.

However, among other things, Revision 1 removes airplanes from the

effectivity listing of the original service bulletin, and revises

certain illustrations to clarify the accomplishment instructions.

Therefore, the applicability statement of this final rule has been

revised to make this AD applicable to, ``Model 747 series airplanes, as

listed in Boeing Service Bulletin 747-27-2367, Revision 1. . . .'' In

addition, the cost impact section has been revised in this final rule

to reflect the reduction in the number of affected airplanes.

Request To Increase Compliance Threshold

One commenter requests that the compliance threshold for

accomplishment of the one-time detailed visual inspections be increased

from 18 months to 36 months. The commenter states that the inspections

must be accomplished during a heavy maintenance check, and that a

similar maintenance task is scheduled for every 2C-check on Model 747

series airplanes. The commenter further states that increasing the

compliance threshold would allow operators to accomplish the

inspections specified in this AD concurrently with that similar task.

The commenter justifies its request for an increased inspection

threshold by stating that a failure effects assessment indicates that,

in the event of failure of two cables about a cable drum, the handling

qualities of Model 747 series airplanes would be ``adequate.''

The FAA does not concur with the commenter's request to increase

the compliance threshold. Service history has indicated that many

aileron cable markers are located incorrectly, which may lead to a

greater exposure to failures of the aileron cables and possible

mishandling of the airplane. The FAA has determined that a compliance

time of 18 months is adequate to allow operators to

[[Page 29784]]

accomplish the actions required by this AD, while not adversely

affecting the safety of the transport airplane fleet. In support of

this determination, the FAA has received information indicating that

certain operators presently perform a detailed inspection of the

aileron cables during every C-check. No change to the final rule is

necessary in this regard.

Request To Revise Compliance Time for Replacement of Discrepant

Marker

One commenter requests that the FAA revise the proposed compliance

time for the replacement of an aileron cable marker that is found to be

improperly identified or located. Paragraph (a)(4) of the proposed AD

states that any aileron cable marker that is found to be improperly

identified or located must be replaced with a new marker prior to

further flight. The commenter states that an improperly installed

aileron cable marker does not affect the functionality of the aileron

control system, and requests that the proposed rule be revised to

require replacement of a discrepant cable marker, ``at the earliest

maintenance opportunity,'' rather than, ``prior to further flight.''

The operator also points out that if an operator needs to replace or

re-route an aileron cable prior to replacement of an improperly

installed marker, the cable can be replaced or rerouted in accordance

with the Airplane Maintenance Manual (AMM) instead of the aileron cable

marker.

The FAA does not concur with the commenter's request. The FAA finds

that revising the compliance time from ``prior to further flight'' to

``at the earliest maintenance opportunity'' would permit each operator

to determine when a discrepant aileron cable marker is replaced. In

light of the identified unsafe condition, the FAA has determined that

allowing this degree of operator discretion is not appropriate.

However, under the provisions of paragraph (c) of the final rule,

operators may request approval of an alternative method of compliance

that would allow extension of the compliance time for replacement of a

discrepant marker. Therefore, no change to the final rule is necessary

in this regard.

With regard to the use of the procedures specified in the AMM,

rather than the aileron cable marker, to replace or reroute an aileron

cable: As pointed out in the ``Discussion'' section of the proposal,

the FAA has received many reports of misrouted aileron cables. These

incidents of misrouted aileron cables have occurred in spite of the

fact that the AMM specifies procedures for routing the aileron cables

that do not rely on the aileron cable markers. For this reason, the FAA

finds it likely that the misrouted aileron cables are due to improperly

identified or located cable markers. No change to the final rule is

necessary in this regard.

Request To Revise the Compliance Time for Reporting Adverse Results

Two commenters request that the FAA increase the proposed

compliance time for reporting adverse inspection results from 10 days

after the inspection to 30 days after the inspection. One of the

commenters states that a 30-day compliance time would allow the

paperwork to be handled according to normal, rather than special,

procedures. The commenter states that such special handling procedures

as would be necessary with a 10-day compliance time often result in

lost or incomplete information. The commenter asserts that a 30-day

compliance time would allow an affected operator to submit ``a concise

and accurate report to the FAA.''

