[Federal Register Volume 71, Number 88 (Monday, May 8, 2006)]
[Rules and Regulations]
[Pages 26679-26682]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-4230]


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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; 
Amendment 39-14586; AD 2006-10-02]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Boeing Model 747 airplanes. This AD requires 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 AD results from a report of extensive 
corrosion of a ballscrew in the drive mechanism of the horizontal 
stabilizer on a similar airplane model. We are issuing 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: This AD becomes effective June 12, 2006.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of June 12, 
2006.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street, SW., Nassif Building, 
Room PL-401, Washington, DC.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this AD.

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:

Examining the Docket

    You may examine the airworthiness directive (AD) docket on the 
Internet at http://dms.dot.gov or 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 street address stated in the ADDRESSES section.

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that would apply to all Boeing Model 747 
airplanes. That NPRM was published in the Federal Register on October 
7, 2005 (70 FR 58623). That NPRM proposed to 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.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Request Credit for Previously Accomplished Inspections

    Northwest Airlines (NWA) asks that, in order to avoid accomplishing 
the initial inspections at the time specified in the NPRM, operators 
who have already done the initial inspections per the referenced 
service bulletin be allowed to continue with the repetitive inspections 
using established maintenance intervals based on the repetitive 
interval specified in Table 1 of the referenced service bulletin. NWA 
states that Table 1 of the referenced service bulletin, which provides 
the compliance intervals, indicates that the compliance time for the 
initial ballnut to ballscrew freeplay check for airplanes not in the 
low utilization maintenance program specifies ``15,000 flight hours 
after the last check'' and the repetitive interval specifies ``18,000 
flight hours recommended, but not more than 21,000 flight hours.'' NWA 
has been accomplishing the lubrication, detailed visual inspections, 
and freeplay checks at the intervals specified in Table 1 of the 
service bulletin. NWA notes that paragraph (e) of the NPRM applies to 
operators that have been accomplishing the inspections in the 
referenced service bulletin, and asks that we ensure that

[[Page 26680]]

the intent of paragraph (e) is maintained in any forthcoming 
airworthiness directive.
    We agree with NWA that operators who have already done the initial 
inspections per the referenced service bulletin are allowed to continue 
with the repetitive inspections using established maintenance intervals 
based on the repetitive interval specified in Table 1 of the referenced 
service bulletin. Paragraph (e) of the NPRM specifies that you are 
responsible for having the actions required by this AD performed within 
the compliance times specified, unless the actions have already been 
done. We have added credit for accomplishing the initial inspections 
per the referenced service bulletin to paragraph (g) of this AD.
    Lufthansa German Airlines (Lufthansa) has performed the initial 
ballscrew-to-ballnut freeplay inspection per the original issue of the 
referenced service bulletin, and has scheduled the next inspection 
within the 18,000 flight hour interval specified therein.
    We infer that Lufthansa is asking to be allowed to continue 
accomplishing their repetitive inspections at the interval of 18,000 
flight hours, since they have already done the initial inspection. As 
stated above, we agree that operators who have already done the initial 
inspections per the referenced service bulletin are allowed to continue 
with the repetitive inspections using established maintenance intervals 
based on the repetitive interval specified in Table 1 of the referenced 
service bulletin. No change to the AD is necessary in this regard.

