[Federal Register Volume 71, Number 95 (Wednesday, May 17, 2006)]
[Rules and Regulations]
[Pages 28570-28574]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-4541]


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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; 
Amendment 39-14600; AD 2006-10-16]
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 superseding two existing airworthiness directives 
(ADs); one AD is applicable to all Boeing Model 747 airplanes and the 
other AD is applicable to certain Boeing Model 747 airplanes. The first 
AD currently 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. 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 new AD adds, 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 new AD adds a detailed inspection to determine the type 
of fasteners, related investigative actions, and repair if necessary. 
This new AD also revises the compliance times for certain inspections 
and adds alternative inspections for cracking of the upper skin of the 
center section and rear spar upper chord. This AD results from 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.

DATES: This AD becomes effective June 21, 2006.
    On July 15, 2003 (68 FR 38583, June 30, 2003), the Director of the 
Federal Register approved the incorporation by reference of Boeing 
Alert Service Bulletin 747-55A2050, Revision 1, dated May 1, 2003.
    On April 3, 2002 (67 FR 12464, March 19, 2002), the Director of the 
Federal Register approved the incorporation by reference of Boeing 
Alert Service Bulletin 747-55A2050, dated February 28, 2002.

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: 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:

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

[[Page 28571]]

part 39 to include an AD that supersedes AD 2002-06-02, amendment 39-
12678 (67 FR 12464, March 19, 2002), and AD 2003-13-09, amendment 39-
13209 (68 FR 38583, June 30, 2003). AD 2002-06-02 applies to all Boeing 
Model 747 airplanes; AD 2003-13-09 applies to certain Boeing Model 747 
airplanes. That NPRM was published in the Federal Register on September 
26, 2005 (70 FR 56145). That NPRM proposed to 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. That NPRM also proposed to 
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. That 
NPRM also proposed, for certain airplanes, to add repetitive 
inspections for cracking of the horizontal stabilizer center and 
outboard section, and repair if necessary. For certain other airplanes, 
that NPRM proposed to add a detailed inspection to determine if 
fasteners are Maraging or H-11 steel fasteners, related investigative 
actions, and corrective action if necessary. That NPRM also proposed to 
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.

Comments

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

Request To Clarify Instructions in Paragraph (g)

    Boeing asks that paragraph (g) of the NPRM be clarified to direct 
operators to the applicable section of the Work Instructions in Boeing 
Alert Service Bulletin 747-55A2050, Revision 1, dated May 1, 2003 
(referenced in the NPRM as the appropriate source of service 
information for accomplishing the required actions). We agree with 
Boeing and have clarified paragraphs (g), (g)(1), and (g)(2) of this AD 
accordingly.

Request To Change Paragraphs (f)(1) and (f)(2)

    Boeing also asks that we change paragraphs (f)(1) and (f)(2) of the 
NPRM to require accomplishing the inspections in accordance with Part 1 
of the Work Instructions of Revision 1 of the alert service bulletin, 
instead of specifying paragraph (f) of the NPRM. Boeing states that 
this change will make the inspection methods consistent with the 
inspection intervals in paragraph (f) and Revision 1 of the alert 
service bulletin.
    We acknowledge Boeing's concern, and we agree that the inspection 
must be accomplished in accordance with Part 1 of the Work 
Instructions; however, paragraph (f) of this AD already requires that 
the inspections be accomplished as of the effective date of this AD in 
accordance with Part 1 of the Work Instructions of Boeing Alert Service 
Bulletin 747-55A2050, Revision 1, dated May 1, 2003. Since paragraphs 
(f)(1) and (f)(2) of this AD require that the repetitive inspections be 
accomplished per paragraph (f); we have made no change to the AD in 
this regard.

Request To Change Paragraph (i)

    Boeing also asks that we change paragraph (i) of the NPRM to 
require accomplishing the inspections in accordance with Part 4 of the 
Work Instructions of Revision 1 of the alert service bulletin. Boeing 
states that this change will direct operators to the correct paragraph 
in the service bulletin.
    We acknowledge Boeing's concern and we agree that the inspection 
must be accomplished in accordance with Part 4 of the Work Instructions 
of Revision 1 of the alert service bulletin. However, paragraph (i) of 
this AD requires that the inspections be accomplished per paragraph 
(g)(2) of this AD, which identifies accomplishing the inspections per 
Part 4 of the Work Instructions of Revision 1 of the alert service 
bulletin. Therefore, it is not necessary to restate those requirements 
in paragraph (i). We have made no change to the AD in this regard.

