E7-6338. Airworthiness Directives; McDonnell Douglas Model DC-8-53, DC-8-55, DC-8F-54, and DC-8F-55 Airplanes; and Model DC-8-60, DC-8-60F, DC-8-70, and DC-8-70F Series Airplanes

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 McDonnell Douglas airplanes, identified above. This proposed AD would require a one-time inspection to determine the configuration of the airplane (tee or angle doubler installed on the left and right side of the flat aft pressure bulkhead from Longeron 9 to Longeron 13). This proposed AD would also require repetitive inspections for cracking of the tee or angle doubler, and corrective actions if necessary. This proposed AD results from a report indicating that numerous operators have found cracks on the tee. We are proposing this AD to detect and correct stress corrosion cracking of the tee or angle doubler installed on the flat aft pressure bulkhead. Cracking in this area could continue to progress and damage the adjacent structure, which could result in loss of structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by May 21, 2007.

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: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9:00 a.m. and 5:00 p.m., Monday through Friday, except Federal holidays.

Contact Boeing Commercial Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024), for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Jon Mowery, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2007-27777; Directorate Identifier 2006-NM-265-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 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 may review 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 may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9:00 a.m. and 5:00 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 Docket Management System receives them.

Discussion

We have received a report indicating that numerous operators have found cracks on the flat aft pressure bulkhead tee. The tee is installed on the left and right side of McDonnell Douglas Model DC-8 airplanes that have a flat aft pressure bulkhead. The cracks, which originate in the corner radius of the tee from Longeron 9 to Longeron 13, are a result of stress corrosion. This condition, if not corrected, could result in cracks continuing to progress, and consequent damage the adjacent structure and loss of structural integrity of the airplane.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin DC8-53A081, dated November 14, 2006. The service bulletin describes procedures for doing an initial inspection using one of the following methods as applicable:

• For airplanes not previously repaired (Configuration 1), the service bulletin specifies doing the initial inspection for cracking of the tee installed on the left and right side of the flat aft pressure bulkhead from Longeron 9 to Longeron 13, according to one of three inspection methods specified in the DC-8 Supplemental Inspection Document (SID) L26-011, Volume II, 53-10-18: Methods 01A (High Frequency Eddy Current (HFEC)) and 01B (Ultrasonic) together; or Method 02 (HFEC); or Method 03 (Visual Aided).
• For airplanes previously repaired with an angle doubler that was installed in accordance with DC-8 Structural Repair Manual 53-2-5, Figure 9 (Configuration 2), the service bulletin specifies an initial HFEC inspection for cracking of the angle doubler.
• For airplanes previously repaired with any repair other than one installed in accordance with DC-8 Structural Repair Manual 53-2-5, Figure 9 (Configuration 3), the service bulletin specifies contacting Boeing for instructions.

The service bulletin specifies the following actions, depending on crack findings:

• If no crack is found, the service bulletin specifies repeating the applicable inspection. For Configuration 1 airplanes, the repetitive intervals depend on the inspection type chosen, and range from within 2 years after the previous SID inspection or 600 flight cycles, whichever occurs earlier; to within 8 years after the previous SID inspection or 17,400 flight cycles, whichever occurs earlier. For Configuration 2 airplanes, the repetitive interval is 4,500 flight cycles.
• If any crack is found, the service bulletin specifies the corrective action of repairing the crack before further flight. The repair involves installing an angle doubler (if not previously installed) or removing the cracked angle doubler and installing a new one (if previously installed). The service bulletin states that the repetitive interval after repair is 4,500 flight cycles, and only the HFEC inspection type is specified for the repetitive inspections.

The service bulletin also specifies that, for Configuration 1 airplanes, if maintenance records show that the flat aft pressure bulkhead tee was previously inspected using one of the three inspection methods specified in the DC-8 SID L26-011, Volume II, 53-10-18, and no crack was found, the inspections may be continued at the applicable repetitive interval specified for Configuration 1 airplanes on which no crack is found during the initial inspection.

