05-2575. Airworthiness Directives; Boeing Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, and -300 Series Airplanes; and Model 747SP and 747SR Series Airplanes; Equipped With Pratt & Whitney Model JT9D-3, and -7 Series Engines

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing transport category airplanes listed above. This proposed AD would require repetitive inspections for cracks of the upper surface of the aft lower spar web of the inboard and outboard struts, as applicable; and repetitive inspections for cracks of the upper surface of the intermediate web bay of the aft lower spar. This proposed AD would also require repetitive inspections and torque checks of the bolts common to the aft lower spar chords and the fitting of the rear engine mount bulkhead for missing, loose, or fractured bolts, as applicable; and corrective action, if necessary. This proposed AD is prompted by reports of cracking in the aft lower spar web and reports of missing and fractured bolts. We are proposing this AD to detect and correct cracking of the aft lower spar web, and to prevent missing, loose, or fractured bolts common to the aft lower spar chords and the fitting of the rear engine mount bulkhead, which could result in the loss of the aft lower spar load path and reduced structural capability of the pylon, which may result in the separation of the engine from the airplane.

DATES:

We must receive comments on this proposed AD by March 28, 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.
• By fax: [phone].
• 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, PO Box 3707, Seattle, Washington 98124-2207.

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov, or at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2005-20325; the directorate identifier for this docket is 2003-NM-129-AD.

FOR FURTHER INFORMATION CONTACT:

Candice Gerretsen, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

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-2005-20325; Directorate Identifier 2003-NM-129-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments submitted by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You can review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

Examining the Docket

You can examine the AD docket in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) 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

We have received several reports of cracking in the aft lower spar web on Boeing Model 747-200B series airplanes equipped with Pratt & Whitney Model JT9D-7 series engines. The cracking in the aft lower spar web is the result of fatigue and sonic induced vibration. We also received reports of missing or fractured bolts common to the aft lower spar chord and the fitting of the rear engine mount bulkhead on Model 747-100 series airplanes. The missing and fractured bolts were found on strut No. 1, No. 3 and No. 4. The missing and fractured bolts are made of Maraging or H-11 steel and are subject to stress corrosion cracking. These conditions, if not corrected, could result in the loss of the aft lower spar load path and reduced structural capability of the pylon, which may result in the separation of the engine from the airplane.

The subject area on Model 747-100 and -200B series airplanes equipped with Pratt & Whitney Model JT9D-3 series engines is identical to that on the affected Model 747-100 and -200B series airplanes equipped with Pratt & Whitney Model JT9D-7 series engines. Therefore, those Model 747-100 and -200B series airplanes equipped with Pratt & Whitney Model JT9D-3 series engines are subject to the unsafe condition revealed on the affected Model 747-100 and -200B series airplanes equipped with Pratt & Whitney Model JT9D-7 series engines.

In addition, the subject area on Model 747-100B, -100B SUD, -200C, -200F, and -300 series airplanes, and Model 747SP and 747SR series airplanes, equipped with Pratt & Whitney Model JT9D-3 and -7 series engines, is identical to that on the affected Model 747-100 and -200B series airplanes equipped with Pratt & Whitney Model JT9D-3 and -7 series engines. Therefore, those Model 747-100B, -100B SUD, -200C, -200F, and -300 series airplanes; and Model 747SP and 747SR series airplanes equipped with Pratt & Whitney Model JT9D-3 and -7 series engines are subject to the unsafe condition revealed on the affected Model 747-100 and -200B series airplanes equipped with Pratt & Whitney Model JT9D-3 and -7 series engines.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-54A2212, dated May 1, 2003, which describes the following procedures:

1. Part 1—Web Inspection

For certain airplanes, do initial and repetitive detailed visual inspections of the upper surface of the aft lower spar web on the inboard struts, and outboard struts as applicable, for cracks. Do repairs, if necessary, and/or do “Part 4—Stiffener Addition.”

2. Part 2—Intermediate Web Bay Inspection

For certain airplanes, do initial and repetitive detailed visual inspections of the upper surface of the intermediate web bay of the aft lower spar for cracks, do repairs if necessary, and/or do “Part 5—Intermediate Stiffener Addition.”

