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AGENCY:
Federal Aviation Administration (FAA), DOT.
ACTION:
Final rule; request for comments.
SUMMARY:
The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 717-200 airplanes and Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes. This AD was prompted by a report of cracked and severed structure found in the aft fuselage cant bulkhead at a certain station (STA) and the vertical stabilizer rear spar installation. This AD requires a one-time inspection of the aft fuselage cant bulkhead at certain STAs and vertical stabilizer rear spar structure, and corrective actions and an inspection report if necessary. This AD also requires an inspection of that same structure if certain conditions occur during any phase of flight. The FAA is issuing this AD to address the unsafe condition on these products.
DATES:
This AD is effective October 21, 2024.
The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of October 21, 2024.
The FAA must receive comments on this AD by November 18, 2024.
ADDRESSES:
You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:
- Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.
- Fax: 202-493-2251.
- Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
- Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
AD Docket: You may examine the AD docket at regulations.gov by searching for and locating Docket No. FAA-2024-2324; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, any comments received, and other information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
- For Boeing material identified in this AD, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-1717; websitemyboeingfleet.com.
- You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. It is also available at regulations.gov under Docket No. FAA-2024-2324.
FOR FURTHER INFORMATION CONTACT:
Wayne Ha, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562-627-5238; email: Wayne.Ha@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments to an address listed under the ADDRESSES section. Include Docket No. FAA-2024-2324 and Project Identifier AD-2024-00514-T at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this final rule because of those comments.
Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this final rule.
Confidential Business Information
CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this AD contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this AD, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this AD. Submissions containing CBI should be sent to Wayne Ha, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562-627-5238; email: Wayne.Ha@faa.gov. Any commentary that the FAA receives that is not specifically designated as CBI will be placed in the public docket for this rulemaking.
Background
The FAA has received a report indicating cracked and severed structure was found in the aft fuselage cant bulkhead at STA 1178.225 and vertical stabilizer rear spar installation, on a Boeing Model 717-200 airplane. The cant bulkhead and vertical stabilizer rear spar structure on Boeing Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes are similar to that of the Model 717-200 airplane and therefore are susceptible to cracking. This condition, if not addressed, could result in reduced structural integrity of the airplane. The FAA is issuing this AD to address the unsafe condition on these products.
FAA's Determination
The FAA is issuing this AD because the agency has determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Boeing Multi Operator Message MOM-MOM-24-0457-01B(R1) and Boeing Multi Operator Message MOM-MOM-24-0456-01B(R1), both dated September 4, 2024. These documents are distinct since they apply to different airplane models. This material specifies procedures for a one-time detailed inspection of the aft fuselage cant bulkhead (at STA 1178.225 for Model 717-200 airplanes, STA 942.225 for Model DC-9-10 and DC-9-20 series airplanes, STA 1121.225 for Model DC-9-30 series airplanes, STA 1197.225 for Model DC-9-40 series airplanes, and STA 1292.225 for Model DC-9-50 series airplanes) and vertical stabilizer rear spar structure for any crack and, if any crack is found during the detailed inspection, obtaining and following approved repair instructions. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.
AD Requirements
This AD requires accomplishing the actions specified in the material already described. This AD also requires sending the inspection findings to the airplane manufacturer if any crack is found during the one-time detailed inspection. This AD also requires a detailed inspection of the cant bulkhead (at STA 1178.225 for Model 717-200 airplanes, STA 942.225 for Model DC-9-10 and DC-9-20 series airplanes, STA 1121.225 for Model DC-9-30 series airplanes, STA 1197.225 for Model DC-9-40 series airplanes, and STA 1292.225 for Model DC-9-50 series airplanes), left and right sides, between longerons 11L through 11R at the forward and aft surfaces; upper cap; upper (cap) doubler; bulkhead webs and doublers; stiffeners; lower tee cap and strap; and vertical stabilizer rear spar cap and web for any discrepancy, if any of the following conditions occur during any phase of flight: (1) high drag/side loads or unusual ground handling, (2) a hard or overweight landing, (3) severe turbulence (or rough air (turbulence)) or an excessive maneuver, or (4) high compressive loads to the hydraulic tail bumper/strut (for Model 717-200 airplanes) or auxiliary gear (tail bumper) (for Model DC-9-10, DC-9-20, DC-9-30, DC-9-40, and DC-9-50 series airplanes). A discrepancy includes buckles, distortion, cracks, loose or missing fasteners, or any other obvious indication of damage.
Justification for Immediate Adoption and Determination of the Effective Date
Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for “good cause,” finds that those procedures are “impracticable, unnecessary, or contrary to the public interest.” Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption. The FAA has found that the risk to the flying public justifies forgoing notice and comment prior to adoption of this rule because cracked and severed structure in the aft fuselage cant bulkhead and vertical stabilizer rear spar, if not addressed, could result in reduced structural integrity of the airplane. Further, analysis has shown that an airplane with this unsafe condition is not capable of sustaining a limit load event, which would be catastrophic. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b).
The compliance time in this AD is shorter than the time necessary for the public to comment and for publication of the final rule. In addition, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days, for the same reasons the FAA found good cause to forgo notice and comment.
Regulatory Flexibility Act
The requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without notice and comment, RFA analysis is not required.
Costs of Compliance
The FAA estimates that this AD affects 133 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:
Estimated Costs
| Action | Labor cost | Parts cost | Cost per product | Cost on U.S. operators |
|---|---|---|---|---|
| One-time inspection | 3 work-hours × $85 per hour = $255 | $0 | $255 | $33,915 |
| Inspection due to certain conditions | 3 work-hours × $85 per hour = $255 | 0 | 255 | 33,915 |
On-Condition Costs
| Action | Labor cost | Parts cost | Cost per product |
|---|---|---|---|
| Reporting | 1 work-hours × $85 per hour = $85 | $0 | $85 |
Table 1 to Paragraph ( l )—Applicable STA
| Model | Paragraph (l) of this AD |
|---|---|
| DC-9-11, DC-9-12, DC-9-13, DC-9-14, DC-9-15, DC-9-15F, and DC-9-21 airplanes | STA 942.225 |
| DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-32F (C-9A, C-9B), DC-9-33F, DC-9-34, and DC-9-34F airplanes | STA 1121.225 |
| DC-9-41 airplanes | STA 1197.225 |
| DC-9-51 airplanes | STA 1292.225 |