01-11968. Airworthiness Directives; Air Tractor, Inc. AT-400, AT-500, and AT-800 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; request for comments.

SUMMARY:

This amendment supersedes Airworthiness Directive (AD) 2000-14-51, which requires inspection of the wing lower spar cap for cracks on Air Tractor, Inc. (Air Tractor) Models AT-501, AT-502, and AT-502A airplanes, and modification or replacement of any cracked wing lower spar cap. This AD lowers the safe life for the wing lower spar cap on Air Tractor AT-400, AT-500, and AT-800 series airplanes. This AD is the result of numerous reports of cracks in the 3/8-inch bolthole of the wing lower spar cap on the affected airplanes. The actions specified by this AD are intended to prevent fatigue cracks from occurring in the wing lower spar cap before the originally established safe life is reached. Fatigue cracks in the wing lower spar cap, if not detected and corrected, could result in the wing separating from the airplane during flight.

DATES:

This AD becomes effective on June 8, 2001.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulation as of June 8, 2001.

The Federal Aviation Administration (FAA) must receive any comments on this rule on or before July 13, 2001.

ADDRESSES:

Submit comments in triplicate to FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2000-CE-72-AD, 901 Locust, Room 506, Kansas City, Missouri 64106.

You may get the service information referenced in this AD from Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374. You may look at this information at FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2000-CE-72-AD, 901 Locust, Room 506, Kansas City, Missouri 64106; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Rob Romero, Aerospace Engineer, FAA, Fort Worth Airplane Certification Office, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0150; telephone: [phone]; facsimile: [phone].

SUPPLEMENTARY INFORMATION:

Discussion

What Events Have Caused This AD?

Several reports of cracked wing lower spar caps on Air Tractor AT-400, AT-500, and AT-800 series airplanes have caused the manufacturer (Air Tractor) to recalculate the fatigue life of the wing lower spar cap on these airplanes. One report was an accident where the wing separated from the airplane during flight. The cracks are originating in the outboard 3/8-inch bolthole of the wing lower spar cap.

Air Tractor fatigue tested 24 wings and all had cracks in the area of the 3/8-inch bolthole. Follow-on field inspections revealed more cracks in this area.

What Are the Consequences if the Condition Is Not Corrected?

This condition could result in fatigue cracks in the wing lower spar cap before the originally established safe life is reached. Fatigue cracks in the wing lower spar cap, if not detected and corrected, could result in the wing separating from the airplane during flight.

Is There Service Information That Applies to This Subject?

Air Tractor has issued the following:

—Snow Engineering Company Service Letter #197, Revised March 26, 2001, which applies to certain Models AT-501, AT-502, and AT-502A airplanes;

—Snow Engineering Company Service Letter #202, Revised March 26, 2001, which applies to certain Models AT-400, AT-401, AT-401B, AT-402, AT-402A, and AT-402B airplanes;

—Snow Engineering Company Service Letter #203, Revised March 26, 2001, which applies to certain Models AT-802 and AT-802A airplanes; and

—Snow Engineering Company Service Letter #205, Revised March 26, 2001, which applies to certain Models AT-501, AT-502, AT-502B, and AT-503A airplanes.

These service letters include procedures for inspecting and replacing/modifying the wing lower spar cap on the affected airplanes.

The FAA's Determination and an Explanation of the Provisions of This AD

What Has FAA Decided?

The FAA has reviewed all available information, including the service information referenced above; and determined that:

—The unsafe condition referenced in this document exists or could develop on other Air Tractor AT-400, AT-500, and AT-800 series airplanes of the same type design;

—The actions specified in the previously-referenced service information (as specified in this AD) should be accomplished on the affected airplanes; and

—AD action should be taken in order to correct this unsafe condition.

What Does This AD Require?

This AD lowers the safe life for the wing lower spar cap on Air Tractor AT-400, AT-500, and AT-800 series airplanes. This AD also allows for inspection, using eddy current methods, of the wing lower spar cap for airplanes that are at or over the lower safe life and parts are not available. Operation of the airplane is not allowed if cracks are found and inspections must be terminated when parts become available or after performing three repetitive inspections.

This AD supersedes AD 2000-14-51, Amendment 39-11837 (65 FR 46567, July 31, 2000), which currently requires inspection of the wing lower spar cap for cracks on Air Tractor Models AT-501, AT-502, and AT-502A airplanes, and modification or replacement of any cracked wing lower spar cap.

Will I Have the Opportunity to Comment Prior to the Issuance of the Rule?

Because the unsafe condition described in this document could result in possible separation of the wing from the airplane during flight, FAA finds that notice and opportunity for public prior comment are impracticable. Therefore, good cause exists for making this amendment effective in less than 30 days.