3. Part 3—Maraging or H-11 Steel Bolt Inspection

For certain airplanes, do initial and repetitive detailed visual inspections and torque checks of the bolts common to the aft lower spar chords and the fitting of the rear engine mount bulkhead for missing, loose, or fractured bolts; and replace bolt with new bolt if necessary. Replacing the bolt in accordance with “Part 3” includes related investigative actions and corrective action. The related investigative actions include high frequency eddy current (HFEC) inspections for cracks of the chord, web, and fitting and detailed visual inspections for corrosion of the hole in the fitting of the rear engine mount bulkhead. The corrective action specifies contacting the manufacturer if any crack or corrosion is found.

4. Part 4—Stiffener Addition (Optional)

For certain airplanes, install stiffeners for inboard and outboard struts as applicable, do related investigative actions, and do repairs if necessary. The related investigative actions include HFEC inspections for cracks of the hole and around the aft fasteners of the fitting of the rear engine mount bulkhead. “Part 4—Stiffener Addition” procedures will either extend the repetitive inspection interval or end the repetitive inspections of “Part 1—Web Inspection.”

5. Part 5—Intermediate Stiffener Addition (Optional)

For certain airplanes, installing stiffeners for inboard and outboard struts will end the repetitive inspections of “Part 2—Intermediate Web Bay Inspection.” Boeing Alert Service Bulletin 747-54A2212 refers to Boeing Service Bulletins 747-71-2188 and 747-54-2115, as additional sources of service information for accomplishment of the installation.

6. Part 6—Maraging or H-11 Steel Bolt Replacement

For certain airplanes, replace all Maraging or H-11 steel bolts with new inconel bolts; do related investigative actions (includes HFEC inspections for cracks of the chord and web, the chord and the fitting of the rear engine mount bulkhead fitting and the pylon skin; and detailed visual inspections for corrosion of the pylon skin and the hole of the fitting of the rear engine mount bulkhead); and do corrective action (includes contacting the manufacturer if any crack, corrosion, or damage is found which cannot be removed within the oversize limit). Replacement of all bolts with new inconel bolts in accordance with “Part 6—Maraging or H-11 Steel Bolt Replacement” ends the repetitive inspections of “Part 3—Maraging or H-11 Steel Bolt Inspection.”

We have determined that accomplishing 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 airplanes of this same type design. Therefore, we are proposing this AD, which would require the following actions:

• Repetitive inspections for cracks of the upper surface of the aft lower spar web on the inboard and outboard struts, as applicable.
• Repetitive inspections for cracks of the upper surface of the intermediate web bay of the aft lower spar, as applicable.
• Repetitive inspections and torque checks of the bolts common to the aft lower spar chords and the fitting of the rear engine mount bulkhead for missing, loose, or fractured bolts, as applicable.
• Corrective action, if necessary.

The proposed AD would require you to use the service information described previously to do 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 following differences between the proposed AD and the service bulletins have been coordinated with the manufacturer:

1. Operators should note that although Boeing Alert Service Bulletin 747-54A2212, dated May 1, 2003, specifies that operators may contact the manufacturer for additional instructions for certain repairs, this proposed AD would require operators to repair according to a method approved by the 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 FAA to make those findings.

2. Operators should also note that where Boeing Alert Service Bulletin 747-54A2212, dated May 1, 2003, references “service bulletin 747-71-2188 Revision 1 or later releases,” this proposed AD would require that operators refer to Boeing Service Bulletin 747-71-2188, Revision 1, dated January 17, 1986; or Revision 2, dated September 24, 1988. When referencing a specific service bulletin in an AD, using the phrase, “or later FAA-approved revisions,” violates Office of the Federal Register regulations for approving materials that are incorporated by reference.

3. Operators should also note, that where the referenced Boeing Service Bulletins 747-71-2188, Revision 1, dated January 17, 1986, and Revision 2, dated September 24, 1988; and Boeing Service Bulletins 747-54-2115, dated February 14, 1986, and Revision 1, dated May 12, 1988; specify to repair according to an operators equivalent procedure, this proposed AD would require operators to repair according to a method approved by the 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 FAA to make those findings.

Clarification of Inspection Terminology

In this proposed AD, the “detailed visual inspection” specified in Boeing Alert Service Bulletin 747-54A2212, dated May 1, 2003, is referred to as a “detailed inspection.” We have included the definition for a detailed inspection in a note in the proposed AD.

