[Federal Register Volume 63, Number 156 (Thursday, August 13, 1998)]
[Proposed Rules]
[Pages 43342-43345]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-21718]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-92-AD]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F27 Mark 050, 100, 200, 
300, 400, 500, 600, and 700 Rough Field Version (RFV) Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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[[Page 43343]]

SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Fokker Model F27 
Mark 100, 200, 300, 400, 500, 600, and 700 Rough Field Version (RFV) 
series airplanes, that currently requires inspection of the main 
landing gear (MLG) legs to determine if parts are missing or damaged, 
and modification, if necessary; and periodic measurements of the 
extension of each MLG shock absorber sliding member. That AD also 
provides for the accomplishment of a certain modification as optional 
terminating action for the periodic measurements. This action would 
require accomplishment of the previously optional terminating action. 
This action also would revise the applicability of the existing AD to 
add an airplane model. This proposal is prompted by issuance of 
mandatory continuing airworthiness information by a foreign civil 
airworthiness authority. The actions specified by the proposed AD are 
intended to prevent loss of the MLG sliding member, which could result 
in reduced structural integrity of the MLG.

DATES: Comments must be received by September 14, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-92-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056. Comments may be inspected at this location 
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal 
holidays.
    The service information referenced in the proposed rule may be 
obtained from Fokker Services B.V., Technical Support Department, P.O. 
Box 75047, 1117 ZN Schiphol Airport, the Netherlands. This information 
may be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, 
International Branch, ANM-116, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-2110; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 98-NM-92-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 98-NM-92-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On October 28, 1993, the FAA issued AD 93-22-02, amendment 39-8727 
(58 FR 60370, November 16, 1993), applicable to certain Fokker Model 
F27 Mark 100, 200, 300, 400, 500, 600, and 700 Rough Field Version 
(RFV) series airplanes, to require inspection of the main landing gear 
(MLG) legs to determine if parts are missing or damaged, and 
modification, if necessary; and periodic measurements of the extension 
of each MLG shock absorber sliding member. That AD also provides for 
the accomplishment of a certain modification as optional terminating 
action for the periodic measurements. That AD was prompted by reports 
of overextension of the MLG sliding member due to missing parts in the 
MLG leg assembly. The requirements of that AD are intended to prevent 
loss of the MLG sliding member, which could result in reduced 
structural integrity of the MLG.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the Rijksluchtvaartdienst (RLD), 
which is the airworthiness authority for the Netherlands, notified the 
FAA that it received a report indicating that, during routine 
maintenance on an in-service Fokker Model F27 Mark 050 series airplane, 
maintenance personnel discovered a dowel and a castellation missing 
from an MLG assembly. Further investigation revealed that the 
inspections of the MLG legs to determine if parts are missing or 
damaged, as specified in Fokker Service Bulletin F50-32-025 (Messier-
Dowty Service Bulletin F50-32-48), had been accomplished previously on 
the airplane.
    Further, the RLD advised the FAA that modification of the MLG 
assembly should be accomplished to ensure correct assembly of the 
piston rod. Therefore, the FAA has determined that this modification 
(which was specified as optional in AD 93-22-02) is necessary in order 
to positively address the identified unsafe condition..
    Additionally, in AD 93-22-02, the FAA referenced the applicability 
as ``Fokker Model F27 Rough Field Version (RFV) series airplanes, 
excluding Model F27 Mark 050 series airplanes.'' However, the FAA has 
determined that the applicability of the existing AD should be 
clarified by specifying that it applies to Fokker Model F27 Mark 100, 
200, 300, 400, 500, 600, and 700 Rough Field Version (RFV) series 
airplanes. In addition, the FAA finds that Fokker Model F27 Mark 050 
series airplanes also are subject to the identified unsafe condition; 
therefore, those airplanes are specified in the applicability of this 
proposed AD.

Explanation of Relevant Service Information

    The manufacturer of the landing gear has issued Messier-Dowty 
Service Bulletin F50-32-48, Revision 4, dated June 21, 1995 (for Model 
F27 Mark 050 series airplanes), which describes detailed procedures for 
inspecting the MLG piston rod and adapter to confirm the correct 
installation of the stepped pin and dowel. It also describes procedures 
for periodic measurements of the extension of the MLG sliding member 
when the landing gear is fully extended.
    The manufacturer of the landing gear also has issued Dowty 
Aerospace Landing Gear Service Bulletin F50-32-27, Revision 4, dated 
December 18, 1992 (for Model F27 Mark 050 series airplanes), which 
describes procedures for modification of the MLG piston rod assembly. 
This modification involves the installation of a shim between the 
contact face of the piston rod and adapter, and the installation of a 
pin in lieu of the currently installed dowel to secure the castellated 
nut to the adapter.

