[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.

-----------------------------------------------------------------------

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
----------------------------------------------------------------------------------------------------------------
                                                                                                  Cost on U.S.
             Action                    Labor cost            Parts cost      Cost per product      operators
----------------------------------------------------------------------------------------------------------------
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.
----------------------------------------------------------------------------------------------------------------

    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
----------------------------------------------------------------------------------------------------------------
                                                                                                     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.
----------------------------------------------------------------------------------------------------------------

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