The FAA concurs with the commenters' request to increase the

compliance time for reporting adverse inspection results. The FAA finds

that an increase in the compliance time from 10 days after

accomplishment of the inspection to 30 days after accomplishment of the

inspection would not have an adverse effect on the safety of the

transport airplane fleet. Paragraph (b) of this final rule has been

revised accordingly.

Explanation of Change Made to the Proposal

The FAA has added a ``Note 2'' to the final rule to clarify the

definition of a detailed visual inspection.

Conclusion

After careful review of the available data, including the comments

noted above, the FAA has determined that air safety and the public

interest require the adoption of the rule with the changes described

previously. The FAA has determined that these changes will neither

increase the economic burden on any operator nor increase the scope of

the AD.

Cost Impact

There are approximately 1,023 Boeing Model 747 series airplanes of

the affected design in the worldwide fleet. The FAA estimates that 224

airplanes of U.S. registry will be affected by this AD.

It will take approximately 9 work hours per airplane to accomplish

the required detailed visual inspections, at an average labor rate of

$60 per work hour. Based on these figures, the cost impact of the AD on

U.S. operators is estimated to be $120,960, or $540 per airplane.

The cost impact figure discussed above is 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 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:

99-11-15 Boeing: Amendment 39-11186. Docket 98-NM-223-AD.

Applicability: Model 747 series airplanes, as listed in Boeing

Service Bulletin 747-27-

[[Page 29785]]

2367, Revision 1, dated December 17, 1998; 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 (c) 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 detect and correct an improperly installed aileron cable,

which could lead to the failure of the aileron cable, and consequent

reduced lateral control capability of the airplane, accomplish the

following:

One-Time Inspections and Corrective Actions

(a) Within 18 months after the effective date of this AD,

perform a one-time detailed visual inspection to detect improper

installation or fraying of the aileron cables on both wings. In

addition, perform a one-time detailed visual inspection of the

aileron cable markers on both wings to detect improper

identification or location. Perform both inspections in accordance

with the Accomplishment Instructions of Boeing Service Bulletin 747-

27-2367, dated June 25, 1998, or Revision 1, dated December 17,

1998.

Note 2: For the purposes of this AD, 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.''

(1) If no improperly installed or frayed aileron cable is found,

and if no aileron cable marker is improperly identified or located,

no further action is required by this AD.

(2) If any aileron cable is found to be improperly installed

(but not frayed), prior to further flight, reroute the discrepant

aileron cable in accordance with the Accomplishment Instructions of

the service bulletin.

(3) If any aileron cable is found to be frayed, prior to further

flight, replace the discrepant aileron cable with a new aileron

cable in accordance with the Accomplishment Instructions of the

service bulletin.

(4) If any aileron cable marker is found to be improperly

identified or located, prior to further flight, replace the

discrepant aileron cable marker with a new aileron cable marker in

accordance with the Accomplishment Instructions of the service

bulletin.

Reporting Requirement

(b) Within 30 days after accomplishing the detailed visual

inspections required by paragraph (a) of this AD, submit a report of

the inspection results (adverse findings only) to the Manager,

Boeing Certificate Management Office, FAA, Transport Airplane

Directorate, 2500 East Valley Road, Suite C2, Renton, Washington

98055; fax (425) 227-1159. Required information for each report must

include the following: description of the adverse finding, airplane

serial number, and total flight cycles and flight hours accumulated

at the time of the inspection. Information collection requirements

contained in this regulation have been approved by the Office of

Management and Budget (OMB) under the provisions of the Paperwork

Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been

assigned OMB Control Number 2120-0056.

Alternative Methods of Compliance

(c) 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.

Special Flight Permits

(d) Special flight permits may be issued in accordance with

Secs. 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

(e) The actions shall be done in accordance with Boeing Service

Bulletin 747-27-2367, dated June 25, 1998; or Boeing Service

Bulletin 747-27-2367, Revision 1, dated December 17, 1998. 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.

(f) This amendment becomes effective on July 8, 1999.

Issued in Renton, Washington, on May 21, 1999.

D.L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 99-13874 Filed 6-2-99; 8:45 am]

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