[Federal Register Volume 80, Number 82 (Wednesday, April 29, 2015)]
[Rules and Regulations]
[Pages 23699-23707]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-08732]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2014-1083; Directorate Identifier 2014-CE-036-AD;
Amendment 39-18140; AD 2015-08-04]
RIN 2120-AA64
Airworthiness Directives; Various Aircraft Equipped With Wing
Lift Struts
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: We are superseding Airworthiness Directive (AD) 99-01-05 R1,
which applied to certain aircraft equipped with wing lift struts. AD
99-01-05 R1 required repetitively inspecting the wing lift struts for
corrosion; repetitively inspecting the wing lift strut forks for
cracks; replacing any corroded wing lift strut; replacing any cracked
wing lift strut fork; and repetitively replacing the wing lift strut
forks at a specified time for certain airplanes. This new AD retains
all requirements of AD 99-01-05R1 and adds additional airplane models
to the Applicability section. This AD was prompted by a report that
additional Piper Aircraft, Inc. model airplanes should be added to the
Applicability section. We are issuing this AD to correct the unsafe
condition on these products.
DATES: This AD is effective June 3, 2015.
The Director of the Federal Register approved the incorporation by
reference of certain other publications listed in this AD as of
February 8, 1999 (63 FR 72132, December 31, 1998).
ADDRESSES: For service information identified in this AD, contact Piper
Aircraft, Inc., Customer Services, 2926 Piper Drive, Vero Beach,
Florida 32960; telephone: (772) 567-4361; Internet: www.piper.com.
Copies of the instructions to the F. Atlee Dodge supplemental type
certificate (STC) and information about the Jensen Aircraft STCs may be
obtained from F. Atlee Dodge, Aircraft Services, LLC., 6672 Wes Way,
Anchorage, Alaska 99518-0409, Internet: www.fadodge.com. You may view
this referenced service information at the FAA, Small Airplane
Directorate, 901 Locust, Kansas City, Missouri 64106. For information
on the availability of this material at the FAA, call (816) 329-4148.
It is also available on the Internet at http://www.regulations.gov by
searching for and locating Docket No. FAA-2014-1083.
Examining the AD Docket
You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2014-
1083; or in person at the Docket Management Facility between 9 a.m. and
5 p.m., Monday through Friday, except Federal holidays. The AD docket
contains this AD, the regulatory evaluation, any comments received, and
other information. The address for the Docket Office (phone: 800-647-
5527) is Document Management Facility, U.S. Department of
Transportation, Docket Operations, M-30, West Building Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: For Piper Aircraft, Inc. airplanes,
contact: Gregory ``Keith'' Noles, Aerospace Engineer, FAA, Atlanta
Aircraft Certification Office (ACO), 1701 Columbia Avenue, College
Park, Georgia 30337; phone: (404) 474-5551; fax: (404) 474-5606; email:
[email protected].
For FS 2000 Corp, FS 2001 Corp, FS 2002 Corporation, and FS 2003
Corporation airplanes, contact: Jeff Morfitt, Aerospace Engineer, FAA,
Seattle ACO, 1601 Lind Avenue SW., Renton, Washington 98057; phone:
(425) 917-6405; fax: (245) 917-6590; email: [email protected].
[[Page 23700]]
For LAVIA ARGENTINA S.A. (LAVIASA) airplanes, contact: S.M.
Nagarajan, Aerospace Engineer, FAA, Small Airplane Directorate, 901
Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329-
4145; fax: (816) 329-4090; email: [email protected].
SUPPLEMENTARY INFORMATION:
Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to supersede AD 99-01-05 R1, Amendment 39-17688 (78 FR 73997,
December 10, 2013; corrected 78 FR 79599, December 31, 2013), (``AD 99-
01-05 R1''). AD 99-01-05 R1 applied to certain aircraft equipped with
wing lift struts. The NPRM published in the Federal Register on
December 31, 2014 (79 FR 78729). The NPRM was prompted by a report that
Piper Aircraft, Inc. (Piper) Models J-3, J3C-65 (Army L-4A), J3P, J4B,
and J4F airplanes should be added to the Applicability section. We were
also informed of a serial number overlap between Piper Model PA-18s
listed in AD 99-01-05 R1 and Piper Model PA-19 (Army L-18C). Certain
serial numbers listed for Model PA-18s should also be listed under
Model PA-19 (Army L-18C). The NPRM proposed to retain all requirements
of AD 99-01-05 R1 and add airplanes to the Applicability section. We
are issuing this AD to correct the unsafe condition on these products.
Comments
We gave the public the opportunity to participate in developing
this AD. The following presents the comments received on the NPRM (79
FR 78729, December 31, 2014) and the FAA's response to each comment.
Request To Remove the ``NO STEP'' Placard Requirement for Models PA-25,
PA-24-235, and PA-25-260 Airplanes
Joe Barr stated that LAVIA ARGENTINA S.A. (LAVIASA) Models PA-25,
PA-24-235, and PA-25-260 airplanes should be exempt from the
requirement in paragraph (m) of the proposed AD to install a ``NO
STEP'' placard on each wing lift strut.
Joe Barr stated that the LAVIASA PA-25 series airplanes are the
only low wing monoplane aircraft of all the affected airplane models
listed in the proposed AD. The LAVIASA PA-25 series airplanes have a
wing support strut that is located on top of, rather than below, the
wing. The upper end of the wing lift strut attaches to the top of the
fuselage and the bottom end of the strut attaches to the top of the
wing at the midpoint region. There is no safe wing walk surface area on
the top of the wing that extends more than a few inches from the wing
root to walk or stand at this mid-wing station. No one could possibly
step on or stand on the strut at or near this wing location without
significant damage to the adjacent fabric covered wing structure
itself. Therefore, it is illogical and irrelevant to have a ``NO STEP''
placard of any kind at the mentioned location on the wing lift struts
of the LAVIASA PA-25 series airplanes. This requirement was clearly
meant for high wing aircraft only.
We agree with the commenter. The intent of the placard is to
prevent damage from stepping on the lower end of the strut. This would
not occur on LAVIASA Models PA-25, PA-24-235, and PA-25-260 airplanes
due to the configuration discussed above.
