Airworthiness directives: Boeing,
[Federal Register: September 26, 2005 (Volume 70, Number 185)]
[Proposed Rules]
[Page 56145-56150]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr26se05-15]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
[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).
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
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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
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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:
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Revised Paragraph Identifiers for AD 2002-06-02
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:
-
Is not a ``significant regulatory action'' under Executive Order 12866;
-
Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and
-
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
-
The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
-
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
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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
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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
