03-9302. Airworthiness Directives; McDonnell Douglas Model DC-8-11, DC-8-12, DC-8-21, DC-8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 Airplanes; Model DC-8-50 Series Airplanes; Model DC-8F-54 and DC-8F-55 Airplanes; Model DC-8-60 Series ...

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas airplanes. This proposal would require an inspection to determine the material composition of the auxiliary spar cap of the lower inboard of the left and right wings. For certain airplanes, this proposal also would require repetitive detailed and dye penetrant inspections for cracking of the spar cap, and corrective actions if necessary. This action is necessary to detect and correct stress corrosion cracking of the auxiliary spar cap, which could cause excessive loads to the structure attaching the support fitting of the main landing gear (MLG) to the wing, and result in loss of the MLG. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by June 2, 2003.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-184-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2001-NM-184-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Boeing Commercial Aircraft Group, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024). This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington FAA, or at the Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California.

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

Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NM-184-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-184-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received numerous reports indicating that cracking has occurred in the auxiliary spar cap of the lower inboard near the outboard attach bolts on various McDonnell Douglas Model DC-8 airplanes. The cracking occurred on airplanes that have accumulated more than 36,000 total flight hours. Investigation indicates that the cracking appeared to be due to stress corrosion. Such cracking of the auxiliary spar cap, if not detected and corrected, could cause excessive loads on the structure attaching the support fitting of the main landing gear (MLG) to the wing, and result in loss of the MLG.

Explanation of Relevant Service Information

The FAA has reviewed and approved McDonnell Douglas DC-8 Service Bulletin 57-85, Revision 1, dated July 5, 1991. That service bulletin describes procedures for performing repetitive detailed and dye penetrant inspections to detect stress cracking of the auxiliary spar cap of the lower inboard of the left and right wings. For cracking that is within certain limits, the service bulletin describes corrective actions such as repair or rework and application of corrosion-inhibiting compound, if necessary. For any cracking that is outside the limits specified in the service bulletin, the service bulletin describes procedures for replacing the auxiliary spar cap with either a new spar cap made with 7075-T6 aluminum or with a new, improved spar cap made with 7075-T73 aluminum. Additionally, for any cracking that is detected at the bathtub end of both forward and aft bolt holes, the service bulletin describes procedures for replacement of those MLG fittings with new or serviceable fittings. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require an inspection to determine the material composition of the auxiliary spar cap. If the spar cap is made of 7075-T6 aluminum, the proposed AD would require accomplishment of the actions and procedures specified in the service bulletin described above for the repetitive inspections for cracking, and repair, rework, and replacement of the spar cap if necessary.

Operators should note that the FAA has received information indicating that there may be a parts availability problem in procuring spar caps made of 7075-T73 aluminum. However, we have determined that the repetitive inspections proposed by this AD can be allowed to continue in lieu of accomplishment of the terminating action (replacement of both spar caps with caps made of 7075-T73 aluminum). In making this determination, we consider that, in this case, long-term continued operational safety will be adequately assured by accomplishing the repetitive inspections to detect cracking of the auxiliary spar cap before it represents a hazard to the airplane.

Differences Between This NPRM and the Service Information

The FAA considers that, prior to performing the inspections and corrective actions described in the service bulletin above, it is necessary to perform an inspection to determine the material composition of the auxiliary spar cap of the lower inboard of the left and right wings. That inspection may be done per a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, or by performing an eddy current test of the auxiliary spar cap per the Non-Destructive Testing Standard Practice Manual MDC-93K0393 (NDTSPM) 06-10-01.006. If the auxiliary spar cap is composed of 7075-T6 aluminum, this proposed AD would require accomplishment of the actions specified in the service bulletin described above, as applicable.

Additionally, operators should note that, although the service bulletin specifies that the manufacturer may be contacted for disposition of certain cracking outside the limits specified in the service bulletin, this proposal would require the disposition of any such cracking that was detected to be accomplished per a method approved by the FAA.