We have changed paragraph (m) in this AD to exclude LAVIASA Models
PA-25, PA-24-235, and PA-25-260 airplanes from this requirement.
Request To Allow a Different Rework Method of an Unsealed Wing Lift
Strut for Model J-3 Airplanes
Mike Teets stated that he wants the option of using a different
method for reworking a non-sealed wing lift strut to a sealed condition
for Piper Aircraft Inc. Model J-3 airplanes.
Mike Teets stated that he has been inspecting the wing life struts
on his Piper Aircraft, Inc. Model J-3 airplane for years and has
developed a method for ``reoperating'' an unsealed wing life strut to a
sealed condition, which would remove the need for the repetitive
inspections and thereby reduce costs associated with the requirements
of the proposed AD.
We do not agree with the commenter. The commenter's request
pertains to only one model airplane affected by this AD and addresses
only a portion of the requirements of the proposed AD. The commenter's
proposal would be more appropriately addressed by requesting an
alternative method of compliance following the procedures specified in
paragraph (n) of this AD.
We have not changed this AD based on this comment.
Conclusion
We reviewed the relevant data, considered the comments received,
and determined that air safety and the public interest require adopting
this AD with the changes described previously and any minor editorial
changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the
NPRM (79 FR 78729, December 31, 2014) for correcting the unsafe
condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM (79 FR 78729, December 31, 2014).
We also determined that these changes will not increase the
economic burden on any operator or increase the scope of this AD.
Related Service Information Under 1 CFR Part 51
We reviewed Piper Aircraft Corporation Mandatory Service Bulletin
No. 528D, dated October 19, 1990, Piper Aircraft Corporation Mandatory
Service Bulletin No. 910A, dated October 10, 1989; F. Atlee Dodge
Aircraft Services, Inc. Installation Instructions No. 3233-I for
Modified Piper Wing Lift Struts Supplemental Type Certificate (STC)
SA4635NM, dated February 1, 1991; and Jensen Aircraft Installation
Instructions for Modified Lift Strut Fittings, which incorporates pages
1 and 5, Original Issue, dated July 15, 1983; pages 2, 4, and 6,
Revision No. 1, dated March 30, 1984; and pages a and 3, Revision No.
2, dated April 20, 1984. The service information describes procedures
for wing lift strut assembly inspection and replacement. This
information is reasonably available at http://www.regulations.gov by
searching for and locating Docket No. FAA-2014-1083, or you may see
ADDRESSES for other ways to access this service information.
Costs of Compliance
We estimate that this AD affects 22,200 airplanes of U.S. registry.
We estimate the following costs to comply with this AD. However,
the only difference in the costs presented below and the costs
associated with AD 99-01-05 R1 is addition of 200 airplanes to the
applicability:
[[Page 23701]]
Estimated Costs
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Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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Inspection of the wing lift 8 work-hours x $85 per Not applicable... $680 per $15,096,000 per
struts and wing lift strut hour = $680 per inspection cycle. inspection
forks. inspection cycle. cycle.
Installation placard........... 1 work-hour x $85 = $30.............. $115............. $2,553,000.
$85.
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We estimate the following costs to do any necessary replacements
that will be required based on the results of the inspection. We have
no way of determining the number of aircraft that might need these
replacements:
On-Condition Costs
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Cost per
Action Labor cost per wing lift strut Parts cost per product per
wing lift strut wing lift strut
----------------------------------------------------------------------------------------------------------------
Replacement of the wing lift strut and/or 4 work-hours x $85 per hour = $440 $780
wing lift strut forks. $340.
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Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, section 106, describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.
Regulatory Findings
We have determined that this AD will not have federalism
implications under Executive Order 13132. This AD will not have a
substantial direct effect 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.
For the reasons discussed above, I certify that this AD:
(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),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 14 CFR part 39 as follows:
PART 39--AIRWORTHINESS DIRECTIVES
0
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]
0
2. The FAA amends Sec. 39.13 by removing Airworthiness Directive (AD)
99-01-05 R1, Amendment 39-17688 (78 FR 73997, December 10, 2013;
corrected 78 FR 79599, December 31, 2013), and adding the following new
AD:
2015-08-04 Various Aircraft: Amendment 39-18140; Docket No. FAA-
2014-1083; Directorate Identifier 2014-CE-036-AD.
(a) Effective Date
This AD is effective June 3, 2015.
(b) Affected ADs
This AD supersedes AD 99-01-05 R1, Amendment 39-17688 (78 FR
73997, December 10, 2013; corrected 78 FR 79599, December 31, 2013)
``AD 99-01-05 R1''. AD 99-26-19 R1, Amendment 39-17681 (78 FR 76040,
December 16, 2013), also relates to the subject of this AD.
(c) Applicability
This AD applies to the following airplanes identified in Table 1
and Table 2 to paragraph (c) of this AD, that are equipped with wing
lift struts, including airplanes commonly known as a ``Clipped Wing
Cub,'' which modify the airplane primarily by removing approximately
40 inches of the inboard portion of each wing; and are certificated
in any category.
(1) Based on optional engine installations some airplanes may
have been re-identified or registered with another model that is not
listed in the type certificate data sheet (TCDS). For instance,
Piper Model J3C-65 airplanes are type certificated on Type
Certificate Data Sheet (TCDS) A-691 but may also have been re-
identified or registered as a Model J3C-115, J3F-50, J3C-75, J3C-
75D, J3C-75S, J3L-75, J3C-85, J3C-85S, J3C-90, J3F-90, J3F-90S, J3C-
100, or J3-L4J airplane.
(2) The airplane model number on the affected airplane or its
registry may or may not contain the dash (-), e.g. J3 and J-3. This
AD applies to both variations.
Note 1 to paragraph (c) of this AD: There is a serial number
overlap between the Piper PA-18 series airplanes and the Piper Model
PA-19 (Army L-18C) airplanes listed in AD 99-01-05 R1. Serial
numbers 18-1 through 18-7632 listed for the PA-18 series airplanes
are also now listed under Model PA-19 (Army L-18C) and Model PA-19S.
Table 1 to Paragraph (c) of This AD--Airplanes Previously Affected by AD
99-01-05 R1
------------------------------------------------------------------------
Type certificate holder Aircraft model Serial Nos.
