AD 97-01-02 ACTIVE

This amendment adopts a new airworthiness directive (AD) that applies to certain Cessna Aircraft Company (Cessna) Model 525 airplanes. This action requires repetitively inspecting the main landing gear (MLG) trunnion pins for proper installation, and either immediately or eventually replacing the existing dry-film lubricated MLG trunnion slot bearings with sealed and self-lubricating bearings. This AD results from an incident where the left MLG collapsed during the landing roll even though the cockpit indications showed that the MLG was in the normal down and locked position. Loss of dry-film lubricant on the MLG trunnion bearings caused this incident. The actions specified by this AD are intended to prevent MLG collapse caused by trunnion bearing failure, which could result in loss of control of the airplane during landing operations.

Final rule; request for comments

97-01-02 CESSNA AIRCRAFT COMPANY: Amendment 39-9873; Docket No. 96-CE-59- AD.

Applicability: Model 525 airplanes (serial numbers 525-0001 through 525-0153), certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, 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 (f) 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 the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated in the body of this AD, unless already accomplished.

To prevent main landing gear (MLG) collapse caused by trunnion bearing failure, which could result in loss of control of the airplane during landing operations, accomplish the following:

(a) Within the next 25 hours time-in-service (TIS) after the effective date of this AD, and thereafter within 25 hours TIS after the initial inspection, inspect the main landing gear trunnion pins (four pins: both forward and aft trunnion pins on both the left and right MLG) for proper installation. Perform this inspection in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Cessna Alert Service Letter SLA525-32-11, Revision 1, dated October 1, 1996.

(b) If any pin is not properly installed as described in Cessna Alert Service Letter SLA525-32-11, Revision 1, dated October 1, 1996, prior to further flight, replace the existing dry-film lubricated MLG trunnion slot bearing with a sealed and self-lubricating bearing. Perform this replacement in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Cessna Service Bulletin SB525-32-08, Revision 1, dated October 1, 1996. The repetitive inspection need not be accomplished on the trunnion pin when the bearing is replaced with a sealed and self-lubricating bearing.

(c) Within the next 75 hours TIS after the effective date of this AD, unless already accomplished in accordance with paragraph (b) of this AD, replace the existing dry-film lubricated MLG trunnion slot bearing with a sealed and self-lubricating bearing at all four main landing gear trunnion locations (both forward and aft trunnion pins on both the left and right MLG). Perform these replacements in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Cessna Service Bulletin SB525-32-08, Revision 1, dated October 1, 1996.

(d) Replacing the existing dry-film lubricated MLG trunnion slot bearing with a sealed and self-lubricating bearing in accordance with the ACCOMPLISHMENT INSTRUCTIONS section of Cessna Service Bulletin SB525-32-08, Revision 1, dated October 1, 1996, on all four main landing gear trunnion locations (both forward and aft trunnion pins on both the left and right MLG) eliminates the repetitive inspection requirement of this AD. These replacements may be accomplished at any time prior to 75 hours TIS after the effective date of this AD, at which time they must be accomplished (see paragraph (c) of this AD).

(e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(f) An alternative method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be approved by the Manager, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Wichita ACO.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Wichita ACO.

(g) The inspections required by this AD shall be done in accordance with Cessna Alert Service Letter SLA525-32-11, Revision 1, dated October 1, 1996. The replacements required by this AD shall be done in accordance with Cessna Service Bulletin SB525-32-08, Revision 1, dated October 1, 1996. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from the Cessna Aircraft Company, Citation Marketing Division, P.O. Box 7706, Wichita, Kansas 67277. Copies may be inspected at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(h) This amendment becomes effective on January 15, 1997.

Events Leading to This AD
Recently, a Cessna Model 525 airplane was involved in an incident where the left main landing gear (MLG) collapsed during the landing roll even though cockpit indications showed that the MLG was in the normal down and locked position. Investigation revealed that loss of dry-film lubricant on the MLG trunnion bearings caused this incident.

Further investigation of the MLG of Cessna Model 525 airplanes indicates that this dry-film lubricant in the MLG trunnion bearings becomes inadequate over time. When these bearings are not properly lubricated, the roll pin that goes through the trunnion and bearing shaft fails, which causes the pin to back out of the bearing. This roll pin supports the entire MLG, so its failure then causes MLG collapse.

Applicable Service Information
Cessna has issued the following service information:

o Cessna Alert Service Letter SLA525-32-11, Revision 1, dated October 1, 1996, which includes procedures for inspecting the MLG trunnion pins for proper installation; and

o Cessna Service Bulletin SB525-32-08, Revision 1, dated October 1, 1996, which includes procedures for replacing the existing dry-film lubricated MLG trunnion slot bearings with sealed and self-lubricating bearings.

The FAA's Determination
After examining the circumstances and reviewing all available information related to the incident described above, including the above-referenced service information, the FAA has determined that AD action should be taken to prevent MLG collapse caused by trunnion bearing failure, which could result in loss of control of the airplane during landing operations.

Explanation of the Provisions of This AD
Since an unsafe condition has been identified that is likely to exist or develop in other Cessna Model 525 airplanes of the same type design, this AD requires repetitively inspecting the main landing gear (MLG) trunnion pins for proper installation, and either immediately or eventually replacing the existing dry-film lubricated MLG trunnion slot bearings with sealed and self-lubricating bearings. Only two inspections will be allowed before mandatory replacement of the MLG trunnion slot bearings. Accomplishment of the inspections required by this AD will be in accordance with Cessna Alert Service Letter SLA525-32-11, Revision 1, dated October 1, 1996. Accomplishment of the replacement required by this AD will be in accordance with Cessna Service Bulletin SB525-32-08, Revision 1, dated October 1, 1996.

Determination of the Effective Date of the AD
Since a situation exists (loss of control of the airplane during landing operations) that requires the immediate adoption of this regulation, it is found that notice and opportunity for public prior comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.

Comments Invited
Although this action is in the form of a final rulethat involves requirements affecting immediate flight safety and, thus, was not preceded by notice and opportunity to comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both beforeand after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 96-CE-59-AD." The postcard will be date stamped and returned to the commenter.

Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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, pursuant to 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 USC 106(g), 40113, 44701.

39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive (AD) to read as follows:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket 96-CE-59-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

Service information that applies to this AD may be obtained from the Cessna Aircraft Company, Citation Marketing Division, P.O. Box 7706, Wichita, Kansas 67277; telephone (316) 941-6000; facsimile (314) 941-8500. This information may also be examined at the Federal Aviation Administration (FAA), Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 96-CE-59-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Mr. Eual Conditt, Aerospace Safety Engineer, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4128; facsimile (316) 946-4407.