[Federal Register Volume 70, Number 185 (Monday, September 26, 2005)]
[Proposed Rules]
[Pages 56145-56150]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-19142]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-22510; Directorate Identifier 2004-NM-32-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Airplanes

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede two existing airworthiness 
directives (ADs), one AD applicable to all Boeing Model 747 airplanes 
and the other AD applicable to certain Boeing Model 747 airplanes. The 
first AD currently requires repetitive inspections for cracking of the 
upper skin of the

[[Page 56146]]

horizontal stabilizer center section and the rear spar upper chord, and 
repair if necessary. The other AD currently requires repetitive 
inspections for cracking of the upper skin of the outboard and center 
sections of the horizontal stabilizer and the rear spar structure, 
hinge fittings, terminal fittings, and splice plates; and repair if 
necessary. This proposed AD would add, for certain airplanes, 
repetitive inspections for cracking of the outboard and center sections 
of the horizontal stabilizer and repair if necessary. For certain other 
airplanes, this proposed AD would add a detailed inspection to 
determine the type of fasteners, related investigative actions, and 
repair if necessary. This proposed AD also would revise the compliance 
times for certain inspections and add alternate inspections for 
cracking of the upper skin of the center section and rear spar upper 
chord. This proposed AD is prompted by reports of cracking in the 
outboard and center section of the aft upper skin of the horizontal 
stabilizer, the rear spar chord, rear spar web, terminal fittings, and 
splice plates; and a report of fractured and cracked steel fasteners. 
We are proposing this AD to detect and correct this cracking, which 
could lead to reduced structural capability of the outboard and center 
sections of the horizontal stabilizer and could result in loss of 
control of the airplane.

DATES: We must receive comments on this proposed AD by November 10, 
2005.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street SW., Nassif Building, room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     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.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-
2207.

FOR FURTHER INFORMATION CONTACT: Nicholas Kusz, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6432; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

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-2005-22510; 
Directorate Identifier 2004-NM-32-AD'' at the beginning 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 received 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 our 
docket 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 the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You can examine the 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 DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the DMS receives them.

Discussion

    On March 11, 2002, we issued AD 2002-06-02, amendment 39-12678 (67 
FR 12464, March 19, 2002), for all Boeing Model 747 airplanes. That AD 
requires repetitive inspections for cracking of the upper skin of the 
horizontal stabilizer center section and the rear spar upper chord, and 
repair, if necessary. That AD was prompted by a report of cracking 
found in the upper skin of the horizontal center section on a Boeing 
Model 747SR series airplane. We issued that AD to find and fix this 
cracking, which could lead to reduced structural capability of the 
horizontal stabilizer center section, and result in the loss of control 
of the airplane.
    On June 18, 2003, we issued AD 2003-13-09, amendment 39-13209 (68 
FR 38583, June 30, 2003), for certain Boeing Model 747 airplanes. That 
AD requires repetitive inspections for cracking of the upper skin of 
the outboard and center sections of the horizontal stabilizer and the 
rear spar structure, hinge fittings, terminal fittings, and splice 
plates; and repair if necessary. That AD was prompted by reports of 
cracking on Model 747 airplanes in areas not covered by certain 
inspections required by AD 2002-06-02. We issued AD 2003-13-09 to find 
and fix this cracking, which could lead to reduced structural 
capability of the outboard and center sections of the horizontal 
stabilizer, and result in loss of control of the airplane.

Actions Since Existing ADs Were Issued

    The preamble to AD 2003-13-09 explains that we considered the 
requirements ``interim action'' and were considering further rulemaking 
action. We now have determined that further rulemaking is indeed 
necessary, and this proposed AD follows from that determination. 
Further rulemaking action would supersede AD 2003-13-09 to address the 
procedures for repetitive inspections of Zone C to find additional 
cracking, and repair of any cracking found, as described in Boeing 
Alert Service Bulletin 747-55A2050, Revision 1, dated May 1, 2003. That 
further rulemaking action would also mandate repetitive inspections of 
Zone B for Groups 4, 5, and 6 airplanes. In addition to superseding AD 
2003-13-09, that rulemaking action would also supersede AD 2002-06-02 
to mandate long-term inspections of all affected zones specified in the 
referenced service bulletin for all 747 series airplanes.