------------------------------------------------------------------------
FS 2000 Corp.................. L-14.................. All.
[[Page 23702]]
FS 2001 Corp.................. J5A (Army L-4F), J5A- All.
80, J5B (Army L-4G),
J5C, AE-1, and HE-1.
FS 2002 Corporation........... PA-14................. 14-1 through 14-
523.
FS 2003 Corporation........... PA-12 and PA-12S...... 12-1 through 12-
4036.
LAVIA ARGENTINA S.A. (LAVIASA) PA-25, PA-25-235, and 25-1 through 25-
PA-25-260. 8156024.
Piper Aircraft, Inc........... TG-8 (Army TG-8, Navy All.
XLNP-1).
Piper Aircraft, Inc........... E-2 and F-2........... All.
Piper Aircraft, Inc........... J3C-40, J3C-50, J3C- All.
50S, J3C-65 (Army L-
4, L-4B, L-4H, L-4J,
Navy NE-1 and NE-2),
J3C-65S, J3F-50, J3F-
50S, J3F-60, J3F-60S,
J3F-65 (Army L-4D),
J3F-65S, J3L, J3L-S,
J3L-65 (Army L-4C),
and J3L-65S.
Piper Aircraft, Inc........... J4, J4A, J4A-S, and 4-401 through 4-
J4E (Army L-4E). 1649.
Piper Aircraft, Inc........... PA-11 and PA-11S...... 11-1 through 11-
1678.
Piper Aircraft, Inc........... PA-15................. 15-1 through 15-
388.
Piper Aircraft, Inc........... PA-16 and PA-16S...... 16-1 through 16-
736.
Piper Aircraft, Inc........... PA-17................. 17-1 through 17-
215.
Piper Aircraft, Inc........... PA-18, PA-18S, PA-18 18-1 through 18-
``105'' (Special), PA- 8309025, 18900
18S ``105'' through
(Special), PA-18A, PA- 1809032, and
18 ``125'' (Army L- 1809034 through
21A), PA-18S ``125'', 1809040.
PA-18AS ``125'', PA-
18 ``135'' (Army L-
21B), PA-18A ``135'',
PA-18S ``135'', PA-
18AS ``135'', PA-18
``150'', PA-18A
``150'', PA-18S
``150'', PA-18AS
``150'', PA-18A
(Restricted), PA-18A
``135'' (Restricted),
and PA-18A ``150''
(Restricted).
Piper Aircraft, Inc........... PA-19 (Army L-18C), 18-1 through 18-
and PA-19S. 7632 and 19-1,
19-2, and 19-3.
Piper Aircraft, Inc........... PA-20, PA-20S, PA-20 20-1 through 20-
``115'', PA-20S 1121.
``115'', PA-20
``135'', and PA-20S
``135''.
Piper Aircraft, Inc........... PA-22, PA-22-108, PA- 22-1 through 22-
22-135, PA-22S-135, 9848.
PA-22-150, PA-22S-
150, PA-22-160, and
PA-22S-160.
------------------------------------------------------------------------
Table 2 to Paragraph (c) of This AD--Airplanes New to This AD
------------------------------------------------------------------------
Type certificate holder Aircraft model Serial Nos.
------------------------------------------------------------------------
Piper Aircraft, Inc........... J-3.............. 1100 through 1200 and
1999 and up that
were manufactured
before October 15,
1939.
Piper Aircraft, Inc........... J3C-65 (Army L- All.
4A).
Piper Aircraft, Inc........... J3P.............. 2325, 2327, 2339,
2340, 2342, 2344,
2345, 2347, 2349,
2351, 2355 and up
that were
manufactured before
January 10, 1942.
Piper Aircraft, Inc........... J4B.............. 4-400 and up that
were manufactured
before December 11,
1942.
Piper Aircraft, Inc........... J4F.............. 4-828 and up.
------------------------------------------------------------------------
(d) Subject
Joint Aircraft System Component (JASC)/Air Transport Association
(ATA) of America Code 57, Wings.
(e) Unsafe Condition
(1) The subject of this AD was originally prompted by reports of
corrosion damage found on the wing lift struts. AD 99-01-05 R1 is
being superseded to include certain Piper Aircraft, Inc. Models J-3,
J3C-65 (Army L4A), J3P, J4B, and J4F airplanes that were
inadvertently omitted from the applicability, paragraph (c), of AD
99-01-05 (64 FR 72524, December 28, 1999) ``99-01-05'' and
subsequently AD 99-01-05 R1.
Note 2 to paragraph (e) of this AD: There is a serial number
overlap between the Piper PA-18 series airplanes and the Piper Model
PA-19 (Army L-18C) airplanes listed in AD 99-01-05 R1. Serial
numbers 18-1 through 18-7632 listed for the PA-18 series airplanes
are also now listed under Model PA-19 (Army L-18C) and Model PA-19S.
(2) AD 99-01-05 R1 was issued to clarify the FAA's intention
that if a sealed wing lift strut assembly is installed as a
replacement part, the repetitive inspection requirement is
terminated only if the seal is never improperly broken. If the seal
is improperly broken, then that wing lift strut becomes subject to
continued repetitive inspections. We did not intend to promote
drilling holes into or otherwise unsealing a sealed strut. This AD
retains all the actions required in AD 99-01-05 R1. There are no new
requirements in this AD except for the addition of certain model
airplanes to the applicability, paragraph (c) of this AD.
(3) We are issuing this AD to detect and correct corrosion and
cracking on the front and rear wing lift struts and forks, which
could cause the wing lift strut to fail. This failure could result
in the wing separating from the airplane.
(f) Compliance
Unless already done (compliance with AD 99-01-05 R1 and AD 93-
10-06, Amendment 39-8586 (58 FR 29965, May 25, 1993) ``AD 93-010-
06''), do the following actions within the compliance times
specified in paragraphs (g) through (m) of this AD, including all
subparagraphs. Properly unsealing and resealing a sealed wing lift
strut is still considered a terminating action for the repetitive
inspection requirements of this AD as long as all appropriate
regulations and issues are considered, such as static strength,
fatigue, material effects, immediate and long-term (internal and
external) corrosion protection, resealing methods, etc. Current FAA
regulations in 14 CFR 43.13(b) specify that maintenance performed
will result in the part's condition to be at least equal to its
original or properly altered condition. Any maintenance actions that
unseal a sealed wing lift strut should be coordinated with the
Atlanta Aircraft Certification Office (ACO) through the local
airworthiness authority (e.g., Flight Standards District Office).
