[Federal Register Volume 60, Number 237 (Monday, December 11, 1995)]
[Proposed Rules]
[Pages 63468-63470]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-30075]



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


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-99-AD]


Airworthiness Directives; Fokker Model F28 Mark 0100 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Fokker Model F28 Mark 0100 
series airplanes. This proposal would require inspections to verify the 
correct operation of the main landing gear (MLG) downlock actuators, 
and replacement of any discrepant unit with a serviceable unit. The 
proposed AD also would require eventual replacement of the MLG downlock 
actuators with improved units. This proposal is prompted by reports of 
improper operation of the MLG downlock actuator due to jamming. The 
actions specified by the proposed AD are intended to prevent such 
jamming of the downlock actuator, which could result in failure of the 
MLG downlock system, and a potential gear-up landing.

DATES: Comments must be received by January 22, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-99-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 Aircraft USA, Inc., 1199 North Fairfax Street, 
Alexandria, Virginia 22314, and Dowty Aerospace, Customer Support 
Center, P.O. Box 49, Sterling, VA 20166. This information may be 
examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, 
SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Tim Dulin, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2141; fax (206) 227-1320.

SUPPLEMENTARY INFORMATION:

Comments Invited -

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such 

[[Page 63469]]
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 95-NM-99-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-103, Attention: Rules 
Docket No. 95-NM-99-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Rijksluchtvaartdienst (RLD), which is the airworthiness 
authority for the Netherlands, recently notified the FAA that an unsafe 
condition may exist on certain Fokker Model F28 Mark 0100 series 
airplanes. The RLD advises that several operators of these airplanes 
have reported that landing gear ``unsafe'' warning indications have 
appeared on the multi-function display unit (MFDU) after the flight 
crew selected the landing gear to the down position. In most cases, 
recycling the landing gear resulted in a positive downlock indication. 
Investigation revealed that the main landing gear (MLG) downlock 
actuator (jack and springpot unit) did not operate properly. Further 
investigation revealed that the tip of a spring carrier broke due to a 
malformed piston rod and a spring that was not square, which caused the 
spring carrier to move at an angle. A jammed actuator could result in 
failure of the MLG downlock system. This condition, if not corrected, 
could result in a gear-up landing.
    Fokker has issued Service Bulletin SBF100-32-072, dated March 30, 
1993, which describes procedures for repetitive inspections to verify 
the correct operation of any MLG downlock actuator having part number 
(P/N) 201218001, 201218002, 201218003, or 201218004, and replacement of 
discrepant units with serviceable units. The Fokker service bulletin 
references Dowty Aerospace Hydraulics Service Bulletin F100-32-505, 
Revision 1, dated April 16, 1993. The Dowty Aerospace Hydraulics 
service bulletin contains additional procedures for accomplishment of 
the inspection. For airplanes on which the MLG downlock actuator 
operates correctly, the Dowty Aerospace Hydraulics service bulletin 
also specifies procedures for recording the accomplishment of each 
inspection on the unit nameplate.
    Fokker also has issued Service Bulletin SBF100-32-074, dated July 
21, 1993, which describes procedures for replacement of any MLG 
downlock actuator having P/N 201218001, 201218002, 201218003, or 
201218004 with an improved unit having P/N 201218005, 201218006, 
201218007, or 201218008, respectively. The improved units have improved 
jack and springpot units with modified spring carriers and spring 
actuators, as well as a new end fitting subassembly and nut. The Fokker 
service bulletin references Dowty Aerospace Hydraulics Service Bulletin 
F100-32-506, dated June 9, 1993, as an additional source of service 
information.
    The RLD classified these service bulletins as mandatory and issued 
Netherlands airworthiness directive BLA 93-052/2 (A), dated September 
10, 1993, in order to assure the continued airworthiness of these 
airplanes in the Netherlands.
    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, 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.
    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 require repetitive 
inspections to verify the correct operation of the MLG downlock 
actuators; and replacement of any discrepant unit with a serviceable 
unit. For airplanes on which no discrepant unit is found, the proposed 
AD also would require recording the accomplishment of each inspection 
on the unit nameplate. In addition, the proposed AD would require 
eventual replacement of the MLG downlock actuators with improved units. 
The actions would be required to be accomplished in accordance with the 
service bulletins described previously.
    The FAA estimates that 119 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 21 work 
hours per airplane to accomplish the proposed actions, at an average 
labor rate of $60 per work hour. Required parts would be supplied by 
the vendor at no cost to operators. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be 
$149,940, or $1,260 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed requirements of 
this AD action, and that no operator would accomplish those actions in 
the future if this AD were not adopted.
    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. 
    