Relevant Service Information

    We have previously reviewed Boeing Alert Service Bulletin 747-
55A2050, dated February 28, 2002. The service bulletin is cited as the 
appropriate source of service information for accomplishing the 
requirements of AD 2002-06-02.
    We have also previously reviewed Boeing Alert Service Bulletin 747-
55A2050, Revision 1, dated May 1, 2003. The service bulletin is cited 
as the appropriate source of service information for accomplishing the 
Zone A and Zone B inspections required by AD 2003-13-09. The service 
bulletin

[[Page 56147]]

also describes Zone C procedures, which this proposed AD would require 
for certain airplanes, as follows:
     Do a magnetic inspection to determine if any fastener 
common to the horizontal stabilizer outboard and center section upper 
chords at the hinge fitting halves and the splice plate is a Maraging 
or H-11 steel fastener.
     Do related investigative actions (includes ultrasonic, 
magnetic particle, or fluorescent particle inspections for any cracked 
or fractured Maraging or H-11 steel fastener common to the horizontal 
stabilizer outboard and center section upper chords at the hinge 
fitting halves and the splice plate). If no crack or fracture is found 
on a Maraging or H-11 steel fastener, the service bulletin specifies 
repeating the related investigative and corrective actions, as 
necessary.
     Do corrective action, if necessary. The corrective action 
includes performing the Part 4 open hole NDT inspection and replacing 
the fastener with a new, improved fastener.
    Boeing Alert Service Bulletin 747-55A2050, Revision 1, dated May 1, 
2003, specifies the following repetitive compliance times:
     Zone B NDT inspection for groups 1, 2, and 3: Repeat 
within 2,400 flight cycles or 13,000 flight hours, whichever comes 
first.
     Zone B Open hole NDT inspection for groups 1 through 6: 
Repeat within 8,000 flight cycles or 44,000 flight hours, whichever 
comes first.
     Zone C ultrasonic inspection of magnetic fasteners for 
groups 1, 2, and 3: If no crack or fracture is found, repeat within 18 
months.
    We have determined that accomplishment of the actions specified in 
the service information will adequately address the unsafe condition.

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 products 
of this same type design. Therefore, we are proposing this AD, which 
would supersede AD 2002-06-02 to continue to require repetitive 
inspections for cracking of the upper skin of the horizontal stabilizer 
center section and the rear spar upper chord, and repair, if necessary. 
This proposed AD would also supersede AD 2003-13-09 to continue to 
require repetitive inspections for cracking of the upper skin of the 
outboard and center sections of the horizontal stabilizer and the rear 
spar structure, hinge fittings, terminal fittings, and splice plates; 
and repair if necessary. This proposed AD also would, for certain 
airplanes, add repetitive inspections for cracking of the horizontal 
stabilizer center and outboard section, and repair if necessary. For 
certain other airplanes, this proposed AD would add a detailed 
inspection to determine if fasteners are Maraging or H-11 steel 
fasteners, related investigative actions, and corrective action if 
necessary. This proposed AD also would revise the compliance times for 
certain inspections and add alternate high frequency eddy current 
(HFEC) inspections for cracking of the upper skin of the center section 
and rear spar upper chord. This proposed AD would require you to use 
Boeing Alert Service Bulletin 747-55A2050, dated February 28, 2002; and 
Revision 1, dated May 1, 2003; to perform these actions except as 
discussed under ``Differences Between the Proposed AD and the Service 
Bulletins.''

Differences Between the Proposed AD and the Service Bulletins

    The service bulletins specifies that you may contact the 
manufacturer for instructions on how to repair certain conditions, but 
this proposed AD would require you to repair those conditions in one of 
the following ways:
     Using a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by an Authorized Representative 
for the Boeing Delegation Option Authorization Organization who has 
been authorized by the FAA to make those findings.
    Revision 1 of the service bulletin allows operators to re-install 
certain H-11 bolts. However, H-11 bolts are subject to stress corrosion 
cracking. We have determined that, because of the safety implications 
and consequences associated with stress corrosion cracking, this 
proposed AD would require that inconel bolts be installed. This 
difference has been coordinated with the manufacturer.