Request To Change Paragraph (k)

    In addition, Boeing asks that we change paragraph (k) of the NPRM 
to add the following: ``If any bolt is cracked or fractured, high 
frequency eddy current (HFEC) inspect the bolt hole and replace the 
bolt, in accordance with Part 5 of the Work Instructions of Revision 1 
of the alert service bulletin.'' Boeing states that the NPRM contains 
no instructions for replacing cracked or broken bolts, and 
reinstallation of those bolts could result in overloaded adjacent 
bolts.
    We do not agree with Boeing that a change is necessary. Paragraph 
(k) of this AD provides instructions for repetitive inspections for 
magnetic fasteners that are not cracked or fractured. It would not be 
appropriate to combine the requirements for bolts that are not cracked 
or fractured, as specified in paragraph (k), with those for cracked or 
fractured bolts. Paragraph (j) of this AD provides instructions for 
inspecting for any cracked or fractured magnetic fastener. Paragraph 
(j) specifies that ``corrective action'' must be accomplished by doing 
all the actions specified in Part 5 of the Work Instructions of 
Revision 1 of the alert service bulletin. Part 5, Step 1.l., describes 
procedures for open hole HFEC inspections of the bolt hole, and 
replacement of the bolt. Therefore, we have made no change to the AD in 
this regard.

Request To Change Paragraph (n)

    Boeing also asks that we change paragraph (n) of the NPRM to allow 
a grace period for replacing H-11 (magnetic) or Maraging steel bolts. 
Boeing states that operators accomplishing magnetic and fluorescent 
particle inspections of H-11 or Maraging steel bolts would be 
prohibited from re-installing undamaged H-11 or Maraging steel bolts. 
Boeing adds that paragraph (n) of the NPRM conflicts with paragraph (k) 
of the NPRM, which allows repeat inspections of H-11 or Maraging steel 
bolts. Boeing notes that operators accomplishing magnetic and 
fluorescent particle inspections of H-11 or Maraging steel bolts, or 
open hole HFEC inspections of Zone B, would be unable to re-install 
undamaged H-11 or Maraging steel bolts. Operators would be required to 
install Inconel bolts within 12 months after the effective date of the 
AD (for Zone B inspections), or within 18 months after the effective 
date of the AD (for Zone C inspections). H-11 or Maraging steel bolts 
were originally installed on 460 airplanes that are currently 
operating, and Boeing is unable to supply 460 bolt kits within a 12 to 
18 month period. Boeing adds that there are currently no bolt kits in 
stock, and only 3 bolt kits scheduled for delivery; therefore, the 
requirements in paragraph (n) could ground up to 460 airplanes. In 
addition, operators accomplishing ultrasonic inspections of H-11 or 
Maraging steel bolts per the Boeing 747 Nondestructive Test Manual D6-
7171, Part 4, Chapter 51-00-00, will require bolt standards with 
identical diameter and grip lengths as the bolts installed on the 
airplane. These bolt standards are not readily available.
    We acknowledge Boeing's concern, and we agree that there would be a 
hardship on operators if we required replacement of bolts when they 
were

[[Page 28572]]

unable to obtain spare parts. However, we have determined that a 
shortage of parts is not a concern since this AD does not require 
removal of H-11 bolts for inspection. The only bolts that this AD 
requires replacing are those that are found cracked or that an operator 
elects to replace. Although paragraph (n) of this AD does not allow re-
installation of a non-cracked H-11 or Maraging steel bolt, that 
paragraph does not require removal of the bolt in the first place. 
Instead, paragraphs (j) and (k) of this AD require inspections of the 
magnetic bolts in accordance with Part 5 of the Work Instructions of 
Revision 1 of the alert service bulletin. Step 1.j. of Part 5 provides 
the option of removing the bolt or leaving the bolt in place and 
accomplishing an ultrasonic inspection. Therefore, there is no hardship 
for operators since they may choose to leave the bolt in place and 
accomplish an ultrasonic inspection. If no cracking is found, operators 
are allowed to repeat that inspection with the bolt in place as long as 
no cracking is found during any inspection. Therefore, we have made no 
change to the AD in this regard.

