00-23852. 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 adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes and C-9 (military) airplanes. This proposal would require, among other actions, various inspections to detect cracks of the cockpit enclosure window sill, and follow-on and corrective actions, as applicable. This action is necessary to prevent fatigue cracking of the internal doublers and frame structure of the fuselage skin of the cockpit enclosure window sill. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by November 2, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-57-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. 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. 2000-NM-57-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: 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, 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; 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 notice 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 notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-57-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. 2000-NM-57-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received several reports of cracking of the internal doublers and frame structure of the fuselage skin of the cockpit enclosure window sill on McDonnell Douglas Model DC-9 series airplanes. These airplanes had accumulated between 61,624 and 100,238 total flight cycles. The cause of such cracking has been attributed to high-cycle fatigue. Fatigue cracking of the subject area, if not corrected, could result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.

Explanation of Relevant Service Information

The FAA has reviewed and approved McDonnell Douglas Service Bulletin DC9-53-290, dated December 14, 1999. The service bulletin describes the following procedures:

• A general visual inspection to determine if a particular type of repair that has been installed;
• A general visual inspection to detect loose or missing fasteners or cracks of the upper nose skins of the cockpit;
• A magnetic particle inspection to detect cracks of the zees; and
• A detailed visual, borescope, and high frequency eddy current (HFEC) inspection to detect cracks of the skins, frames, beams, and angles. The service bulletin also describes the following follow-on and corrective actions, as applicable, that include:
• A permanent repair (including visual and magnetic particle inspections, and replacement/rework);
• Inspections to detect cracks of the completed repair; and repair, if necessary;
• A temporary repair; and follow-on inspections to detect cracks of the internal structure and external doublers; and
• Replacement of any cracked zee with a new part.

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

Differences Between Proposed Rule and Service Bulletin

Operators should note that, although the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair 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 Model DC-9-10, -20, -30, -40, and -50 series airplanes and C-9 (military) 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, that it would take approximately 7 work hours per airplane to accomplish the proposed inspections, and 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 $240,240, or $420 per airplane.

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 2000-NM-57-AD.

Applicability: Model DC-9-10, -20, -30, -40, and -50 series airplanes and C-9 (military) airplanes; as listed in McDonnell Douglas Service Bulletin DC9-53-290, December 14, 1999; 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 (k) 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 prevent fatigue cracking of the internal doublers and frame structure of the fuselage skin of the cockpit enclosure window sill, accomplish the following:

Note 2:

Where there are differences between the AD and the referenced service bulletin, the AD prevails.

Various Inspections

(a) Before the accumulation of 40,000 total landings, or within 5,000 landings after the effective date of this AD, whichever occurs later, do the actions specified in (a)(1), (a)(2), (a)(3), and (a)(4) of this AD per paragraph 3., “Accomplishment Instructions,” of McDonnell Douglas Service Bulletin DC9-53-290, dated December 14, 1999.

(1) Do a general visual inspection to determine if any repair identified in paragraphs 3.A.6. and 3.A.8. of the Accomplishment Instructions of the service bulletin has been accomplished prior to the effective date of this AD. AND

(2) Do a general visual inspection to detect cracks of the upper nose skins of the cockpit. AND

(3) Do a magnetic particle inspection to detect cracks of the zees. AND

(4) Do a detailed visual, borescope, and high frequency eddy current (HFEC) inspection to detect cracks of the skins, frames, beams, and angles.

Note 3:

For the purposes of this AD, a general visual inspection is defined as “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Note 4:

For the purposes of this AD, a detailed visual 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.”

Condition 1 (No Crack and No Previous Repair)

(b) If no crack and no previous repair is detected during any inspection required by paragraphs (a)(1) through (a)(4) of this AD, do the actions specified in paragraph (b)(1) of this AD, or in paragraphs (b)(2) and (b)(3) of this AD, at the times specified in those paragraphs.

(1) Repeat the inspections required by paragraphs (a)(2), (a)(3), and (a)(4) of this AD thereafter every 5,000 landings.

(2) Before further flight, do the permanent repair (including visual and magnetic particle inspections, and replacement/rework) specified in Condition 1, Option 2 of the Accomplishment Instructions of McDonnell Douglas Service Bulletin DC9-53-290, dated December 14, 1999. Accomplishment of the permanent repair stops the repetitive inspections required by paragraph (b)(1) of this AD.