Differences in Compliance Time/Inspections Between the Proposed AD and 
AD 2002-06-02

    Operators should note that AD 2002-06-02 requires repetitive 
detailed and HFEC inspections, as applicable, at intervals not to 
exceed 1,000 flight cycles. This interval matches the interval 
specified in Boeing Alert Service Bulletin 747-55A2050, dated February 
28, 2002, which was referenced as the appropriate source of service 
information for accomplishing the requirements of AD 2002-06-02. 
However, for the same detailed inspections, this proposed AD would 
require repetitive inspections, specified as Zone A inspections, at 
intervals not to exceed 1,000 flight cycles or 5,600 flight hours, 
whichever occurs first. The interval for Zone A inspections matches the 
interval specified in Revision 1, dated May 1, 2003, of the service 
bulletin, which is referenced as the appropriate source of service 
information for accomplishing the requirements of this proposed AD. We 
have determined this interval to be appropriate in consideration of the 
safety implications.
    Operators should also note that while AD 2002-06-02 requires doing 
repetitive detailed and HFEC inspections, as applicable, this proposed 
AD would require doing repetitive detailed inspections, specified as 
Zone A inspections, or as an option, doing repetitive HFEC inspections, 
specified as Zone B inspections. We have determined the Zone A 
inspections ensure an adequate level of safety for the affected fleet. 
The Zone B inspections, if done, have a greater repetitive inspection 
interval.

Differences in Compliance Time Between the Proposed AD and AD 2003-13-
09

    Operators should note that, for Groups 1, 2, and 3 airplanes, the 
thresholds specified in AD 2003-13-09 for the Zone B inspections are at 
the later of the following times: 90 days after the effective date of 
the AD; or before the accumulation of 27,000 total flight cycles or 
117,000 total flight hours, whichever occurs later.
    However for the same airplanes, this proposed AD adds additional 
thresholds specified in paragraph (i)(2) of the proposed AD. The new 
thresholds match the thresholds specified in Revision 1, dated May 1, 
2003, of the service bulletin for airplanes with less than 27,000 
flight cycles and 117,000 flight hours. Airplanes which have more than 
27,000 flight cycles and 117,000 flight hours should have already done 
the Zone B inspections in accordance with AD 2003-13-09. We have 
determined these thresholds to be appropriate in consideration of the 
safety implications.

Change to Existing AD

    This proposed AD would retain certain requirements of AD 2002-06-
02. Since AD 2002-06-02 was issued, the AD format has been revised, and 
certain paragraphs have been rearranged. As a result, the corresponding 
paragraph identifiers have changed in this proposed AD, as listed in 
the following table:

[[Page 56148]]



             Revised Paragraph Identifiers for AD 2002-06-02
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                                             Corresponding  requirement
       Requirement in AD 2002-06-02             in this  proposed AD
------------------------------------------------------------------------
Paragraph (a).............................  Paragraph (f).
------------------------------------------------------------------------

    This proposed AD also would retain certain requirements of AD 2003-
13-09. The corresponding paragraph identifiers have changed in this 
proposed AD, as listed in the following table:

             Revised Paragraph Identifiers for AD 2003-13-09
------------------------------------------------------------------------
                                             Corresponding  requirement
       Requirement in AD 2003-13-09             in this  proposed AD
------------------------------------------------------------------------
Paragraph (a).............................  Paragraph (h)
Paragraph (b).............................  Paragraph (i).
------------------------------------------------------------------------

Costs of Compliance

    This proposed AD would affect about 1,087 Model 747 airplanes 
worldwide and would affect about 227 airplanes of U.S. registry. The 
following table provides the estimated costs for U.S. operators to 
comply with this proposed AD. The costs for the inspections are per 
inspection cycle.

