Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 Series Airplanes, and C-9 (Military) Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes and C-9 (military) airplanes, that currently requires a one-time visual inspection to determine if the doorstops and corners of the doorjamb of the forward passenger door have been modified, various follow-on repetitive inspections, and modification, if necessary. This action would require a reduction in the inspection threshold and repetitive intervals for a certain doubler configuration and an increase in the repetitive inspection interval for a certain other doubler configuration. This proposal is prompted by a determination that certain inspection compliance times were incorrect. The actions specified by the proposed AD are intended to detect and correct fatigue cracking, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.

DATES:

Comments must be received by May 22, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-333-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.

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: Technical Publications Business Administration, Dept. C1-L51 (2-60). This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Transport Airplane Directorate, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California.

FOR FURTHER INFORMATION CONTACT:

Wahib Mina, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Transport Airplane Directorate, 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 notice may be changed in light of the comments received.

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 notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 99-NM-333-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. 99-NM-333-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On December 11, 1998, the FAA issued AD 98-26-09, amendment 39-10949 (63 FR 70005, December 18, 1998), applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes and C-9 (military) airplanes, to require a one-time visual inspection to determine if the doorstops and corners of the doorjamb of the forward passenger door have been modified, various follow-on repetitive inspections, and modification, if necessary. That action was prompted by reports of fatigue cracks found in the fuselage skin and doubler at the corners and doorstops of the doorjamb of the forward passenger door. The requirements of that AD are intended to detect and correct such fatigue cracking, which could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, the manufacturer has informed the FAA that the initial and repetitive inspection compliance times were incorrect in McDonnell Douglas Service Bulletin DC9-53-280, Revision 01, dated July 30, 1998, for the doorstops and corners of the forward passenger doorjamb that have been modified previously, using steel doublers. Therefore, McDonnell Douglas has issued Service Bulletin DC9-53-280, Revision 02, dated July 26, 1999, to correct this condition. Paragraph (c)(1) of the existing AD specifies that the high frequency eddy current (HFEC) initial inspection should be performed “Prior to accumulation of 28,000 landings after accomplishment of the modification, or within 3,500 landings after the effective date of this AD, whichever occurs later. * * *” The correct initial HFEC inspection compliance time should be 6,000 landings after accomplishment of the modification, or within 3,575 landings after the effective date of the AD, whichever occurs later.

Also, paragraph (c)(1)(i) of AD 98-26-09 specifies that the HFEC repetitive inspection interval is 20,000 landings. The correct repetitive HFEC inspection interval is 3,000 landings.

Explanation of Relevant Service Information

The FAA has reviewed and approved McDonnell Douglas Service Bulletin DC-9-53-280, Revision 02, dated July 26, 1999, which describes procedures for the following:

1. Performing a one-time visual inspection to determine if the doorstops and corners of the forward passenger door doorjamb have been modified;

2. For certain airplanes: Performing a low frequency eddy current (LFEC) or x-ray inspection to detect cracks at all corners and doorstops of the doorjamb of the forward passenger door;

3. For certain other airplanes: Performing an HFEC inspection to detect cracks on the skin adjacent to the modification;

4. Conducting repetitive inspections, or modifying the doorstops and corners of the doorjamb of the forward passenger door, and performing follow-on HFEC inspections, if no cracking is detected;

5. Performing repetitive HFEC inspections to detect cracks on the skin adjacent to any doorstop or corner that has been modified; and

6. Modifying doorstops and corners if any crack is found to be 0.5 inch or less in length at all doorstops and corners that have not been modified, and performing follow-on repetitive HFEC inspections.

Accomplishment of the action 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 supersede AD 98-26-09, amendment 39-10949, to require accomplishment of the actions specified in the service bulletin described previously, except as discussed below.

The FAA has also noted that a typographical error exists in paragraph (d) of AD 98-26-09 that involves the compliance time for performing an HFEC inspection to detect cracks in the skin adjacent to a certain modification of the doorstops and corners of the forward passenger door doorjamb. That AD specifies that the HFEC inspection should be performed “Prior to the accumulation of 28,000 landings since accomplishment of that modification, or within 3,500 landings after the effective date of this AD, whichever occurs later.” However, the intent of the FAA was to specify that compliance time as “Prior to the accumulation of 28,000 landings since accomplishment of that modification, or within 3,575 landings after the effective date of this AD, whichever occurs later.” Paragraph (d) of this proposed AD has been revised to correctly specify 3,575 landings.

Differences Between Proposed Rule and Service Bulletin

Operators should note that, although the service bulletin specifies that the manufacturer must be contacted for disposition of certain conditions, this proposal would require the repair of those conditions to be accomplished in accordance with a method approved by the FAA.

Cost Impact

There are approximately 809 airplanes of the affected design in the worldwide fleet. The FAA estimates that 572 airplanes of U.S. registry would be affected by this proposed AD.

The visual inspection that is currently required by AD 98-26-09 and that is retained in this AD takes approximately 1 work hour per airplane to accomplish the proposed visual inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required visual inspection proposed by this AD on U.S. operators is estimated to be $34,320 or $60 per airplane.

Should an operator be required to accomplish the proposed LFEC or x-ray inspection, it would take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of any necessary LFEC or x-ray inspection proposed by this AD on U.S. operators is estimated to be $120 per airplane, per inspection cycle.

Should an operator be required to accomplish the proposed HFEC inspection, it would take approximately 2 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of any necessary HFEC inspection proposed by this AD on U.S. operators is estimated to be $60 per airplane, per inspection cycle.

Should an operator be required to accomplish the proposed modification, it would take approximately 8 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would cost between $898 and $1,037 per airplane, depending on the service kit purchased. Based on these figures, the cost impact of the modification proposed by this AD on U.S. operators is estimated to be between $1,378 and $1,517 per airplane.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact

The regulations proposed herein would not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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 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.