Comments Invited

How do I Comment on This AD?

Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, we invite your comments on the rule. You may submit whatever written data, views, or arguments you choose. You need to include the rule's docket number and submit your comments in triplicate to the address specified under the caption ADDRESSES. We will consider all comments received on or before the closing date specified above. We may amend this rule in light of comments received. Factual information that supports your ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether we need to take additional rulemaking action.

Are There any Specific Portions of the AD I Should Pay Attention To?

The FAA specifically invites comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. You may examine all comments we receive before and after the closing date of the rule in the Rules Docket. We will file a report in the Rules Docket that summarizes each FAA contact with the public that concerns the substantive parts of this AD.

We are reviewing the writing style we currently use in regulatory documents, in response to the Presidential memorandum of June 1, 1998. That memorandum requires federal agencies to communicate more clearly with the public. We are interested in your comments on whether the style of this document is clear, and any other suggestions you might have to improve the clarity of FAA communications that affect you. You can get more information about the Presidential memorandum and the plain language initiative at http://www.plainlanguage.gov.

How Can I Be Sure FAA Receives my Comment?

If you want us to acknowledge the receipt of your comments, you must include a self-addressed, stamped postcard. On the postcard, write “Comments to Docket No. 2000-CE-72-AD.” We will date stamp and mail the postcard back to you.

Regulatory Impact

Does This AD Impact Various Entities?

These regulations 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. Therefore, FAA has determined that this final rule does not have federalism implications under Executive Order 13132.

Does This AD Involve a Significant Rule or Regulatory Action?

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a significant regulatory action under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket (otherwise, an evaluation is not required). A copy of it, if filed, may be obtained from the Rules Docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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. FAA amends § 39.13 by removing AD 2000-14-51, Amendment 39-11837 ( 65 FR 46567, July 31, 2000), and by adding a new airworthiness directive (AD) to read as follows:

2001-10-04 Air Tractor, Inc.: Amendment 39-12230; Docket No. 2000-CE-72-AD; Supersedes AD 2000-14-51, Amendment 39-11837.

(a) What airplanes are affected by this AD? The following presents the airplanes (certificated in any category) that are affected by this AD, along with the new safe life limit (presented in hours time-in-service (TIS)) of the wing lower spar cap for all airplane models and serial numbers:

Model	Serial numbers	Safe life
AT-400	All serial numbers beginning with 0416	13,300 hours TIS.
AT-401	0662 through 0951	10,757 hours TIS.
AT-401B	0952 through 1014 and 1016 though 1020	6,948 hours TIS.
AT-401B	1015 and 1021 through 1124	7,777 hours TIS.
AT-402	0694 through 0951	7,440 hours TIS.
AT-402A	0738 through 0951	7,440 hours TIS.
AT-402A	0952 through 1020	4,589 hours TIS.
AT-402B	0966 through 1020	4,589 hours TIS.
AT-402A	1021 through 1124	5,268 hours TIS.
AT-402B	1021 through 1124	5,268 hours TIS.
AT-501	0002 through 0061	4,531 hours TIS.
AT-501	All serial numbers beginning with 0062	7,693 hours TIS.
AT-502	0003 through 0236	4,000 hours TIS.
AT-502A	0158 through 0618	3,000 hours TIS.
AT-502B	0187 through 0618	4,000 hours TIS.
AT-503A	All serial numbers beginning with 0067	4,000 hours TIS.
AT-802	0001 through 0059	4,132 hours TIS.
AT-802A	0003 through 0059	4,969 hours TIS.
AT-802	0060 through 0091	4,188 hours TIS.
AT-802	0092 through 0101 except those equipped with the factory-supplied part number 80540 computerized fire gate	8,163 hours TIS.
AT-802A	0060 through 0091 except those equipped with the factory-supplied part number 80540 computerized fire gate	4,531 hours TIS.
AT-802A	0092 through 0101 except those equipped with the factory-supplied part number 80540 computerized fire gate	8,648 hours TIS.

Note 1:

Piston powered aircraft that have been converted to turbine power should use the limits for corresponding serial number turbine-powered aircraft.

(b) Who must comply with this AD? Anyone who wishes to operate any of the above airplanes must comply with this AD.

(c) What problem does this AD address? The actions specified by this AD are intended to prevent fatigue cracks from occurring in the wing lower spar cap before the originally established safe life is reached. Fatigue cracks in the wing lower spar cap, if not detected and corrected, could result in the wing separating from the airplane during flight.

