[Federal Register Volume 62, Number 11 (Thursday, January 16, 1997)]
[Proposed Rules]
[Pages 2324-2327]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1029]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 96-NM-269-AD]
RIN 2120-AA64
Airworthiness Directives; Fokker Model F28 Mark 0100 and 0070
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 all Fokker Model F28 Mark
0100 and 0070 series airplanes, that currently requires revising the
Airplane Flight Manual (AFM) 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. That AD was 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. This
action would require a new terminating modification for the existing
AFM revisions. This action would also require a new AFM revision to
inform the flightcrew that, under certain conditions, an ``EMER DC
BUS'' warning on the multi-function display unit (MFDU) will occur, and
to take appropriate corrective actions. The actions specified by the
proposed AD are intended to prevent failures of the emergency DC/AC bus
power supply, which could reduce the ability of the flightcrew to
control the airplane.
DATES: Comments must be received by February 25, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-269-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 Service B.V., Technical Support Department, P.O.
Box 75047, 1117 ZN
[[Page 2325]]
Schipol Airport, The Netherlands. 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) 227-1149.
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.
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 96-NM-269-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. 96-NM-269-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On October 4, 1995, the FAA issued AD 95-21-10, amendment 39-9396
(60 FR 53110, October 12, 1995), applicable to all Fokker Model F28
Mark 0100 and 0070 series airplanes. That AD requires revising the
Abnormal and Normal Procedures Sections of the FAA-approved Airplane
Flight Manual (AFM) 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. That action was 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
requirements of that 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.
In the preamble to AD 95-21-10, the FAA specified that the actions
required by that AD were considered ``interim action'' and that the
manufacturer was developing a modification to positively address the
unsafe condition. The FAA indicated that it may consider further
rulemaking once the modification was developed, approved, and
available. The manufacturer now has developed such a modification, and
the FAA has determined that further rulemaking action is necessary;
this proposed AD follows from that determination.
Actions Since Issuance of Previous Rule
Since the issuance of that AD, Fokker has issued Service Bulletin
SBF100-24-032, dated September 12, 1996, which describes procedures for
modification of the DC bus transfer system. For certain airplanes, the
modification involves removal of diode CR3; replacement of the DC bus 1
circuit breaker and TRU 3 circuit breaker of the DC emergency bus
supply, and replacement of the essential circuit breaker of the AC bus
supply. The modification also involves replacement of the two battery
power contactors (BPC) with a single BPC and addition of a control
relay to the DC emergency bus system. For all airplanes, the
modification involves alteration of the wiring to detect a battery
drain. The modification will improve the switching logic of the
emergency DC bus. Accomplishment of this modification would eliminate
the need for the AFM revisions required by AD 95-21-10.
In addition, Fokker has developed procedural information, for
inclusion in the Abnormal Procedures Section of the AFM for the
affected airplanes, to inform the flightcrew that an ``EMER DC BUS''
warning on the multi-function display unit (MFDU) will occur when the
emergency DC bus is transferred to battery power, and to take
appropriate corrective actions.
Accomplishment of the modification and the new AFM revision will
positively address the unsafe condition identified as failures of the
emergency DC/AC bus power supply, which could lead to loss of on-side
displays, autopilot, pressure control, and all communications; this
situation could reduce the ability of the flightcrew to control the
airplane.
The Rijksluchtvaartdienst (RLD), which is the airworthiness
authority for the Netherlands, classified these service bulletins and
the AFM revision as mandatory and issued Netherlands airworthiness
directive (BLA) 1995-089/4 (A), dated September 30, 1996, in order to
assure the continued airworthiness of these airplanes in the
Netherlands.
FAA's Conclusions
These airplanes are manufactured in the Netherlands and are 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 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 95-21-10. It
would continue to require 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 corrective actions. However, the
proposed AD also would require modification of the DC bus transfer
system, which would terminate the existing requirements for the AFM
revisions. The modification would be required to be accomplished in
accordance with the service bulletin described previously.
Following accomplishment of the modification, the proposed AD also
would require revising the Abnormal Procedures Section of the AFM to
inform the flightcrew that an ``EMER DC BUS'' warning on the multi-
function
[[Page 2326]]
display unit (MFDC) will occur when the emergency DC bus is transferred
to battery power, and to take appropriate corrective actions.
Cost Impact
There are approximately 132 Fokker Model F28 Mark 0100 and 0070
series airplanes of U.S. registry that would be affected by this
proposed AD.
The actions that are currently required by AD 95-21-10, and
retained in this proposed AD, 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 $7,920, or $60 per
airplane.
