[Federal Register Volume 62, Number 22 (Monday, February 3, 1997)]
[Proposed Rules]
[Pages 4944-4946]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-2520]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-29-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain Fokker Model F28 Mark 0070 and 
0100 series airplanes, that would have required a one-time operational 
test of the pitot heating system, and repair or replacement of failed 
elements. That action also proposed to require the replacement of the 
pitot heating system with a new improved system. This new action would 
revise the proposal by adding a requirement to install power supply 
wiring with increased gauge thickness and a circuit breaker with an 
increased amperage rating. This action also would add additional 
airplanes to the applicability of the rule. The actions specified by 
this proposed AD are intended to prevent icing of the No. 1 pitot tube, 
which could result in failure of the No. 1 Air Data Computer, or output 
of erroneous airspeed data to all on-side subsidiary systems, including 
the Automatic Flight Control and Augmentation System.

DATES: Comments must be received by February 24, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-29-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: 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

[[Page 4945]]

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 95-NM-29-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. 95-NM-29-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to 
certain Fokker Model F28 Mark 0100 and 0070 series airplanes, was 
published as a supplemental notice of proposed rulemaking (NPRM) in the 
Federal Register on February 12, 1996 (61 FR 5329). That supplemental 
NPRM proposed to require a one-time operational test of the pitot 
heating system, and repair or replacement of failed elements. That 
supplemental NPRM also proposed to require the replacement of the No. 1 
pitot heating system powered by direct current (DC) with a new improved 
pitot heating system powered by alternating current (AC). That 
supplemental NPRM was prompted by reports indicating that the captains 
airspeed indicator and the No. 1 Air Data Computer (ADC #1) failed on 
Model F28 Mark 0100 series airplanes due to icing of the No. 1 pitot 
tube, even though both DC-powered heating elements were operating 
normally. Icing of the No. 1 pitot heat system, if not corrected, could 
result in failure of the ADC #1, or lead to output of erroneous data to 
all on-side subsidiary systems, including the Automatic Flight Control 
and Augmentation System (AFCAS).

Actions Since Issuance of Previous Proposal

    Since the issuance of that supplemental NPRM, the 
Rijksluchtvaartdienst (RLD), which is the airworthiness authority for 
the Netherlands, and Fokker have notified the FAA that during emergency 
power conditions (battery power only), the new AC-powered (853BR) pitot 
tube described in Fokker Service Bulletin SBF100-30-017 may not de-ice 
sufficiently due to a low DC battery voltage input to the No. 1 pitot 
tube inverter. The low voltage is due to insufficient thickness of the 
wire gauge of the power supply wiring. Additionally, during emergency 
power conditions, the inverter draws more current to maintain the 
specified power to the pitot tube, which could trip the No. 1 pitot 
heating circuit breaker.
    In light of this information, the actions proposed in the previous 
proposal would be inadequate to prevent icing of the No. 1 pitot tube, 
and the same unsafe condition would continue to exist.

New Service Information

    In light of the above, Fokker has issued Service Bulletin SBF100-
30-019, dated June 20, 1996, which supersedes Fokker Service Bulletin 
SBF100-30-017 (which was referenced in the previous supplemental NPRM). 
This new service bulletin describes procedures for:
    1. Replacement of the captains pitot heating system with type 853BR 
pitot heating system,
    2. Installation of a new power supply wiring with increased gauge 
thickness of AWG 12, and
    3. Installation of a new No. 1 pitot tube circuit breaker with an 
increased amperage rating to 20 Amps.
    Accomplishment of these actions will ensure that the No. 1 pitot 
tubes have adequate de-icing capability.
    Fokker also has issued Service Bulletin SBF100-30-020, dated June 
20, 1996, which describes procedures for installation of new power 
supply wiring with increased gauge thickness of AWG 12, and a new No. 1 
pitot tube circuit breaker with an increased amperage rating of 20 
Amps, for those airplanes on which type 853BR pitot heating system has 
previously been installed in accordance with Fokker Service Bulletin 
SBF100-30-017.
    The RLD classified these service bulletins as mandatory and issued 
Netherlands airworthiness directive BLA 1994-114/4 (A), dated July 31, 
1996, in order to assure the continued airworthiness of these airplanes 
in the Netherlands.


FAA's Conclusions

    The FAA has examined the findings of the RLD and reviewed the new 
service information. The FAA finds that the proposed actions in the 
previously issued supplemental NPRM may not prevent freezing of the No. 
1 pitot tube during emergency power conditions. Therefore, to ensure 
the safety of the fleet, the FAA finds that, in addition to the 
previously proposed actions, other actions are necessary.

