[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]
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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).
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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