[Federal Register Volume 71, Number 119 (Wednesday, June 21, 2006)]
[Proposed Rules]
[Pages 35572-35575]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-9714]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-25086; Directorate Identifier 2006-NM-019-AD]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F27 Mark 500 Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all Fokker Model F27 Mark 500 airplanes. This proposed AD would 
require an inspection to determine whether certain main landing gear 
(MLG) drag stay units (DSUs) are installed. This proposed AD would also 
require an ultrasonic inspection to determine if certain tubes are 
installed in the affected DSUs of the MLG, and related investigative/
corrective actions if necessary. This proposed AD results from a report 
that, due to fatigue cracking from an improperly machined radius of the 
inner tube, a drag stay broke, and, consequently, led to the collapse 
of the MLG during landing. We are proposing

[[Page 35573]]

this AD to prevent such fatigue cracking, which could result in reduced 
structural integrity or collapse of the MLG.

DATES: We must receive comments on this proposed AD by July 21, 2006.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street SW., Washington, DC, between 9 a.m. 
and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Fokker Services B.V., P.O. Box 231, 2150 AE Nieuw-Vennep, 
the Netherlands, for service information identified in this proposed 
AD.

FOR FURTHER INFORMATION CONTACT: Tom Rodriguez, Aerospace Engineer, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1137; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``FAA-2006-
25086; Directorate Identifier 2006-NM-019-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that Web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review the DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

Discussion

    The Civil Aviation Authority--The Netherlands (CAA-NL), which is 
the airworthiness authority for the Netherlands, notified us that an 
unsafe condition may exist on certain Fokker Model F27 Mark 500 
airplanes. The CAA-NL advises that it has received a report that, due 
to a broken drag stay, the main landing gear (MLG) on one airplane 
collapsed during landing. The broken drag stay is attributed to fatigue 
cracking, which originated at the lower side of a transition from a 
smaller internal diameter on the upper piece to a larger internal 
diameter on the lower piece. The apparent cause of such fatigue 
cracking has been attributed to an improperly machined radius of the 
inner tube of the drag stay. This condition, if not corrected, could 
result in reduced structural integrity or collapse of the MLG.
    The CAA-NL states that Dutch airworthiness directive BLA 93-169/2 
(A), dated April 29, 1994, was issued following a similar incident to 
address the identified unsafe condition on all F27 airplanes. However, 
the related Fokker Service Bulletin F27/32-167, dated November 19, 
1993, contained a statement that may have led to confusion whether 
Model F.27 Mark 500 airplanes were affected by the actions specified in 
the service bulletin. Thus, Model F27 Mark 500 airplanes may be 
operating without fully complying with actions necessary to address the 
identified unsafe condition.

Other Relevant Rulemaking

    On February 7, 1997, we issued AD 97-04-08, amendment 39-9932 (62 
FR 7924, February 21, 1997), for certain Fokker Model F27 Mark 050, 
100, 200, 300, 400, 600, and 700 airplanes. That AD is parallel to 
Dutch airworthiness directive BLA 93-169/2 (A), dated April 29, 1994, 
and does not include Model F27 Mark 500 airplanes in its applicability. 
AD 97-04-08 requires an ultrasonic inspection to determine if certain 
tubes are installed in the drag stay units of the main landing gear 
(MLG), and various follow-on actions. That AD resulted from a report 
that, due to fatigue cracking from an improperly machined radius of the 
inner tube, a drag stay broke, and, consequently, led to the collapse 
of the MLG during landing. We issued that AD to prevent such fatigue 
cracking, which could result in reduced structural integrity or 
collapse of the MLG.

Relevant Service Information

    Fokker Services B.V has issued Fokker Service Bulletin F27/32-171, 
dated December 16, 2004 (for Model F27 Mark 500 airplanes). The service 
bulletin describes procedures for performing an inspection of the MLG 
drag stay units (DSUs) in accordance with Dowty Aerospace Landing Gear 
Service Bulletin 32-82W, Revision 2, including Appendix A, dated July 
29, 1994, and including Appendix B, Revision 1, dated November 10, 
1993; or Dowty Aerospace Landing Gear Service Bulletin 32-169B, 
Revision 2, including Appendix A, dated July 29, 1994, and including 
Appendix B, Revision 1, dated November 10, 1993.
    Dowty Aerospace Landing Gear Service Bulletins 32-82W and 32-169B 
describe procedures for performing an ultrasonic inspection to 
determine if a tube having part number (P/N) 200485300 with a straight 
bore, or a tube having P/N 200259300 with a change in section (stepped 
bore), is installed in the DSUs of the MLG. The service bulletins also 
describe procedures for related investigative actions and corrective 
actions, including ultrasonic inspection for cracking of the DSUs, 
rework and re-identification of certain tubes, replacement of certain 
DSUs with new/re-identified DSUs, and repetitive ultrasonic inspections 
of certain DSUs. Both service bulletins include the ultrasonic 
inspection to determine P/Ns for DSUs having P/N 200485001. Service 
bulletin 32-82W also addresses the ultrasonic inspection for DSUs 
having P/N 200684001. Service Bulletin 32-169B also addresses the 
ultrasonic inspection for DSUs having P/N 200261001.
    CAA-NL mandated the service information and issued airworthiness 
directive NL-2005-003, dated April 29, 2005, to ensure the continued 
airworthiness of these airplanes in the Netherlands.

