AD 96-09-08

This amendment adopts a new airworthiness directive (AD) that is applicable to Aviat Aircraft Inc., Models S-2A, S-2B, and S-2S airplanes (formerly Pitts Models S-2A, S-2B, and S-2S airplanes). This action requires inspecting the longerons aft of the rear cabane struts for cracks, and if cracked, prior to further flight, repairing the cracks. Reports of longeron failure caused by fatigue aft of the rear cabane struts prompted this action. The actions specified by this AD are intended to prevent cracking and subsequent failure of the longerons resulting in possible loss of control of the airplane .

Final rule; request for comments.

96-09-08 AVIAT AIRCRAFT INC.: Amendment 39-9584; Docket No. 95-CE-101-AD.

Applicability: Models S-2A, S-2B, and S-2S airplanes (formerly Pitts Models S-2A, S-2B, and S-2S airplanes), all serial numbers, 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 (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 the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance:Required at the accumulation of 300 hours total time-in-service (TIS), or within the next 25 hours TIS, whichever occurs later, and thereafter at intervals not to exceed 25 hours TIS, unless already accomplished.

To prevent cracking and subsequent failure of the longerons, which could result in loss of control of the airplane, accomplish the following:

(a) Inspect (using a 10x magnifying glass) the longerons aft of the rear cabane struts for cracks in accordance with paragraphs 1.) through 5.) in the Aviat Service Bulletin (SB) No. 24, dated February 8, 1996. If cracks are found during any inspection required by this AD, prior to further flight, contact the Manager of the Denver ACO for an approved repair scheme.

(b) Prior to further flight, repair any cracks found in accordance with the approved repair scheme provided by the ACO manager.

(c) Report the results of the initial inspection to the Manager of the Denver Aircraft Certification Office (ACO), FAA, Denver Aircraft Certification Office, 5440 Roslyn St., suite 133, Denver, Colorado, 80216, within 10 days of the inspection. The information provided should include airplane model number, serial number, registration number, location of cracks found, number of cracks, and total TIS. Reporting requirements have been approved by the Office of Management and Budget and assigned OMB control number 2120-0056.

(d) 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 inspection requirements of this AD can be accomplished, provided that aerobatic flying is prohibited.

(e) An alternative method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent level of safety may be approved by the Manager, Denver Aircraft Certification Office, FAA, Denver Aircraft Certification Office, 5440 Roslyn St., suite 133, Denver, Colorado, 80216. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Denver Aircraft Certification Office.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Denver Aircraft Certification Office.

(f) The inspections required by this AD shall be done in accordance with Aviat Aircraft Inc. Service Bulletin No. 24, dated February 8, 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 Aviat Aircraft Inc., The Airport-Box No. 1240, 672 South Washington Street, Afton, Wyoming, 83110. 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.

(g) This amendment becomes effective on May 20, 1996.

The FAA has been notified that an unsafe condition may exist on Aviat Models S-2A, S-2B, and S-2S airplanes. The owners/operators of several of these airplanes have reported cracking and failure of the longerons aft of the rear cabane struts. One incident reported that the cracked longeron made it very difficult to control the airplane to a safe landing.

Aviat has issued service bulletin (SB) No. 24, dated February 8, 1996, which specifies inspecting for cracks and repairing any cracks found in the longerons aft of the rear cabane struts.

After examining the circumstances and reviewing all available information related to the incidents described above, the FAA has determined that AD action should be taken in order to prevent cracking and subsequent failure of the longerons resulting in possible loss of control of the airplane.

Since an unsafe condition has been identified that is likely to exist or develop in other Aviat Models S-2A, S-2B, and S-2S airplanes of the same type design registered for operation in the United States, this AD requires:

-- inspecting the longerons around the rear cabane struts for cracks,

-- if no cracks are found, repetitively inspecting, and

-- if cracks are found during any inspection, prior to further flight, contact the Denver ACO manager for an approved repair scheme.

-- repair any cracks found according to the approved repair scheme provided by the ACO manger.

The inspections are to be done in accordance with the instructions in the Aviat SB No. 24, dated February 8, 1996.

Since a situation exists 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 rule that involves requirements affecting immediate flight safetyand, 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 before and 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 notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 95-CE-101-AD." The postcard will be date stamped and returned to the commenter.

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 thatmust 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.

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