[Federal Register Volume 70, Number 194 (Friday, October 7, 2005)]
[Proposed Rules]
[Pages 58623-58626]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-20268]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-22624; Directorate Identifier 2004-NM-81-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all Boeing Model 747 airplanes. This proposed AD would require the 
following actions for the drive mechanism of the horizontal stabilizer: 
Repetitive detailed inspections for discrepancies and loose ball 
bearings; repetitive lubrication of the ballnut and ballscrew; 
repetitive measurements of the freeplay between the ballnut and the 
ballscrew; and corrective action if necessary. This proposed AD is 
prompted by a report of extensive corrosion of a ballscrew in the drive 
mechanism of the horizontal stabilizer on a similar airplane model. We 
are proposing this AD to prevent an undetected failure of the primary 
load path for the ballscrew in the horizontal stabilizer and subsequent 
wear and failure of the secondary load path, which could lead to loss 
of control of the horizontal stabilizer and consequent loss of control 
of the airplane.

DATES: We must receive comments on this proposed AD by November 21, 
2005.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
    <bullet> DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
    <bullet> Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
    <bullet> Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
    <bullet> By fax: (202) 493-2251.
    <bullet> Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. 
and 5 p.m., Monday through Friday, except Federal holidays.
    You can get the service information identified in this proposed AD 
from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 
98124-2207.
    You can examine the contents of this AD docket on the Internet at 
http://dms.dot.gov, or at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street SW., Room PL-401, on 
the plaza level of the Nassif Building, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Kelly McGuckin, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Airplane 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6490; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

    The FAA has implemented new procedures for maintaining AD dockets 
electronically. As of May 17, 2004, new AD actions are posted on DMS 
and assigned a docket number. We track each action and assign a 
corresponding directorate identifier. The DMS AD docket number is in 
the form ``Docket No. FAA-2005-99999.'' The Transport Airplane 
Directorate identifier is in the form ``Directorate Identifier 2005-NM-
999-AD.'' Each DMS AD docket also lists the directorate identifier 
(``Old Docket Number'') as a cross-reference for searching purposes.

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2005-22624; 
Directorate Identifier 2004-NM-81-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments submitted by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review DOT's complete Privacy Act Statement in the 
Federal Register

[[Page 58624]]

published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You can get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the Docket

    You can examine the AD docket in person at the Docket Management 
Facility office between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Management Facility office 
(telephone (800) 647-5227) is located on the plaza level of the Nassif 
Building at the DOT street address stated in the ADDRESSES section. 
Comments will be available in the AD docket shortly after the DMS 
receives them.

Discussion

    On January 31, 2000, there was an accident involving a McDonnell 
Douglas Model DC-9-83 (MD-83) airplane. The National Transportation 
Safety Board (NTSB) determined that the probable cause of this accident 
was a loss of airplane pitch control resulting from the in-flight 
failure of the acme nut threads of the jackscrew assembly of the 
horizontal stabilizer trim system. The NTSB concluded that the thread 
failure was caused by excessive wear, resulting from insufficient 
lubrication of the jackscrew assembly.
    The drive mechanism of the horizontal stabilizer on McDonnell 
Douglas Model DC-9-83 (MD-83) airplanes has a jackscrew assembly with 
an acme screw. The drive mechanism of the horizontal stabilizer on 
Boeing Model 747 airplanes uses a ballscrew. Acme screws and ballscrews 
have some differences in design, but perform similar functions and have 
the same airplane level effect following failure. The manufacturer's 
safety analysis of the 747 drive mechanism found no safety problems 
with the configuration of the drive mechanism, but showed that changes 
to the maintenance procedures and maintenance intervals are required to 
keep the drive mechanism properly maintained and operating as designed.
    We have received a report indicating that the ballscrew in the 
drive mechanism of the horizontal stabilizer on a Boeing Model 757 
series airplane showed extensive corrosion, which could lead to 
excessive wear. The ballscrew on Boeing Model 757 airplanes is similar 
to that on the Boeing Model 747 airplanes that are the subject of this 
proposed AD. Therefore, both of these airplane models could have the 
same unsafe condition. We are considering separate action for Boeing 
Model 757 airplanes and other similar Boeing airplanes.
    Extensive corrosion of the ballscrew in the drive mechanism of the 
horizontal stabilizer, if not corrected, could cause an undetected 
failure of the primary load path for the ballscrew and subsequent wear 
and failure of the secondary load path, which could lead to loss of 
control of the horizontal stabilizer and consequent loss of control of 
the airplane.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 747-27A2396, 
Revision 1, dated August 4, 2005.
    The compliance times specified in the service bulletin is as 
follows:
    For all airplanes: The compliance times for the initial detailed 
inspections and lubrication of the ballnut and ballscrew is 15,000 
total flight hours or 18 months after the original issue date on the 
service bulletin, whichever occurs later. The inspection is repeated at 
intervals not to exceed between 2,000 and 4,000 flight hours or 24 
months, whichever occurs first; the lubrication is repeated at 
intervals not to exceed 2,000 flight hours or 12 months, whichever 
occurs first.
    For all airplanes except those on which an FAA-approved low 
utilization maintenance program is in effect: The compliance time for 
the initial ballscrew-to-ballnut freeplay inspection is 15,000 flight 
hours after accomplishing the last ballscrew-to-ballnut freeplay 
inspection or 18 months after the original issue date on the service 
bulletin, whichever occurs later. If the inspection has never been 
done, the compliance time for the initial inspection is 15,000 flight 
hours after the delivery date of the airplane or 18 months after the 
original issue date on the service bulletin, whichever occurs later. 
The inspection is repeated at intervals not to exceed between 18,000 
flight hours and 21,000 flight hours.
    For all airplanes except those on which an FAA-approved low 
utilization maintenance program is in effect: The compliance time for 
the initial ballscrew-to-ballnut freeplay inspection is 60 months after 
accomplishing the last ballscrew-to-ballnut freeplay inspection. If the 
inspection has never been done, the compliance time for the initial 
inspection is within 60 months after the delivery date of the airplane. 
The inspection is repeated at intervals not to exceed 72 months.
    The service bulletin also describes the procedures in the following 
table for the drive mechanism of the horizontal stabilizer.

