Airworthiness Directives; PILATUS Aircraft Ltd. Model PC-7 Airplanes

[Federal Register Volume 68, Number 192 (Friday, October 3, 2003)]
[Rules and Regulations]
[Pages 57343-57345]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-24685]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-CE-29-AD; Amendment 39-13323; AD 2003-20-05]
RIN 2120-AA64


Airworthiness Directives; PILATUS Aircraft Ltd. Model PC-7 
Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA adopts a new airworthiness directive (AD) for certain 
PILATUS Aircraft Ltd. (Pilatus) Model PC-7 airplanes. This AD requires 
you to inspect the forward and aft dihedral fittings for cracks and 
replace any cracked fitting. This AD also requires you to modify the 
aft dihedral fitting and spar-cap bolt holes. This AD is the result of 
mandatory continuing airworthiness information (MCAI) issued by the 
airworthiness authority for Switzerland. The actions specified by this 
AD are intended to prevent cracks from developing in the forward and 
aft dihedral fittings, which could result in failure of the wing in 
certain maneuvers. Such failure could lead to loss of control of the 
airplane.

DATES: This AD becomes effective on November 14, 2003.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the regulation as of 
November 14, 2003.

ADDRESSES: You may get the service information identified in this AD 
from Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, 
Switzerland; telephone: +41 41 619 63 19; facsimile: +41 41 619 6224; 
or from Pilatus Business Aircraft Ltd., Product Support Department, 
11755 Airport Way, Broomfield, Colorado 80021; telephone: (303) 465-
9099; facsimile: (303) 465-6040.
    You may view the AD docket at FAA, Central Region, Office of the 
Regional Counsel, Attention: Rules Docket No. 2003-CE-29-AD, 901 
Locust, Room 506, Kansas City, Missouri 64106. Office hours are 8 a.m. 
to 4 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Doug Rudolph, Aerospace Engineer, FAA, 
Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 
64106; telephone: (816) 329-4059; facsimile: (816) 329-4090.

SUPPLEMENTARY INFORMATION: 

Discussion

What Events Have Caused This AD?

    The Federal Office for Civil Aviation (FOCA), which is the 
airworthiness authority for Switzerland, recently notified FAA that an 
unsafe condition may exist on certain Pilatus Model PC-7 airplanes. The 
FOCA reports that an operator of a similar aircraft type design, which 
uses identical dihedral fittings, reported a crack in one fitting. An 
inspection of the fleet revealed stress corrosion cracking in six aft 
dihedral fittings. Each cracked fitting was found on airplanes that had 
logged more than 3,000 hours time-in-service (TIS) or had been in 
service for 10 years or more.

What Is the Potential Impact if FAA Took No Action?

    Cracks in the forward and aft dihedral fittings could result in 
failure of the wing in certain maneuvers. Such failure could lead to 
loss of control of the airplane.

Has FAA Taken Any Action to This Point?

    We issued a proposal to amend part 39 of the Federal Aviation 
Regulations (14 CFR part 39) to include an AD that would apply to 
certain Pilatus Model PC-7 airplanes. This proposal was published in 
the Federal Register as a notice of proposed rulemaking (NPRM) on July 
3, 2003 (68 FR 398970). The NPRM proposed to require you to:

--Inspect the forward and aft dihedral fittings for cracks;
--Replace any cracked fittings found; and
--Modify the aft dihedral fittings and spar-cap bolt holes.

Was the Public Invited To Comment?

    We provided the public the opportunity to participate in the 
development of this AD. We received no comments on the proposal or on 
the determination of the cost to the public.

Conclusion

What Is FAA's Final Determination on This Issue?

    We have carefully reviewed the available data and determined that 
air safety and the public interest require adopting the AD as proposed 
except for minor editorial corrections. We have determined that these 
minor corrections:

--Provide the intent that was proposed in the NPRM for correcting the 
unsafe condition; and
--Do not add any additional burden upon the public than was already 
proposed in the NPRM.

Changes to 14 CFR Part 39--Effect on the AD

How Does the Revision to 14 CFR Part 39 Affect This AD?

    On July 10, 2002, the FAA published a new version of 14 CFR part 39 
(67 FR 47997, July 22, 2002), which governs the FAA's AD system. This 
regulation now includes material that relates to altered products, 
special flight permits, and alternative methods of compliance. This 
material previously was included in each individual AD. Since this 
material is included in 14 CFR part 39, we will not include it in 
future AD actions.

Costs of Compliance

How Many Airplanes Does This AD Impact?

    We estimate that this AD affects 10 airplanes in the U.S. registry.

