[Federal Register Volume 60, Number 197 (Thursday, October 12, 1995)]
[Rules and Regulations]
[Pages 53110-53112]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-25160]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 95-NM-179-AD; Amendment 39-9396; AD 95-21-10]
Airworthiness Directives; Fokker Model F28 Mark 0100 and Model
F28 Mark 0070 Series Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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[[Page 53111]]
SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to all Fokker Model F28 Mark 0100 and Model F28 Mark 0070
series airplanes. This action requires revising the Limitations Section
of the Airplane Flight Manual to include information that will enable
the flightcrew to identify failures of the emergency direct current
(DC)/alternating current (AC) bus power supply and to take appropriate
corrective actions. This amendment is prompted by one report indicating
that a diode failed, which resulted in battery drain and loss of the
emergency DC bus power supply; and another report indicating that the
circuit breaker of the transformer rectifier unit No. 3 tripped, which
resulted in the loss of the emergency DC/AC bus power supply. The
actions specified in this AD are intended to ensure that the flightcrew
is advised of the potential hazard related to failures of the emergency
bus power supply, and the procedures necessary to address it.
DATES: Effective October 27, 1995.
Comments for inclusion in the Rules Docket must be received on or
before December 11, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-179-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056.
Information concerning this amendment may be obtained from or
examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue,
SW., Renton, Washington.
FOR FURTHER INFORMATION CONTACT: Ruth Harder, Aerospace Engineer,
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)
227-1721; fax (206) 227-1149.
SUPPLEMENTARY INFORMATION: The Rijksluchtvaartdienst (RLD), which is
the airworthiness authority for the Netherlands, recently notified the
FAA that an unsafe condition may exist on all Fokker Model F28 Mark
0100 and Model F28 Mark 0070 series airplanes. The RLD advises that it
has received a report that a diode failed on a Fokker Model F28 Mark
0100 series airplane. The flightcrew had no indication of this failure
until the battery voltage dropped below a certain value. The RLD also
advises that it has received another similar report, but on a Fokker
Model Mark 0070 series airplane, in which the circuit breaker of the
transformer rectifier unit No. 3 of the emergency direct current (DC)
bus supply tripped; this situation resulted in an oscillating behavior
of the electrical relays, causing the failure of not only the systems
powered by the emergency DC bus, but also of the systems powered by the
emergency alternating current (AC) bus. The cause of these failures is
unknown at this time.
Failure of a diode in the emergency DC bus supply could result in a
battery drain, and the loss of the emergency DC bus and the subsequent
loss of all systems powered by it. If the circuit breaker of the
transformer rectifier unit No. 3 of the emergency DC bus supply trips,
the resultant oscillations of the electrical relays could result in
loss of both the emergency DC bus and emergency AC bus; this situation
could lead to loss of on-side displays, autopilot, pressure control,
and all communications, which could reduce the ability of the
flightcrew to control the airplane.
Fokker has developed procedural information, for inclusion in the
Airplane Flight Manual (AFM) of the affected airplanes, that will
enable the flight crew to identify failures of the emergency DC/AC bus
power supply and to take appropriate corrective actions. The RLD
classified this AFM material as mandatory, and issued Dutch
airworthiness directive BLA 1995-089/2 (A), dated September 29, 1995,
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, this AD is being issued to ensure that the
flightcrew is advised of the potential hazard related to failures of
the emergency DC/AC bus power supply, and the procedures necessary to
address it. This AD requires revising the Abnormal and Normal
Procedures sections of the FAA-approved AFM to include information that
will enable the flightcrew to identify failures of the emergency DC/AC
bus power supply and to take appropriate procedures necessary to
address it.
This is considered to be interim action. The manufacturer has
advised it currently is developing a modification that will positively
address the unsafe condition addressed by this AD. Once this
modification is developed, approved, and available, the FAA may
consider additional rulemaking.
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
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 95-NM-179-AD.'' The postcard will be date stamped and
returned to the commenter.
The regulations adopted herein will not have substantial direct
effects on the States, on the relationship between the
[[Page 53112]]
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 USC 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
95-21-10 Fokker: Amendment 39-9396. Docket 95-NM-179-AD.
Applicability: All Model F28 Mark 0070 and Model F28 Mark 0100
series airplanes, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To ensure that the flightcrew is advised of the potential hazard
related to failures of the emergency direct current (DC)/alternating
current (AC) bus power supply, and the procedures necessary to
address it, accomplish the following:
(a) For all airplanes: Within 7 days after the effective date of
this AD, revise the Abnormal Procedures section of the FAA-approved
Airplane Flight Manual (AFM) to include the following statement.
This may be accomplished by inserting a copy of this AD in the AFM.
``Section 4--Abnormal Procedures Add to Sub-section 4.04--
Electrical Power
STANDBY ANNUNCIATOR PANEL RED AC SUPPLY LIGHT ``ON''
On overhead electric panel:
GEN LOAD--CHECK
If all generator loads are approximately zero:
LOSS OF AC SUPPLY PROCEDURE--APPLY
If not all generator loads are approximately zero:
DC EMER BUS SUPPLY TRU3 CIRCUIT BREAKER--CHECK
If circuit breaker has tripped:
DC EMER BUS SUPPLY TRU3 CIRCUIT BREAKER--RESET
--If reset is unsuccessful:
L and R AUDIO--ALTN
Anticipate the effects of an eventual EMER DC BUS failure, see
EMER DC BUS FAULT procedure.
If circuit breaker has not tripped:
L and R AUDIO--ALTN
Anticipate the effects of an eventual EMER DC BUS failure, see
EMER DC BUS FAULT procedure.''
(b) For all airplanes: Within 7 days after the effective date of
this AD, revise the Normal Procedures section of the FAA-approved
AFM to include the following statement. This may be accomplished by
inserting a copy of this AD in the AFM.
``Section 5--Normal Procedures Insert in front of Sub-section
5.01.01--Take-off
After engine start, select the Standby Annunciator
Panel (SAP) backup mode ON via the BACKUP p/b at the SAP.
Keep the SAP in the backup mode for the whole duration
of flight until engine shutdown.
Monitor the SAP.
Note: Failure conditions as presented on the SAP bypass the
Flight Warning Computer (FWC) and are not subject to alert
inhibition. Be aware that the red LG light on the SAP will
illuminate in case one or both thrustlever(s) are below the minimum
take-off position and the landing gear is not down.''
(c) For all Model F28 Mark 0070 series airplanes; and for all
Model F28 Mark 0100 in pre-SBF100-24-009 configuration or in post
SBF100-24-030 configuration: Within 7 days after the effective date
of this AD, revise the Abnormal Procedures section of the FAA-
approved Airplane Flight Manual (AFM) to include the following
statement. This may be accomplished by inserting a copy of this AD
in the AFM.
``Section 4--Abnormal Procedures Add to Sub-section 4.04--
Electrical Power
ERRATIC ELECTRICAL SYSTEM BEHAVIOR
In case of a continuous rattling sound, caused by the fast
switching of relays and accompanied by blanking or erratic behavior
of the three displays on the electric panel:
BATTERIES--SELECT MOMENTARILY OFF, THEN ON
AFFECTED SYSTEMS--RESTORE IF REQD
If the red AC SUPPLY light on the SAP comes ON:
SAP RED AC SUPPLY LIGHT `ON' PROCEDURE--APPLY''
(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: 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
Secs. 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.
(f) This amendment becomes effective on October 27, 1995.
Issued in Renton, Washington, on October 4, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-25160 Filed 10-11-95; 8:45 am]
BILLING CODE 4910-13-U