Explanation of Requirements of Proposed AD

    This new action proposes to continue to require operational tests 
of the No. 1 pitot heating system and replacement of the pitot heating 
system with a new improved system. This new action would add a 
requirement to install a new power supply wiring with increased gauge 
thickness, and a circuit breaker with an increased amperage rating. 
These new proposed requirements would affect airplanes on which the new 
improved pitot heating system has been installed previously (in 
accordance with Fokker Service Bulletin SBF100-30-017). In addition, 
this new proposal would add additional airplanes to the applicability 
of the rule. These actions would be required to be accomplished in 
accordance with the applicable service bulletins described previously.
    Operators should note that the operational test of the No. 1 pitot 
heating system, as proposed previously, continues to be required in 
this supplemental NPRM. The service information describing that 
operational test (referenced as Fokker Service Bulletin SBF100-30-015, 
Revision 2, dated January 25, 1995, in the previous proposal) has been 
superseded by a later service bulletin (Fokker Service Bulletin SBF100-
30-017, dated August 23, 1995, which was superseded by Fokker Service 
Bulletin SFB100-30-019); but the procedures for accomplishing the 
operational test were not included in the superseding service 
bulletins. However, the FAA has determined that accomplishment of this 
operational test is necessary in accordance with Fokker Service 
Bulletin SBF100-30-015 to determine if any pitot tube heating element 
is inoperative, and to ensure that any failed element is repaired or 
replaced.

Conclusion

    Since these changes expand the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

Cost Impact

    There are approximately 285 Fokker Model F28 Mark 0100 and 0070 
series airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 129 airplanes of U.S. registry would be affected by this 
proposed AD.
    The proposed operational check would take approximately 1 work hour 
per airplane to accomplish, at an average labor rate of $60 per work 
hour.

[[Page 4946]]

Based on these figures, the cost impact for the proposed operational 
check on U.S. operators is estimated to be $7,740, or $60 per airplane.
    The proposed replacement of the pitot heating system would take 
approximately 36 work hours per airplane, at an average labor rate of 
$60 per work hour. Required parts would cost approximately $16,000 per 
airplane. Based on these figures, the cost impact of the proposed AD on 
U.S. operators is estimated to be $18,160 per airplane.
    For airplanes on which replacement of the pitot heating system has 
been accomplished previously, the proposed installation of the power 
supply electrical wiring and circuit breaker would take approximately 
12 work hours per airplane at an average labor rate of $60 per work 
hour. Required parts would cost approximately $350 per airplane. Based 
on these figures, the cost impact is estimated to be $1,070 per 
airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the 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 adding the following new 
airworthiness directive:

Fokker: Docket 95-NM-29-AD.

    Applicability: Model F28 Mark 0070 and 0100 series airplanes, 
certificated in any category, and having the following serial 
numbers: 11244 through 11495, inclusive; 11497 through 11507, 
inclusive; 11509; 11511 through 11517, inclusive; 11519 through 
11523, inclusive; 11527 through 11529, inclusive; 11532; 11536 
through 11541, inclusive; 11543; 11545; 11547; 11549; 11551; 11553 
through 11565, inclusive; 11567; 11570; 11573; and 11574.

    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 (d) 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 icing of the No. 1 pitot tube, which could result in 
failure of the No. 1 Air Data Computer (ADC #1) or output of 
erroneous airspeed data to all on-side subsidiary systems, including 
the Automatic Flight Control and Augmentation System (AFCAS), 
accomplish the following:
    (a) For airplanes that have type 853JB pitot tubes installed: 
Within 30 days after the effective date of this AD, perform an 
operational test of the No. 1 pitot heating system in accordance 
with Part 1 of the Accomplishment Instructions of Fokker Service 
Bulletin SBF100-30-015, Revision 2, dated January 25, 1995.
    (1) If the pitot heating system passes the operational test, 
accomplish the requirements of either paragraph (b)(1) or (b)(2) of 
this AD, as applicable, at the times specified.
    (2) If any pitot tube heating element is found to be 
inoperative, prior to further flight, repair or replace the failed 
element with a serviceable element, in accordance with the Fokker 
100 Aircraft Maintenance Manual (AMM).
    (b) For airplanes on which Fokker Service Bulletin SBF100-30-
017, dated August 23, 1995, has not been accomplished: At the 
applicable time specified in either paragraph (b)(1) or (b)(2) of 
this AD, replace the type 853JB or type 853KK No. 1 pitot tube, with 
a type 853BR pitot tube; and install the inverter, current sensor, 
wiring, and circuit breaker; in accordance with Fokker Service 
Bulletin SBF100-30-019, dated June 20, 1996.
    (1) For airplanes with the flight warning system (FWS) speed 
comparator not activated and with a type 853JB No. 1 pitot tube 
installed: Accomplish the replacement within 9 months after the 
effective date of this AD.
    (2) For airplanes with the FWS speed comparator activated or 
with a type 853KK No. 1 pitot tube installed: Accomplish the 
replacement within 18 months after the effective date of this AD.
    (c) For airplanes on which Fokker Service Bulletin SBF100-30-
017, dated August 23, 1995, has been accomplished, either in service 
or factory-incorporated: Within 18 months after the effective date 
of the AD, replace the No. 1 pitot heating circuit breaker and 
modify the power supply electrical wiring, in accordance with Fokker 
Service Bulletin SBF100-30-020, dated June 20, 1996.
    (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, 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.

    (e) 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 27, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-2520 Filed 1-31- 97; 8:45 am]
BILLING CODE 4910-13-P