[Federal Register Volume 62, Number 249 (Tuesday, December 30, 1997)]
[Rules and Regulations]
[Pages 67708-67711]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-33512]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-CE-17-AD; Amendment 39-10263; AD 97-26-20]
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: Final rule.
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SUMMARY: This amendment supersedes Airworthiness Directive AD 96-09-08
R1, which applies to Aviat Aircraft Inc. (Aviat) Models S-2A, S-2B, and
S-2S airplanes (formerly Pitts Models S-2A, S-2B, and S-2S), and
currently requires repetitively inspecting the upper longerons just aft
of the rear cabane struts for cracks and repairing any cracks. This
action retains the same actions as the current AD; lengthens the time
interval between repetitive inspections; requires 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, requires inserting revisions into the Airplane Flight Manual
(AFM). This action is the result of reports of cracking in the upper
longerons caused by operating the airplane outside of the certificated
design limits and the availability of a design modification that, when
incorporated, repairs the damaged upper longeron area. The actions
specified by this AD are intended to prevent cracking and subsequent
failure of the longerons with consequent loss of control of the
airplane.
DATES: Effective January 22, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of January 22, 1998.
ADDRESSES: Service information that applies to this AD may be obtained
from Aviat Aircraft Inc., P. O. Box 1240, 672 South Washington Street,
Afton, Wyoming, 83110; telephone (307) 886-3151; facsimile (307) 886-
9674. This information may also be examined at the Federal Aviation
Administration (FAA), Central Region, Office of the Regional Counsel,
Attention: Rules Docket 97-CE-17-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.
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:
Events Leading to the Issuance of This AD
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) to supersede AD 96-09-08 R1, Amendment 39-9690 (61 FR
35936, No. 132, July 9, 1996), that applies to Aviat Models S-2A, S-2B,
and S-2S airplanes (formerly Pitts Models S-2A, S-2B, and S-2S), was
published in the Federal Register on May 30, 1997 (62 FR 29309). AD 96-
09-08 R1 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. The proposed AD would supersede AD 96-09-08 R1 with a new
AD that would require:
(1) Repetitively inspecting the upper longerons aft of the rear
cabane struts
[[Page 67709]]
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: March 20, 1996, Revised: November 22, 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.''
Accomplishment of this action would be in accordance with the Aviat
Aircraft Inc. Service Bulletin No. 24, Date: March 20, 1996; Revised:
November 22, 1996, and Aviat Aircraft Inc. Installation Instructions to
Kit No. S-2-513, dated August 26, 1996; Revised May 9, 1997.
Comments
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Several comments were received on the
proposed rule. Due consideration has been given to the following
comments.
A commenter suggested that the Aviat Pitts Model S-2A be eliminated
from the applicability of the action because the aircraft does not have
enough horsepower to sustain airspeeds that will damage the airframe
structure.
The FAA does not concur. The FAA is obligated to address the whole
fleet (all models) since it is possible to exceed the fatigue limits on
all models regardless of horsepower. The aircraft weight and maneuver
entry speed is the factor that drives the resultant gravity (``g'')
load. All of the Aviat models addressed can enter a snap roll while in
a dive with the airspeed higher than the recommended entry speed. The
final rule will not be changed as a result of this comment.
A commenter wanted the FAA to withdraw the NPRM because no fleet-
wide problem exists.
The FAA does not concur. The reason this action was taken is
because of four known incidents where cracked longerons were the cause.
After additional investigation, tests showed that exceeding the ``g''
force limitations causes stress to the longerons, thus producing
cracks. Therefore, the FAA is requiring additional measures to assure
that the operation of the affected airplanes does not exceed the
certification limits. The FAA also wants to assure that the affected
airplanes are flying without cracks. If the upper longerons are not
repetitively inspected for cracks, then the airplane is susceptible to
an unsafe condition. The final rule will not be changed as a result of
this comment.
One commenter suggested that the frequency of the longeron
inspection occur at every 100-hour time-in-service (TIS) intervals.
The FAA concurs and notes that a 100 hour TIS interval for
repetitive inspections of the upper longeron area was proposed in the
NPRM. The final rule will not be changed as a result of this comment.
A commenter wants the ``g'' limitation placard to read ``+4.5g and
-2.5g while performing a snap roll maneuver'' because the twisting
forces imposed on the airframe by snap rolls are more likely to cause
structural failure than straight positive ``g'' force.
The FAA does not concur. There has been no convincing analysis to
indicate that anything less than the original certificated maximum
``g'' force levels of +6 and -3 should not be the airplane operating
limits. The final rule will not be changed as a result of this comment.