[[Page 35574]]

FAA's Determination and Requirements of the Proposed AD

    This airplane model is manufactured in the Netherlands and is 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, CAA-NL has kept the FAA informed of 
the situation described above. We have examined the CAA-NL's findings, 
evaluated all pertinent information, and determined that we need to 
issue an AD for airplanes this type design that are certificated for 
operation in the United States.
    Therefore, we are proposing this AD, which would require 
accomplishing the actions specified in the service information 
described previously.

Costs of Compliance

    The following table provides the estimated costs for U.S. operators 
to comply with this proposed AD.

                                                                     Estimated Costs
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                                                                                                                        Number of U.S.-
                               Action                                   Work hours     Average labor       Cost per        registered       Fleet cost
                                                                                       rate per hour       airplane        airplanes
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Inspection.........................................................               2              $80             $160                7           $1,120
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Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the proposed 
regulation:
    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 regulatory evaluation of the estimated costs to 
comply with this proposed AD and placed it in the AD docket. See the 
ADDRESSES section for a location to examine the regulatory evaluation.

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 FAA proposes to amend 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. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Fokker Services B.V.: Docket No. FAA-2006-25086; Directorate 
Identifier 2006-NM-019-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by July 21, 
2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Fokker Model F27 Mark 500 airplanes, 
certificated in any category.

Unsafe Condition

    (d) This AD results from a report that, due to fatigue cracking 
from an improperly machined radius of the inner tube, a drag stay 
broke, and, consequently, led to the collapse of the MLG during 
landing. We are issuing this AD to prevent such fatigue cracking, 
which could result in reduced structural integrity or collapse of 
the MLG.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Inspections of the DSUs

    (f) Within 60 days after the effective date of this AD: Inspect 
main landing gear (MLG) drag stay units (DSU) to determine whether 
Dowty Aerospace is the manufacturer and before further flight 
inspect Dowty Aerospace MLG DSUs to determine whether part number 
(P/N) 200261001, 200261002, 200485001, 200485002, 200684001, or 
200684002 is installed. A review of airplane maintenance records is 
acceptable in lieu of these inspections if the manufacturer and P/N 
of the MLG DSU can be conclusively determined from that review. For 
airplanes equipped with MLG DSUs other than Dowty Aerospace MLG 
DSUs, and for airplanes equipped with Dowty Aerospace MLG DSUs 
having P/Ns other than P/N 200261001, 200261002, 200485001, 
200485002, 200684001, and 200684002, no further action is required 
by this AD, except as specified in paragraph (k) of this AD.
    (g) For airplanes equipped with DSUs having P/N 200261001, 
200485001, or 200684001: Within 60 days after the effective date of 
this AD, perform an ultrasonic inspection to determine if a tube 
having P/N 200485300 with a straight bore, or a tube having P/N 
200259300 with a change in section (stepped bore), is installed on 
the DSUs of the MLG, in accordance with the Accomplishment 
Instructions of Fokker Service Bulletin F27/32-171, dated December 
16, 2004.

    Note 1: Fokker Service Bulletin F27/32-171, dated December 16, 
2004, references Dowty Aerospace Landing Gear Service Bulletin 32-
82W, Revision 2, including Appendix A, dated July 29, 1994, and 
including Appendix B, Revision 1, dated November 10, 1993; and Dowty 
Aerospace Landing Gear Service Bulletin 32-169B, Revision 2, 
including Appendix A, dated July 29, 1994, and including Appendix B, 
Revision 1, dated November 10, 1993; as

[[Page 35575]]

applicable, as appropriates sources of service information for 
inspecting MLG DSUs.