There are provisions in paragraph (n) of this AD for approving such
actions as an alternative method of compliance (AMOC).
[[Page 23703]]
(g) Remove Wing Lift Struts
(1) For all airplanes previously affected by AD 99-01-05 R1:
Within 1 calendar month after February 8, 1999 (the effective date
retained from AD 99-01-05), or within 24 calendar months after the
last inspection done in accordance with AD 93-10-06 (which was
superseded by AD 99-01-05), whichever occurs later, remove the wing
lift struts following Piper Aircraft Corporation Mandatory Service
Bulletin (Piper MSB) No. 528D, dated October 19, 1990, or Piper MSB
No. 910A, dated October 10, 1989, as applicable. Before further
flight after the removal, do the actions in one of the following
paragraphs (h)(1), (h)(2), (i)(1), (i)(2), or (i)(3) of this AD,
including all subparagraphs.
(2) For all airplanes new to this AD (not previously affected by
AD 99-01-05 R1): Within 1 calendar month after the effective date of
this AD or within 24 calendar months after the last inspection done
in accordance with AD 93-10-06 (which was superseded by AD 99-01-
05), whichever occurs later, remove the wing lift struts following
Piper Aircraft Corporation Mandatory Service Bulletin (Piper MSB)
No. 528D, dated October 19, 1990, or Piper MSB No. 910A, dated
October 10, 1989, as applicable. Before further flight after the
removal, do the actions in one of the following paragraphs (h)(1),
(h)(2), (i)(1), (i)(2), or (i)(3) of this AD, including all
subparagraphs.
(h) Inspect Wing Lift Struts
For all airplanes listed in this AD: Before further flight after
the removal required in paragraph (g) of this AD, inspect each wing
lift strut following paragraph (h)(1) or (h)(2) of this AD,
including all subparagraphs, or do the wing lift strut replacement
following one of the options in paragraph (i)(1), (i)(2), or (i)(3)
of this AD.
(1) Inspect each wing lift strut for corrosion and perceptible
dents following Piper MSB No. 528D, dated October 19, 1990, or Piper
MSB No. 910A, dated October 10, 1989, as applicable.
(i) If no corrosion is visible and no perceptible dents are
found on any wing lift strut during the inspection required in
paragraph (h)(1) of this AD, before further flight, apply corrosion
inhibitor to each wing lift strut following Piper MSB No. 528D,
dated October 19, 1990, or Piper MSB No. 910A, dated October 10,
1989, as applicable. Repetitively thereafter inspect each wing lift
strut at intervals not to exceed 24 calendar months following the
procedures in paragraph (h)(1) or (h)(2) of this AD, including all
subparagraphs.
(ii) If corrosion or perceptible dents are found on any wing
lift strut during the inspection required in paragraph (h)(1) of
this AD or during any repetitive inspection required in paragraph
(h)(1)(i) of this AD, before further flight, replace the affected
wing lift strut with one of the replacement options specified in
paragraph (i)(1), (i)(2), or (i)(3) of this AD. Do the replacement
following the procedures specified in those paragraphs, as
applicable.
(2) Inspect each wing lift strut for corrosion following the
procedures in the Appendix to this AD. This inspection must be done
by a Level 2 or Level 3 inspector certified using the guidelines
established by the American Society for Non-destructive Testing or
the ``Military Standard for Nondestructive Testing Personnel
Qualification and Certification'' (MIL-STD-410E).
(i) If no corrosion is found on any wing lift strut during the
inspection required in paragraph (h)(2) of this AD and all
requirements in the Appendix to this AD are met, before further
flight, apply corrosion inhibitor to each wing lift strut following
Piper MSB No. 528D, dated October 19, 1990, or Piper MSB No. 910A,
dated October 10, 1989, as applicable. Repetitively thereafter
inspect each wing lift strut at intervals not to exceed 24 calendar
months following the procedures in paragraph (h)(1) or (h)(2) of
this AD, including all subparagraphs.
(ii) If corrosion is found on any wing lift strut during the
inspection required in paragraph (h)(2) of this AD or during any
repetitive inspection required in paragraph (h)(2)(i) of this AD, or
if any requirement in the Appendix of this AD is not met, before
further flight after any inspection in which corrosion is found or
the Appendix requirements are not met, replace the affected wing
lift strut with one of the replacement options specified in
paragraph (i)(1), (i)(2), or (i)(3) of this AD. Do the replacement
following the procedures specified in those paragraphs, as
applicable.
(i) Wing Lift Strut Replacement Options
Before further flight after the removal required in paragraph
(g) of this AD, replace the wing lift struts following one of the
options in paragraph (i)(1), (i)(2), or (i)(3) of this AD, including
all subparagraphs, or inspect each wing lift strut following
paragraph (h)(1) or (h)(2) of this AD.
(1) Install original equipment manufacturer (OEM) part number
wing lift struts (or FAA-approved equivalent part numbers) that have
been inspected following the procedures in either paragraph (h)(1)
or (h)(2) of this AD, including all subparagraphs, and are found to
be airworthy. Do the installations following Piper MSB No. 528D,
dated October 19, 1990, or Piper MSB No. 910A, dated October 10,
1989, as applicable. Repetitively thereafter inspect the newly
installed wing lift struts at intervals not to exceed 24 calendar
months following the procedures in either paragraph (h)(1) or (h)(2)
of this AD, including all subparagraphs.
(2) Install new sealed wing lift strut assemblies (or FAA-
approved equivalent part numbers) (these sealed wing lift strut
assemblies also include the wing lift strut forks) following Piper
MSB No. 528D, dated October 19, 1990, and Piper MSB No. 910A, dated
October 10, 1989, as applicable. Installing one of these new sealed
wing lift strut assemblies terminates the repetitive inspection
requirements in paragraphs (h)(1) and (h)(2) of this AD, and the
wing lift strut fork removal, inspection, and replacement
requirement in paragraphs (j) and (k) of this AD, including all
subparagraphs, for that wing lift strut assembly.