Request To Extend Compliance Time for Initial Inspection

    Lufthansa suggests that, for airplanes on which the initial and 
repetitive inspections have been done, the compliance time be changed 
to 18,000 flight hours for both the initial and repetitive inspections, 
as specified in the original issue of the referenced service bulletin. 
Lufthansa states that the proposed compliance time of 15,000 flight 
hours for the initial inspection, for all airplanes except those with 
an FAA-approved low utilization program, is not technically justified 
and is a burden for maintenance planning. Lufthansa adds that, in its 
opinion, the compliance time specified for the initial inspection is 
only justified if the inspection has never been done.
    We do not agree to extend the compliance time for the initial 
inspection to 18,000 flight hours; initial inspections accomplished per 
the original issue of the referenced service bulletin meet the intent 
of this AD. In developing an appropriate compliance time, we considered 
the safety implications, the manufacturer's recommendation, and normal 
maintenance schedules for timely accomplishment of the initial 
inspection. We have determined that the compliance time, as proposed, 
represents the maximum interval of time allowable for the affected 
airplanes to continue to safely operate before the initial inspection 
is done. We have made no change to the AD in this regard.
    Lufthansa also suggests that, for airplanes with more than 15,000 
total flight hours, the compliance time for the detailed inspection 
specified in paragraph (f) of the NPRM be changed to within 18 months 
from the issue date of the referenced service bulletin. Lufthansa adds 
that another option would be to state that accomplishment of the 
detailed inspection task specified in the original issue of the 
referenced service bulletin meets the initial inspection requirements. 
The commenter states that the proposed compliance time is too short for 
airplanes with more than 15,000 total flight hours to perform the 
detailed inspection.
    We do not agree with Lufthansa. As discussed previously, initial 
inspections accomplished per the original issue of the referenced 
service bulletin meet the intent of this AD. As specified in paragraph 
(f) of this AD, the compliance time is relative to the effective date 
of this AD.

Requests To Change Paragraph (h)

    UPS, Lufthansa, and NWA ask that paragraph (h) of the NPRM be 
changed to clarify that the overhaul instructions for the horizontal 
stabilizer actuator are not contained in the referenced service 
bulletin.
    UPS reiterates the language in paragraph (h) and contends that no 
overhaul instructions are provided in the referenced service bulletin. 
UPS states that the service bulletin specifies that if replacement is 
required, and a new or overhauled unit is not installed, then a 
detailed inspection and freeplay check are required. UPS adds that when 
a unit is overhauled per the component maintenance manual (CMM), it 
provides sufficient inspection requirements to meet the intent of the 
AD. Therefore, UPS recommends paragraph (h) be changed as follows: ``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 the CMM; or has been inspected, 
lubricated, and measured in accordance with paragraph (f) of this AD.'' 
UPS notes that the referenced service bulletin does not provide any 
direction over and above the requirements of the CMM.
    Lufthansa also reiterates the language in paragraph (h) and states 
that the referenced service bulletin does not provide overhaul 
procedures. Lufthansa adds that the Boeing Overhaul Manual (OHM 27-41-
31) does not provide overhaul procedures either, but contains 
Inspection/Check and Repair sections. The overhaul limits are contained 
in OHM 27-40-05 (Lear Siegler) and CMM 27-31-01 (Beaver). Lufthansa 
states that it is inappropriate for the NPRM to refer to an overhaul 
procedure in a document which was not intended to include it. Lufthansa 
recommends that paragraph (h) be changed to specify ``the appropriate 
component manufacturer's overhaul procedures'' instead of the 
referenced service bulletin.
    NWA states that it does not overhaul any components in accordance 
with service bulletins. NWA recommends that the statement ``or has been 
overhauled in accordance with Boeing Alert Service Bulletin 747-
27A2396, Revision 1'' be changed to ``or has been overhauled in 
accordance with Boeing Alert Service Bulletin 747-27A2396, Revision 1 
or subsequent.''
    We partially agree with UPS, Lufthansa, and NWA. We agree to change 
paragraph (h) of this AD as follows: ``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 overhauled in accordance with Boeing Alert 
Service Bulletin 747-27A2396, Revision 1, dated August 4, 2005 (which 
refers to the applicable overhaul manual); or has been inspected, 
lubricated, and measured in accordance with paragraph (f) of this AD.'' 
We find that there are no overhaul procedures in the referenced service 
bulletin; therefore, we have removed that reference accordingly.

Request To Change Relevant Service Information Section

    Boeing and Lufthansa ask that we clarify the ``Relevant Service 
Information'' section of the NPRM.
    Boeing asks that the first sentence in the last paragraph of that 
section be changed to read, ``For airplanes on which an FAA-approved 
low utilization maintenance program is in effect.'' That sentence, as 
written in the NPRM, specifies ``For all airplanes except those on 
which an FAA-approved low utilization maintenance program is in 
effect.'' Boeing suggests that the words ``all'' and ``except those'' 
which were included in that sentence, be deleted.