(3) Within 40,000 landings after doing the permanent repair required by paragraph (b)(2) of this AD, do the inspections specified in paragraphs (a)(2), (a)(3), and (a)(4) of this AD to detect cracks of the completed repair, per McDonnell Douglas Service Bulletin DC9-53-290, dated December 14, 1999.

(i) I no crack is detected, repeat the inspections specified in paragraph (b)(3) of this AD thereafter every 5,000 landings.

(ii) If any crack is detected, before further flight, repair per a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA.

Condition 2 (Any Crack Within Limits)

(c) If any crack is detected during any inspection required by paragraphs (a)(2) through (a)(4) of this Ad, and that crack is WITHIN the limits specified in Condition 2 of the Accomplishment Instructions of McDonnell Douglas Service Bulletin DC9-53-290, dated December 14, 1999, do the actions specified in paragraphs (c)(1) through (c)(4) of this AD, or in paragraphs (b)(2) and (b)(3) of this AD; at the times specified in those paragraphs. The actions required by paragraphs (c)(1) through (c)(3) of this AD must be done per the Accomplishment Instructions of McDonnell Douglas Service Bulletin DC9-53-290, dated December 14, 1999.

(1) Before further flight, do the temporary repair per Condition 2, Option 1 of the Accomplishment Instructions of the service bulletin.

(2) Within 2,000 landings after doing the temporary repair, do a general visual inspection to detect cracks of the external doublers.

(3) Within 3,500 landings after doing the temporary repair, do borescope and HFEC inspections to detect cracks of the internal structure.

(4) Within 8,000 landings after doing the temporary repair, do the action specified in paragraphs (b)(2) of this AD; and at the time specified in paragraph (b)(3) of this AD, do the actions specified in that paragraph.

(d) If no crack is detected during any general visual inspection required by paragraph (c)(2) of this AD, repeat the general visual inspection thereafter every 2,000 landings.

(e) If no crack is detected during any borescope or HFEC inspection required by paragraph (c)(3) of this AD, repeat the borescope and HFEC inspections thereafter every 3,500 landings.

(f) If any crack is detected during any inspection required by paragraph (c)(2) or (c)(3) of this AD, at the times specified in paragraphs (b)(2) and (b)(3) of this AD, do the actions specified in those paragraphs.

Condition 3 (Existing Repairs Accomplished Per Certain Service Information)

(g) If any repair is detected during any inspection required by paragraph (a)(1) of this AD, and that repair has been accomplished previously in accordance with the service information identified in Condition 3 of the Accomplishment Instructions of McDonnell Douglas Service Bulletin DC9-53-290, dated December 14, 1999, do the actions specified in paragraph (g)(1) of this AD, or in paragraphs (g)(2) and (g)(3) of this AD, at the times specified in those paragraphs.

(1) At the times specified in paragraphs (c)(2) and (c)(3) of this AD, do the actions specified in those paragraphs; and at the time specified in paragraphs (d), (e), and (f) of this AD, do the applicable follow-on or corrective actions specified in those paragraphs.

(2) Within 8,000 landings after doing the temporary repair, do the action specified in paragraph (b)(2).

(3) Within 40,000 landings after doing the permanent repair, do the actions specified in paragraph (b)(3) of this AD.

Condition 4 (Existing Repairs Not Accomplished Per Certain Service Information)

(h) If any repair is detected during any inspection required by paragraph (a)(1) of this AD, and the repair has not been accomplished previously in accordance with the service information identified in Condition 3 of the Accomplishment Instructions of McDonnell Douglas Service Bulletin DC9-53-290, dated December 14, 1999, before further flight, repair per a method approved by the Manager, Los Angeles ACO.

Condition 5 (Any Crack Outside Limits)

(i) If any crack is detected during any inspection required by paragraphs (a)(2) through (a)(4) of this AD, and that crack is OUTSIDE the limits specified in Condition 2 of the Accomplishment Instructions of McDonnell Douglas Service Bulletin DC9-53-290, dated December 14, 1999, at the times specified in paragraphs (b)(2) and (b)(3) of this AD, do the actions specified in paragraphs (b)(2) and (b)(3) of this AD.

Corrective Action for Cracked Zee

(j) If any cracked zee is detected during any inspection required by paragraph (a)(3) of this AD, before further flight, replace the cracked zee with a new part per McDonnell Douglas Service Bulletin DC9-53-290, dated December 14, 1999.

Alternative Methods of Compliance

(k) 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. 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.

Note 5:

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 Permit

(l) Special flight permits may be issued in accordance with sections 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 September 12, 2000.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.