    Procedures Specified in Boeing Alert Service Bulletin 747-27A2396
------------------------------------------------------------------------
    Work package         Repetitive actions         Corrective action
------------------------------------------------------------------------
1...................  Accomplishing detailed    Replacing the ballscrew
                       visual inspections for    actuator with a new or
                       discrepancies             overhaulted actuator if
                       (including cracks,        any discrepancy is
                       corrosion, damage, and    found during any
                       worn areas); and a        inspection.
                       detailed inspection for
                       loose ball bearings of
                       the external areas of
                       the drive mechanism and
                       areas below the drive
                       mechanism.
2...................  Lubricating the ballnut   Not applicable.
                       and ballscrew of the
                       horizontal stabilizer
                       drive mechanism.
3...................  Measuring the freeplay    Replacing the ballscrew
                       between the ballnut and   actuator with a new or
                       ballscrew.                overhauled actuator if
                                                 the freeplay is more
                                                 than the specified
                                                 limit.
------------------------------------------------------------------------

    We have determined that accomplishing the actions specified in the 
service bulletin will adequately address the unsafe condition.
    The service bulletin refers to the 747 Airplane Maintenance Manuals 
(AMM) in the following table as additional sources of service 
information for accomplishing the detailed inspections, lubrications, 
freeplay measurements, and corrective action.

[[Page 58625]]



                Additional Sources of Service Information
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                       Boeing AMM                             Subject
------------------------------------------------------------------------
747-100/200/300 AMM.....................................        12-21-19
747-100/200/300 AMM.....................................        27-41-06
747-400 AMM.............................................        12-21-19
747-400 AMM.............................................        27-41-06
------------------------------------------------------------------------

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other airplanes 
of this same type design. Therefore, we are proposing this AD, which 
would require the following actions for the drive mechanism of the 
horizontal stabilizer:
    <bullet> Repetitive detailed inspections for discrepancies of the 
ballscrew assembly;
    <bullet> Repetitive lubrication of the ballnut and ballscrew;
    <bullet> Repetitive measurements of freeplay between the ballnut 
and the ballscrew; and
    <bullet> Corrective action if necessary.
    The proposed AD would require you to use the service bulletin 
described previously to perform these actions; except as discussed 
under ``Difference Between the Proposed AD and Service Information.''

Differences Between the Proposed AD and Service Information

    The service bulletin specifies compliance times relative to the 
date of issuance of the service bulletin; however, this proposed AD 
would require compliance before the specified compliance time after the 
effective date of this AD.

