89 FR 161 pgs. 67267-67270 - Airworthiness Directives; Air Tractor, Inc. Airplanes
Type: RULEVolume: 89Number: 161Pages: 67267 - 67270
Pages: 67267, 67268, 67269, 67270Docket number: [Docket No. FAA-2024-2013; Project Identifier AD-2024-00363-A; Amendment 39-22812; AD 2024-16-06]
FR document: [FR Doc. 2024-18586 Filed 8-15-24; 11:15 am]
Agency: Transportation Department
Sub Agency: Federal Aviation Administration
Official PDF Version: PDF Version
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-2013; Project Identifier AD-2024-00363-A; Amendment 39-22812; AD 2024-16-06]
RIN 2120-AA64
Airworthiness Directives; Air Tractor, Inc. Airplanes
AGENCY:
Federal Aviation Administration (FAA), DOT.
ACTION:
Final rule; request for comments.
SUMMARY:
The FAA is superseding Airworthiness Directive (AD) 2023-15-07, which applied to all Air Tractor, Inc. (Air Tractor) Model AT-802 and AT-802A airplanes with Wipaire, Inc. Supplemental Type Certificate (STC) No. SA01795CH installed. AD 2023-15-07 required repetitively inspecting the left and right forward horizontal stabilizer spars for cracks, replacing any forward horizontal stabilizer spar found cracked, and reporting inspection results to the FAA. This AD requires repetitively inspecting the left and right, forward and rear, horizontal stabilizer spars for cracks at shorter intervals than those required by AD 2023-15-07, replacing any horizontal stabilizer spar found cracked or damaged, installing bathtub fittings, and reporting inspection results to the FAA. This AD was prompted by additional reports of cracks in the horizontal stabilizer spars and the need to incorporate a new finlet attach design on the horizontal stabilizer spars to reduce the cracking. The FAA is issuing this AD to address the unsafe condition on these products.
DATES:
This AD is effective September 4, 2024.
The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of September 4, 2024.
The FAA must receive comments on this AD by October 4, 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 under Docket No. FAA-2024-2013; 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 Wipaire, Inc. material identified in this AD, contact Wipaire, Inc., 1700 Henry Avenue, Fleming Field (KSGS), South St. Paul, MN 55075; phone: (651) 451-1205; email: customerservice@wipaire.com; website: wipaire.com.
• You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. For information on the availability of this material at the FAA, call (817) 222-5110. It is also available at regulations.gov under Docket No. FAA-2024-2013.
FOR FURTHER INFORMATION CONTACT:
Tim Eichor, Aviation Safety Engineer, Central Certification Branch, FAA, 1801 S. Airport Road, Wichita, KS 67209; phone: (847) 294-7141; email: tim.d.eichor@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-2024-2013; Project Identifier AD-2024-00363-A" 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 Tim Eichor, Aviation Safety Engineer, Central Certification Branch, FAA, 1801 S. Airport Road, Wichita, KS 67209. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.
Background
The FAA issued AD 2023-15-07, Amendment 39-22519 (88 FR 53761, August 9, 2023) (AD 2023-15-07), for all Air Tractor Model AT-802 and AT-802A airplanes with Wipaire, Inc. STC No. SA01795CH installed. AD 2023-15-07 required repetitively inspecting the left and right forward horizontal stabilizer spars for cracks, replacing any forward horizontal stabilizer spar found cracked, and reporting inspection results to the FAA. For certain airplanes, AD 2023-15-07 required the inspection before the airplane accumulated 200 hours time-in-service (TIS) after installation of STC No. SA01795CH. AD 2023-15-07 resulted from cracks found in the forward horizontal stabilizer spar bend radius located at the STC finlet mounting locations. The FAA issued AD 2023-15-07 to detect and correct cracks in the forward horizontal stabilizer spar, which could result in structural failure of the horizontal tail with consequent loss of control of the airplane.
Actions Since AD 2023-15-07 Was Issued
[top] As a result of the reports of the inspections required by AD 2023-15-07, additional cracks have been found in the forward horizontal stabilizer spar, including cracks found before the airplane accumulated 200 hours TIS after installation of the STC.
FAA's Determination
The FAA is issuing this AD because the agency 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 Wipaire, Inc. Service Letter 253, Revision D, dated July 3, 2024 (Wipaire SL 253D), which specifies procedures for repetitively inspecting the left and right, forward and rear, horizontal stabilizer spars for cracks and installing bathtub fittings using Service Kit 1012347-01 or 1012347-02. This material also specifies procedures for repetitively inspecting the left and right, forward and rear, horizontal stabilizer spars for cracks, elongated holes, and corrosion after installation of the bathtub fittings. 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 retains none of the requirements of AD 2023-15-07. This AD requires repetitively inspecting both the left and right, forward and rear, horizontal stabilizer spars for cracks, replacing any horizontal stabilizer spar found cracked or damaged, installing bathtub fittings (Service Kit 1012347-01 or 1012347-02), and reporting inspection results to the FAA. The inspection intervals in this AD are shorter than the intervals required by AD 2023-15-07.