(d) What must I do to address this problem? To address this problem, you must accomplish the following actions:

Action	Compliance time	Procedures
(1) Modify the applicable aircraft records as follows to show the reduced safe life for the wing lower spar cap (that is specified in the table in paragraph (a) of this AD): (i) For the affected Models AT-802 and AT-802A airplanes: update the Owners Manual, Section 6—Airworthiness Limitations, Life Limited Parts. (ii) For all affected airplanes other than the Models AT-802 and AT-802A airplanes: incorporate the following into the Aircraft Logbook “In accordance with AD **-**-**, the wing lower spar cap is life limited to XXX (insert the applicable safe life number from the chart in paragraph (a) of this AD). (iii) If, as of the time of the logbook entry requirements of paragraph (d)(1) of this AD, your airplane is over or within 10 hours of the safe life limit, an additional 10 hours TIS is allowed to accomplish the replacement/modification.	Accomplish the logbook entry within the next 10 hours TIS after June 8, 2001, (the effective date of this AD). An additional 10 hours TIS to accomplish the modification/replacement is allowed if you are already over the safe life limit	The owner/operator holding at least a private pilot certificate as authorized by section 43.7 of the Federal Aviation Regulations (14 CFR 43.7) may modify the aircraft records as specified in paragraphs (d)(1)(i) and (d)(1)(ii) of this AD. Make an entry into the aircraft records showing compliance with this portion of the AD in accordance with section 43.9 of the Federal Aviation Regualtions (14 CFR 43.9). Accomplish the actual replacements/modifications in accordance with Snow Engineering Service Letter #197, #202, #203, or #205, all Revised March 26, 2001, as applicable.
(2) If you have ordered parts from the factory when it is time to replace the wing lower spar cap (as required per the logbook safe life reduction in paragraph (d)(1) of this AD), but the parts are not available, inspect, using eddy current methods, the wing lower spar cap. These inspections are allowed until one of the following occurs, at which time the replacement/modification (required when the lower spar cap has reached its safe life) must be accomplished:	Prior to further flight after ordering the parts and therafter at intervals not to exceed 400 hours TIS until one of the criteria in paragraphs (d)(2)(i), (d)(2)(ii), and (d)(2)(iii) of this AD is met	In accordance with the procedures in Snow Engineering Service Letter #197, #202, #203, or #205, all Revised March 26, 2001, as applicable.
(i) Crack(s) is/are found;
(ii) Parts become available from the manufacturer; or
(iii) Not more than three inspections or 1,200 hours TIS go by: the first inspection would have to be accomplished upon accumulating the safe life; the second inspection would have to be accomplished within 400 hours TIS after accumulating the safe life; the third inspection would have to be accomplished 400 hours TIS after the second inspection; and the replacement/modification would have to be accomplished within 400 hours TIS after the third inspection (maximum elapsed time would be 1,200 hours TIS).

(e) Can I comply with this AD in any other way? You may use an alternative method of compliance or adjust the compliance time if:

(1) Your alternative method of compliance provides an equivalent level of safety; and

(2) The Manager, Fort Worth Airplane Certification Office (ACO), approves your alternative. Submit your request through an FAA Principal Maintenance Inspector. The inspector may add comments before sending it to the Manager, Fort Worth ACO.

(3) Alternative methods of compliance approved for AD 2000-14-51 are not considered approved for this AD.

Note 2:

This AD applies to each airplane identified in paragraph (a) of this AD, 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 (e) 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 you have not eliminated the unsafe condition, specific actions you propose to address it.

(f) Where can I get information about any already-approved alternative methods of compliance? Contact Rob Romero, Aerospace Engineer, FAA, Fort Worth ACO, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0150; telephone: [phone]; facsimile: [phone].

(g) What if I need to fly the airplane to another location to comply with this AD? The FAA can issue a special flight permit under sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate your airplane to a location where you can accomplish the requirements of this AD provided that the following is adhered to:

(1) Only operate in day visual flight rules (VFR) only.

(2) Ensure that the hopper is empty.

(3) Limit airspeed to 135 miles per hour (mph) indicated airspeed (IAS).

(4) Avoid any unnecessary g-forces.

(5) Avoid areas of turbulence.

(6) Plan the flight to follow the most direct route.

(h) Are any service bulletins incorporated into this AD by reference? Replacement actions required by this AD must be done in accordance with Snow Engineering Service Letter #197, #202, #203, or #205, all Revised March 26, 2001, as applicable. The Director of the Federal Register approved this incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 51. You may get copies of this document from Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374. You can look at copies at FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

(i) When does this amendment become effective? This amendment becomes effective on June 8, 2001.

Issued in Kansas City, Missouri, on May 7, 2001.

Melvin D. Taylor,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.