05-23655. Airworthiness Directives; McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 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 Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes. This proposed AD would require repetitive inspections for stress corrosion cracks of the main fuselage frame, and corrective actions if necessary. This proposed AD also would provide an optional terminating action for the repetitive inspections. This proposed AD results from several reports of cracking of the main fuselage frame. We are proposing this AD to detect and correct stress corrosion cracking of the main fuselage frame, which could result in extensive damage to adjacent structure, and reduced structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by January 20, 2006.

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 a.m. and 5 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:

Wahib Mina, 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. Include the docket number “FAA-2005-23197; Directorate Identifier 2005-NM-109-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 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 Docket Management System receives them.

Discussion

In April 1988, a high-cycle transport category airplane (specifically, a Boeing Model 737) was involved in an accident in which the airplane suffered major structural damage during flight. Investigation of this accident revealed that the airplane had numerous fatigue cracks and a great deal of corrosion. Subsequent inspections conducted by the operator on other high-cycle transport category airplanes in its fleet revealed that other airplanes had extensive fatigue cracking and corrosion.

Prompted by the data gained from this accident, the FAA sponsored a conference on aging airplanes in June 1988, which was attended by representatives from the aviation industry and airworthiness authorities from around the world. It became obvious that, because of the tremendous increase in air travel, the relatively slow pace of new airplane production, and the apparent economic feasibility of operating older technology airplanes rather than retiring them, increased attention needed to be focused on the aging airplane fleet and maintaining its continued operational safety.

The Air Transport Association (ATA) of America and the Aerospace Industries Association (AIA) of America agreed to undertake the task of identifying and implementing procedures to ensure the continued structural airworthiness of aging transport category airplanes. An Airworthiness Assurance Working Group (AAWG) was established in August 1988, with members representing aircraft manufacturers, operators, regulatory authorities, and other aviation industry representatives worldwide. The objective of the AAWG was to sponsor “Task Groups” to:

1. Select service bulletins, applicable to each airplane model in the transport fleet, to be recommended for mandatory modification of aging airplanes;

2. Develop corrosion-directed inspections and prevention programs;

3. Review the adequacy of each operator's structural maintenance program;

4. Review and update the Supplemental Inspection Documents (SID); and

5. Assess repair quality.

In addition, we have received several reports of cracking of the main fuselage frame on McDonnell Douglas Model DC 9-10 series airplanes at station Y=642.000. The cracking has been attributed to stress corrosion. The AAWG task group for McDonnell Douglas Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes has determined that we should mandate inspections for cracks of the main fuselage frame, and repair if necessary, in accordance with the service bulletin described below. Stress corrosion cracking, if not detected and corrected, could propagate and result in extensive damage to adjacent structure, and reduced structural integrity of the airplane.

The subject area on certain McDonnell Douglas Model DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes is identical to that on the affected Model DC 9-10 series airplanes. Therefore, all of these models may be subject to the same unsafe condition.

Relevant Service Information

We have reviewed McDonnell Douglas DC-9 Service Bulletin 53-168, dated November 17, 1983; including McDonnell Douglas Service Sketch 3529, dated August 23, 1983 (attached to the service bulletin). The service bulletin describes procedures for repetitive inspections for stress corrosion cracks of the main fuselage frame at Station Y=642.000 (for Model DC-9-10 and DC-9-20 series airplanes), Station Y=756.000 (for Model DC-9-30 series airplanes), Station Y=794.000 (for Model DC-9-40 series airplanes), and Station Y=851.000 (for Model DC-9-50 series airplanes). The service bulletin specifies that operators should use one of four inspection methods during each repetitive inspection cycle: optical-aided visual, dye-penetrant, eddy current, or ultrasonic. The service bulletin specifies that operators should record all inspection results, and send a report to the manufacturer. If no crack is found, the service bulletin provides procedures for repeating the inspection until the frame is replaced. If any crack is found in a pocket area and the crack is within the trim-out limits specified in Service Sketch 3529, the service bulletin provides procedures for repeating the inspection until the frame is replaced. If any crack is found in a pocket area and the crack exceeds the trim-out limits specified in Service Sketch 3529, the service bulletin specifies that the corrective action is replacing the frame. In addition, if any crack is found in the web, the service bulletin specifies that the corrective action is replacing the frame. The service bulletin specifies that replacing the frame with a new or serviceable frame made of 7075-T73 aluminum material terminates the repetitive inspection requirements for that frame only. 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 “Differences Between the Proposed AD and the Service Information.”