Request To Change Compliance Time in Paragraph (f)(1)

    Boeing also asks that we change paragraph (f)(1) of the NPRM to add 
a 5,600-flight-hour cap to the compliance time for the initial 
inspection done after the effective date of the AD. Boeing states that 
this change will make the inspection methods consistent with the 
inspection intervals in paragraph (f) and with Revision 1 of the alert 
service bulletin.
    We do not agree with Boeing. We did not add a 5,600-flight-hour cap 
to the compliance time for the initial inspection so that operators 
would be allowed to transition to the new interval if they were already 
accomplishing the repetitive inspections required by AD 2002-06-02. 
Certain requirements of that AD have been retained in this AD. After 
the initial inspection, operators will be limited to repeating the 
inspection within 1,000 flight cycles or 5,600 flight hours, whichever 
is first, which coincides with Revision 1 of the alert service 
bulletin. We have made no change to the AD in this regard.

Request To Extend Compliance Time in Paragraph (h)

    Northwest Airlines (NWA) asks that we extend the compliance time 
for the initial inspection, as specified in paragraphs (h)(2)(i)(B) and 
(h)(2)(ii)(B) of the NPRM, from 12 to 18 months. NWA states that the 
most significant impact in the NPRM is the requirement to perform the 
paragraph (g) inspections within the initial inspection threshold 
specified in paragraphs (h)(2)(i)(B) and (h)(2)(ii)(B). NWA notes that 
the proposed thresholds differ significantly from those in AD 2003-13-
09 (referenced in paragraph (h)(1)(ii) of the NPRM). NWA adds that 6 of 
its Model 747-200 airplanes may require inspections within 12 months 
from the effective date of a new adopted rule. NWA states that 
extending the compliance time to 18 months will allow accomplishment of 
the inspections during planned heavy maintenance C-check visits.
    We do not agree with NWA. The 12-month compliance time in 
paragraphs (h)(2)(i)(B) and (h)(2)(ii)(B) is in the referenced service 
bulletin, but was not included in AD 2003-13-09 because it did not meet 
the criteria necessary to be included in an immediately adopted rule. 
AD 2003-13-09 included interim action which specified that we were 
considering a separate rulemaking action to address these inspections 
at a later date. 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 inspections 
are done. Since maintenance schedules vary among operators, there would 
be no assurance that the airplane would be inspected during that 
maximum interval of 18 months. In addition, the 12-month compliance 
time agrees with the manufacturer's service bulletin referenced in the 
AD. We have made no change to the AD in this regard.

Conclusion

    We have carefully reviewed the available data, including the 
comments that have been 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 1,087 Model 747 airplanes worldwide and 
affects about 227 airplanes of U.S. registry. The following table 
provides the estimated costs for U.S. operators to comply with this AD. 
The costs for the inspections are per inspection cycle.

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

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.

[[Page 28573]]

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 
removing amendment 39-12678 (67 FR 12464, March 19, 2002), and 
amendment 39-13209 (68 FR 38583, June 30, 2003), and by adding the 
following new airworthiness directive (AD):

2006-10-16 Boeing: Amendment 39-14600. Docket No. FAA-2005-22510; 
Directorate Identifier 2004-NM-32-AD.

Effective Date

    (a) This AD becomes effective June 21, 2006.

Affected ADs

    (b) This AD supersedes AD 2002-06-02 and AD 2003-13-09.

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), whichever occurs 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 Part 3 of 
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 Work 
Instructions 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 Work 
Instructions 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).

[[Page 28574]]

    (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 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 or AD 2003-13-
09, are approved as AMOCs for the corresponding provisions of this 
AD, for the repaired area only.

Material Incorporated by Reference

    (p) You must use Boeing Alert Service Bulletin 747-55A2050, 
dated February 28, 2002; or Boeing Alert Service Bulletin 747-
55A2050, Revision 1, dated May 1, 2003; as applicable; to perform 
the actions that are required by this AD, unless the AD specifies 
otherwise.
    (1) On July 15, 2003 (68 FR 38583, June 30, 2003), the Director 
of the Federal Register approved the incorporation by reference of 
Boeing Alert Service Bulletin 747-55A2050, Revision 1, dated May 1, 
2003.
    (2) On April 3, 2002 (67 FR 12464, March 19, 2002), the Director 
of the Federal Register approved the incorporation by reference of 
Boeing Alert Service Bulletin 747-55A2050, dated February 28, 2002.
    (3) 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 May 8, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 06-4541 Filed 5-16-06; 8:45 am]
BILLING CODE 4910-13-P