Differences Between This AD and the Referenced Material
As part of the instructions for installing the bathtub fittings, Wipaire SL 253D specifies that to be eligible for reinstallation, finlet mount weldments must include a certain welded gusset, but that constraint is not required by this AD.
Wipaire SL 253D includes an inspection of the finlets and forward bathtub fittings at intervals of 1,500 hours TIS and establishes a life limit of 7,800 hours TIS on the forward spar and forward bathtub fittings. This AD does not include those requirements because the compliance times would allow sufficient time to provide notice and opportunity for public comment. The FAA is evaluating these actions and may consider future rulemaking.
This AD requires an initial compliance time of within 7 days or before the airplane accumulates 110 hours TIS since installation of STC No. SA01795CH, whichever occurs later, while Wipaire SL 253D specifies different compliance times for different configurations of STC No. SA01795CH.
Wipaire SL 253D specifies repeating the inspections at intervals of 200 hours TIS, but this AD requires the repetitive inspections at intervals not to exceed 110 hours TIS.
Interim Action
The FAA considers this AD to be an interim action. The FAA is evaluating the need to establish a life limit (potentially as low as 2,000 hours TIS) on the horizontal stabilizer spars to further mitigate the unsafe condition long term. The FAA may consider future rulemaking on this subject.
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 cracks in the horizontal stabilizer spars could lead to structural failure of the horizontal tail with consequent loss of control of the airplane. Airplanes with the affected STC installed are used in fire-fighting missions and put frequent high repetitive fatigue loads in this area at a high utilization rate (about 100 hours TIS monthly). Based on the number of cracks found to date, a significant number of airplanes need to be inspected within 7 days after the effective date of this AD and modified with bathtub fittings within 300 hours TIS (about 3 months for the high utilization airplanes). These compliance times are shorter than the time necessary for the public to comment and for publication of the final rule. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b).
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 FAA has determined that it has good cause to adopt this rule without prior notice and comment, RFA analysis is not required.
Costs of Compliance
The FAA estimates that this AD affects 30 airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:
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| Action | Labor cost | Parts cost | Cost per airplane | Cost on U.S. operators |
|---|---|---|---|---|
| Inspect horizontal stabilizer spars (without bathtub fittings) | 20 work-hours × $85 per hour = $1,700 | $0 | $1,700 per inspection cycle | $51,000 per inspection cycle. |
| Install bathtub fittings | 40 work-hours × $85 per hour = $3,400 | 3,100 | $6,500 | $195,000. |
| Inspect horizontal stabilizer spars (with bathtub fittings) | 3 work-hours × $85 per hour = $255 | 0 | $255 per inspection cycle | $7,650 per inspection cycle. |
| Report inspection results | 1 work-hour × $85 per hour = $85 | 0 | $85 per inspection cycle | $2,550 per inspection cycle. |
The FAA estimates the following costs to do any necessary replacements that would be required based on the results of the inspection. The agency has no way of determining the number of airplanes that might need this replacement:
| Action | Labor cost | Parts cost | Cost per airplane |
|---|---|---|---|
| Replace horizontal stabilizer spar | 40 work-hours × $85 per hour = $3,400 | $2,800 | $6,200 |
The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators.
Paperwork Reduction Act
A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a currently valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to be approximately 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. All responses to this collection of information are mandatory. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to: Information Collection Clearance Officer, Federal Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177-1524.
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.
The FAA is 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
This AD will not have federalism implications under Executive Order 13132. This AD will 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 this AD:
(1) Is not a "significant regulatory action" under Executive Order 12866, and
(2) Will not affect intrastate aviation in Alaska.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
The Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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 FAA amends §?39.13 by:
a. Removing Airworthiness Directive 2023-15-07, Amendment 39-22519 (88 FR 53761, August 9, 2023); and
b. Adding the following new airworthiness directive:
2024-16-06 Air Tractor, Inc.: Amendment 39-22812; Docket No. FAA-2024-2013; Project Identifier AD-2024-00363-A.
(a) Effective Date
This airworthiness directive (AD) is effective September 4, 2024.
(b) Affected ADs
This AD replaces AD 2023-15-07, Amendment 39-22519 (88 FR 53761, August 9, 2023) (AD 2023-15-07).
(c) Applicability
This AD applies to Air Tractor, Inc. Model AT-802 and AT-802A airplanes, all serial numbers, certificated in any category, that have Wipaire, Inc. Supplemental Type Certificate (STC) No. SA01795CH installed.