    (h) If any tube having P/N 200485300 with a straight bore is 
found installed during the inspections required by paragraph (g) of 
this AD: Before further flight, re-identify the DSU with P/N 
200261004, 200485004, or 200684004, in accordance with the 
Accomplishment Instructions of Dowty Aerospace Landing Gear Service 
Bulletin 32-82W, Revision 2, including Appendix A, dated July 29, 
1994, and including Appendix B, Revision 1, dated November 10, 1993; 
or Dowty Aerospace Landing Gear Service Bulletin 32-169B, Revision 
2, including Appendix A, dated July 29, 1994, and including Appendix 
B, Revision 1, dated November 10, 1993; as applicable. After re-
identifying the DSU, no further action is required by this AD for 
that DSU; however airplanes are still subject to the requirements 
specified in paragraph (k) of this AD.
    (i) If any tube having P/N 200259300 with a change in section 
(stepped bore) is found installed during the inspection required by 
paragraph (g) of this AD: Before further flight, re-identify the DSU 
in accordance with paragraphs 2.A.(4)(a) and 2.A.(4)(b) of the 
Accomplishment Instructions Dowty Aerospace Landing Gear Service 
Bulletin 32-82W, Revision 2, including Appendix A, dated July 29, 
1994, and including Appendix B, Revision 1, dated November 10, 1993; 
or Dowty Aerospace Landing Gear Service Bulletin 32-169B, Revision 
2, including Appendix A, dated July 29, 1994, and including Appendix 
B, Revision 1, dated November 10, 1993; as applicable. Following 
accomplishment of the re-identification, before further flight, do 
the inspection specified in paragraph (j) of this AD.

Ultrasonic Inspection for Cracking

    (j) For airplanes equipped with re-identified DSUs having 
200261002, 200485002, 200684002, 200261003, 200485003, or 200684003: 
Within 60 days after the effective date of this AD, perform an 
ultrasonic inspection to detect cracking in the re-identified DSUs, 
in accordance with the Accomplishment Instructions of Dowty 
Aerospace Landing Gear Service Bulletin 32-82W, Revision 2, 
including Appendix A, dated July 29, 1994, and including Appendix B, 
Revision 1, dated November 10, 1993; or Dowty Aerospace Landing Gear 
Service Bulletin 32-169B, Revision 2, including Appendix A, dated 
July 29, 1994, and including Appendix B, Revision 1, dated November 
10, 1993; as applicable.
    (1) For airplanes equipped with any DSU re-identified as P/N 
200684003, 200261003, or 200485003: If no crack is detected, no 
further action is required by this AD for that DSU; however 
airplanes are still subject to the requirements specified in 
paragraph (k) of this AD.
    (2) For airplanes equipped with any DSU re-identified as P/N 
200684002, 200261002, or 200485002: If no crack is detected, do the 
actions specified in paragraphs (j)(2)(i) and (j)(2)(ii) of this AD.
    (i) Repeat the ultrasonic inspection required by paragraph (j) 
of this AD thereafter at intervals not to exceed 1,500 flight cycles 
until the actions specified in paragraph (j)(2)(ii) of this AD are 
done.
    (ii) At the next MLG overhaul but no later than 12,000 flight 
cycles after the effective date of this AD, rework and re-identify 
the DSU as P/N 200261003, 200485003, or 200684003, as applicable, in 
accordance with the applicable service bulletin.
    (3) If any crack is detected and the crack signal indication of 
any DSU tube is greater than or equal to 80 percent, before further 
flight, replace the DSU with a re-identified DSU having P/N 
200261004, 200485004, 200684004, 200261003, 200485003, or 200684003, 
in accordance with the applicable service bulletin.
    (4) If any crack is detected and the crack signal indication of 
any DSU tube is greater than zero percent but less than 80 percent, 
do the actions specified in paragraphs (j)(4)(i) and (j)(4)(ii) of 
this AD.
    (i) Repeat the ultrasonic inspection required by paragraph (j) 
of this AD thereafter at intervals not to exceed 1,500 flight cycles 
until the actions specified in paragraph (j)(4)(ii) of this AD are 
done.
    (ii) At the next MLG overhaul but no later than 12,000 flight 
cycles after the effective date of this AD, replace the DSU with a 
DSU having P/N 200261004, 200485004, 200684004, 200261003, 
200485003, or 200684003, in accordance with the applicable service 
bulletin.

Parts Installation

    (k) As of the effective date of this AD, no person may install a 
MLG DSU, P/N 200261001, 200261002, 200485001, 200485002, 200684001, 
or 200684002, on any airplane, except as specified in paragraph (i) 
of this AD.

Alternative Methods of Compliance (AMOCs)

    (l)(1) The Manager, International Branch, ANM-116, Transport 
Airplane Directorate, FAA, has the authority to approve AMOCs for 
this AD, if requested in accordance with the procedures found in 14 
CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

Related Information

    (m) Dutch airworthiness directive NL-2005-003, dated April 29, 
2005, also addresses the subject of this AD.

    Issued in Renton, Washington, on June 14, 2006.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-9714 Filed 6-20-06; 8:45 am]
BILLING CODE 4910-13-P