Costs of Compliance

There are about 244 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 82 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Applicable airplanes identified in Boeing alert service bulletin 747-54A2212 as—	Action	Work hours	Average labor rate per hour	Cost per airplane, per inspection cycle
Groups 1-6	Web Inspection	8	$65	$520
Groups 7-8	Web Inspection	4	65	260
Groups 1-5	Web Bay Inspection	4	65	260
Groups 1-6	Bolt Inspection	4	65	260

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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2005-20325; Directorate Identifier 2003-NM-129-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by March 28, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, and -300 series airplanes, and Model 747SP and 747SR series airplanes; certificated in any category; equipped with Pratt & Whitney Model JT9D-3 and -7 series engines; as identified in Boeing Alert Service Bulletin 747-54A2212, dated May 1, 2003.

Unsafe Condition

(d) This AD was prompted by reports of cracking in the aft lower spar web and reports of missing and fractured bolts. We are issuing this AD to detect and correct cracking of the aft lower spar web and to prevent missing, loose, or fractured bolts common to the aft lower spar chords and the fitting of the rear engine mount bulkhead, which could result in the loss of the aft lower spar load path and reduced structural capability of the pylon, which may result in the separation of the engine from 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.

Service Bulletin Reference

(f) The term “service bulletin,” as used in this AD, means Boeing Alert Service Bulletin 747-54A2212, dated May 1, 2003.

Part 1—Web Inspections

(g) At the applicable times specified in paragraph (g)(1), (g)(2), or (g)(3) of Table 1 of this AD, do initial and repetitive detailed inspections for cracks of the upper surface of the aft lower spar web of the inboard and outboard struts, as applicable; and before further flight, do any applicable repair; by doing all the actions specified in “Part 1—Web Inspection” of the Work Instructions of the service bulletin. For certain airplanes, the repetitive inspections may be deferred or ended provided that the optional stiffener addition specified in paragraph (k) of this AD is done.

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.”

Table 1.—Compliance Times for Web Inspection

For Airplanes Identified in the Service Bulletin As—	Initial Compliance Time Is—	Repetitive Interval Is—
(1) Group 1 airplanes on which the modification specified in Boeing Service Bulletin 747-54-2028, dated August 1, 1972, has been done; and Group 2 airplanes	Within 12 months after the effective date of this AD	At intervals not to exceed 2,400 flight cycles.
(2) Group 1 airplanes on which the modification specified in Boeing Service Bulletin 747-54-2028, dated August 1, 1972, has not been done; and Group 7 airplanes	Within 6 months after the effective date of this AD	At intervals not to exceed 350 flight cycles.
(3) Group 3, 4, 5, 6, and 8 airplanes	Within 12 months after the effective date of this AD	At intervals not to exceed 1,200 flight cycles.

Part 2—Intermediate Web Bay Inspection

(h) At the applicable times specified in paragraph (h)(1) or (h)(2) of Table 2 of this AD, do initial and repetitive detailed inspections for cracks of the upper surface of the intermediate web bay of the aft lower spar; and before further flight do any applicable repair; by doing all the actions specified in “Part 2—Intermediate Web Bay Inspection” of the Work Instructions of the service bulletin. The repetitive inspections may be ended provided that the optional intermediate stiffener addition specified in paragraph (l) of this AD is done.

Table 2.—Compliance Times for Intermediate Web Bay Inspections

For Airplanes Identified in the Service Bulletin As—	Initial Compliance Time Is—	Repetitive Interval Is—
(1) Group 1 through 4 airplanes on which the modification specified in Boeing Service Bulletin 747-71-2188, dated March 14, 1983, has been done and on which the additional work specified in Boeing Service Bulletin AD 747-71-2188, Revision 1, dated January 17, 1986; or Revision 2, dated September 24, 1988; has not been done	Within 6 months after the effective date of this AD	At intervals not to exceed 350 flight cycles.
(2) Group 5 airplanes on which the modification specified in Boeing Service Bulletin 747-54-2115, dated February 14, 1986; or Revision 1, dated May 12, 1988; has not been done	Within 6 months after the effective date of this AD	At intervals not to exceed 350 flight cycles.