[[Page 26681]]

Boeing states that this paragraph addresses compliance requirements for 
``low utilization'' airplanes, but as written in the NPRM includes the 
words for normal utilization airplanes.
    Lufthansa also suggests that there is a typographical error within 
that section. Lufthansa states that the fourth and fifth paragraphs 
start with the same sentence, and asks if the first sentence in the 
fifth paragraph should read ``For airplanes with an FAA-approved low 
maintenance program.''
    We agree with Boeing and Lufthansa that clarifying the first 
sentence in the last paragraph of the ``Relevant Service Information'' 
section would be helpful, because the first sentence in the last 
paragraph, which describes ``low utilization'' airplanes, is incorrect. 
That sentence should specify ``For airplanes on which an FAA-approved 
low utilization maintenance program is in effect:'' However, since the 
``Relevant Service Information'' section of the NPRM does not reappear 
in the final rule, no change to the AD is necessary in this regard.
    Lufthansa also asks that the compliance time specified in the 
``Relevant Service Information'' section, the ``18 months after the 
original issue date of the service bulletin,'' specify which revision 
of the service bulletin.
    We do not agree with Lufthansa. The first sentence under the 
``Relevant Service Information'' section specifies that we have 
reviewed Boeing Alert Service Bulletin 747-27A2396, Revision 1, dated 
August 4, 2005. The second sentence defines the compliance times in 
that service bulletin. That section is not restated in this AD and no 
change to the AD is necessary in this regard.

Request for Clarification of Lubrication Action

    Lufthansa suggests that we clarify that the lubrication action 
specified in the NPRM is not related to oil servicing of the stabilizer 
actuator drive gearbox.
    We disagree that clarification is necessary. The NPRM and 
referenced service bulletin contain clear and specific instructions for 
the lubrication of the horizontal stabilizer ballscrew and ballnut. No 
change to the AD is necessary in this regard.

Clarification of Alternative Method of Compliance (AMOC) Paragraph

    We have revised this action to clarify the appropriate procedure 
for notifying the principal inspector before using any approved AMOC on 
any airplane to which the AMOC applies.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
These changes will neither increase the economic burden on any operator 
nor increase the scope of the AD.

Costs of Compliance

    This AD affects about 1,082 Model 747 series airplanes worldwide. 
The following table provides the estimated costs for U.S. operators to 
comply with this 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 AD will not have federalism 
implications under Executive Order 13132. This 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 this AD:
    (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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket. See the ADDRESSES 
section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

2006-10-02 Boeing: Amendment 39-14586; Docket No. FAA-2005-22624; 
Directorate Identifier 2004-NM-81-AD.

Effective Date

    (a) This AD becomes effective June 12, 2006.

Affected ADs

    (b) None.

[[Page 26682]]

Applicability

    (c) This AD applies to all Boeing Model 747-100, 747-100B, 747-
100B SUD, 747-200B, 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 results from a report of extensive corrosion of a 
ballscrew in the drive mechanism of the horizontal stabilizer on a 
similar airplane model. We are issuing 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.

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 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 or the 
date of issuance of the original export certificate of 
airworthiness. 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) Initial inspections accomplished before the effective date 
of this AD in accordance with Boeing Alert Service Bulletin 747-
27A2396, dated September 4, 2003, are considered acceptable for 
compliance with the corresponding action specified in this AD. 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 (which refers 
to the applicable overhaul manual); or has been inspected, 
lubricated, and measured in accordance with paragraph (f) of this 
AD.

Alternative Methods of Compliance (AMOCs)

    (i)(1) 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.
    (2) Before using any AMOC approved in accordance with 14 CFR 
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

Material Incorporated by Reference

    (j) You must use Boeing Alert Service Bulletin 747-27A2396, 
Revision 1, dated August 4, 2005, to perform the actions that are 
required by this AD, unless the AD specifies otherwise. The Director 
of the Federal Register approved the incorporation by reference of 
this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 
Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for a copy of this service information. You 
may review copies at the Docket Management Facility, U.S. Department 
of Transportation, 400 Seventh Street, SW., Room PL-401, Nassif 
Building, Washington, DC; on the Internet at http://dms.dot.gov; or 
at the National Archives and Records Administration (NARA). For 
information on the availability of this material at the NARA, call 
(202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on April 28, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 06-4230 Filed 5-5-06; 8:45 am]
BILLING CODE 4910-13-P