[[Page 63470]]


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 USC 106(g), 40101, 40113, 44701.


Sec. 39.13  [Amended] -

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Fokker: Docket 95-NM-99-AD.

    -Applicability: Model F28 Mark 0100 series airplanes equipped 
with Dowty Aerospace Hydraulics main landing gear (MLG) downlock 
actuators having part number (P/N) 201218001, 201218002, 201218003, 
or 201218004, all serial numbers; 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 use the authority 
provided in paragraph (d) of this AD to request approval from the 
FAA. This approval may address either no action, if the current 
configuration eliminates the unsafe condition; or different actions 
necessary to address the unsafe condition described in this AD. Such 
a request should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD. -
    Compliance: Required as indicated, unless accomplished 
previously. -
    To prevent jamming of the MLG downlock actuator and a potential 
gear-up landing, accomplish the following: -
    (a) Within 2 months after the effective date of this AD, and 
thereafter at intervals not to exceed 1,250 landings: Perform an 
inspection to verify correct operation of the MLG downlock actuator 
having P/N 201218001, 201218002, 201218003, or 201218004, all serial 
numbers, in accordance with Fokker Service Bulletin SBF100-32-072, 
dated March 30, 1993, and Dowty Aerospace Hydraulics Service 
Bulletin F100-32-505, Revision 1, dated April 16, 1993. -
    (1) If the MLG downlock actuator operates as specified in the 
inspection procedure contained in the Accomplishment Instructions of 
Dowty Aerospace Hydraulics Service Bulletin F100-32-505, Revision 1, 
dated April 16, 1993, prior to further flight, record the 
accomplishment of the inspection on the unit nameplate in accordance 
with the Dowty Aerospace Hydraulics service bulletin. Following 
accomplishment of each subsequent inspection required by this AD, 
record the accomplishment of the inspection in accordance with the 
requirement of this paragraph. -
    (2) If any MLG downlock actuator does not operate as specified 
in the inspection procedure contained in the Accomplishment 
Instructions of Dowty Aerospace Hydraulics Service Bulletin F100-32-
505, Revision 1, dated April 16, 1993, prior to further flight, 
replace the downlock actuator with a serviceable unit, in accordance 
with Chapter 32-32-05 of the Aircraft Maintenance Manual. 
Thereafter, perform repetitive inspections of the replacement unit 
in accordance with paragraph (a) of this AD until the replacement 
required by paragraph (b) of this AD is accomplished. -
    (b) Within 9 months after the effective date of this AD, replace 
any MLG downlock actuator having P/N 201218001, 201218002, 
201218003, or 201218004, any serial number, with an improved unit 
having P/N 201218005, 201218006, 201218007, or 201218008, 
respectively; in accordance with Fokker Service Bulletin SBF100-32-
074, dated July 21, 1993, and Dowty Aerospace Hydraulics Service 
Bulletin F100-32-506, dated June 9, 1993. Accomplishment of this 
replacement constitutes terminating action for the repetitive 
inspections required by paragraph (a) of this AD. -
    (c) As of the effective date of this AD, no person shall install 
on any airplane a MLG downlock actuator having P/N 201218001, 
201218002, 201218003, or 201218004, any serial number. -
    (d) 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, Standardization Branch, ANM-113, 
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, 
Standardization Branch, ANM-113. -
    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

     -(e) 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.

    Issued in Renton, Washington, on December 5, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-30075 Filed 12-8-95; 8:45 am]
BILLING CODE 4910-13-U