Cost Impact

There are approximately 264 airplanes of the affected design in the worldwide fleet. The FAA estimates that 244 airplanes of U.S. registry would be affected by this proposed AD. We estimate that it would take approximately 2 work hours per airplane to accomplish the proposed inspection to determine the material of the spar cap. We estimate that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $29,280, or $120 per airplane, per inspection cycle.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive:

McDonnell Douglas: Docket 2001-NM-184-AD.

Applicability: Model DC-8-11, DC-8-12, DC-8-21, DC-8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 airplanes; Model DC-8-51, DC-8-52, DC-8-53, and DC-8-55 airplanes; Model DC-8F-54 and DC-8F-55 airplanes; Model DC-8-61, DC-8-62, and DC-8-63 airplanes; Model DC-8-61F, DC-8-62F, and DC-8-63F airplanes; Model DC-8-71, DC-8-72, and DC-8-73 airplanes; as listed in McDonnell Douglas DC-8 Service Bulletin 57-85, Revision 1, dated July 5, 1991; certificated in any category.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To detect and correct cracking of the auxiliary spar cap, which could cause excessive loads to the structure attaching the support fitting of the main landing gear (MLG) to the wing, and result in loss of the MLG; accomplish the following:

Inspection To Determine the Material of the Auxiliary Spar Cap

(a) Within 24 months or 2,000 flight cycles after the effective date of this AD, whichever occurs later, inspect to determine the material composition of the auxiliary spar cap (Part Numbers 5615058-1 through -506 inclusive) of the lower inboard of the left and right wings, in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, or by performing an eddy current test of the auxiliary spar cap per the Non-Destructive Testing Standard Practice Manual MDC-93K0393 (NDTSPM) 06-10-01.006. If the material of the spar cap is 7075-T73 aluminum, no further action is required by this paragraph.

Inspections for Cracking and Follow-on Corrective Actions

(b) If the material of the auxiliary spar cap found during the inspection required by paragraph (a) of this AD is 7075-T6 aluminum: Within 2 years or 2,000 flight cycles after accomplishing the inspection required by paragraph (a) of this AD, perform a detailed inspection and a dye penetrant inspection for cracking of the auxiliary spar cap and the bathtub end of either the forward or the aft bolt hole of the lower inboard of the left and right wings, as applicable, per McDonnell Douglas DC-8 Service Bulletin 57-85, Revision 1, dated July 5, 1991.

Note 2:

For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

(1) If no cracking is detected, repeat the inspection at intervals not to exceed 6,400 flight hours, until the auxiliary spar cap is replaced with a spar cap made with 7075-T73 aluminum, in accordance with the service bulletin.

(2) If any cracking of the auxiliary spar cap or at the bathtub end of either the forward or the aft bolt hole is detected that is within the limits specified in the service bulletin, before further flight, rework or repair the spar cap, as applicable, and apply corrosion inhibiting compound, in accordance with the service bulletin. Repeat the inspection for cracking at intervals not to exceed 1,600 flight hours, until the auxiliary spar cap is replaced with a spar cap composed of 7075-T73 aluminum. Replacement of both spar caps with 7075-T73 aluminum is terminating action for the requirements of this AD.

(3) If any cracking at the bathtub end of both the forward and aft bolt holes is detected that is within the limits specified in the service bulletin, before further flight, replace the MLG fitting with a new or serviceable fitting, in accordance with the service bulletin.

(4) If any cracking of the auxiliary spar cap is detected that is outside the limits specified in the service bulletin, before further flight, replace the auxiliary spar cap with a cap composed of 7075-T73 aluminum, in accordance with the service bulletin, or by a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA. For a repair method to be approved by the Manager, Los Angeles ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.

Alternative Methods of Compliance

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Los Angeles ACO, FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO, FAA.

Note 3:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles ACO.

Special Flight Permits

(d) Special flight permits may be issued in accordance with §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Issued in Renton, Washington, on April 8, 2003.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.