[Federal Register Volume 61, Number 225 (Wednesday, November 20, 1996)]
[Rules and Regulations]
[Pages 58987-58989]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-29608]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-262-AD; Amendment 39-9825; AD 96-23-16]
RIN 2120-AA64


Airworthiness Directives; Fokker Model F28 Mark 0070 and 0100 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This document publishes in the Federal Register an amendment 
adopting airworthiness directive (AD) 96-23-16 that was sent previously 
to all known U.S. owners and operators of Fokker Model F28 Mark 0070 
and 0100 series airplanes by individual notices. This AD requires a 
revision to the Airplane Flight Manual that will enable the flightcrew 
to determine if the thrust reversers are properly locked prior to take-
off. This AD also prohibits dispatch of the airplane, under certain 
conditions, with both autothrottle channels inoperative. In addition, 
this AD requires revising the maintenance program to provide 
instructions to correct thrust reverser malfunctions. This amendment is 
prompted by preliminary results of an investigation of an accident in 
which a thrust reverser may have deployed inadvertently during flight. 
The actions specified by this AD are intended to prevent an 
unannunciated failure of the secondary lock of the thrust reversers, 
which could result in reduced protection against inadvertent deployment 
of the thrust reversers during flight.

DATES: Effective November 25, 1996 to all persons except those persons 
to whom it was made immediately effective by emergency AD 96-23-16, 
issued November 8, 1996, which contained the requirements of this 
amendment.
    Comments for inclusion in the Rules Docket must be received on or 
before January 21, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-262-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    Information concerning this rulemaking action 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) 227-1149.

SUPPLEMENTARY INFORMATION: On November 8, 1996, the FAA issued 
emergency AD 96-23-16, which is applicable to all Fokker Model F28 Mark 
0070 and 0100 series airplanes.
    That AD was prompted by notification from the Rijksluchtvaartdienst 
(RLD), which is the airworthiness authority for the Netherlands, that 
an unsafe condition may exist on all Fokker Model F28 Mark 0070 and 
0100 series airplanes. The RLD advised that, on October 31, 1996, a 
Fokker Model F28 Mark 0100 series airplane was involved in an accident 
shortly after take-off in Sao Paulo, Brazil.
    Preliminary accident investigation results indicate that, during 
take-off, the thrust reverser of the right-hand engine may have 
inadvertently deployed. The cause of this possible deployment is 
unknown at this time.
    However, the results of a study conducted by Fokker following the 
accident revealed that a malfunction of the secondary lock of the 
thrust reverser may occur without indication to the flightcrew. The 
secondary lock of the thrust reverser may remain in the unlocked 
position (i.e., No. 1 relay energized) in conditions when it should be 
locked. The secondary lock is a backup to the primary actuator lock and 
is designed to open only when thrust reverser deployment is commanded. 
If the flightcrew is unaware that the secondary lock is in the unlocked 
position, the airplane may take off with reduced safety margins. 
Currently, there are no indications that the secondary lock No. 1 relay 
failure contributed to the accident that occurred on October 31.
    An unannunciated failure of the secondary lock of the thrust 
reversers could result in reduced protection against inadvertent 
deployment of the thrust reversers in-flight.
    The thrust reverser system that is installed on Fokker Model F28 
Mark 0100 series airplanes is identical in design to that installed on 
Fokker Model F28 Mark 0070 series airplanes. Therefore, the FAA finds 
that both of these models are subject to the same unsafe condition 
identified in this AD.

Explanation of Relevant Service Information

    Fokker has developed procedural information, for inclusion in the 
Airplane Flight Manual (AFM) of the affected airplanes, that will 
enable the flightcrew to determine if the thrust reversers are properly 
locked prior to take-off by monitoring proper engagement of the 
autothrottle system (ATS).
    Fokker also has developed procedural information to prohibit 
dispatch of the airplane with both autothrottle channels inoperative, 
unless both thrust reversers are deactivated and secured in the stowed 
position, and no operations are conducted that are predicated on thrust 
reverser operation.
    In addition, Fokker has developed procedural information, for 
inclusion in the airplane maintenance program of the affected 
airplanes, that will provide instructions to correct thrust reverser 
malfunctions.
    All of the procedures described in these documents will contribute 
to preventing the unannunciated failure of the secondary lock of the 
thrust reversers, which could result in reduced protection against 
inadvertent deployment of the thrust reversers during flight.
    The RLD classified these procedures as mandatory, and issued 
Netherlands airworthiness directive BLA 1996-138 (A), dated November 7, 
1996, in order to assure the continued airworthiness of these airplanes 
in the Netherlands.

FAA's Conclusions

    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.

