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Proposed Rule

Airworthiness Directives; Air Tractor, Inc. Models AT-401, AT-401B, AT-402, AT-402A, AT-402B, AT-501, AT-502, AT-502A, AT-502B, AT-503A, AT-602, AT-802, and AT-802A Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

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Start Preamble

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede Airworthiness Directive (AD) 2002-19-10, which applies to certain Air Tractor, Inc. (Air Tractor) Models AT-402, AT-402A, AT-402B, AT-602, AT-802, and AT-802A airplanes. AD 2002-19-10 currently requires you to repetitively inspect the upper longeron and upper diagonal tube on the left hand side of the aft fuselage structure for cracks and contact the manufacturer for a repair scheme if cracks are found. This proposed AD is the result of reports of the same cracks recently found on AT-500 series airplanes. The manufacturer has also issued new and revised service information that incorporates a modification to terminate the repetitive inspection requirements. Consequently, this proposed AD would retain the inspection actions required in AD 2002-19-10, would add certain AT-500 series airplanes to the applicability section, would change the compliance times, and would incorporate new and revised manufacturer service information that contains a terminating action for the repetitive inspection requirement. We are issuing this proposed AD to detect and correct cracks in the upper aft longeron, which could cause the fuselage to fail. Such failure could result in loss of control of the airplane.

DATES:

We must receive any comments on this proposed AD by June 7, 2004.

ADDRESSES:

Use one of the following to submit comments on this proposed AD:

  • By mail: FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2004-CE-05-AD, 901 Locust, Room 506, Kansas City, Missouri 64106.
  • By fax: (816) 329-3771.
  • By e-mail: 9-ACE-7-Docket@faa.gov. Comments sent electronically must contain “Docket No. 2004-CE-05-AD” in the subject line. If you send comments electronically as attached electronic files, the files must be formatted in Microsoft Word 97 for Windows or ASCII.

You may get the service information identified in this proposed AD from Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374.

You may view the AD docket at FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2004-CE-05-AD, 901 Locust, Room 506, Kansas City, Missouri 64106. Office hours are 8 a.m. to 4 p.m., Monday through Friday, except Federal holidays.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Andrew D. McAnaul, Aerospace Engineer, FAA, Fort Worth Airplane Certification Office (ACO), 2601 Meacham Boulevard, Fort Worth, Texas 76193-0150. Current duty station: San Antonio Manufacturing Inspection District Office (MIDO), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: (210) 308-3365; facsimile: (210) 308-3370.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Comments Invited

How do I comment on this proposed AD? We invite you to submit any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 2004-CE-05-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it. We will date-stamp your postcard and mail it back to you.

Are there any specific portions of this proposed AD I should pay attention to? We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. If you contact us through a nonwritten communication and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend this proposed AD in light of those comments and contacts.

Discussion

Has FAA taken any action to this point? We received reports of cracks found on the left hand upper longeron and upper diagonal support tubes where they intersect on the left hand side of the fuselage frame just forward of the vertical fin front spar attachment point on Air Tractor Model AT-602 airplanes. Additional cracking was later reported on AT-400, AT-602, and AT-802 series airplanes.

Air Tractor started installing extended reinforcement gussets on AT-402 and AT-802 series airplanes at the factory to alleviate the crack condition from occurring. The extended reinforcement gussets were intended to transfer the loads away from the joint. However, an AT-802 airplane with the extended reinforcement gusset installed during factory production was discovered cracked in service at the forward end of the gusset.

These conditions caused us to issue AD 2002-19-10, Amendment 39-12890 (67 FR 61481, October 1, 2002). AD 2002-19-10 currently requires you to do the following on certain Air Tractor Models AT-402, AT-402A, AT-402B, AT-602, AT-802, and AT-802A airplanes:

—Repetitively inspect the upper longeron and upper diagonal tube on the left hand side of the aft fuselage structure for cracks; and

—Contact the manufacturer for a repair scheme if cracks are found.

What has happened since AD 2002-19-10 to initiate this proposed action? We have received additional reports of the same cracks found on an Air Tractor Model AT-502 and AT-502A airplane.

The manufacturer has also issued new and revised service information. The new service information contains procedures for replacing and modifying the upper aft longeron as a terminating action for the repetitive inspection requirement.

What is the potential impact if FAA took no action? This condition, if not detected and corrected, could cause the fuselage to fail. Such failure could result in loss of control of the airplane.

Is there service information that applies to this subject? Snow Start Printed Page 18849Engineering Co. has issued the following Service Letters:

—Service Letter #195, reissued: November 10, 2003;

—Service Letter #195A, revised: November 10, 2003;

—Service Letter #195B, dated November 10, 2003;

—Service Letter #213A, dated November 10, 2003;

—Service Letter #213B, revised November 10, 2003;

—Service Letter #217A, dated November 10, 2003;

—Service Letter #217B, revised November 10, 2003;

—Service Letter #218A, dated November 10, 2003; and

—Service Letter #218B, revised November 10, 2003.

