[Federal Register Volume 68, Number 128 (Thursday, July 3, 2003)]
[Proposed Rules]
[Pages 39870-39873]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-16844]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-CE-29-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to certain PILATUS Aircraft Ltd. (Pilatus) Model 
PC-7 airplanes. This proposed AD would require you to inspect the 
forward and aft dihedral fittings for cracks and replace any cracked 
fitting. This proposed AD would also require you to modify the aft 
dihedral fitting and spar-cap bolt holes. This proposed AD is the 
result of mandatory continuing airworthiness information (MCAI) issued 
by the airworthiness authority for Switzerland. The actions specified 
by this proposed 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.

[[Page 39871]]


DATES: The Federal Aviation Administration (FAA) must receive any 
comments on this proposed rule on or before August 4, 2003.

ADDRESSES: Submit comments to FAA, Central Region, Office of the 
Regional Counsel, Attention: Rules Docket No. 2003-CE-29-AD, 901 
Locust, Room 506, Kansas City, Missouri 64106. You may view any 
comments at this location between 8 a.m. and 4 p.m., Monday through 
Friday, except Federal holidays. You may also send comments 
electronically to the following address: [email protected]. 
Comments sent electronically must contain ``Docket No. 2003-CE-29-AD'' 
in the subject line. If you send comments electronically as attached 
electronic files, the files must be formatted in Microsoft Word 97 for 
Windows or ASCII text.
    You may get service information that applies to this proposed 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 also view this information at 
the Rules Docket at the address above.

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:

Comments Invited

    How do I comment on this proposed AD? The FAA invites comments on 
this proposed rule. You may submit whatever written data, views, or 
arguments you choose. You need to include the proposed rule's docket 
number and submit your comments to the address specified under the 
caption ADDRESSES. We will consider all comments received on or before 
the closing date. We may amend this proposed rule in light of comments 
received. Factual information that supports your ideas and suggestions 
is extremely helpful in evaluating the effectiveness of this proposed 
AD action and determining whether we need to take additional rulemaking 
action.
    Are there any specific portions of this proposed AD I should pay 
attention to? The FAA specifically invites comments on the overall 
regulatory, economic, environmental, and energy aspects of this 
proposed rule that might suggest a need to modify the rule. You may 
view all comments we receive before and after the closing date of the 
rule in the Rules Docket. We will file a report in the Rules Docket 
that summarizes each contact we have with the public that concerns the 
substantive parts of this proposed AD.
    How can I be sure FAA receives my comment? If you want FAA to 
acknowledge the receipt of your mailed comments, you must include a 
self-addressed, stamped postcard. On the postcard, write ``Comments to 
Docket No. 2003-CE-29-AD.'' We will date stamp and mail the postcard 
back to you.

Discussion

    What events have caused this proposed 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 are the consequences if the condition is not corrected? 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.
    Is there service information that applies to this subject? Pilatus 
has issued Pilatus PC-7 Service Bulletin No. 57-006, Revision No. 3, 
dated January 15, 2003.
    What are the provisions of this service information? The service 
bulletin includes procedures for:

--inspecting the forward and aft dihedral fittings for cracks; and
--modifying the aft dihedral fitting and spar-cap bolt holes.
    What action did the FOCA take? The FOCA classified this service 
information as mandatory and issued Swiss AD Number HB 2003-196, dated 
May 12, 2003, in order to ensure the continued airworthiness of these 
airplanes in Switzerland.
    Was this in accordance with the bilateral airworthiness agreement? 
These airplane models are manufactured in Switzerland and are type 
certificated for operation in the United States under the provisions of 
section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement.
    Pursuant to this bilateral airworthiness agreement, the FOCA has 
kept FAA informed of the situation described above.

The FAA's Determination and an Explanation of the Provisions of this 
Proposed AD

    What has FAA decided? The FAA has examined the findings of the 
FOCA; reviewed all available information, including the service 
information referenced above; and determined that:

--the unsafe condition referenced in this document exists or could 
develop on other Pilatus Model PC-7 airplanes of the same type design 
that are on the U.S. registry;
--the actions specified in the previously-referenced service 
information should be accomplished on the affected airplanes; and
--AD action should be taken in order to correct this unsafe condition.
    What would this proposed AD require? This proposed AD would 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.
    How does the revision to 14 CFR part 39 affect this proposed AD? On 
July 10, 2002, FAA published a new version of 14 CFR part 39 (67 FR 
47997, July 22, 2002), which governs FAA's AD system. This regulation 
now includes material that relates to special flight permits, 
alternative methods of compliance, and altered products. 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.

Cost Impact

    How many airplanes would this proposed AD impact? We estimate that 
this proposed AD affects 10 airplanes in the U.S. registry.
    What would be the cost impact of this proposed AD on owners/
operators of the affected airplanes? We estimate the following costs to 
accomplish the proposed actions of this AD:

[[Page 39872]]



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


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


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

Compliance Time of This Proposed AD

    What would be the compliance time of this proposed AD? The 
compliance time of this proposed 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 the proposed AD.
    Why is the compliance time of this proposed 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 utilized.

Regulatory Impact

    Would this proposed AD impact various entities? The regulations 
proposed herein would 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. Therefore, it is determined that this 
proposed rule would not have federalism implications under Executive 
Order 13132.
    Would this proposed AD involve a significant rule or regulatory 
action? For the reasons discussed above, I certify that this proposed 
action: (1) Is not a ``significant regulatory action'' under Executive 
Order 12866; (2) is not a ``significant rule'' under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if 
promulgated, will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act. A copy of the draft regulatory 
evaluation prepared for this action has been placed in the Rules 
Docket. A copy of it may be obtained by contacting the Rules Docket at 
the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

    2. FAA amends Sec.  39.13 by adding a new airworthiness directive 
(AD) to read as follows:

Pilatus Aircraft Ltd.: Docket No. 2003-CE-29-AD

    (a) What airplanes are affected by this AD? This AD affects 
Model PC-7 airplanes, manufacturer serial numbers (MSN) 101 through 
618, that are:
    (1) 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; and
    (2) certificated in any category.
    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the airplanes identified in paragraph (a) of this AD must 
comply with this AD.
    (c) What problem does this AD address? 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.
    (d) What actions must I accomplish to address this problem? To 
address this problem, you must accomplish the following:

[[Page 39873]]



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

    (e) Can I comply with this AD in any other way? To use an 
alternative method of compliance or adjust the compliance time, 
follow the procedures in 14 CFR 39.19. Send these requests to the 
Manager, Standards Office, Small Airplane Directorate. 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.
    (f) How do I get copies of the documents referenced in this AD? 
You may get copies of the documents referenced 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 
these documents at FAA, Central Region, Office of the Regional 
Counsel, 901 Locust, Room 506, Kansas City, Missouri 64106.

    Note: The subject of this AD is addressed in Swiss AD HB 2003-
196, dated May 12, 2003.


    Issued in Kansas City, Missouri, on June 26, 2003.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 03-16844 Filed 7-2-03; 8:45 am]
BILLING CODE 4910-13-P