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                             Average
                           Action                              Work hours   labor rate    Cost per    Fleet cost
                                                                             per hour     airplane
----------------------------------------------------------------------------------------------------------------
Zone A Detailed Inspection (required by AD 2002-06-02)......            8          $65         $520     $118,040
Zone A NDT Inspection, if done..............................           10           65          650  ...........
Zone B NDT Inspection (required by AD 2003-13-09 for Groups             8           65          520  ...........
 1, 2, and 3 airplanes).....................................
Zone B Open-hole NDT Inspection (new proposed action for               30           65        1,950  ...........
 Groups 3, 4, and 5 airplanes; and for Groups 1, 2, and 3
 airplanes, if done)........................................
Zone C Maraging or H-11 Steel Fastener Inspection (new                  8           65          520  ...........
 proposed action for Groups 1, 2, and 3 airplanes)..........
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    The FAA's authority to issue rules regarding aviation safety is 
found in Title 49 of the United States Code. 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.
    This rulemaking is promulgated 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 
proposed AD.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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, Aircraft, 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 removing amendment 39-12678 (67 FR 
12464, March 19, 2002) and amendment 39-13209 (68 FR 38583, June 30, 
2003), and adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2005-22510; Directorate Identifier 2004-NM-
32-AD.

Comments Due Date

    (a) The Federal Aviation Administration must receive comments on 
this airworthiness directive (AD) action by November 10, 2005.

Affected ADs

    (b) This AD supersedes AD 2002-06-02, amendment 39-12678; and AD 
2003-13-09, amendment 39-13209.

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 was prompted by reports of cracking in the outboard 
and center section of the aft upper skin of the horizontal 
stabilizer, the rear spar chord, rear spar web, terminal fittings, 
and splice plates; and a report of fractured and cracked steel 
fasteners. We are issuing this AD to detect and correct this 
cracking, which could lead to reduced structural capability of the 
outboard and center sections of the horizontal stabilizer and could 
result in 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.

Certain Requirements of AD 2002-06-02: To Be Done in Accordance With 
New Revision of the Service Bulletin

Repetitive Inspections for Zone A

    (f) Before the accumulation of 24,000 total flight cycles, or 
within 90 days after April 3, 2002 (the effective date of AD 2002-
06-02, amendment 39-12678), whichever occurs

[[Page 56149]]

later: Except as provided by paragraph (l) of this AD, ``Optional 
High Frequency Eddy Current (HFEC) Inspections for Zone A,'' do a 
detailed inspection for cracking of the upper skin of the horizontal 
stabilizer center section and the rear spar upper chord, in 
accordance with the Work Instructions and Figure 1 of Boeing Alert 
Service Bulletin 747-55A2050, dated February 28, 2002; or in 
accordance with Part 1 of the Work Instructions of Boeing Alert 
Service Bulletin 747-55A2050, Revision 1, dated May 1, 2003. (The 
inspection procedures include a detailed inspection for cracking of 
the upper horizontal skin and of the vertical and horizontal flanges 
of the rear spar upper chord.) As of the effective date of this AD, 
do the detailed inspection in accordance with Part 1 of the Work 
Instructions of Boeing Alert Service Bulletin 747-55A2050, Revision 
1, dated May 1, 2003. Repeat the detailed inspection thereafter at 
the times specified in paragraphs (f)(1) and (f)(2) of this AD, as 
applicable.

    Note 1: For the purposes of this AD, a detailed inspection is 
``an intensive examination of a specific item, installation, or 
assembly to detect damage, failure, or irregularity. Available 
lighting is normally supplemented with a direct source of good 
lighting at an intensity deemed appropriate. Inspection aids, such 
as mirrors, magnifying lenses, etc., may be necessary. Surface 
cleaning and elaborate procedures may be required.''

    (1) For airplanes on which the detailed inspection required by 
paragraph (a) of AD 2002-06-02 has been done before the effective 
date of this AD: Within 1,000 flight cycles after the last detailed 
inspection, do the detailed inspection specified in paragraph (f) of 
this AD and repeat the detailed inspection specified in paragraph 
(f) of this AD thereafter at intervals not to exceed 1,000 flight 
cycles or 5,600 flight hours, whichever comes first.
    (2) For airplanes on which the detailed inspection required by 
paragraph (a) of AD 2002-06-02 has not been done before the 
effective date of this AD: After accomplishing the initial 
inspection, repeat the detailed inspection specified in paragraph 
(f) of this AD thereafter at intervals not to exceed 1,000 flight 
cycles or 5,600 flight hours, whichever comes first.