(3) Install F. Atlee Dodge wing lift strut assemblies following
F. Atlee Dodge Aircraft Services, Inc. Installation Instructions No.
3233-I for Modified Piper Wing Lift Struts Supplemental Type
Certificate (STC) SA4635NM, dated February 1, 1991. Repetitively
thereafter inspect the newly installed wing lift struts at intervals
not to exceed 60 calendar months following the procedures in
paragraph (h)(1) or (h)(2) of this AD, including all subparagraphs.
(j) Remove Wing Lift Strut Forks
(1) For all airplanes previously affected by AD 99-01-05 R1,
except for Model PA-25, PA-25-235, and PA-25-260 airplanes: Within
the next 100 hours time-in-service (TIS) after February 8, 1999 (the
effective date retained from AD 99-01-05) or within 500 hours TIS
after the last inspection done in accordance with AD 93-10-06 (which
was superseded by AD 99-01-05), whichever occurs later, remove the
wing lift strut forks (unless already replaced in accordance with
paragraph (i)(2) of this AD). Do the removal following Piper MSB No.
528D, dated October 19, 1990, or Piper MSB No. 910A, dated October
10, 1989, as applicable. Before further flight after the removal, do
the actions in one of the following paragraphs (k) or (l) of this
AD, including all subparagraphs.
(2) For all airplanes new to this AD (not previously affected by
AD 99-01-05 R1): Within the next 100 hours TIS after the effective
date of this AD or within 500 hours TIS after the last inspection
done in accordance with AD 93-10-06 (which was superseded by AD 99-
01-05), whichever occurs later, remove the wing lift strut forks
(unless already replaced in accordance with paragraph (i)(2) of this
AD). Do the removal following Piper MSB No. 528D, dated October 19,
1990, or Piper MSB No. 910A, dated October 10, 1989, as applicable.
Before further flight after the removal, do the actions in one of
the following paragraphs (k) or (l) of this AD, including all
subparagraphs.
(k) Inspect and Replace Wing Lift Strut Forks
For all airplanes affected by this AD: Before further flight
after the removal required in paragraph (j) of this AD, inspect the
wing lift strut forks following paragraph (k) of this AD, including
all subparagraphs, or do the wing lift strut fork replacement
following one of the options in paragraph (l)(1), (l)(2), (l)(3), or
(l)(4) of this AD, including all subparagraphs. Inspect the wing
lift strut forks for cracks using magnetic particle procedures, such
as those contained in FAA Advisory Circular (AC) 43.13-1B, Chapter
5, which can be found on the Internet http://rgl.faa.gov/
Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/
99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2005.pdf.
Repetitively thereafter inspect at intervals not to exceed 500 hours
TIS until the replacement time requirement specified in paragraph
(k)(2) or (k)(3) of this AD is reached provided no cracks are found.
(1) If cracks are found during any inspection required in
paragraph (k) of this AD or during any repetitive inspection
required in paragraph (k)(2) or (k)(3) of this AD, before further
flight, replace the affected wing lift strut fork with one of the
replacement options specified in paragraph (l)(1), (l)(2), (l)(3),
or (l)(4) of this AD,
[[Page 23704]]
including all subparagraphs. Do the replacement following the
procedures specified in those paragraphs, as applicable.
(2) If no cracks are found during the initial inspection
required in paragraph (k) of this AD and the airplane is currently
equipped with floats or has been equipped with floats at any time
during the previous 2,000 hours TIS since the wing lift strut forks
were installed, at or before accumulating 1,000 hours TIS on the
wing lift strut forks, replace the wing lift strut forks with one of
the replacement options specified in paragraph (l)(1), (l)(2),
(l)(3), or (l)(4) of this AD, including all subparagraphs. Do the
replacement following the procedures specified in those paragraphs,
as applicable. Repetitively thereafter inspect the newly installed
wing lift strut forks at intervals not to exceed 500 hours TIS
following the procedures specified in paragraph (k) of this AD,
including all subparagraphs.
(3) If no cracks are found during the initial inspection
required in paragraph (k) of this AD and the airplane has never been
equipped with floats during the previous 2,000 hours TIS since the
wing lift strut forks were installed, at or before accumulating
2,000 hours TIS on the wing lift strut forks, replace the wing lift
strut forks with one of the replacement options specified in
paragraph (l)(1), (l)(2), (l)(3), or (l)(4) of this AD, including
all subparagraphs. Do the replacement following the procedures
specified in those paragraphs, as applicable. Repetitively
thereafter inspect the newly installed wing lift strut forks at
intervals not to exceed 500 hours TIS following the procedures
specified in paragraph (k) of this AD, including all subparagraphs.
(l) Wing Lift Strut Fork Replacement Options
Before further flight after the removal required in paragraph
(j) of this AD, replace the wing lift strut forks following one of
the options in paragraph (l)(1), (l)(2), (l)(3), or (l)(4) of this
AD, including all subparagraphs, or inspect the wing lift strut
forks following paragraph (k) of this AD, including all
subparagraphs.
(1) Install new OEM part number wing lift strut forks of the
same part numbers of the existing part (or FAA-approved equivalent
part numbers) that were manufactured with rolled threads. Wing lift
strut forks manufactured with machine (cut) threads are not to be
used. Do the installations following Piper MSB No. 528D, dated
October 19, 1990, or Piper MSB No. 910A, dated October 10, 1989, as
applicable. Repetitively thereafter inspect and replace the newly
installed wing lift strut forks at intervals not to exceed 500 hours
TIS following the procedures specified in paragraph (k) of this AD,
including all subparagraphs.
(2) Install new sealed wing lift strut assemblies (or FAA-
approved equivalent part numbers) (these sealed wing lift strut
assemblies also include the wing lift strut forks) following Piper
MSB No. 528D, dated October 19, 1990, and Piper MSB No. 910A, dated
October 10, 1989, as applicable. This installation may have already
been done through the option specified in paragraph (i)(2) of this
AD. Installing one of these new sealed wing lift strut assemblies
terminates the repetitive inspection requirements in paragraphs
(h)(1) and (h)(2) of this AD, and the wing lift strut fork removal,
inspection, and replacement requirements in paragraphs (j) and (k)
of this AD, including all subparagraphs, for that wing lift strut
assembly.