Another commenter suggested inspecting the fuselage for structural
damage if a ``g'' factor of +6 is exceeded during landing. The
commenter did not provide any justification to support this argument.
As a result, this comment will not change the final rule.
One commenter wanted a requirement to mark the accelerometers at
the operating limitations. The FAA agrees. This requirement was
proposed in the NPRM. The final rule will not change as a result of
this comment.
A commenter suggested delaying the final rule pending further study
of the effect of snap roll maneuvers because the AD does not recognize
or discuss the twisting forces imposed on the airframe by snap rolling
maneuvers, and that the snap roll maneuvers result in a higher ``g''
force than straight positive ``g'' forces.
The FAA does not concur. Flight test analysis shows that the
original operating limits that were determined during certification of
these airplanes are adequate as long as the operator flies the airplane
within the ``g'' force limits. The final rule will not change as a
result of this comment.
Another comment requested that the FAA delete the requirement for
the placard on the accelerometer. No justification was presented for
this request. The FAA has determined that this placard is necessary to
fully address the unsafe condition. The final rule will not change as a
result of this comment.
One comment recommended amending the aircraft documents to reflect
a mandatory VNE (never exceed speed) for snap roll maneuvers to limit
the ``g'' force loads. The commenter presented no justification for
this recommendation.
The FAA does not concur. This recommendation offers no benefit over
the already proposed placard placed near the accelerometer because the
flight manual already states the certificated operating ``g'' limits
and entry speeds for maneuvers.
Aviat Aircraft Inc. commented that they agree with the need for the
AD, but Aviat felt that the general theme of the preamble to the NPRM
was degrading and made hostile references to the Aviat airplanes. Aviat
submitted a re-written preamble to NPRM. The FAA did not re-print this
submission as part of the final rule comments because the comments made
did not speak to the AD only to the discussion in the preamble of the
NPRM. The preamble to the NPRM is not published as part of the final
rule. Therefore, this final rule is not changed as a result of this
comment. The document submitted can be obtained by written request to
the Office of the Regional Counsel's Rules Docket found in the
ADDRESSES section of this AD.
The FAA's Determination
After careful review of all available information related to the
subject presented above, the FAA has determined that air safety and the
public interest require the adoption of the rule as proposed except for
minor editorial corrections. The FAA has determined that these minor
corrections will not change the meaning of the AD and will not add any
additional burden upon the public than was already proposed.
Cost Impact
The FAA estimates that 500 airplanes in the U.S. registry will be
affected by this AD, that it will take approximately 8 workhours per
airplane to accomplish the 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 Secs. 43.7 and 43.9 of the Federal
Aviation Regulations (14 CFR 43.7 and 43.9). Therefore, the only labor
cost associated with this step is the time of the owner/
[[Page 67710]]
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 this 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 this AD on U.S. operators will be reduced from
$445,000 to $441,440.
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.
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) 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 final evaluation prepared for this
action is contained 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, 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.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing airworthiness directive
(AD) 96-09-08 R1, Amendment No. 39-9690 and by adding a new AD to read
as follows:
97-26-20 Aviat Aircraft Inc.: Amendment No. 39-10263; 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. 4. 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) Disregard the instructions in paragraph A. 5. in the
ACCOMPLISHMENT INSTRUCTIONS of Aviat SB No. 24, Date: March 20,
1996, Revised: November 22, 1996. This AD takes precedence over the
instructions in paragraph A. 5 referenced above.
(2) 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.
(3) 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
Sec. 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 Sec. 43.9 of the Federal Aviation
Regulations (14 CFR 43.9).
(e) Special flight permits may be issued in accordance with
Secs. 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) The inspection, modification, and replacements required by
this AD shall be done in accordance with Aviat Aircraft Inc. Service
Bulletin (SB) No. 24, Revised: November 22, 1996, and Aviat Aircraft
Inc. Installation Instructions in Aviat Aircraft Inc. Kit No. S-2-
513, dated August 26, 1996, Revised: May 9, 1997. 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 Regional
Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at
the Office of the Federal Register, 800
[[Page 67711]]
North Capitol Street, NW., suite 700, Washington, DC.
(h) This Amendment supersedes AD 96-09-08 R1, Amendment 39-9690.
(i) This Amendment (39-10263) becomes effective on January 22,
1998.
Issued in Kansas City, Missouri, on December 16, 1997.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 97-33512 Filed 12-29-97; 8:45 am]
BILLING CODE 4910-13-U