What are the provisions of this service information? These service letters include procedures for:

—Service Letter #195 specifies inspecting the upper longeron in the aft fuselage structure on all the affected model airplanes;

—Service Letter #195B, Service Letter #213A, Service Letter #217A, and Service Letter #218A provides the inspection requirements for all affected model airplanes; and

—Service Letter #195A, Service Letter #213B, Service Letter #217B, and Service Letter #218B give the procedures for replacing and modifying the upper aft longeron if cracks are found for all affected model airplanes and is the terminating action for the repetitive inspection requirements.

FAA's Determination and Requirements of This Proposed AD

What has FAA decided? We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other products of this same type design. Therefore, we are proposing AD action.

What would this proposed AD require? This proposed AD would supersede 2002-19-10 with a new AD that would require you to repetitively inspect the upper longeron and upper diagonal tube on the left hand side of the aft fuselage structure for cracks. If cracks are found, this proposed AD would also require you to replace and modify the upper aft longeron. Replacing and modifying the upper aft longeron would terminate the repetitive inspection requirement.

How does the revision to 14 CFR part 39 affect this proposed AD? On July 10, 2002, we published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs FAA's AD system. This regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Costs of Compliance

How many airplanes would this proposed AD impact? We estimate that this proposed AD affects 1,194 airplanes in the U.S. registry.

What would be the cost impact of this proposed AD on owners/operators of the affected airplanes? We estimate the following costs to accomplish the proposed inspections:

Labor costParts costTotal cost per airplaneTotal cost on U.S. operators
1 workhour × $65 per hour = $65No parts required$65$65 × 1,194 = $77,610.

We estimate the following costs to accomplish any necessary replacements that would be required based on the results of the proposed inspection(s). We have no way of determining the number of airplanes that may need this replacement:

Labor costParts costTotal cost per airplane
27 workhours × $65 per hour = $1,755For AT-400, AT-500, and AT-600 series airplanes: $35For AT-400, AT-500, and AT-600 series airplanes: $1,755 + $35 = $1,790.
For AT-800 series airplanes: $45For AT-800 series airplanes: $1,755 + $45 = $1,800.

What is the difference between the cost impact of this proposed AD and the cost impact of AD 2002-19-10? The difference is the addition of certain Model AT-501, AT-502, AT-502A, AT-502B, and AT-503A airplanes to the applicability section of this proposed AD and the cost of replacing any cracked upper aft longeron. There is no difference in cost to perform the proposed inspection.

Regulatory Findings

Would this proposed AD impact various entities? We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

Would this proposed AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this proposed AD:

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. 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.

We prepared a summary of the costs to comply with this proposed AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 2004-CE-05-AD” in your request.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 14 CFR part 39 as follows:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
Start Printed Page 18850
[Amended]

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 2002-19-10, Amendment 39-12890 (67 FR 61481, October 1, 2002), and by adding a new AD to read as follows:

Air Tractor, Inc.: Docket No. 2004-CE-05-AD.

When Is the Last Date I Can Submit Comments on This Proposed AD?

(a) We must receive comments on this proposed airworthiness directive (AD) by June 7, 2004.

What Other ADs Are Affected by This Action?

(b) This AD supersedes AD 2002-19-10.

What Airplanes Are Affected by This AD?

(c) This AD affects the following airplane models and serial numbers that are certificated in any category:

ModelSerial Nos.
AT-401, AT-401B, AT-402, AT-402A, and AT-402B0716 through 1144.
AT-501, AT-502, AT-502A, AT-502B, and AT-503A0037 through 0658.
AT-6020337 through 0664.
AT-802 and AT-802A0001 through 0139.

What Is the Unsafe Condition Presented in This AD?

(d) This AD is the result of reports of cracks in the aft fuselage upper longeron, originally detected as excessive movement in the empennage due to the loss of fuselage torsional rigidity. The actions specified in this AD are intended to detect and correct cracks in the upper aft longeron, which could cause the fuselage to fail. Such failure could result in loss of control of the airplane.

What Must I Do To Address This Problem?

(e) To address this problem, you must inspect the upper longeron and upper diagonal tube on the left hand side of the fuselage frame just forward of the vertical fin front spar attachment for cracks at the times specified below. You must also replace and modify any cracked upper and diagonal longerons found during any inspection required by this AD before further flight after the inspection in which cracks are found.