[[Page 57344]]

What Is the Cost Impact of This AD on Owners/Operators of the Affected 
Airplanes?

    We estimate the following costs to accomplish the actions of this 
AD:

                                                   Inspections
----------------------------------------------------------------------------------------------------------------
                                                              Total cost  per
            Labor cost                    Parts cost              airplane         Total cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
3 workhours per fitting (4          Not applicable.......  $180 x 4 fittings per  $720 x 10 = $7,200.
 fittings per airplane) x $60 per                           airplane = $720.
 hour = $180 per fitting..
----------------------------------------------------------------------------------------------------------------


                                      Forward Dihedral Fitting Replacement
----------------------------------------------------------------------------------------------------------------
                Labor cost                          Parts cost                   Total cost  per airplane
----------------------------------------------------------------------------------------------------------------
93 workhours per fitting (2 fittings per   $142 per replacement fitting  $5,722 per fitting.
 airplane) x $60 per hour = $5,580 per
 fitting.
----------------------------------------------------------------------------------------------------------------


            Aft Dihedral Fitting Replacement and Modification
------------------------------------------------------------------------
                                                       Total cost  per
         Labor cost                Parts cost             airplane
------------------------------------------------------------------------
20 workhours per fitting for  $76 per replacement   $1,200 + $76 + $66 =
 replacement and               fitting and $66 for   $1,342 (labor,
 modification (2 fittings      modification bolts.   replacement, and
 per airplane) x $60 per                             modification per
 hour = $1,200 per fitting.                          fitting).
10 workhours per fitting for                        $600 + $66 = $666
 modification only (2                                (labor and
 fittings per airplane) x                            modification per
 $60 per hour = $600 per                             fitting).
 fitting.
------------------------------------------------------------------------

Compliance Time of This AD

What Is the Compliance Time of This AD?

    The compliance time of this AD is whichever occurs later: (1) upon 
the accumulation of 3,000 hours time-in-service (TIS) on the dihedral 
fittings or 10 years after installation of the dihedral fittings, 
whichever occurs first; or (2) within 90 days after the effective date 
of this AD.

Why Is the Compliance Time of This AD Presented in Both Hours TIS and 
Calendar Time?

    Cracking of the dihedral fittings on the affected airplanes is 
caused by stress corrosion, which starts as a result of high local 
stress incurred through operation. Corrosion can then develop 
regardless of whether the airplane is in flight or on the ground. The 
cracks may not be noticed initially as a result of the stress loads, 
but could then progress as a result of corrosion. The stress incurred 
during flight operations or temperature changes could then cause rapid 
crack growth. In order to ensure that these stress corrosion cracks do 
not go undetected, a compliance time of specific hours TIS and calendar 
time is used.

Regulatory Findings

Will This AD Impact Various Entities?

    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.

Will This AD Involve a Significant Rule or Regulatory Action?

    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 the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979); and
    3. Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a summary of the costs to comply with this AD and 
placed it in the AD Docket. You may get a copy of this summary by 
sending a request to us at the address listed under ADDRESSES. Include 
``AD Docket No. 2003-CE-29-AD'' in your request.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration amends part 39 of the Federal 
Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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. FAA amends Sec.  39.13 by adding a new AD to read as follows:

2003-20-05 Pilatus Aircraft Ltd.: Amendment 39-13323; Docket No. 
2003-CE-29-AD.

When Does This AD Become Effective?

    (a) This AD becomes effective on November 14, 2003.

Are Any Other ADs Affected by This Action?

    (b) None.

[[Page 57345]]

What Airplanes Are Affected by This AD?

    (c) This AD affects the following airplane models and serial 
numbers that are:
    (1) Certificated in any category; and
    (2) Equipped with forward and aft dihedral fittings, part number 
(P/N) 111.34.07.469, 111.34.07.470, 111.34.07.471, and P/N 
111.34.07.472.

------------------------------------------------------------------------
                 Model                   Manufacturer  serial Nos. (MSN)
------------------------------------------------------------------------
PC-7...................................  101 through 618.
------------------------------------------------------------------------

What Is the Unsafe Condition Presented in This AD?

    (d) This AD is the result of mandatory continuing airworthiness 
information (MCAI) issued by the airworthiness authority for 
Switzerland. The actions specified by this AD are intended to 
prevent cracks from developing in the forward and aft dihedral 
fittings, which could result in failure of the wing in certain 
maneuvers. Such failure could lead to loss of control of the 
airplane.

What Must I Do To Address This Problem?

