[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

[[Page 29310]]

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,

[[Page 29311]]

``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

[[Page 29312]]

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