[Federal Register Volume 63, Number 80 (Monday, April 27, 1998)]
[Proposed Rules]
[Pages 20554-20556]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-11092]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-16-AD]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F.28 Mark 1000, 2000, 
3000, and 4000 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain Fokker Model F.28 
Mark 1000, 2000, 3000, and 4000 series airplanes, that currently 
requires an inspection to detect free movement of the actuator servo-
valve sub-assembly of the horizontal stabilizer actuator, and 
replacement, if necessary. This action would add a one-time inspection 
to determine the residual strength of the servo-valve sub-assembly of 
the horizontal stabilizer actuator, and replacement of the actuator 
with a new or serviceable actuator, if necessary; and eventual 
replacement of the horizontal stabilizer actuator with an improved 
actuator. 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 
uncommanded trimming or failure of the trim system of the horizontal 
stabilizer, and consequent reduced controllability of the airplane.

DATES: Comments must be received by May 27, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-16-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.

[[Page 20555]]

    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-16-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-16-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On August 7, 1992, the FAA issued AD 92-18-04, amendment 39-8348 
(57 FR 38432, August 25, 1992), applicable to certain Fokker Model F.28 
Mark 1000, 2000, 3000, and 4000 series airplanes, to require an 
inspection to detect free movement of the actuator servo-valve sub-
assembly of the horizontal stabilizer actuator, and replacement, if 
necessary. That action was prompted by a report of a horizontal 
stabilizer malfunction and subsequent uncommanded stabilizer movement 
caused by a broken spool in the actuator servo-valve assembly of the 
horizontal stabilizer control unit. The requirements of that AD are 
intended to prevent uncommanded trimming or failure of the trim system 
of the horizontal stabilizer.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the manufacturer and the 
Rijksluchtvaartdienst (RLD), which is the airworthiness authority for 
the Netherlands, have determined that currently installed servo-valve 
sub-assemblies of the horizontal stabilizer may have suffered damage as 
a result of excessive control forces experienced during past heavy 
operation. This damage could result in a dormant failure of the 
actuator servo-valve assembly of the horizontal stabilizer control 
unit. This condition, if not corrected, could lead to an uncommanded 
nose-up trimming condition in the event of a horizontal stabilizer 
servo-valve failure, and consequent reduced controllability of the 
airplane.

Explanation of Relevant Service Information

    Fokker has issued Service Bulletin F28/27-183, dated November 21, 
1994, which describes procedures for a one-time inspection to determine 
the residual strength of the servo-valve sub-assembly of the horizontal 
stabilizer actuator, and replacement of the actuator with a new or 
serviceable actuator, if necessary. The service bulletin also describes 
procedures for replacement of the horizontal stabilizer actuator with 
an improved actuator that incorporates a revised servo-valve creep 
rate. This replacement is intended to ensure that a failure of the 
horizontal stabilizer actuator would result in a nose-down trim 
position. The RLD classified this service bulletin as mandatory and 
issued Dutch airworthiness directive 1992-077/2(A), dated January 31, 
1995, 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 Sec. 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 92-18-04 to 
continue to require an inspection to detect free movement of the 
actuator servo-valve sub-assembly of the horizontal stabilizer 
actuator, and replacement, if necessary. The proposed AD also would 
require a one-time inspection to determine the residual strength of the 
servo-valve sub-assembly of the horizontal stabilizer actuator, and 
replacement of the actuator with a new or serviceable actuator, if 
necessary; and eventual replacement of the horizontal stabilizer 
actuator with an improved actuator. The actions would be required to be 
accomplished in accordance with the service bulletin described 
previously.

Cost Impact

    There are approximately 27 airplanes of U.S. registry that would be 
affected by this proposed AD.
    The inspection that is currently required by AD 92-18-04 would take 
approximately 1 work hour 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 actions on U.S. operators is estimated 
to be $1,620, or $60 per airplane.
    The inspection that is proposed in this new AD action would take 
approximately 2 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 proposed inspection of this AD on U.S. operators is 
estimated to be $3,240, or $120 per airplane.
    The replacement proposed in this new AD action would take 
approximately 8 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts would be provided by 
the manufacturer at no cost to the operator. Based on these figures, 
the cost impact of the proposed replacement of this AD on U.S. 
operators is estimated to be $12,960, or $480 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,

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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 39-8348 (57 FR 
38432, August 25, 1992), and by adding a new airworthiness directive 
(AD), to read as follows:

Fokker: Docket 98-NM-16-AD. Supersedes AD 92-18-04, Amendment 39-
8348.

    Applicability: Model F.28 Mark 1000, 2000, 3000, and 4000 series 
airplanes; equipped with Menasco horizontal stabilizer actuators 
having part number (P/N)
11100-(  ); 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 (e) 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 uncommanded trimming or failure of the trim system of 
the horizontal stabilizer, and consequent reduced controllability of 
the airplane, accomplish the following:
    (a) Within 20 days after September 9, 1992 (the effective date 
of AD 92-18-04, amendment 39-8348), perform an inspection of the 
servo-valve sub-assembly rod-end bearing and servo-valve sub-
assembly for movement, in accordance with Fokker Service Bulletin 
F28/27-180, dated July 3, 1992.
    (1) If the servo-valve sub-assembly rod-end bearing and servo-
valve sub-assembly move freely within the load limits specified in 
the service bulletin, reassemble and conduct a functional test, in 
accordance with the service bulletin.
    (2) If the servo-valve sub-assembly rod-end bearing or servo-
valve sub-assembly require higher loads for movement than specified 
in the service bulletin, prior to further flight, remove and replace 
the horizontal stabilizer control unit with a serviceable control 
unit that has been inspected and found to be within the load limits 
of the service bulletin, or that has been inspected and repaired in 
accordance with Chapter 27-42-4 of the Menasco Overhaul Manual 
(OHM), as revised by Temporary Revision Number 3, dated July 10, 
1992.
    (b) Within 6 months after the effective date of this AD, perform 
a one-time inspection to determine the residual strength of the 
servo-valve sub-assembly of the horizontal stabilizer actuator, in 
accordance with Part 1 of the Accomplishment Instructions of Fokker 
Service Bulletin F28/27-183, dated November 21, 1994. If any 
discrepancy is found, prior to further flight, replace the actuator 
with a new or serviceable actuator in accordance with the service 
bulletin.
    (c) Within 3 years after the effective date of this AD, replace 
the horizontal stabilizer actuator with an actuator that has been 
modified and re-marked in accordance with Part 2 of the 
Accomplishment Instructions of Fokker Service Bulletin F28/27-183, 
dated November 21, 1994.
    (d) As of the effective date of this AD, no person shall install 
a horizontal stabilizer control unit on any airplane, unless the 
horizontal stabilizer actuator has been modified and re-marked in 
accordance with Part 2 of the Accomplishment Instructions of Fokker 
Service Bulletin F28/27-183, dated November 21, 1994.
    (e) 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.

    (f) 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 1992-007/2(A), dated January 31, 1995.

    Issued in Renton, Washington, on April 21, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-11092 Filed 4-24-98; 8:45 am]
BILLING CODE 4910-13-U