Costs of Compliance

    This proposed AD would affect about 1,082 Model 747 series 
airplanes worldwide. The following table provides the estimated costs 
for U.S. operators to comply with this proposed AD, per cycle.

                                                                     Estimated Costs
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                                                                                                                          Number of U.S.-
            Repetitive actions                Work hours     Average labor              Parts                Cost per       registered      Fleet cost
                                                             rate per hour                                   airplane        airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Detailed inspection.......................               1             $65  None........................             $65             236         $15,340
Lubrication...............................               1              65  None........................              65             236          15,340
Freeplay measurement......................               3              65  None........................             195             236          46,020
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Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
subtitle VII, part A, subpart III, section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD will not have federalism 
implications under Executive Order 13132. This proposed AD will not 
have a substantial direct effect 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.
    For the reasons discussed above, I certify that the 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. 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. See the ADDRESSES section for a location 
to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Airplane, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

Boeing: Docket No. FAA-2005-22624; Directorate Identifier 2004-NM-
81-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this AD action by November 21, 2005.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model 747-100, 747-100B, 747-
100B SUD, -200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 
747-400F, 747SR, and 747SP series airplanes; certificated in any 
category.

Unsafe Condition

    (d) This AD was prompted by a report of extensive corrosion of a 
ballscrew in the horizontal stabilizer of a similar airplane model. 
We are issuing this AD to prevent an undetected failure of the 
primary load path for the ballscrew in the drive mechanism of the 
horizontal stabilizer and subsequent wear and failure of the 
secondary load path, which could lead to loss of control of the 
horizontal stabilizer and consequent loss of control of the 
airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Repetitive Detailed Inspection/Lubrication/Freeplay Measurement and 
Corrective Action

    (f) Do all the applicable actions, including any applicable 
corrective action, specified in Work Packages 1, 2, and 3 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
27A2396, Revision 1, dated August 4, 2005. Do the actions at the 
applicable compliance time specified in Table 1 of paragraph 1.E. 
``Compliance'' of

[[Page 58626]]

the service bulletin; except, where the service bulletin specifies a 
compliance time relative to the original issue date of the service 
bulletin, this AD requires compliance relative to the effective date 
of this AD. Where the service bulletin specifies a compliance time 
relative to the delivery date of the airplane, this AD requires 
compliance relative to the date of issuance of the original standard 
airworthiness certificate. Do any applicable corrective action 
before further flight. Repeat the actions at the applicable repeat 
interval specified in Table 1 of paragraph 1.E ``Compliance'' of the 
service bulletin.

    Note 1: Boeing Alert Service Bulletin 747-27A2396, Revision 1, 
dated August 4, 2005, refers to the Airplane Maintenance Manuals 
(AMMs) in Table 1 of this AD as additional sources of service 
information for accomplishing the detailed visual inspections, 
lubrications, freeplay measurements, and corrective actions.


           Table 1.--Additional Sources of Service Information
------------------------------------------------------------------------
                       Boeing AMM                             Subject
------------------------------------------------------------------------
747-100/200/300 AMM.....................................        12-21-19
747-100/200/300 AMM.....................................        27-41-06
747-400 AMM.............................................        12-21-19
747-400 AMM.............................................        27-41-06
------------------------------------------------------------------------

Previously Accomplished Actions

    (g) For airplanes on which the drive mechanism of the horizontal 
stabilizer was replaced before the effective date of this AD with a 
drive mechanism that was not new or overhauled, and the detailed and 
freeplay inspections were not accomplished in accordance with Boeing 
Alert Service Bulletin 747-27A2396, dated September 4, 2003: Within 
4,000 flight hours or 24 months after the effective date of this AD, 
whichever is first, accomplish the inspections, and perform any 
applicable corrective action before further flight, in accordance 
with Work Package 3 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 747-27A2396, Revision 1, dated August 4, 
2005.

Parts Installation

    (h) As of the effective date of this AD, no person may install 
on any airplane a horizontal stabilizer trim actuator unless it is 
new or has been overhauled in accordance with Boeing Alert Service 
Bulletin 747-27A2396, Revision 1, dated August 4, 2005; or has been 
inspected, lubricated, and measured in accordance with paragraph (f) 
of this AD.

Alternative Methods of Compliance (AMOCs)

    (i) The Manager, Seattle Airplane Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19.

    Issued in Renton, Washington, on September 30, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Airplane Certification 
Service.
[FR Doc. 05-20268 Filed 10-6-05; 8:45 am]
BILLING CODE 4910-13-P