Part 3—Maraging or H-11 Steel Bolt Inspection

(i) For Group 1 through 6 airplanes identified in the service bulletin: Within 12 months after the effective date of this AD, do a detailed inspection and torque check of the bolts common to the aft lower spar chords and the fitting of the rear engine mount bulkhead for missing, loose, or fractured bolts, and do any applicable replacement (including related investigative actions and corrective action), by doing all the actions specified in “Part 3 “ Maraging or H-11 Steel Bolt Inspection” of the Work Instructions of the service bulletin, except as provided by paragraph (o) of this AD. Do any applicable replacements (including related investigative actions and corrective action) before further flight, except as provided by paragraph (j) of this AD. Repeat the actions thereafter at intervals not to exceed 18 months. The inspections and torque checks specified in paragraph (i) of this AD may be ended provided that the replacement specified in paragraph (n) of this AD is done.

(j) If during any inspection required by paragraph (i) of this AD, one of the conditions specified in paragraphs (j)(1) and (j)(2) of this AD is found, do the applicable actions specified in paragraphs (j)(1) and (j)(2) of this AD.

(1) If a missing or fractured bolt is found on the inboard strut in any one bay, within 36 months after replacing the bolt with a new bolt, do the replacement specified in paragraph (n) of this AD.

(2) If two or more missing or fractured bolts are found in any one bay, before further flight, do the replacement specified in paragraph (n) of this AD.

Part 4—Optional Stiffener Addition

(k) Except as provided by paragraph (o) of this AD, accomplishing the optional stiffener addition for the inboard and outboard struts, doing the related investigation actions, and doing any applicable repair, by doing all the actions specified in “Part 4—Stiffener Addition” of the Work Instructions of the service bulletin before further flight after accomplishing the actions specified in paragraph (g) of this AD, defers or ends the repetitive inspections required by paragraph (g) of this AD as follows:

(1) For airplanes listed in paragraph (g)(2) of Table 1 of this AD, accomplishing the optional stiffener addition extends the repetitive inspections required by paragraph (g) of this AD to intervals not to exceed 2,400 flight cycles.

(2) For airplanes listed in paragraph (g)(3) of Table 1 of this AD, accomplishing the optional stiffener addition ends the repetitive inspections required by paragraph (g) of this AD.

Part 5—Optional Intermediate Stiffener Addition

(l) For airplanes identified in paragraphs (h)(1) and (h)(2) of Table 2 of this AD: Accomplishing the optional intermediate stiffener addition for the inboard and outboard struts, by doing all the actions specified in “Part 5—Intermediate Stiffener Addition” of the Work Instructions of the service bulletin before further flight after accomplishing the actions specified in paragraph (h) of this AD, except as provided by paragraph (m) of this AD, ends the repetitive inspections required by paragraph (h) of this AD.

(m) Where the service bulletin specifies to install stiffeners as shown in “service bulletin 747-71-2188 Revision 1 or later releases (Group 1, 2,3, and 4 Airplanes) or 747-54-2115 Original Issue or Revision 1 (Group 5 Airplanes),” this AD requires that those actions be done in accordance with Boeing Service Bulletin 747-71-2188, Revision 1, dated January 17, 1986, or Revision 2, dated September 24, 1988; or Boeing Service Bulletin 747-54-2115, dated February 14, 1986, or Revision 1, dated May 12, 1988; as applicable, except as provided by paragraph (o) of this AD.

Part 6—Maraging or H-11 Steel Bolt Replacement

(n) For Group 1 through 6 airplanes identified in the service bulletin: Except as provided by paragraph (o) of this AD, replacing all Maraging or H-11 steel bolts with new inconel bolts, doing the related investigation actions, and doing any applicable corrective action, by doing all the actions specified in “Part 6—Maraging or H-11 Steel Bolt Replacement” of the Work Instructions of the service bulletin ends the inspections and torque checks required by paragraph (i) of this AD.

Contact the FAA

(o) If during any action required by this AD the service bulletin specifies to contact Boeing for additional instructions; or if Boeing Service Bulletin 747-71-2188, Revision 1, dated January 17, 1986, or Revision 2, dated September 24, 1988; or Boeing Service Bulletin 747-54-2115, dated February 14, 1986, or Revision 1, dated May 12, 1988, specifies to repair according to operators equivalent procedures: 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 approval must specifically reference this AD.

Parts Installation

(p) As of the effective date of this AD, no person may install a Maraging or H-11 steel bolt in the locations specified in this AD, on any airplane.

Alternative Methods of Compliance (AMOCs)

(q) The Manager, Seattle ACO, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

Issued in Renton, Washington, on January 26, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.