Airworthiness Directives; Aviat Aircraft Inc. Models S-2A, S-2B, and S-2S Airplanes (formerly Pitts Models S-2A, S-2B, and S-2S airplanes)

[Federal Register Volume 62, Number 104 (Friday, May 30, 1997)] [Proposed Rules] [Pages 29309-29312] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 97-14180]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-17-AD] RIN 2120-AA64

Airworthiness Directives; Aviat Aircraft Inc. Models S-2A, S-2B, and S-2S Airplanes (formerly Pitts Models S-2A, S-2B, and S-2S airplanes)

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to supersede Airworthiness Directive (AD) 96-09-08 R1 applicable to certain Aviat

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Aircraft Inc. (Aviat) Models S-2A, S-2B, and S-2S airplanes, which currently requires repetitively inspecting the upper longerons just aft of the rear cabane struts for cracks and repairing any cracks found. The proposed action would retain the same actions as the current AD, lengthen the time interval between repetitive inspections, require either installing a marked accelerometer in order to continue to perform acrobatic maneuvers and installing a placard that specifies gravity (``g'') force limitations; or, installing a placard prohibiting acrobatic maneuvers; and, require inserting revisions into the Airplane Flight Manual (AFM). The proposed AD is prompted by reports of cracking in the upper longerons and the availability of an improved design modification that, when incorporated, reinforces the upper longeron area. The actions specified by the proposed AD are intended to prevent cracking and subsequent failure of the airframe, resulting in possible loss of control of the airplane.

DATES: Comments must be received on or before July 25, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 97-CE-17-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. Comments may be inspected at this location between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted. Service information that applies to the proposed AD may be obtained from Aviat Aircraft Inc., The Airport-Box No. 1240, 672 South Washington Street, Afton, Wyoming, 83110; telephone (307) 886-3151; facsimile (307) 886-9674. This information also may be examined at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Roger Caldwell, Project Engineer, FAA, Denver Aircraft Certification Office, 26805 East 68th Ave., Room 214, Denver, Colorado 80216; telephone (303) 342-1086; facsimile (303) 342- 1088.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 proposal 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. 97-CE-17-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Central Region, Office of the Assistant Chief Counsel, Attention: Rules Docket No. 97-CE-17-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

Discussion

Airworthiness Directive (AD) 96-09-08 R1, Amendment 39-9690 (61 FR 35936, No. 132, July 9, 1996), currently requires repetitively inspecting the longerons around the rear cabane struts for cracks on Aviat Models S-2A (all serial numbers (S/N)), S-2B (S/N 5000 through 5350), and S-2S (all S/N), and repairing and reinforcing any crack found during the inspections.

Actions Since Issuance of Previous Rule

Additional reports have been received by the FAA regarding failures of the upper longerons just aft of the rear cabane struts and forward of the instrument panel on these airplanes. Upon investigation of the incidents, further analysis and testing show that hard landings and snap roll maneuvers in excess of the +6 and -3 gravity (``g'') force limits cause enough stress and fatigue to crack the upper longerons. This condition, if not corrected, could result in failure of the airframe and possible loss of control of the airplane. Aviat has developed FAA-approved Kit No. S-2-513, which includes the parts and procedures to repair and reinforce the longeron aft of the rear cabane strut on Aviat Models S-2A, S-2B, and S-2S.

Relevant Service Information

Aviat revised Service Bulletin (SB) No. 24, Dated: March 20, 1996, Revised: November 22 1996, and issued Installation Instructions to Kit No. S-2-513, dated August 26, 1996, Revised: May 9, 1997. Aviat SB No. 24, Dated: March 20, 1996, Revised: November 22, 1996, specifies procedures for repetitively inspecting the longerons for cracks, installing an accelerometer and a placard that specifies ``g'' force limitations of +6 & -3, and inserting the revisions into the AFM. The Installation Instructions to Kit No. S-2-513, dated August 26, 1996, Revised: May 9, 1997, specify procedures for reinforcing the longeron area.

The FAA's Determination

After examining the circumstances and reviewing all available information related to the incidents described above, including the referenced service information. The FAA has determined that AD action should be taken to prevent cracking and subsequent failure of the airframe with consequent loss of control of the airplane.

Explanation of the Provisions of the Proposed AD

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 of the same type design, the proposed AD would supersede AD 96-09-08 R1 to require: (1) Repetitively inspecting the upper longerons aft of the rear cabane struts and forward of the instrument panel for cracks; (2) Modifying any cracked longeron found during any inspection required by the proposed AD by incorporating Aviat Kit No. S-2-513; (3) Inserting the revisions referenced in the Aviat SB No. 24, Date: November 22, 1996; Revised: March 20, 1996 into the AFM; and (4) Accomplishing one of the following:

-- Installing a redlined accelerometer marked at the +6g and -3g hash marks indicating the acrobatic ``g'' force limitations and a placard (part number 2-7604-47) stating the ``g'' force limitations; or -- Fabricating and installing a placard in the pilot's clear view using at least \1/8\-inch letters that incorporate the words: ``ACROBATIC MANEUVERS PROHIBITED.''