The modification of the DC bus transfer system that is proposed in
this new AD would take approximately 17 (Part 1) or 5 (Part 2) work
hours per airplane to accomplish, at an average labor rate of $60 per
work hour. The cost of required parts could range from $160 to as much
as $2,360 per airplane. Based on these figures, the cost impact of the
modification proposed by this AD on U.S. operators is estimated to be
between $460 and $3,380 per airplane.
The AFM revision that is proposed in this new AD 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 AFM revision proposed by this AD on U.S. operators is
estimated to be $7,920, or $60 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, 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 39-9396 (60 FR
53110, October 12, 1995), and by adding a new airworthiness directive
(AD), to read as follows:
Fokker: Docket 96-NM-269-AD. Supersedes AD 95-21-10, Amendment 39-
9396.
Applicability: All Model F28 Mark 0100 and 0070 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
otherwise 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 (g) 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 failures of the emergency DC/AC bus power supply,
which could reduce the ability of the flightcrew to control the
airplane, accomplish the following:
RESTATEMENT OF ACTIONS REQUIRED BY AD 95-21-10, AMENDMENT 39-9396
Note 2: For Model F28 Mark 0070 series airplanes, on which the
procedures specified in Fokker Service Bulletins SBF100-24-033 and
SBF100-24-034 have been accomplished, the AFM revisions required by
paragraphs (a), (b), and (c) of this AD may be removed from the AFM.
Note 3: For Model F28 Mark 0100 series airplanes, on which the
procedures specified in Fokker Service Bulletin SBF100-24-030 have
not been accomplished, or on which the procedures specified in
Fokker Service Bulletin SBF100-24-033 have been accomplished; the
AFM revisions required by paragraphs (a), (b), and (c) of this AD
may be removed from the AFM.
(a) For all airplanes: Within 7 days after October 27, 1995 (the
effective date of AD 95-21-10, amendment 39-9396), 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 electrical 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 October 27, 1995,
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) 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 Model F28
Mark 0100 series
[[Page 2327]]
airplanes, in pre-SBF100-24-009 configuration or in post SBF100-24-
030 configuration: Within 7 days after October 27, 1995, revise the
Abnormal 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 4--Abnormal Procedures
Add to Sub-section 4.04--Electrical Power
ERRATIC ELECTRICAL SYSTEM BEHAVIOR
In case of 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''
NEW ACTIONS REQUIRED BY THIS AD
(d) For Model F28 Mark 0070 and 0100 series airplanes, as listed
in Fokker Service Bulletin SBF100-24-032, dated September 12, 1996:
Within 12 months after the effective date of this AD, modify the DC
bus transfer system in accordance with Fokker Service Bulletin
SBF100-24-032, dated September 12, 1996. Prior to further flight
following accomplishment of this modification, accomplish paragraph
(e) of this AD.
Note 4: For Fokker Model F28 Mark 0070 series airplanes, Fokker
Service Bulletin SBF100-24-032 recommends prior or concurrent
accomplishment of the procedures specified in Fokker Service
Bulletin SBF100-24-034, dated October 17, 1995, or Revision 1, dated
September 12, 1996 (which is currently required by AD 96-26-03,
amendment 39-9866).
(e) Revise the Abnormal 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 4--Abnormal Procedures
Sub-section 4.04.05--Electrical Power--Bus Equipment List
Insert a marker {time} in each Bus Equipment List table, at the
top of the column marked: EMERGENCY--DC.
Add the following note at the beginning of the affected sub-
section:
Note: {time} When an ``EMER DC BUS'' fault is presented on the
multi-function display unit (MFDU), check whether the electric panel
digital readouts are operative.
If operative, the EMER DC bus is supplied from the
battery chargers via the batteries for 90 minutes and all services
connected to this bus will remain available. After this time period,
batteries will start to discharge and the effects of an EMER DC BUS
fault should then be expected.
If inoperative, continue with the EMER DC BUS FAULT
procedure.
At the bottom of each succeeding page (Bus Equipment List table)
of sub-section 4.04.05, make a clear reference to the note marked
{time} located at the beginning of sub-section 4.04.05.''
(f) Accomplishment of the modification in accordance with
paragraph (d) of this AD constitutes terminating action for the
requirements of paragraphs (a), (b), and (c) of this AD. After the
modification has been accomplished, the previously required AFM
revision may be removed from the AFM.
(g) 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, 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 5: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Standardization Branch, ANM-113.
(h) 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 January 9, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-1029 Filed 1-15-97; 8:45 am]
BILLING CODE 4910-13-U