    (e) To address this problem, you must accomplish the following:

------------------------------------------------------------------------
           Actions                 Compliance            Procedures
------------------------------------------------------------------------
(1) Accomplish the following  At whichever of the   Inspect in
 inspections:                  following occurs      accordance with
(i) Using Impedance-Plane      later, unless         Pilatus PC-7
 Eddy-Current inspection       already               Service Bulletin
 procedures, inspect the aft   accomplished: upon    No. 57-006,
 dihedral fittings, P/N        the accumulation of   Revision No. 3,
 111.34.07.469 and P/N         3,000 hours time-in-  dated January 15,
 111.34.07.470, for cracks;    service (TIS) on      2003.
 and.                          the dihedral
(ii) Using Radiographic        fittings or 10
 inspection procedures,        years after
 inspect the forward           installation of the
 dihedral fittings, P/N        dihedral fittings,
 111.34.07.471 and P/N         whichever occurs
 111.34.07.472, for cracks.    first; or within 90
                               days after November
                               14, 2003 (the
                               effective date of
                               this AD).
-----------------------------
(2) If a crack is found in    Prior to further      Modify in accordance
 any aft dihedral fittings,    flight after the      with Pilatus PC-7
 P/N 111.34.07.469 and/or P/   inspection required   Service Bulletin
 N 111.34.07.470, replace      in paragraph (e)(1)   No. 57-006,
 with an improved fitting, P/  of this AD.           Revision No. 3,
 N 557.10.09.071 and/or P/N                          dated January 15,
 557.10.09.072 (as                                   2003.
 applicable or FAA-approved
 equivalent P/N), and modify
 the spar-cap bolt holes
-----------------------------
(3) If no cracks are found    Prior to further      Modify in accordance
 in any aft dihedral           flight after the      with Pilatus PC-7
 fittings, P/N 111.34.07.469   inspection required   Service Bulletin
 and P/N 111.34.07.470,        in paragraph (e)(1)   No. 57-006,
 modify the fittings and the   of this AD.           Revision No. 3,
 spar-cap bolt holes                                 dated January 15,
                                                     2003.
-----------------------------
(4) If cracks are found in    Prior to further      Not applicable.
 any forward dihedral          flight after the
 fittings, P/N 111.34.07.471   inspection required
 and/or P/N 111.34.07.472,     in paragraph (e)(1)
 replace with a new part       of this AD.
-----------------------------
(5) If no cracks are found    Not applicable......  Not applicable.
 in any forward dihedral
 fittings, P/N 111.34.07.471
 and P/N 111.34.07.472, no
 further action is required
-----------------------------
(6) Only install aft          As of November 14,    Modify the spar-cap
 dihedral fittings that have   2003 (the effective   bolt holes in
 a P/N of 557.10.09.071 and    date of this AD).     accordance with
 P/N 557.10.09.072. You must                         Pilatus PC-7
 also accomplish the spar-                           Service Bulletin
 cap bolt hole modification                          No. 57-006,
                                                     Revision No. 3,
                                                     dated January 15,
                                                     2003.
------------------------------------------------------------------------

What About Alternative Methods of Compliance?

    (f) You may request a different method of compliance or a 
different compliance time for this AD by following the procedures in 
14 CFR 39.13. Send your request to the Manager, Standards Office, 
Small Airplane Directorate, FAA. For information on any already 
approved alternative methods of compliance, contact Doug Rudolph, 
Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, 
Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4059; 
facsimile: (816) 329-4090.

Is There Material Incorporated by Reference?

    (g) Actions required by this AD must be done in accordance with 
Pilatus PC-7 Service Bulletin No. 57-006, Revision No. 3, dated 
January 15, 2003. The Director of the Federal Register approved the 
incorporation by reference of this service bulletin in accordance 
with 5 U.S.C. 552(a) and 1 CFR part 51. You may get a copy from 
Pilatus Aircraft Ltd., Customer Liaison Manager, CH-6371 Stans, 
Switzerland; telephone: +41 41 619 63 19; facsimile: +41 41 619 
6224; or from Pilatus Business Aircraft Ltd., Product Support 
Department, 11755 Airport Way, Broomfield, Colorado 80021; 
telephone: (303) 465-9099; facsimile: (303) 465-6040. You may review 
copies at FAA, Central Region, Office of the Regional Counsel, 901 
Locust, Room 506, Kansas City, Missouri 64106; or at the Office of 
the Federal Register, 800 North Capitol Street, NW, suite 700, 
Washington, DC.

Is There Other Information That Relates to This Subject?

    (h) Swiss AD HB 2003-196, dated May 12, 2003, also addresses the 
subject of this AD.


    Issued in Kansas City, Missouri, on September 24, 2003.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 03-24685 Filed 10-2-03; 8:45 am]
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