Airworthiness Directives; Cessna Aircraft Company Model 172RG Airplanes

Summary:

This document proposes to adopt a new airworthiness directive (AD) that would apply to certain Cessna Aircraft Company (Cessna) Model 172 airplanes. The proposed AD would require you to inspect the main landing gear pivot assemblies for cracks, replace any cracked main landing gear pivot assemblies, and install new bushings on the pivot assembly shaft. Many service difficulty reports of cracked main landing gear pivot assemblies on the affected airplanes prompted the proposed action. The actions specified by the proposed AD are intended to detect, correct, and prevent future cracks on the original design landing gear pivots. Cracked main landing gear pivots could fail resulting in gear-up landings or loss of braking.

Table of Contents

Dates:

The Federal Aviation Administration (FAA) must receive any comments on this proposed rule by December 7, 2000.

Addresses:

Send comments in triplicate to the FederalAviation Administration (FAA), Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2000-CE-24-AD, 901 Locust, Room 506, Kansas City, Missouri 64106. You may read comments at this location between 8 a.m. and 4 p.m., Monday through Friday, except holidays.

You may get the service information referenced in this proposed AD from the Cessna Aircraft Company, Product Support, P.O. Box 7706, Wichita, Kansas 67277; telephone: (316) 517-5800; facsimile: (316) 942-9006. You may examine this information at the Rules Docket at the above address.

For further information contact:

Steven Litke, Aerospace Engineer, Wichita Aircraft Certification Office, FAA, 1801 Airport Road, Mid-Continent Airport, Wichita, Kansas 67209; telephone: (316) 946-4127; facsimile: (316) 946-4407.

Supplementary information:

Comments Invited

How do I comment on the proposed AD? We invite your comments on the proposed rule. You may send whatever written data, views, or arguments you choose. You need to include the rule's docket number and send your comments in triplicate to the address named under the caption ADDRESSES. We will consider all comments received by the closing date named above, before taking action on the proposed rule. We may change the proposals contained in this notice because of the comments received.

Are there any specific portions of the proposed AD I should pay attention to? The FAA specifically invites comments on the overall regulatory, economic, environmental, and energy aspects of the proposed rule that might call for a need to change the proposed rule. You may examine all comments we receive before and after the closing date for comments 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 proposal.

The FAA is reexamining 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 want to read your comments on the ease of understanding this document, 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.faa.gov/language/.

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-24-AD.” We will date stamp and mail the postcard back to you.

Discussion

What events have caused this proposed AD? The FAA has received many service difficulty reports of failures of pivot assemblies on Cessna Model 172RG airplanes. Failure of the main landing gear pivots has resulted in gear-up landings or loss of braking. The end of the pivot experiences overload stresses because of improper bushing clearance. This stress can produce fatigue cracks that spread until the pivot fitting fails, preventing the landing gear from extending. In other cases, brake fluid leaks through the fatigue crack resulting in loss of braking action.

What are the consequences if the condition is not corrected? Original design landing gear pivots, if not replaced with improved pivots, could crack and fail, resulting in gear-up landings or loss of braking.

Relevant Service Information

Is there service information that applies to this subject? Cessna has issued Service Bulletin SEB90-1,Revision 3, dated March 15, 1999.

What are the provisions of this service bulletin? The service bulletin contains procedures for:

—Inspecting the main landing gear pivot assemblies for cracks,

—Replacing any cracked main landing gear pivot assemblies, and

—Installing new bushings on the pivot assembly shaft.

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

What has FAA decided? After examining the circumstances and reviewing all available information related to the incidents, we have determined that:

—The unsafe condition referenced in this document exists or could develop on other Cessna Model 172RG airplanes of the same type design;

—These airplanes should have the actions named in the service bulletin incorporated; and

—The FAA should take AD action to correct this unsafe condition.

What would this proposed AD require? This proposed AD would require you to follow the Cessna Service BulletinSEB90-1, Revision 3, dated March 15, 1999, and the Model 172RG Series Service Manual and do these actions:

—Inspect the main landing gear pivot assemblies for cracks;

—Replace any cracked main landing gear pivot assemblies; and

—Install new bushings on the pivot assembly shaft.

Cost Impact

How many airplanes would this proposed AD impact? We estimate the proposed AD would affect 766 airplanes in the U.S. registry.