[[Page 43344]]

Accomplishment of the modification would eliminate the need for 
inspections and periodic measurements of the extension of the MLG shock 
absorber sliding member.
    For Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 series 
airplanes, Fokker has issued Service Bulletin F27-32-165, Revision 1, 
dated April 28, 1993; and the manufacture of the landing gear has 
issued Dowty Aerospace Landing Gear Service Bulletin 32-81W, Revision 
2, dated February 3, 1993, and Dowty Aerospace Landing Gear Service 
Bulletin 32-77W, Revision 4, dated February 3, 1993. As described in AD 
93-22-02, these service bulletins inspection of the MLG legs to 
determine if parts are missing or damaged, and modification, if 
necessary; and periodic measurements of each MLG shock absorber sliding 
member. Further, Dowty Aerospace Landing Gear Service Bulletin 32-77W 
describes procedures for modification of the MLG assembly, which would 
eliminate the need for the inspections and periodic measurements 
discussed previously.
    Accomplishment of the actions specified in the service bulletins is 
intended to adequately address the identified unsafe condition. The RLD 
classified these service bulletins as mandatory and issued Dutch 
airworthiness directive 1996-159/2 (A), dated July 31, 1997, in order 
to assure the continued airworthiness of these airplanes in the 
Netherlands.

FAA's Conclusions

    These airplane models are manufactured in the Netherlands 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 RLD has kept the FAA 
informed of the situation described above. The FAA has examined the 
findings of the RLD, reviewed all available information, and determined 
that AD action is necessary for products of this type design that are 
certificated for operation in the United States.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would supersede AD 93-22-02 to 
continue to require inspection of the MLG legs to determine if parts 
are missing or damaged, and modification, if necessary; and periodic 
measurements of the extension of each MLG shock absorber sliding 
member. In addition, this proposed AD also would require accomplishment 
of the previously optional terminating action and would revise the 
applicability of the existing AD to add an airplane model.
    The actions would be required to be accomplished in accordance with 
the service bulletins described previously.

Cost Impact

    There are approximately 34 Fokker Model F27 Mark 100, 200, 300, 
400, 500, 600, and 700 RFV series airplanes, and no Fokker Model F27 
Mark 050 series airplanes, of U.S. registry that would be affected by 
this proposed AD.
    The actions that are currently required by AD 93-22-02, and 
retained in this proposed AD, would take approximately 3 work hours per 
airplane to accomplish, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the currently required 
inspections on U.S. operators is estimated to be $6,120, or $180 per 
airplane, per inspection cycle.
    The new modification that is proposed in this AD action would take 
approximately 2 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would be supplied by 
the manufacturer at no cost to the operators. Based on these figures, 
the cost impact of the modification proposed by this AD on U.S. 
operators is estimated to be $4,080, or $120 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the current or proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.

Regulatory Impact

    The regulations proposed herein would not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this 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) 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 is contained 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, pursuant to 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. Section 39.13 is amended by removing amendment 39-8727 (58 FR 
60370, November 16, 1993), and by adding a new airworthiness directive 
(AD), to read as follows:

Fokker Services B.V.: Docket 98-NM-92-AD. Supersedes AD 93-22-02, 
Amendment 39-8727.
    Applicability: Model F27 Mark 050, 100, 200, 300, 400, 500, 600, 
and 700 Rough Field Version (RFV) series airplanes, equipped with 
Dowty Aerospace MLG Legs, part and serial numbers as listed in Dowty 
Aerospace Landing Gear Service Bulletin 32-77W, Revision 4, dated 
February 3, 1993, or Dowty Aerospace Landing Gear Service Bulletin 
F50-32-27, Revision 4, dated December 18, 1992; certificated in any 
category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (g) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent loss of the MLG sliding member, which could result in 
reduced

[[Page 43345]]

structural integrity of the MLG, accomplish the following:

Restatement of Requirements of AD 93-22-02

    (a) For Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 RFV 
series airplanes, equipped with Dowty Aerospace MLG, part numbers 
200563001, 200679001, 200679002, 200679003, or 200679004: Within 30 
days after December 16, 1993 (the effective date of AD 93-22-02, 
amendment 39-8727), inspect the MLG legs to confirm the correct 
installation of the sliding member out-stop installation, in 
accordance with Fokker Service Bulletin F27-32-165, Revision 1, 
dated April 28, 1993, and paragraph 2.C. (``Part A Procedure'') of 
Dowty Aerospace Landing Gear Service Bulletin 32-81W, Revision 2, 
dated February 3, 1993. If any parts are determined to be missing or 
damaged, prior to further flight, modify the MLG assembly, in 
accordance with Dowty Aerospace Landing Gear Service Bulletin 32-
77W, Revision 4, dated February 3, 1993.
    (b) For Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 RFV 
series airplanes, equipped with Dowty Aerospace MLG, part numbers 
200563001, 200679001, 200679002, 200679003, or 200679004: Within 30 
days after December 16, 1993, measure and record the extension of 
the MLG sliding member when the landing gear is fully extended, in 
accordance with paragraph 2.D. (``Part B Procedure'') of Dowty 
Aerospace Landing Gear Service Bulletin 32-81W, Revision 2, dated 
February 3, 1993.
    (1) If the extension dimension exceeds 410.2 mm (16.15 inches), 
prior to further flight, modify the MLG assembly in accordance with 
Dowty Aerospace Landing Gear Service Bulletin 32-77W, Revision 4, 
dated February 3, 1993.
    (2) If the extension dimension is equal to or less than 410.2 mm 
(16.15 inches), repeat the measurement thereafter at intervals not 
to exceed 500 flight cycles.
    (3) If the extension dimension increases by more than 1.0 mm 
(0.40 inch) above the initially recorded dimension during any 
measurement required by this paragraph, prior to further flight, 
inspect the MLG in accordance with paragraph (a) of this AD.

New Requirements of This AD

    (c) For airplanes other than those identified in paragraph (a) 
of this AD: Within 30 days after the effective date of this AD, 
inspect the MLG legs to confirm the correct installation of the 
sliding member out-stop installation, in accordance with paragraph 
2.C. (``Part A Procedure'') of Messier-Dowty Service Bulletin F50-
32-48, Revision 4, dated June 21, 1995. If any parts are determined 
to be missing or damaged, prior to further flight, modify the MLG 
assembly, in accordance with Dowty Aerospace Landing Gear Service 
Bulletin F50-32-27, Revision 4, dated December 18, 1992.
    (d) For airplanes other than those identified in paragraph (a) 
of this AD: Within 30 days after the effective date of this AD, 
measure and record the extension of the MLG sliding member when the 
landing gear is fully extended, in accordance with paragraph 2.D. 
(``Part B Procedure'') of Messier-Dowty Service Bulletin F50-32-48, 
Revision 4, dated June 21, 1995.
    (1) If the extension dimension exceeds 410.2 mm (16.15 inches), 
prior to further flight, modify the MLG assembly in accordance with 
Dowty Aerospace Landing Gear Service Bulletin F50-32-27, Revision 4, 
dated December 18, 1992.
    (2) If the extension dimension is equal to or less than 410.2 mm 
(16.15 inches), repeat the measurement thereafter at intervals not 
to exceed 500 flight cycles.
    (3) If the extension dimension increases by more than 1.0 mm 
(0.40 inch) above the initially recorded dimension during any 
measurement required by this paragraph, prior to further flight, 
inspect the MLG in accordance with paragraph (c) of this AD.
    (e) For all airplanes: Within 5,000 flight cycles or 24 months 
after the effective date of this AD, whichever occurs earlier, 
modify the MLG piston rod assembly, in accordance with Dowty 
Aerospace Landing Gear Service Bulletin 32-77W, Revision 4, dated 
February 3, 1993 (for Model F27 Mark 100, 200, 300, 400, 500, 600, 
and 700 series airplanes), or Dowty Aerospace Landing Gear Service 
Bulletin F50-32-27, Revision 4, dated December 18, 1992 (for Model 
F27 Mark 050 series airplanes), as applicable. Accomplishment of 
this modification constitutes terminating action for the repetitive 
actions required by this AD.
    (f) As of the effective date of this AD, no person shall install 
on any airplane, an MLG piston rod assembly, unless it has been 
modified in accordance with Dowty Aerospace Landing Gear Service 
Bulletin 32-77W, Revision 4, dated February 3, 1993 (for Model F27 
Mark 100, 200, 300, 400, 500, 600, and 700 series airplanes), or 
Dowty Aerospace Landing Gear Service Bulletin F50-32-27, Revision 4, 
dated December 18, 1992 (for Model F27 Mark 050 series airplanes), 
as applicable.
    (g) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, International Branch, ANM-116, FAA, 
Transport Airplane Directorate. Operators shall submit their 
requests through an appropriate FAA Principal Maintenance Inspector, 
who may add comments and then send it to the Manager, International 
Branch, ANM-116.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

    (h) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

    Note 3: The subject of this AD is addressed in Dutch 
airworthiness directive 1996-159/2 (A), dated July 31, 1997.

    Issued in Renton, Washington, on August 7, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-21718 Filed 8-12-98; 8:45 am]
BILLING CODE 4910-13-P