[Federal Register Volume 63, Number 25 (Friday, February 6, 1998)]
[Rules and Regulations]
[Pages 6066-6069]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-2825]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-269-AD; Amendment 39-10310; AD 98-03-18]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes 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. This amendment requires a new terminating modification for the 
existing AFM revisions. This amendment also requires 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. This amendment is prompted by 
the issuance of mandatory continuing airworthiness information by a 
foreign civil airworthiness authority. The actions specified by this 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: Effective March 23, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 23, 1998.

ADDRESSES: The service information referenced in this AD 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 Federal Aviation Administration (FAA), Transport 
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
Washington; or at the Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC.

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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 95-21-10, 
amendment 39-9396 (60 FR 53110, October 12, 1995), which is applicable 
to all Fokker Model F28 Mark 0100 and 0070 series airplanes, was 
published in the Federal Register on January 16, 1997 (62 FR 2324). The 
action proposed to supersede AD 95-21-10 to continue to require 
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. The action also proposed to require a 
modification of the DC bus transfer system, which would terminate the 
existing requirements for the AFM revisions. In addition, the action 
proposed to require revising the Abnormal Procedures Section of the AFM 
to inform the flightcrew that an ``EMER DC BUS'' warning on the multi-
function display unit (MFDC) will occur when the emergency DC bus is 
transferred to battery power, and to take appropriate corrective 
actions.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request to Revise Cost Impact Information

    One commenter supports the proposed rule, but estimates that the 
modification required by this AD will cost $4,250 per airplane, which 
is more than the $3,380 per airplane estimate in the proposed rule.
    The FAA infers that the commenter requests that the cost impact 
information for this AD be revised. The FAA agrees that cost impact of 
the required modification is more than the estimated $3,380 per 
airplane contained in the proposed rule. Since issuance of the Notice 
of Proposed Rulemaking (NPRM), Fokker has issued Service Bulletin 
SBF100-24-032, Revision 1, dated April 25, 1997, and Revision 2, dated 
July 28, 1997, to correct minor errors, and to revise the work hour 
estimates and part cost estimates for accomplishment of the 
modification. The estimate for accomplishment of Part 1 of the 
Accomplishment Instructions of the service bulletin has been changed

[[Page 6067]]

from 17 work hours to 22 work hours, and the estimate for 
accomplishment of Part 2 of the Accomplishment Instructions of the 
service bulletin has been changed from 5 work hours to 13 work hours. 
In addition, the estimate for parts costs has been changed from a range 
of $160 to $2,360, to a range of $160 to $2,580. The FAA has revised 
the cost impact information, below, accordingly.
    The FAA has determined that accomplishment of the modification in 
accordance with the original issue, Revision 1, or Revision 2 of Fokker 
Service Bulletin SBF100-24-032 adequately addresses the identified 
unsafe condition. Therefore, this AD has been revised to include Fokker 
Service Bulletin SBF100-24-032, Revision 1, dated April 25, 1997, and 
Revision 2, dated July 28, 1997, as additional sources of service 
information.