Operators should note that, while it is not the FAA's usual policy to allow flight with known cracks, this AD permits further flight with cracking within certain limits. The manufacturer has advised us that they have data showing that the fuselage frame with the trim-out area, specified in McDonnell Douglas Service Sketch 3529, meets the certification basis of the airplane. The cracked frame supports limit load without detrimental permanent deformation, and ultimate load without failure. The repetitive inspection interval of 3,400 flight hours for this area (specified in paragraph (h)(1) of this proposed AD) is intended to detect crack growth caused by stress corrosion until the terminating action is accomplished. In consideration of these findings and the FAA's criteria for flight with known cracking, further flight with cracking within certain limits is permissible.

Differences Between the Proposed AD and the Service Information

Although the service bulletin referenced in this proposed AD specifies to submit certain information to the manufacturer, this proposed AD does not include that requirement.

Although the service bulletin does not give a compliance time for replacing the frame if a crack is found in a pocket area and the crack exceeds the limits specified in Service Sketch 3529; or if a crack is found in the web; this proposed AD would require doing that replacement before further flight.

Although the service bulletin does not give a compliance time for doing the inspection for crack growth if a crack in the pocket area is within the trim-out limits specified in Service Sketch 3529, this proposed AD would require doing that inspection before further flight.

Clarification of Inspection Terminology

In this proposed AD, the “optical-aided visual inspection” specified in the service bulletin 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 1,017 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.- registered airplanes	Fleet cost
Inspection, per inspection cycle	2	$65	$0	$130, per inspection cycle	376	$48,880, per inspection cycle.
Optional terminating acton (replacing the frame)	1 96	65	7,305	$13,545	376	Up to $5,092,920.
1 Per airplane.

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-2005-23197; Directorate Identifier 2005-NM-109-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by January 20, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to McDonnell Douglas Model DC-9-11, DC-9-12, DC-9-13, DC-9-14, DC-9-15, DC-9-15F, DC-9-21, DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-33F, DC-9-34, DC-9-34F, DC-9-32F (C-9A, C-9B), DC-9-41, and DC-9-51 airplanes; certificated in any category; as identified in McDonnell Douglas DC-9 Service Bulletin 53-168, dated November 17, 1983.

Unsafe Condition

(d) This AD results from several reports of cracking of the main fuselage frame. We are issuing this AD to detect and correct stress corrosion cracking of the main fuselage frame, which could result in extensive damage to adjacent structure, and reduced 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.

Service Bulletin Reference

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of McDonnell Douglas DC-9 Service Bulletin 53-168, dated November 17, 1983, including McDonnell Douglas Service Sketch 3529, dated August 23, 1983.

Repetitive Inspections and Corrective Actions

(g) Prior to the accumulation of 15,000 total flight hours, or within 3,400 flight hours after the effective date of this AD, whichever occurs later: Do a detailed inspection, dye-penetrant inspection, eddy current inspection, or ultrasonic inspection for stress corrosion cracks of the main fuselage frame in accordance with the service bulletin. Except as provided by paragraph (h) of this AD, repeat the inspection thereafter at intervals not to exceed 8,000 flight hours until the replacement in paragraph (i) of this AD is accomplished.

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 mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

Corrective Actions

(h) If any crack is found during any inspection required by this AD, do the applicable action in paragraph (h)(1), (h)(2), or (h)(3) of this AD.

(1) If the crack is in the pocket area and the crack is within the trim-out limits specified in McDonnell Douglas Service Sketch 3529, dated August 23, 1983: Repeat the inspection specified in paragraph (g) of this AD at intervals not to exceed 3,400 flight hours until the action in paragraph (i) of this AD is accomplished.

(2) If the crack is in the pocket area and the crack exceeds the trim-out limits specified in McDonnell Douglas Service Sketch 3529, dated August 23, 1983, before further flight: Do the action in paragraph (i) of this AD.

(3) If the crack is in the web, before further flight: Do the action in paragraph (i) of this AD.

Optional Terminating Action

(i) Replacing the frame with a new or serviceable frame made of 7075-T73 aluminum material in accordance with the service bulletin terminates the repetitive inspection requirements of this AD for that frame only.

No Reporting Required

(j) Although the service bulletin referenced in this AD specifies to submit certain information to the manufacturer, this AD does not include that requirement.

Parts Installation

(k) After the effective date of this AD, no person may install on any airplane a frame made of 7075-T6 aluminum material.

Alternative Methods of Compliance (AMOCs)

(l) 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.

Issued in Renton, Washington, on November 25, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.