Explanation of the Requirements of the AD

    Since the unsafe condition described is likely to exist or develop 
on other airplanes of the same type design registered in the United 
States, the FAA

[[Page 58988]]

issued emergency AD 96-23-16 to prevent an unannunciated failure of the 
secondary lock of the thrust reversers, which could result in reduced 
protection against inadvertent deployment of the thrust reversers 
during flight. The AD requires:
    1. Revising the Limitations Section of the FAA-approved AFM to 
enable the flightcrew to determine if the thrust reversers are properly 
locked prior to take-off by monitoring proper engagement of the ATS;
    2. Prohibiting the dispatch of the airplane with both autothrottle 
channels inoperative, unless both thrust reversers are deactivated and 
secured in the stowed position, and no operations are conducted that 
are predicated on thrust reverser operation; and
    3. Revising the FAA-approved maintenance program to provide 
instructions to correct thrust reverser malfunctions.
    Since it was found that immediate corrective action was required, 
notice and opportunity for prior public comment thereon were 
impracticable and contrary to the public interest, and good cause 
existed to make the AD effective immediately by individual notices 
issued on November 8, 1996, to all known U.S. owners and operators of 
Fokker Model F28 Mark 0070 and 0100 series airplanes. These conditions 
still exist, and the AD is hereby published in the Federal Register as 
an amendment to section 39.13 of the Federal Aviation Regulations (14 
CFR 39.13) to make it effective as to all persons.

Interim Action

    This is considered to be interim action until final action is 
identified, at which time the FAA may consider further rulemaking.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 96-NM-262-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, may be obtained from 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.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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 adding the following new 
airworthiness directive:

96-23-16  Fokker: Amendment 39-9825. Docket 96-NM-262-AD.

    Applicability: All Model F28 Mark 0070 and 0100 series 
airplanes, 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 (b) 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 an unannunciated failure of the secondary lock of the 
thrust reversers, which could result in reduced protection against 
inadvertent deployment of the thrust reversers in-flight, accomplish 
the following:
    (a) Within 48 hours after receipt of this AD, accomplish 
paragraphs (a)(1), (a)(2), and (a)(3) of this AD.
    (1) Revise the Section 1 of the Limitations Section of the FAA-
approved Airplane Flight Manual (AFM) to include the following. This 
may be accomplished by inserting a copy of this AD in the AFM.
    `` Before take-off, arm the autothrottle system (ATS).
     When cleared for take-off, activate the take-off/go-
around (TOGA) trigger(s), and positively verify ATS engagement 
[throttle movement and white steady AT1, AT2, or AT in the flight 
mode annunciator (FMA) engage window].
     If the ATS does NOT engage correctly, abort the take-
off, return, and report to maintenance.
     If the ATS does engage correctly, you may continue 
take-off with either ATS engaged or disengaged, as necessary.''
    (2) Dispatch of the airplane with both autothrottle channels 
inoperative is prohibited, unless both thrust reversers are 
deactivated and secured in the stowed position, and no operations 
are conducted that are predicated on thrust reverser operation.
    (3) Revise the FAA-approved maintenance program to incorporate 
the following:

[[Page 58989]]

``DETAILED MAINTENANCE PROCEDURE

    If the autothrottle system does NOT engage correctly, perform 
the following:
     Select the engine multiplexer (EMUX) 1 and 2 input 
verification page [refer to Chapter 31-61-00 of the airplane 
maintenance manual (AMM)].
     If the multi-function display unit (MFDU) shows:

REVERSER
    NOT DEPL
REVERSER
    STOWED

    These indications mean that the autothrottle (A/T) fault is not 
caused by a thrust reverser problem. Repair the affected ATS in 
accordance with the FAA-approved airplane maintenance program (refer 
to Chapter 22-41-00 of the AMM).
     If the MFDU shows:

REVERSER
    NOT DEPL
REVERSER
    NOT STOWED

AND

    If there is no reverser alert [REVERSER ENG 1 (2)] on the MFDU, 
prior to further flight, accomplish either of the following:

--Replace the left-hand relay K1265A or right-hand relay K1266A. 
Check the thrust reverser system (refer to Chapter 78-30-00 of the 
AMM); or
--Deactivate both thrust reversers (refer to task 78-00-00-040-812 
of the AMM).

    (b) 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.

    (c) 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.
    (d) This amendment becomes effective on November 25, 1996 to all 
persons except those persons to whom it was made immediately 
effective by emergency AD 96-23-16, issued November 8, 1996, which 
contained the requirements of this amendment.

    Issued in Renton, Washington, on November 13, 1996.
James V. Devany,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-29608 Filed 11-19-96; 8:45 am]
BILLING CODE 4910-13-U