Differences Between the Proposed AD and the Aviat Service Bulletin

Aviat SB No. 24, Dated: March 20, 1996, Revised: November 22, 1996,

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``ACCOMPLISHMENT INSTRUCTIONS, 6. B. 1.'' recommends (1) installing the placard on the panel above the accelerometer and marking the accelerometer with red lines at the +6g and -3g hash marks, (2) inserting the revision to flight limitations into the AFM, (3) changing step 1 of the 100 HOURLY INSPECTION of the Owner's and Maintenance Manual to include an inspections for cracks in the region just aft of the welds attaching the rear cabane struts, and (4) making an entry in the log book stating compliance with this revision and method of compliance. The proposed AD recommends items (1) and (2) in the preceding paragraph, except that the proposed AD would require either installing an accelerometer (if not already installed), marking red lines on the accelerometer, and installing a placard stating the ``g'' force limitations; or fabricating and installing a placard to prohibit acrobatic maneuvers. The proposed AD also would not require items (3) and (4) in the preceding paragraph because the purpose of an AD is to correct an unsafe condition that is likely to exist or develop in aircraft, not to make corrections to the maintenance manual. Revisions to the maintenance manual are the responsibility of the aircraft owner and the aircraft manufacturer.

Cost Impact

The FAA estimates that 500 airplanes in the U.S. registry would be affected by the proposed AD, that it would take approximately 8 workhours per airplane to accomplish the proposed initial inspection and modification, and that the average labor rate is approximately $60 an hour. The installation of the revisions to the AFM and the placard may be performed by 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). Therefore, the only labor cost associated with this step is the time of the owner/operator. Parts costs are estimated to be approximately $400 for Aviat Kit No. S-2-513 and $10 for the placard. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $445,000 or $890 per airplane. The estimated cost does not account for the repetitive inspections because the FAA has no way to determine the number of repetitive inspections that might be incurred over the life of the airplane. The manufacturer has informed the FAA that they have distributed kits to reinforce 4 airplanes. With this in mind, the approximate cost for the proposed AD on U.S. operators would be reduced from $445,000 to $441,440.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. 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 promulgated, 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. A copy of the draft regulatory evaluation prepared for this action has been placed in the Rules Docket. A copy of it may be obtained 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

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration 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.

Sec. 39.13 [Amended]

2. Section 39.13, is amended by removing Airworthiness Directive (AD) 96-09-08 R1, Amendment 39-9690, and adding a new AD to read as follows:

Aviat Aircraft Inc.: Docket No. 97-CE-17-AD; Supersedes AD 96-09-08 R1, Amendment 39-9690.

Applicability: Models S-2A (all serial numbers (S/N)), S-2B (S/N 5000 through 5350), and S-2S (all serial numbers) airplanes (formerly Pitts Models S-2A, S-2B, and S-2S), 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 cracking and subsequent failure of the longerons with consequent loss of control of the airplane, accomplish the following: (a) At the accumulation of 300 hours total time-in-service (TIS) or within the next 25 hours TIS after the effective date of this AD, whichever occurs later, and thereafter at intervals not to exceed 100 hours TIS, inspect (using a 10x magnifying glass) the longerons aft of the rear cabane strut and forward of the instrument panel for cracks in accordance with paragraphs A. 1. through A. 5. and Figure 1 in the ACCOMPLISHMENT INSTRUCTIONS of Aviat Aircraft Inc. (Aviat) Service Bulletin (SB) No. 24, Date: March 20, 1996, Revised: November 22, 1996. (1) If cracks are found during any inspection required by this AD, prior to further flight, modify the cracked area by incorporating Aviat Kit No. S-2-513 in accordance with the INSTALLATION INSTRUCTIONS section in Aviat Kit No. S-2-513, dated August 26, 1996, Revised: May 9, 1997. (2) The modification does not eliminate the 100-hour TIS interval repetitive inspections. (b) At the accumulation of 300 hours total TIS or within the next 25 hours TIS after the effective date of this AD, whichever occurs later, insert revisions to the Airplane Flight Manual (AFM) in accordance with paragraph B. 2. in the ACCOMPLISHMENT INSTRUCTIONS of Aviat SB No. 24, Dated: March 20, 1996, Revised November 22, 1996. (c) At the accumulation of 300 hours total TIS or within the next 25 hours TIS after the effective date of this AD, whichever occurs later, accomplish either (c)(1) or (c)(2) below: (1) Install an accelerometer and permanently mark the face with red marks (\3/16\-inch x \1/16\-inch) at the +6 g and -3 g hash marks, and install a placard (Aviat part number 2-7604-47) stating the gravity (``g'') force limitations within the pilot's clear view in accordance with paragraph B. 1. of the ACCOMPLISHMENT INSTRUCTIONS in Aviat SB No. 24, Date: March 20, 1996, Revised: November 22, 1996; or (2) Fabricate and install a placard in the pilot's clear view using at least \1/8\-inch letters that incorporates the following words: ``ACROBATIC MANEUVERS PROHIBITED.'' (d) The installation of the placard and the insertion of the revisions into the AFM may be performed by 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), and must be entered into the aircraft records showing compliance with this AD in accordance with

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section 43.11 of the Federal Aviation Regulations (14 CFR 43.11). (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 action can be accomplished, provided no cracks are found during any inspections required by paragraph (a) of this AD. No special flight permits may be issued to any airplane with cracks in the upper longerons just aft of the rear cabane struts. (f) 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, 26805 East 68th Ave., Room 214, 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.

(g) All persons affected by this directive may obtain copies of the documents referred to herein upon request to Aviat Aircraft Inc., The Airport-Box No. 1240, 672 South Washington Street, Afton, Wyoming, 83110; or may examine this document at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

Issued in Kansas City, Missouri, on May 23, 1997. Henry A. Armstrong, Acting Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 97-14180 Filed 5-29-97; 8:45 am] BILLING CODE 4910-13-U