(3) For the airplanes specified below, install Jensen Aircraft
wing lift strut fork assemblies specified below in the applicable
STC following Jensen Aircraft Installation Instructions for Modified
Lift Strut Fitting. Installing one of these wing lift strut fork
assemblies terminates the repetitive inspection requirement of this
AD only for that wing lift strut fork. Repetitively inspect each
wing lift strut as specified in paragraph (h)(1) or (h)(2) of this
AD, including all subparagraphs.
(i) For Models PA-12 and PA-12S airplanes: STC SA1583NM, which
can be found on the Internet at http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/2E708575849845B285256CC1008213CA?OpenDocument&Highlight=sa1583nm;
(ii) For Model PA-14 airplanes: STC SA1584NM, which can be found
on the Internet at http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/39872B814471737685256CC1008213D0?OpenDocument&Highlight=sa1584nm;
(iii) For Models PA-16 and PA-16S airplanes: STC SA1590NM, which
can be found on the Internet at http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/B28C4162E30D941F85256CC1008213F6?OpenDocument&Highlight=sa1590nm;
(iv) For Models PA-18, PA-18S, PA-18 ``105'' (Special), PA-18S
``105'' (Special), PA-18A, PA-18 ``125'' (Army L-21A), PA-18S
``125'', PA-18AS ``125'', PA-18 ``135'' (Army L-21B), PA-18A
``135'', PA-18S ``135'', PA-18AS ``135'', PA-18 ``150'', PA-18A
``150'', PA-18S ``150'', PA-18AS ``150'', PA-18A (Restricted), PA-
18A ``135'' (Restricted), and PA-18A ``150'' (Restricted) airplanes:
STC SA1585NM, which can be found on the Internet at http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/A2BE010FB1CA61A285256CC1008213D6?OpenDocument&Highlight=sa1585nm;
(v) For Models PA-20, PA-20S, PA-20 ``115'', PA-20S ``115'', PA-
20 ``135'', and PA-20S ``135'' airplanes: STC SA1586NM, which can be
found on the Internet at http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/873CC69D42C87CF585256CC1008213DC?OpenDocument&Highlight=sa1586nm;
and
(vi) For Model PA-22 airplanes: STC SA1587NM, which can be found
on the Internet at http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/B051D04CCC0BED7E85256CC1008213E0?OpenDocument&Highlight=sa1587nm.
(4) Install F. Atlee Dodge wing lift strut assemblies following
F. Atlee Dodge Installation Instructions No. 3233-I for Modified
Piper Wing Lift Struts (STC SA4635NM), dated February 1, 1991. This
installation may have already been done in accordance paragraph
(i)(3) of this AD. Installing these wing lift strut assemblies
terminates the repetitive inspection requirements of this AD for the
wing lift strut fork only. Repetitively inspect the wing lift struts
as specified in paragraph (h)(1) or (h)(2) of this AD, including all
subparagraphs.
(m) Install Placard
(1) For all airplanes previously affected by AD 99-01-05 R1,
except for Models PA-25, PA-25-235, and PA-25-260 airplanes: Within
1 calendar month after February 8, 1999 (the effective date retained
from AD 99-01-05), or within 24 calendar months after the last
inspection required by AD 93-10-06 (which was superseded by AD 99-
01-05), whichever occurs later, and before further flight after any
replacement of a wing lift strut assembly required by this AD, do
one of the following actions in paragraph (m)(1)(i) or (m)(1)(ii) of
this AD. The ``NO STEP'' markings required by paragraph (m)(1)(i) or
(m)(1)(ii) of this AD must remain in place for the life of the
airplane.
(i) Install ``NO STEP'' decal, Piper (P/N) 80944-02, on each
wing lift strut approximately 6 inches from the bottom of the wing
lift strut in a way that the letters can be read when entering and
exiting the airplane; or
(ii) Paint the words ``NO STEP'' approximately 6 inches from the
bottom of the wing lift strut in a way that the letters can be read
when entering and exiting the airplane. Use a minimum of 1-inch
letters using a color that contrasts with the color of the airplane.
(2) For all airplanes new to this AD (not previously affected by
AD 99-01-05 R1): Within 1 calendar month after the effective date of
this AD or within 24 calendar months after the last inspection
required by AD 93-10-06 (which was superseded by AD 99-01-05),
whichever occurs later, and before further flight after any
replacement of a wing lift strut assembly required by this AD, do
one of the following actions in paragraph (m)(2)(i) or (m)(2)(ii) of
this AD. The ``NO STEP'' markings required by paragraph (m)(2)(i) or
(m)(2)(ii) of this AD must remain in place for the life of the
airplane.
(i) Install ``NO STEP'' decal, Piper (P/N) 80944-02, on each
wing lift strut approximately 6 inches from the bottom of the wing
lift strut in a way that the letters can be read when entering and
exiting the airplane; or
(ii) Paint the words ``NO STEP'' approximately 6 inches from the
bottom of the wing lift strut in a way that the letters can be read
when entering and exiting the airplane. Use a minimum of 1-inch
letters using a color that contrasts with the color of the airplane.
(n) Alternative Methods of Compliance (AMOCs)
(1) The Manager, Atlanta ACO, FAA, has the authority to approve
AMOCs for this AD related to Piper Aircraft, Inc. airplanes; the
Manager, Seattle ACO, FAA has the authority to approve AMOCs for
this AD related to FS 2000 Corp, FS 2001 Corp, FS 2002 Corporation,
and FS 2003 Corporation airplanes; and the Manager, Standards
Office, FAA, has the authority to approve AMOCs for this AD related
to LAVIA ARGENTINA S.A. (LAVIASA) airplanes, if requested using the
procedures found in 14 CFR 39.19. In
[[Page 23705]]
accordance with 14 CFR 39.19, send your request to your principal
inspector or local Flight Standards District Office, as appropriate.
If sending information directly to the manager of the ACO, send it
to the attention of the appropriate person identified in paragraph
(o) of this AD.