(d) Subject
Joint Aircraft System Component (JASC) Code 5510, Horizontal Stabilizer Structure; 5511 Horizontal stabilizer, Spar/Rib; 5514, Horizontal Stabilizer Miscellaneous Structure; 5530, Vertical Stabilizer Structure.
(e) Unsafe Condition
[top] This AD was prompted by additional reports of cracks found in the horizontal stabilizer spars and the need to incorporate a new finlet attach design on the horizontal stabilizer spars to reduce the cracking. The FAA is issuing this AD to prevent structural failure of the horizontal stabilizer spars. The unsafe condition, if not addressed, could result in structural failure of the horizontal
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Required Actions
(1) Within 7 days after the effective date of this AD or before the airplane accumulates 110 hours time-in-service (TIS) after installation of STC No. SA01795CH, whichever occurs later, and thereafter at intervals not to exceed 110 hours TIS until the airplane is modified as required by paragraph (g)(3) of this AD: Inspect the left and right horizontal stabilizer spars for cracks in accordance with Steps 1 through 9 of the Work Instructions-Inspection, Method 1 in Wipaire, Inc. Service Letter 253, Revision D, dated July 3, 2024 (Wipaire SL 253D).
(2) If any crack is found in a horizontal stabilizer spar during any inspection required by paragraph (g)(1) of this AD, or if any crack, elongated hole, or corrosion is found in a horizontal stabilizer spar during any inspection required by paragraph (g)(4) of this AD, before further flight, replace the horizontal stabilizer spar.
(3) Within 300 hours TIS or 12 months after the effective date of this AD, whichever occurs first, install bathtub fittings (Service Kit 1012347-01 or 1012347-02) in accordance with Steps 1 through 10 of the Work Instructions-Install Bathtub Fittings in Wipaire SL 253D except where Step 2 specifies that to be eligible for reinstallation, finlet mount weldments must include the welded gussets shown in figure 8 of Wipaire SL 253D, that constraint is not required by this AD. If any spars were previously modified by installing 7D1-4399 Revision L or earlier, regardless of condition, those spars must be replaced at the same time the bathtub fittings kit is installed.
(4) Within 110 hours TIS after installing the bathtub fittings, and thereafter at intervals not to exceed 110 hours TIS, inspect the horizontal stabilizer spars for cracks, elongated holes, and corrosion in accordance with Steps 1, 2, 4 through 6, 9, and 10 of the Work Instructions-Inspection, Method 2 in Wipaire SL 253D.
(5) Within 5 days after each inspection required by paragraphs (g)(1) and (4) of this AD or within 5 days after the effective date of this AD, whichever occur later, report the following to the FAA at the address in paragraph (j)(1) of this AD. Report this information regardless of whether cracks are found.
(i) Model, engine configuration (with horsepower limits), and propeller type;
(ii) Serial number and N number;
(iii) Total hours TIS on airframe;
(iv) Total hours TIS operated with floats, if known;
(v) STC configuration and total hours with STC installed;
(vi) Crack location (right or left, upper/lower caps inboard/outboard hole);
(vii) Crack size;
(viii) Photos of cracks found, if available; and
(ix) Any additional operator/mechanic comments.
(h) Credit for Previous Actions
You may take credit for the initial inspection required by paragraph (g)(1) of this AD if, before the effective date of this AD, you complied with Wipaire, Inc. Service Letter 253, Revision A, dated April 5, 2023; or Wipaire Service Letter 253, Revision B, dated July 27, 2023.
(i) Alternative Methods of Compliance (AMOCs)
(1) The Manager, Central Certification Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the Certification Branch, send it to the attention of the person identified in paragraph (j)(1) of this AD and email to: AMOC@faa.gov.
(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.
(j) Related Information
(1) For more information about this AD, contact Tim Eichor, Aviation Safety Engineer, Central Certification Branch, FAA, 1801 S. Airport Road, Wichita, KS 67209; phone: (847) 294-7141; email: tim.d.eichor@faa.gov.
(2) Material identified in this AD that is not incorporated by reference is available at the address specified in paragraph (k)(3) of this AD.
(k) Material Incorporated by Reference
(1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise.
(i) Wipaire, Inc. Service Letter 253, Revision D, dated July 3, 2024.
(ii) [Reserved]
(3) For Wipaire, Inc. material identified in this AD, contact Wipaire, Inc., 1700 Henry Avenue, Fleming Field (KSGS), South St. Paul, MN 55075; phone: (651) 451-1205; email: customerservice@wipaire.com; website: wipaire.com .
(4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. For information on the availability of this material at the FAA, call (817) 222-5110.
(5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email fr.inspection@nara.gov.
Issued on August 14, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.
[FR Doc. 2024-18586 Filed 8-15-24; 11:15 am]
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