What would be the cost impact of the proposed actions for the affected airplanes on the U.S. Register? We estimate that it would take about 20 workhours for each airplane to do both proposed pivot assembly inspections, at an average labor rate of $60 an hour. Based on the figures presented above, we estimate the total cost impact of the proposed inspection on U.S. operators is $919,200, or $1,200 for each airplane.

We estimate that it would take about 5 workhours for each airplane to do both proposed bushing replacements concurrent with the pivot assembly inspection, at an average labor rate of $60 an hour. Parts cost about $200 for each airplane. Based on the figures presented above, we estimate the total cost impact of the proposed bushing replacement on U.S. operators is $500 for each airplane.

If a crack is found during the pivot assembly inspection, the pivot assembly must be replaced. We estimate that it would take about 3 workhours to do each proposed pivot assembly replacement, at an average labor rate of $60 an hour. Parts cost about $2,783 for each pivot assembly. Based on the figures presented above, we estimate the total cost impact of the proposed pivot assembly replacement on U.S. operators is $2,963 for each pivot assembly.

We have no way of knowing how many airplanes will require replacement pivot assemblies. The total cost for each airplane for this proposed AD depends on whether a crack is found during the inspection of the pivot assembly. We estimate the total cost impact of this AD for each airplane to U.S. operators is:

Neither pivot crackedOne pivot crackedBoth pivots cracked
$1700 $4663 $7626

Regulatory Impact

Would this proposed AD impact relations between Federal and Stategovernments? The regulations proposed would not have a substantial direct effect on the States, between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. We have determined that this proposed rule would not have federalism implications under Executive Order 13132.

Would this proposed AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if put into effect, 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 have placed a copy of the draft regulatory evaluation prepared for this action in the Rules Docket. You may geta copy of it 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

Therefore, under the authority delegated to me by the Administrator, the Federal Aviation Administration (FAA) 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

2. FAA amends Section 39.13 by adding a new airworthiness directive (AD) to read as follows:

Cessna Aircraft Company: Docket No. 2000-CE-24-AD.

(a)What airplanes are affected by this AD? Model 172RG, with the serial numbers 691 and 172RG0001 through 172RG1191, certified in any category.

(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 in this AD are intended to detect, correct, and prevent future cracks on the original design landing gear pivots. Cracked main landing gear pivots could fail, resulting in gear-up landings or loss of braking.

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

ActionsCompliance timesProcedures
(1) Inspect the main landing gear pivot assemblies for cracks Within the next 100 time-inservice after the effective date of this AD Do this action following the ACCOMPLISHMENT INSTRUCTIONS in Cessna Service Bulletin SEB90-1, Revision 3, dated March 15, 1999, and the Model 172RG Series Service Manual.
(2) If you find cracks, replace the affected main landing gear pivot assembly with the part referenced in the service bulletin Before further flight after the inspection Do this action following the ACCOMPLISHMENT INSTRUCTIONS in Cessna Service Bulletin SEB90-1, Revision 3, dated March 15, 1999, and the Model 172RG Series Service Manual.
(3) Install new bushings on both main landing gear pivot assemblies using the applicable kit referenced in the service bulletin Before further flight after the inspection Do this action following the ACCOMPLISHMENT INSTRUCTIONS in Cessna Service Bulletin SEB90-1, Revision 3, dated March 15, 1999, and the Model 172RG Series Service Manual.

(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, Wichita Aircraft CertificationOffice (ACO), approves your alternative. Send your request through an FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Wichita ACO.

Note:

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 the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance under 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 Steven Litke, Aerospace Engineer, Wichita Aircraft Certification Office, FAA, 1801 Airport Road, Mid-Continent Airport, Wichita, Kansas 67209; telephone:(316) 946-4127; facsimile: (316) 946-4407.

(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 §§ 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 do the requirements of this AD.

(h)How do I get copies of the documents referenced in this AD? You may get copies of the documents referenced in this AD from the Cessna Aircraft Company, Product Support, P.O. Box 7706,Wichita, Kansas 67277; or read this document at FAA,Central Region, Office of the Regional Counsel, 901Locust, Room 506, Kansas City, Missouri 64106.

Issued in Kansas City, Missouri, on October 23, 2000. Marvin R. Nuss,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.

References

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