Requirements of AD 2003-13-09 With New Compliance Times Required by 
This AD

Repetitive Inspections for Zone B: Groups 1 Through 3

    (g) For Groups 1, 2, and 3 airplanes identified in paragraph 
1.A. Effectivity of Boeing Alert Service Bulletin 747-55A2050, 
Revision 1, dated May 1, 2003: At the time specified in paragraph 
(h) of this AD, do the Zone B inspections, as required by either 
paragraph (g)(1) or (g)(2) of this AD, in accordance with the Work 
Instructions of Boeing Alert Service Bulletin 747-55A2050, Revision 
1, dated May 1, 2003, except as provided by paragraph (n) of this 
AD. Repeat the applicable inspection at the applicable time 
specified in Sheet 2 of Figure 1 of the service bulletin.
    (1) Do nondestructive test (NDT) inspections for cracking of the 
upper skin of the outboard and center sections of the horizontal 
stabilizer and the rear spar structure, hinge fittings, terminal 
fittings, and splice plates, in accordance with Part 3 of the 
service bulletin. The inspections include an ultrasonic inspection 
of the outboard and center sections, rear spar upper chords under 
the hinge fitting halves, upper skins under the splice plates, and 
the rear spar webs behind the terminal fittings; a HFEC inspection 
of the terminal fitting around the fasteners; a low frequency eddy 
current inspection of the splice plates around the fasteners; a 
surface HFEC inspection of the rear spar upper chords in the radius 
area above the terminal fitting and the lower surface of the 
horizontal flange; and an HFEC inspection of the rear spar webs in 
the exposed area above the terminal fitting.
    (2) In lieu of the inspections specified in paragraph (g)(1) of 
this AD: Do an alternate open hole HFEC inspection for cracking of 
the splice plates, terminal fittings, hinge fitting halves, rear 
spar upper chords, rear spar webs, and upper skins; and replace H-11 
bolts with inconel bolts; in accordance with Part 4 of the service 
bulletin, except as provided by paragraph (n) of this AD.
    (h) For Groups 1, 2, and 3 airplanes identified in paragraph 
1.A. Effectivity of Boeing Alert Service Bulletin 747-55A2050, 
Revision 1, dated May 1, 2003: Do the inspections required by 
paragraph (g) of this AD at the earlier of the times specified in 
paragraphs (h)(1) and (h)(2) of this AD.
    (1) At the later of the times specified in paragraphs (h)(1)(i) 
and (h)(1)(ii) of this AD.
    (i) Before the accumulation of 27,000 total flight cycles or 
117,000 total flight hours, whichever is first.
    (ii) Within 90 days after July 15, 2003 (the effective date of 
AD 2003-13-09, amendment 39-13209).
    (2) At the applicable times specified in paragraphs (h)(2)(i) 
and (h)(2)(ii) of this AD.
    (i) For Groups 1 and 3 airplanes identified in paragraph 1.A. 
Effectivity of Boeing Alert Service Bulletin 747-55A2050, Revision 
1, dated May 1, 2003: At the latest of the times specified in 
paragraphs (h)(2)(i)(A) and (h)(2)(i)(B) of this AD.
    (A) Before the accumulation of 20,000 total flight cycles or 
85,000 total flight hours, whichever is first.
    (B) Within 12 months after the effective date of this AD.
    (ii) For Group 2 airplanes identified in paragraph 1.A. 
Effectivity of Boeing Alert Service Bulletin 747-55A2050, Revision 
1, dated May 1, 2003: At the latest of the times specified in 
paragraphs (h)(2)(ii)(A) and (h)(2)(ii)(B) of this AD.
    (A) Before the accumulation of 22,000 total flight cycles or 
95,000 total flight hours, whichever is first.
    (B) Within 12 months after the effective date of this AD.