Accomplishing the actions specified in the service information is intended to 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. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Difference between the Proposed AD and the Service Bulletin.” This proposed AD also would require determining the configuration of the airplane.

Difference Between the Proposed AD and the Service Bulletin

The service bulletin specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing 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 Commercial Airplanes Delegation Option Authorization Organization whom we have authorized to make those findings.

Costs of Compliance

There are about 321 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 139 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD. The average labor rate is $80 per work hour.

Estimated Costs

Action	Work hours	Cost per airplane	Fleet cost
Inspection to determine the configuration of the airplane, and to determine previous inspection method	1	$80	$11,120.
Configuration 1, per inspection cycle	11	$880, per inspection cycle	Up to $122,320, per inspection cycle.
Configuration 2, per inspection cycle	5	$400, per inspection cycle	Up to $55,600, per inspection cycle.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this 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 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
• 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 Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

McDonnell Douglas: Docket No. FAA-2007-27777; Directorate Identifier 2006-NM-265-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by May 21, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to McDonnell Douglas Model DC-8-53, DC-8-55, DC-8-61, DC-8-61F, DC-8-62, DC-8-62F, DC-8-63, DC-8-63F, DC-8-71, DC-8-71F, DC-8-72, DC-8-72F, DC-8-73, DC-8-73F, DC-8F-54, and DC-8F-55 airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin DC8-53A081, dated November 14, 2006.

Unsafe Condition

(d) This AD results from a report indicating that numerous operators have found cracks on the tee installed on the left and right side of the flat aft pressure bulkhead from Longeron 9 to Longeron 13. We are issuing this AD to detect and correct stress corrosion cracking of the tee or angle doubler installed on the flat aft pressure bulkhead. Cracking in this area could continue to progress and damage the adjacent structure, which could result in loss of structural integrity 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.

Inspections and Related Investigative/Corrective Actions

(f) For all airplanes: Within 24 months after the effective date of this AD, inspect the left and right side of the flat aft pressure bulkhead from Longeron 9 to Longeron 13 to determine whether a tee is installed (also called Configuration 1 airplanes) or an angle is installed; and if any angle was installed in accordance with the DC-8 Structural Repair Manual 52-2-5, Figure 9 (also called Configuration 2 airplanes), or in accordance with any other repair method (also called Configuration 3 airplanes). A review of airplane maintenance records is acceptable in lieu of this inspection if the applicable installation can be conclusively determined from that review.

(1) For airplanes determined to be either Configuration 1 or Configuration 2: Within 24 months after the effective date of this AD, do the applicable inspection for cracking of the tee or angle doubler, and do all applicable corrective actions before further flight, by accomplishing all the actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin DC8-53A081, dated November 14, 2006. Repeat the applicable inspection thereafter at the applicable interval specified in Paragraph 1.E, “Compliance,” of Boeing Alert Service Bulletin DC8-53A081, dated November 14, 2006.

(2) For airplanes determined to be Configuration 1 airplanes: A review of the airplane maintenance records to determine if the tee was previously inspected using one of the three inspection methods specified in the DC-8 Supplemental Inspection Document (SID) L26-011, Volume II, 53-10-18; and to determine that no crack was found; is acceptable to determine the type of inspection and corresponding repetitive interval if the inspection type and crack finding can be conclusively determined from that review.

(3) For airplanes determined to be Configuration 3 airplanes: Within 24 months after the effective date of this AD, repair the previous installation. Where Boeing Alert Service Bulletin DC8-53A081, dated November 14, 2006, specifies to contact Boeing for instructions, repair using a method approved in accordance with the procedures specified in paragraph (g) of this AD.

Alternative Methods of Compliance (AMOCs)

(g)(1) The Manager, Los Angeles Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 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) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Los Angeles ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane and 14 CFR 25.571, Amendment 45, and the approval must specifically refer to this AD.

Issued in Renton, Washington, on March 29, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.