Request To Extend Compliance Time for Modification

    The Air Transport Association (ATA) of America, on behalf of one of 
its members, requests that the compliance time for accomplishing the 
modification be extended from the proposed 12 months to 18 months. The 
commenter states that if it is forced to meet the proposed 12-month 
compliance schedule, approximately 20 of the 40 affected airplanes in 
its fleet would require modification in a line environment or during 
unscheduled heavy maintenance visits. The commenter noted that this 
would result in significant additional costs. In addition, the 
commenter states that the modification would be difficult to accomplish 
during routine overnight line station maintenance due to the complexity 
of the task and accessibility. The commenter also noted that the 
elapsed time to accomplish the modification will be twice the service 
bulletin estimate of 8 hours, since only one person at a time could 
work on this modification. The commenter further noted that only three 
diode failures have been experienced on its affected fleet of airplanes 
since operation commenced in 1989. The commenter considers that this 
relatively low failure rate also supports its request for an extension 
of the compliance time.
    The FAA does not concur with the commenter's request to extend the 
compliance time. In developing an appropriate compliance time for this 
action, the FAA considered not only the degree of urgency associated 
with addressing the subject unsafe condition, but the manufacturer's 
and foreign airworthiness authority's recommendations as to an 
appropriate compliance time, the availability of required parts, and 
the practical aspect of installing the required modification within an 
interval of time that parallels the normal scheduled maintenance for 
the majority of affected operators. The FAA has determined that the 
compliance time, as proposed, represents the maximum interval of time 
allowable for the affected airplanes to continue to operate prior to 
accomplishing the required modification without compromising safety. 
The commenter has not provided data to substantiate why an extension of 
the compliance time would not compromise safety. The failure rate data 
of a single operator does not substantiate why an extension of the 
compliance time would not compromise safety.
    In consideration of all of these factors, and in consideration of 
the amount of time that has already elapsed since issuance of the 
original NPRM, the FAA has determined that further delay of this 
modification is not appropriate. However, under the provisions of 
paragraph (g) of the final rule, the FAA may approve requests for 
adjustments to the compliance time if data are submitted to 
substantiate that such an adjustment would provide an acceptable level 
of safety.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the changes previously 
described. The FAA has determined that these changes will neither 
significantly increase the economic burden on any operator nor increase 
the scope of the AD.

Cost Impact

    There are approximately 132 Fokker Model F28 Mark 0100 and 0070 
series airplanes of U.S. registry that will be affected by this AD.
    The actions that are currently required by AD 95-21-10 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 previously 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 required by 
this new AD will take approximately 22 (Part 1 of the Accomplishment 
Instructions of the service bulletin) or 13 (Part 2 of the 
Accomplishment Instructions of the service bulletin) work hours per 
airplane to accomplish, at an average labor rate of $60 per work hour. 
The cost of required parts will range from $160 to as much as $2,580 
per airplane. Based on these figures, the cost impact of the 
modification required by this AD on U.S. operators is estimated to be 
between $940 and $3,900 per airplane.
    The AFM revision that is required by 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 required 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 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 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.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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, Incorporation by 
reference, 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:

[[Page 6068]]

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), amendment 39-10310, to read as follows:

98-03-18  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 
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 direct current (DC)/
alternating current (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 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, 
or Revision 1, dated April 25, 1997, or Revision 2, dated July 28, 
1997: 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; or Revision 1, 
dated April 25, 1997; or Revision 2, dated July 28, 1997. 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, International Branch, ANM-116, FAA,

[[Page 6069]]

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 5: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the International Branch, ANM-116.

    (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.
    (i) The actions shall be done in accordance with the following 
Fokker service bulletins, which contain the specified effective 
pages:

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  Service bulletin referenced and                          Revision level shown                                 
               date                       Page No.               on page                Date shown on page      
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SBF100-24-032, September 12, 1996.  1-46................  Original.............  September 12, 1996.            
SBF100-24-032, Revision 1, April    1-4, 7-62...........  1....................  April 25, 1997.                
 25, 1997.                                                                                                      
                                    5-6.................  Original.............  September 12, 1996.            
SBF100-24-032, Revision 2, July     1-2, 13, 15, 29-30..  2....................  July 28, 1997.                 
 28, 1997.                                                                                                      
                                    3-4, 7-12, 14, 16-    1....................  April 25, 1997.                
                                     28, 31-62.                                                                 
                                    5-6.................  Original.............  September 12, 1996.            
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    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from Fokker Services B.V., Technical 
Support Department, P.O. Box 75047, 1117 ZN Schiphol Airport, the 
Netherlands. Copies may be inspected at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.

    Note 6: The subject of this AD is addressed in Dutch 
airworthiness directive BLA 1995-089/4, dated September 30, 1996.

    (j) This amendment becomes effective on March 23, 1998.

    Issued in Renton, Washington, on January 30, 1998.
Stewart R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-2825 Filed 2-5-98; 8:45 am]
BILLING CODE 4910-13-P