Additional Requirements of This AD

Repetitive Inspections for Zone B: Groups 4 Through 6

    (i) For Groups 4, 5, and 6 airplanes identified in paragraph 
1.A. Effectivity of Boeing Alert Service Bulletin 747-55A2050, 
Revision 1, dated May 1, 2003: At the later of the times specified 
in paragraphs (i)(1) and (i)(2) of this AD, do the Zone B 
inspections as specified in paragraph (g)(2) of this AD. Repeat the 
applicable inspection at the applicable time specified in Sheet 3 of 
Figure 1 of the service bulletin.
    (1) Before the accumulation of 20,000 total flight cycles or 
85,000 total flight hours, whichever is first.
    (2) Within 12 months after the effective date of this AD.

Repetitive Inspections for Zone C: Groups 1 Through 3

    (j) For Groups 1, 2, and 3 airplanes identified in paragraph 
1.A. Effectivity of Boeing Alert Service Bulletin 747-55A2050, 
Revision 1, dated May 1, 2003: Within 18 months after the effective 
date of this AD, do a detailed inspection to determine if fasteners 
common to the horizontal stabilizer outboard and center section 
upper chords at the hinge fitting halves and the splice plates are 
magnetic, related investigative actions (includes ultrasonic, 
magnetic particle, or fluorescent particle inspections for any 
cracked or fractured Maraging or H-11 steel fastener), and 
corrective actions by accomplishing all the actions specified in 
Part 5 of the Work Instructions of the service bulletin, except as 
provided by paragraph (n) of this AD.
    (k) If, during the actions required by paragraph (j) of this AD, 
any fastener is found to be magnetic and is not cracked or 
fractured, repeat the related investigative actions and corrective 
actions specified in paragraph (j) of this AD at the time specified 
in Sheet 4 of Figure 1 of Boeing Alert Service Bulletin 747-55A2050, 
Revision 1, dated May 1, 2003.

Optional High Frequency Eddy Current (HFEC) Inspections for Zone A

    (l) In lieu of the detailed inspection specified in paragraph 
(f) of this AD: Do an HFEC inspection for cracking of the upper skin 
of the horizontal stabilizer center section and the rear spar upper 
chord, in accordance with Part 2 of the Work Instructions of Boeing 
Alert Service Bulletin 747-55A2050, Revision 1, dated May 1, 2003. 
Repeat the HFEC inspection thereafter at intervals not to exceed 
2,700 flight cycles or 15,000 flight hours, whichever comes first.

Repair

    (m) If any discrepancy (cracking or damage) is found during any 
inspection or related investigative action required by paragraphs 
(f), (g), (i), or (l) of this AD: Before further flight, repair in 
accordance with the Work Instructions of Boeing Alert Service 
Bulletin 747-55A2050, Revision 1, dated May 1, 2003, except as 
provided by paragraph (n) of this AD. Where the service bulletin 
specifies to contact the manufacturer for appropriate action: Before 
further flight, repair according to a method approved by the 
Manager, Seattle Aircraft Certification Office (ACO), FAA; or 
according to data meeting the certification basis of the airplane 
approved by an Authorized Representative for the Boeing Delegation 
Option Authorization Organization who has been authorized by the 
Manager, Seattle ACO, to make those findings. For a repair method to 
be approved, the repair must meet the certification basis of

[[Page 56150]]

the airplane, and the approval must specifically refer to this AD.

Parts Installation

    (n) As of the effective date of this AD, no person may install 
any Maraging or H-11 steel fasteners in the locations specified in 
this AD. Where Boeing Alert Service Bulletin 747-55A2050, Revision 
1, dated May 1, 2003, specifies to install H-11 bolts (kept 
fasteners), this AD requires installation of inconel bolts.

Alternative Methods of Compliance (AMOCs)

    (o)(1) The Manager, Seattle 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 Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.
    (3) AMOCs, approved previously per AD 2002-06-02, amendment 39-
12678; or AD 2003-13-09, amendment 39-13209; are approved as AMOCs 
for the corresponding provisions of this AD, for the repaired area 
only.

    Issued in Renton, Washington, on September 16, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-19142 Filed 9-23-05; 8:45 am]
BILLING CODE 4910-13-P