Airworthiness Directives; McDonnell Douglas Model DC-9-15, DC-9-31, and DC-9-32 Airplanes

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 Model DC-9-15, DC-9-31, and DC-9-32 airplanes. This proposal would require repetitive visual and x-ray inspections to detect cracks of the upper and lower corners and upper center of the door cutout of the aft pressure bulkhead; corrective actions, if necessary; and follow-on actions. For certain airplanes, the proposal also would require modification of the ventral aft pressure bulkhead. This action is necessary to detect and correct fatigue cracks in the corners and upper center of the door cutout of the aft pressure bulkhead, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 20, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-60-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 (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-60-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 or 2000 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; or at the FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California.

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 (562) 627-5324; fax (562) 627-5210.

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 2003-NM-60-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. 2003-NM-60-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received reports indicating that the repetitive x-ray inspections required by AD 85-01-02 R1, amendment 39-5241 (51 FR 6101, February 20, 1986), do not adequately detect fatigue cracks in all layers of a repaired or modified aft pressure bulkhead on certain Model DC-9 airplanes. Fatigue cracks in the corners and upper center of the door cutout of the aft pressure bulkhead, if not detected and corrected, could

result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.

Related Rulemaking

The FAA normally would issue an AD to supersede AD 85-01-02 R1 to continue to require the existing requirements, until the new proposed actions that address the identified unsafe condition are done. This involves restating the existing requirements of AD 85-01-02 R1 in the new AD. Because of the complexity of the requirements of AD 85-01-02 R1, we previously issued AD 2002-07-06 as a “stand—alone” AD that did not supersede AD 85-01-02 R1. We included a paragraph in AD 2002-07-06 that terminates the repetitive inspection requirements of AD 85-01-02 R1.

AD 2002-07-06, amendment 39-12700 (67 FR 16987, April 9, 2002), is applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes, and C-9 airplanes. That AD requires repetitive visual and x-ray inspections to detect cracks of the upper and lower corners and upper center of the door cutout of the aft pressure bulkhead; corrective actions, if necessary; and follow-on actions. The actions specified by that AD are intended to detect and correct fatigue cracks in the corners and upper center of the door cutout of the aft pressure bulkhead which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.

Other Related Rulemaking

The FAA also has previously issued AD 96-10-11, amendment 39-9618 (61 FR 24675, May 16, 1996), applicable to McDonnell Douglas Model DC-9 and DC-9-80 series airplanes, Model MD-88 airplanes, and C-9 (military) series airplanes. That AD requires certain inspections and structural modifications. Accomplishment of the modification (reference Boeing (McDonnell Douglas) Service Bulletin DC9-53-166) required by paragraph (d) or (e) of AD 96-10-11 (which references “DC-9/MD-80 Aging Aircraft Service Action Requirements Document” (SARD), McDonnell Douglas Report No. MDC K1572, Revision A, dated June 1, 1990, or Revision B, dated January 15, 1993, as the appropriate source of service information for accomplishing the modification) terminates the repetitive inspection requirements of paragraphs (b) and (c) of this proposed AD.

Explanation of Applicability

Since issuance of AD 2002-07-06, the FAA was advised that 13 Model DC-9-15, DC-9-31, and DC-9-32 airplanes (manufacturer's fuselage numbers 0030, 0094, 0220, 0221, 0863, 0900, 0901, 0913, 0914, 0918, 0923, 0926, and 0930) were excluded inadvertently from the effectivity of paragraph 1.A. of McDonnell Douglas Service Bulletin DC9-53-137, Revision 07, dated February 6, 2001, which was referenced in the applicability of that AD as the appropriate source of service information for determining the affected airplanes. Therefore, we have determined that the additional airplanes are also subject to the same unsafe condition addressed in AD 2002-07-06. This proposed AD follows from that determination.

Explanation of Relevant Service Information

The FAA has reviewed and approved McDonnell Douglas Service Bulletin DC9-53-137, Revision 09, dated January 30, 2003, which describes procedures that are essentially the same as those procedures included in McDonnell Douglas Service Bulletin DC9-53-137, Revision 07, dated February 6, 2001, as cited in AD 2002-07-06. This revision also adds 13 additional airplane fuselage numbers to the effectivity. The airplanes were inadvertently omitted from Revision 07 of the service bulletin. No more work is necessary on airplanes changed as shown in Revision 07 of the service bulletin.

The FAA also has reviewed and approved McDonnell Douglas DC-9 Service Bulletin 53-165, Revision 3, dated May 3, 1989, which describes procedures for modification of the ventral aft pressure bulkhead structure (including cutting and removing flange of the upper; cutting and removing the lower flange of formers and replacing it with a clip; installing pads at the outboard end clips of formers; and replacing clearance fit bolts at the upper corner doubler angles with interference fit Hi-Lok pins and monel rivets).