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local flight standards district office/certificate holding
district office.
(3) AMOCs approved for AD 93-10-06, AD 99-01-05, and AD 99-01-05
R1, are approved as AMOCs for this AD.
(o) Related Information
(1) For more information about this AD related to Piper
Aircraft, Inc. airplanes, contact: Gregory ``Keith'' Noles,
Aerospace Engineer, FAA, Atlanta ACO, 1701 Columbia Avenue, College
Park, Georgia 30337; phone: (404) 474-5551; fax: (404) 474-5606;
email: [email protected].
(2) For more information about this AD related to FS 2000 Corp,
FS 2001 Corp, FS 2002 Corporation, and FS 2003 Corporation
airplanes, contact: Jeff Morfitt, Aerospace Engineer, FAA, Seattle
ACO, 1601 Lind Avenue SW., Renton, Washington 98057; phone: (425)
917-6405; fax: (245) 917-6590; email: [email protected].
(3) For more information about this AD related to LAVIA
ARGENTINA S.A. (LAVIASA) airplanes, contact: S.M. Nagarajan,
Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust,
Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4145;
fax: (816) 329-4090; email: [email protected].
(p) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference (IBR) of the service information listed
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do
the actions required by this AD, unless the AD specifies otherwise.
(3) The following service information was approved for IBR on
February 8, 1999 (63 FR 72132, December 31, 1998).
(i) Piper Aircraft Corporation Mandatory Service Bulletin No.
528D, dated October 19, 1990.
(ii) Piper Aircraft Corporation Mandatory Service Bulletin No.
910A, dated October 10, 1989.
(iii) F. Atlee Dodge Aircraft Services, Inc. Installation
Instructions No. 3233-I for Modified Piper Wing Lift Struts
Supplemental Type Certificate (STC) SA4635NM, dated February 1,
1991.
(iv) Jensen Aircraft Installation Instructions for Modified Lift
Strut Fittings, which incorporates pages 1 and 5, Original Issue,
dated July 15, 1983; pages 2, 4, and 6, Revision No. 1, dated March
30, 1984; and pages a and 3, Revision No. 2, dated April 20, 1984.
(4) For Piper Aircraft, Inc. service information identified in
this AD, contact Piper Aircraft, Inc., Customer Services, 2926 Piper
Drive, Vero Beach, Florida 32960; telephone: (772) 567-4361;
Internet: www.piper.com. Copies of the instructions to the F. Atlee
Dodge STC and information about the Jensen Aircraft STCs may be
obtained from F. Atlee Dodge, Aircraft Services, LLC., 6672 Wes Way,
Anchorage, Alaska 99518-0409, Internet: www.fadodge.com.
(5) You may review copies of the referenced service information
at the FAA, Small Airplane Directorate, 901 Locust, Kansas City,
Missouri 64106. For information on the availability of this material
at the FAA, call (816) 329-4148. It is also available on the
Internet at http://www.regulations.gov by searching for and locating
Docket No. FAA-2014-1083.
(6) You may view this service information that is incorporated
by reference at the National Archives and Records Administration
(NARA). For information on the availability of this material at
NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.
Appendix to AD 2015-08-04
Procedures and Requirements for Ultrasonic Inspection of Piper Wing
Lift Struts
Equipment Requirements
1. A portable ultrasonic thickness gauge or flaw detector with
echo-to-echo digital thickness readout capable of reading to 0.001-
inch and an A-trace waveform display will be needed to do this
inspection.
2. An ultrasonic probe with the following specifications will be
needed to accomplish this inspection: 10 MHz (or higher), 0.283-inch
(or smaller) diameter dual element or delay line transducer designed
for thickness gauging. The transducer and ultrasonic system shall be
capable of accurately measuring the thickness of AISI 4340 steel
down to 0.020-inch. An accuracy of +/- 0.002-inch throughout a
0.020-inch to 0.050-inch thickness range while calibrating shall be
the criteria for acceptance.
3. Either a precision machined step wedge made of 4340 steel (or
similar steel with equivalent sound velocity) or at least three shim
samples of same material will be needed to accomplish this
inspection. One thickness of the step wedge or shim shall be less
than or equal to 0.020-inch, one shall be greater than or equal to
0.050-inch, and at least one other step or shim shall be between
these two values.
4. Glycerin, light oil, or similar non-water based ultrasonic
couplants are recommended in the setup and inspection procedures.
Water-based couplants, containing appropriate corrosion inhibitors,
may be utilized, provided they are removed from both the reference
standards and the test item after the inspection procedure is
completed and adequate corrosion prevention steps are then taken to
protect these items.
NOTE: Couplant is defined as ``a substance used between
the face of the transducer and test surface to improve transmission
of ultrasonic energy across the transducer/strut interface.''
NOTE: If surface roughness due to paint loss or
corrosion is present, the surface should be sanded or polished
smooth before testing to assure a consistent and smooth surface for
making contact with the transducer. Care shall be taken to remove a
minimal amount of structural material. Paint repairs may be
necessary after the inspection to prevent further corrosion damage
from occurring. Removal of surface irregularities will enhance the
accuracy of the inspection technique.
1. Set up the ultrasonic equipment for thickness measurements as
specified in the instrument's user's manual. Because of the variety
of equipment available to perform ultrasonic thickness measurements,
some modification to this general setup procedure may be necessary.
However, the tolerance requirement of step 13 and the record keeping
requirement of step 14, must be satisfied.
2. If battery power will be employed, check to see that the
battery has been properly charged. The testing will take
approximately two hours. Screen brightness and contrast should be
set to match environmental conditions.
3. Verify that the instrument is set for the type of transducer
being used, i.e. single or dual element, and that the frequency
setting is compatible with the transducer.
4. If a removable delay line is used, remove it and place a drop
of couplant between the transducer face and the delay line to assure
good transmission of ultrasonic energy. Reassemble the delay line
transducer and continue.
5. Program a velocity of 0.231-inch/microsecond into the
ultrasonic unit unless an alternative instrument calibration
procedure is used to set the sound velocity.