Affected models and serial numbersInspection compliance timesProcedures
(1) AT-401, AT-401B, AT-402, AT-402A, and AT-402B: serial numbers (S/Ns) 0716 through 1144.Initially inspect upon the accumulation of 1,250 total hours time-in-service (TIS) or within the next 100 hours TIS after the effective date of this AD, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper and diagonal longerons are replaced and modified. Replacing and modifying the upper and diagonal longerons is the terminating action for the repetitive inspection requirement in this AD.Inspect following Snow Engineering Co. Service Letter #218A, dated November 10, 2003, as specified in Snow Engineer Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #218B, dated November 10, 2003.
(2) AT-501, AT-502, AT-502B, and AT-503A, S/Ns 0037 through 0658.Initially inspect upon the accumulation of 4,800 total hours TIS or within the next 100 hours TIS after the effective date of this AD, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper and diagonal longerons are replaced and modified. Replacing and modifying the upper and diagonal longerons is the terminating action for the repetitive inspection requirement in this AD.Inspect following Snow Engineering Co. Service Letter #218A, dated November 10, 2003, as specified in Snow Engineer Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #195A, revised November 10, 2003.
(3) AT-502A, S/Ns 0037 through 0658.Initially inspect upon the accumulation of 2,800 total hours TIS or within the next 100 hours TIS after the effective date of this AD, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper and diagonal longerons are replaced and modified. Replacing and modifying the upper and diagonal longerons is the terminating action for the repetitive inspection requirement in this AD.Inspect following Snow Engineering Co. Service Letter #195B, dated November 10, 2003, as specified in Snow Engineer Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #195A, revised November 10, 2003.
(4) AT-602, S/Ns 0337 through 0661.Initially inspect upon the accumulation of 700 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper and diagonal longerons are replaced and modified. Replacing and modifying the upper and diagonal longerons is the terminating action for the repetitive inspection requirement in this AD.Inspect following Snow Engineering Co. Service Letter #213A, dated November 10, 2003, as specified in Snow Engineer Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #218B, dated November 10, 2003.
Start Printed Page 18851
(5) AT-602, S/Ns 0662 through 0664.Initially inspect upon the accumulation of 1,750 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper and diagonal longerons are replaced and modified. Replacing and modifying the upper and diagonal longerons is the terminating action for the repetitive inspection requirement in this AD.Inspect following Snow Engineering Co. Service Letter #213A, dated November 10, 2003, as specified in Snow Engineer Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #213B, revised November 10, 2003.
(6) AT-802 and AT-802A, S/Ns 0001 through 0004 and 0012 through 0118.Initially inspect upon the accumulation of 250 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper and diagonal longerons are replaced and modified. Replacing and modifying the upper and diagonal longerons is the terminating action for the repetitive inspection requirement in this AD.Inspect following Snow Engineering Co. Service Letter #217A, dated November 10, 2003, as specified in Snow Engineer Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #217B, revised November 10, 2003.
(7) AT-802 and AT-802A, S/Ns 0005 through 0011.Initially inspect upon the accumulation of 900 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper and diagonal longerons are replaced and modified. Replacing and modifying the upper and diagonal longerons is the terminating action for the repetitive inspection requirement in this AD.Inspect following Snow Engineering Co. Service Letter #217A, dated November 10, 2003, as specified in Snow Engineer Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #217B, dated November 10, 2003.
(8) AT-802 and AT-802A, S/Ns 0119 through 0139.Initially inspect upon the accumulation of 1,750 total hours TIS or within the next 100 hours TIS after the last inspection required by AD 2002-19-10, whichever occurs later. Repetitively inspect thereafter at intervals not to exceed 100 hours TIS until the upper and diagonal longerons are replaced and modified. Replacing and modifying the upper and diagonal longerons is the terminating action for the repetitive inspection requirement in this AD.Inspect following Snow Engineering Co. Service Letter #217A, dated November 10, 2003, as specified in Snow Engineer Co. Service Letter #195, reissued November 10, 2003. Replace and modify following Snow Engineering Co. Service Letter #217B, revised November 10, 2003.

(f) You may replace and modify the upper and diagonal longeron at any time as a terminating action for the repetitive inspection requirement in this AD. However, you must replace and modify the upper and diagonal longeron before further flight after any inspection in which cracks are found.

May I Request an Alternative Method of Compliance?

(g) You may request a different method of compliance or a different compliance time for this AD by following the procedures in 14 CFR 39.19. Unless FAA authorizes otherwise, send your request to your principal inspector. The principal inspector may add comments and will send your request to the Manager, Fort Worth Aircraft Certification Office (ACO), FAA. For information on any already approved alternative methods of compliance, contact Andrew D. McAnaul, Aerospace Engineer, FAA, Fort Worth ACO, 2601 Meacham Boulevard, Fort Worth, Texas 76193-0150. Current duty station: San Antonio Manufacturing Inspection District Office (MIDO), 10100 Reunion Place, Suite 650, San Antonio, Texas 78216; telephone: (210) 308-3365; facsimile: (210) 308-3370.

May I Get Copies of the Documents Referenced in This AD?

(h) You may get copies of the documents referenced in this AD from Air Tractor, Incorporated, P.O. Box 485, Olney, Texas 76374. You may view these documents at FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri 64106.

Start Signature

Issued in Kansas City, Missouri, on April 1, 2004.

David R. Showers,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 04-8056 Filed 4-8-04; 8:45 am]

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