In addition, the FAA has reviewed and approved McDonnell Douglas DC-9 Service Bulletin 53-157, Revision 1, dated January 7, 1985, which describes, for certain airplanes, procedures for modification of the ventral aft pressure bulkhead (including encapsulating the head and nut of the attachments and applying a fillet seal of sealant around parts located on the forward and aft sides of the aft pressure bulkhead; and applying a soft film corrosion inhibiting compound to the forward and aft sides of the aft pressure bulkhead). For certain airplanes, these procedures must be done in conjunction with those in McDonnell Douglas DC-9 Service Bulletin 53-165.

Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe condition.

Accomplishment of the actions specified in AD 2002-07-06 is acceptable for compliance with the requirements of this proposed AD.

FAA's Determination

The FAA finds that if, after the effective date of this AD, the airplane is operated without cabin pressurization and a placard that prohibits operation with cabin pressurization is installed in the cockpit in full view of the pilot, the inspections and modification specified in the service bulletins described previously are not necessary.

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 accomplishment of the actions specified in the service bulletins described previously, except as discussed below.

Since this AD expands the applicability of AD 2002-07-06, the FAA has considered a number of factors in determining whether to issue a new AD or to supersede the “old” AD. The FAA has considered the entire fleet size that would be affected by superseding AD 2002-07-06 and the consequent workload associated with revising maintenance record entries. In light of this, the FAA has determined that a less burdensome approach is to issue a separate AD applicable only to the additional airplanes. This proposed AD would not supersede AD 2002-07-06 or AD 85-01-02 R1; airplanes listed in the applicability of AD 2002-07-06 and AD 85-01-02 R1 are required to continue to comply with the requirements of those ADs. This proposed AD is a separate AD action, and is applicable only to the McDonnell Douglas Model DC-9-15, DC-9-31, and DC-9-32 airplanes, manufacturer's fuselage numbers 0030, 0094, 0220, 0221, 0863, 0900, 0901, 0913, 0914, 0918, 0923, 0926, and 0930. Once the final rule has been issued and it becomes effective, we plan to rescind AD 85-01-02 R1.

Differences Between the Proposed AD and a Certain Referenced Service Bulletin

McDonnell Douglas DC-9 Service Bulletin 53-165, Revision 3, dated May 3, 1989; and McDonnell Douglas Service Bulletin DC9-53-137, Revision 09, dated January 30, 2003; recommend compliance times with only a “threshold” (i.e., before the airplane accumulates 15,000 total landings, within 15,000 landings after the bulkhead modification, and at the earliest practical maintenance period feasible on airplanes that have accumulated more than 15,000 landings, respectively). These service bulletins do not provide a “grace period” for airplanes that have already reached (or will soon reach) the 15,000-landing threshold, which would result in some airplanes being in immediate non-compliance with the rule upon reaching the stated number of landings. Therefore, the compliance times specified in paragraphs (a), (d)(1), and (d)(2) of this proposed AD include a grace period of “within 4,000 landings after the effective date of this AD.” The FAA finds such a grace period for completing the required actions to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Operators should note that, although the Accomplishment Instructions of McDonnell Douglas Service Bulletin DC9-53-137, Revision 09, dated January 30, 2003, describe procedures for reporting results of inspections, this proposed AD would not require those actions. The FAA does not need this information from operators.

Cost Impact

There are 13 airplanes of the affected design in the worldwide fleet. The FAA estimates that seven airplanes of U.S. registry would be affected by this proposed AD.

It would take approximately 5 work hours per airplane to accomplish the proposed inspections, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $2,275 or $325 per airplane.

For certain airplanes, it would take approximately between 21 and 26 work hours per airplane depending on the airplane configuration to accomplish the proposed modification specified in McDonnell Douglas DC-9 Service Bulletin 53-165, Revision 3, dated May 3, 1989, at an average labor rate of $65 per work hour. Required parts would cost approximately between $3,470 and $11,831 per airplane, depending on the airplane configuration. Based on these figures, the cost impact of this proposed modification on U.S. operators is estimated to be between $4,835, or $13,521 per airplane.

For certain airplanes, it would take approximately 9 work hours per airplane to accomplish the proposed modification specified in McDonnell Douglas DC-9 Service Bulletin 53-157, Revision 1, dated January 7, 1985, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of this proposed modification on U.S. operators is estimated to be $585 per airplane.

The cost impact figures discussed above are 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.