6. Obtain a step wedge or steel shims per item 3 of the
EQUIPMENT REQUIREMENTS. Place the probe on the thickest sample using
couplant. Rotate the transducer slightly back and forth to ``ring''
the transducer to the sample. Adjust the delay and range settings to
arrive at an A-trace signal display with the first backwall echo
from the steel near the left side of the screen and the second
backwall echo near the right of the screen. Note that when a single
element transducer is used, the initial pulse and the delay line/
steel interface will be off of the screen to the left. Adjust the
gain to place the amplitude of the first backwall signal at
approximately 80% screen height on the A-trace.
7. ``Ring'' the transducer on the thinnest step or shim using
couplant. Select positive half-wave rectified, negative half-wave
rectified, or filtered signal display to obtain the cleanest signal.
Adjust the pulse voltage, pulse width, and damping to obtain the
best signal resolution. These settings can vary from one transducer
to another and are also user dependent.
8. Enable the thickness gate, and adjust the gate so that it
starts at the first backwall echo and ends at the second backwall
echo. (Measuring between the first and second backwall echoes will
produce a measurement of the steel thickness that is not affected by
the paint layer on the strut). If instability of the gate trigger
occurs, adjust the gain, gate level, and/or damping to stabilize the
thickness reading.
9. Check the digital display reading and if it does not agree
with the known thickness of the thinnest thickness, follow your
instrument's calibration recommendations to
[[Page 23706]]
produce the correct thickness reading. When a single element
transducer is used this will usually involve adjusting the fine
delay setting.
10. Place the transducer on the thickest step of shim using
couplant. Adjust the thickness gate width so that the gate is
triggered by the second backwall reflection of the thick section. If
the digital display does not agree with the thickest thickness,
follow your instruments calibration recommendations to produce the
correct thickness reading. A slight adjustment in the velocity may
be necessary to get both the thinnest and the thickest reading
correct. Document the changed velocity value.
11. Place couplant on an area of the lift strut which is thought
to be free of corrosion and ``ring'' the transducer to surface.
Minor adjustments to the signal and gate settings may be required to
account for coupling improvements resulting from the paint layer.
The thickness gate level should be set just high enough so as not to
be triggered by irrelevant signal noise. An area on the upper
surface of the lift strut above the inspection area would be a good
location to complete this step and should produce a thickness
reading between 0.034-inch and 0.041-inch.
12. Repeat steps 8, 9, 10, and 11 until both thick and thin shim
measurements are within tolerance and the lift strut measurement is
reasonable and steady.
13. Verify that the thickness value shown in the digital display
is within +/- 0.002-inch of the correct value for each of the three
or more steps of the setup wedge or shims. Make no further
adjustments to the instrument settings.
14. Record the ultrasonic versus actual thickness of all wedge
steps or steel shims available as a record of setup.
1. Clean the lower 18 inches of the wing lift struts using a
cleaner that will remove all dirt and grease. Dirt and grease will
adversely affect the accuracy of the inspection technique. Light
sanding or polishing may also be required to reduce surface
roughness as noted in the EQUIPMENT REQUIREMENTS section.
2. Using a flexible ruler, draw a 1/4-inch grid on the surface
of the first 11 inches from the lower end of the strut as shown in
Piper MSB No. 528D, dated October 19, 1990, or Piper MSB No. 910A,
dated October 10, 1989, as applicable. This can be done using a soft
(#2) pencil and should be done on both faces of the strut. As an
alternative to drawing a complete grid, make two rows of marks
spaced every 1/4-inch across the width of the strut. One row of
marks should be about 11 inches from the lower end of the strut, and
the second row should be several inches away where the strut starts
to narrow. Lay the flexible ruler between respective tick marks of
the two rows and use tape or a rubber band to keep the ruler in
place. See Figure 1.
3. Apply a generous amount of couplant inside each of the square
areas or along the edge of the ruler. Re-application of couplant may
be necessary.
4. Place the transducer inside the first square area of the
drawn grid or at the first 1/4-inch mark on the ruler and ``ring''
the transducer to the strut. When using a dual element transducer,
be very careful to record the thickness value with the axis of the
transducer elements perpendicular to any curvature in the strut. If
this is not done, loss of signal or inaccurate readings can result.
5. Take readings inside each square on the grid or at 1/4-inch
increments along the ruler and record the results. When taking a
thickness reading, rotate the transducer slightly back and forth and
experiment with the angle of contact to produce the lowest thickness
reading possible. Pay close attention to the A-scan display to
assure that the thickness gate is triggering off of maximized
backwall echoes.
NOTE: A reading shall not exceed .041 inch. If a
reading exceeds .041-inch, repeat steps 13 and 14 of the INSTRUMENT
SETUP section before proceeding further.
6. If the A-trace is unsteady or the thickness reading is
clearly wrong, adjust the signal gain and/or gate setting to obtain
reasonable and steady readings. If any instrument setting is
adjusted, repeat steps 13 and 14 of the INSTRUMENT SETUP section
before proceeding further.
7. In areas where obstructions are present, take a data point as
close to the correct area as possible.
NOTE: The strut wall contains a fabrication bead at
approximately 40% of the strut chord. The bead may interfere with
accurate measurements in that specific location.
8. A measurement of 0.024-inch or less shall require replacement
of the strut prior to further flight.
9. If at any time during testing an area is encountered where a
valid thickness measurement cannot be obtained due to a loss of
signal strength or quality, the area shall be considered suspect.
These areas may have a remaining wall thickness of less than 0.020-
inch, which is below the range of this setup, or they may have small
areas of localized corrosion or pitting present. The latter case
will result in a reduction in signal strength due to the sound being
scattered from the rough surface and may result in a signal that
includes echoes from the pits as well as the backwall. The suspect
area(s) shall be tested with a Maule ``Fabric Tester'' as specified
in Piper MSB No. 528D, dated October 19, 1990, or Piper MSB No.
910A, dated October 10, 1989.
10. Record the lift strut inspection in the aircraft log book.
[GRAPHIC] [TIFF OMITTED] TR29AP15.000
[[Page 23707]]
Issued in Kansas City, Missouri, on April 8, 2015.
Earl Lawrence,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2015-08732 Filed 4-28-15; 8:45 am]
BILLING CODE 4910-13-P