[Federal Register Volume 61, Number 29 (Monday, February 12, 1996)]
[Proposed Rules]
[Pages 5329-5331]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-2997]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-29-AD]


Airworthiness Directives; Fokker Model F28 Mark 0100 and 0070 
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 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 AD also would have required modification of certain electrical 
wiring, and replacement of the pitot head and a certain relay. This 
action revises the proposed rule by adding a new requirement to replace 
the pitot heating system with a new improved system, in lieu of 
modifying the electrical wiring and replacing the pitot head and relay. 
This action also revises the applicability of the proposed rule to 
include additional airplanes. 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 March 4, 1996.

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 Aircraft USA, Inc., 1199 North Fairfax Street, 
Alexandria, Virginia 22314. This information may be examined at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Timothy 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 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 series airplanes, was published as a 
notice of proposed rulemaking (NPRM) in the Federal Register on April 
18, 1995 (60 FR 19383). That NPRM would have required a one-time 
operational test of the No. 1 pitot heating system, and repair or 
replacement of failed elements. That AD also would have required 
modification of certain electrical wiring, replacement of the pitot 
head with a new pitot head, and replacement of the single direct 
current (DC) current-sensing relay with two new DC current sensing 
relays. That NPRM was prompted by reports indicating that the No. 1 Air 
Data Computer (ADC #1) failed on Model F28 Mark 0100 series airplanes 
due to icing at the No. 1 pitot tube. 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).
    Since the issuance of that NPRM, one operator has reported that 
several failures of the captain's airspeed indicator and ADC #1 have 
occurred during encounters with severe icing. These failures were 
accompanied by a malfunction alert from all on-side subsidiary systems; 
however, no failures of the pitot heating system were reported. 
Subsequent investigation revealed that the DC heating capacity of the 
captain's pitot tube is inadequate to prevent freezing of the pitot 
tube in severe icing conditions.
    The captain's DC powered pitot heating systems installed on Fokker 
Model F28 Mark 0100 series airplanes are also installed on certain 
Fokker Model F28 Mark 0070 series airplanes; therefore, those airplanes 
are also 

[[Page 5330]]
subject to the addressed unsafe condition.
    Additionally, since the issuance of that NPRM, Fokker has issued 
Service Bulletin SBF100-30-017, dated August 23, 1995. This service 
bulletin describes procedures for replacement of the captain's pitot 
heating system with a new improved pitot heating system. This 
replacement involves a new pitot tube that has an alternating current 
(AC) powered heating system, that will prevent freezing of the 
captain's pitot tube during severe icing conditions. (This pitot 
heating system is the same system as that currently used on the First 
Officer's position and auxiliary systems.) The effectivity of this 
service bulletin includes certain additional Model F28 Mark 0100 series 
airplanes, and certain Model F28 Mark 0070 series airplanes, that are 
subject to the unsafe condition. (These airplanes were not identified 
in the original NPRM.) The Rijksluchtvaartdienst (RLD), which is the 
airworthiness authority for the Netherlands, approved this service 
bulletin and issued Netherlands airworthiness directive BLA 1994-114/
3(A), dated September 29, 1995, in order to assure the continued 
airworthiness of these airplanes in the Netherlands.
    The FAA has examined the findings of the RLD and reviewed the new 
service information. The FAA finds that the actions proposed in 
paragraph (b) of the original NPRM will not prevent freezing of the 
pitot head during severe icing conditions. Therefore, to ensure safety 
of the fleet, the FAA finds that replacement of the pitot heating 
system with new improved pitot heating system, as specified in Fokker 
Service Bulletin SBF100-30-017, dated August 23, 1995, is necessary. 
The FAA has revised paragraph (b) of this supplemental NPRM 
accordingly.
    In addition, the FAA has revised the applicability of this proposed 
rule to include airplanes as listed in Fokker Service Bulletin SBF100-
30-017, dated August 23, 1995.
    Since this change expands 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.
    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 FAA has determined that accomplishment of 
this operational test is necessary to determine if any pitot tube 
heating element is inoperative, and to ensure that any failed element 
is repaired or replaced.
    The FAA estimates that 129 airplanes of U.S. registry would be 
affected by this proposed AD. It would take approximately 1 work hour 
per airplane to accomplish the operational test and 36 work hours to 
accomplish the replacement, at an average labor rate of $60 per work 
hour. Required replacement parts would cost approximately $10,500 per 
airplane. Based on these figures, the cost impact of the proposed AD on 
U.S. operators is estimated to be $1,640,880, or $12,720 per airplane.
    The cost impact figure discussed above is 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.
    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 USC 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 0100 and 0070 series airplanes; as 
listed in Fokker SBF100-30-015, Revision 2, dated January 25, 1995, 
and Fokker Service SBF100-30-017, dated August 23, 1995; 
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 (c) 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 listed in Fokker SBF100-30-015, Revision 2, 
dated January 25, 1995: 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 that service bulletin.
    (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 all airplanes: Replace the No. 1 pitot heating system 
with a new pitot heating system, in accordance with Part 1, 2, 3, or 
4 of the Accomplishment Instructions of Fokker Service Bulletin 
SBF100-30-017, dated August 23, 1995. Accomplish this action at the 
time specified in paragraph (b)(1) or (b)(2) of this AD, as 
applicable.
    (1) For airplanes that are equipped with a Flight Warning System 
(FWS) speed comparator that is not activated, and a Rosemount type 
853JB No. 1 pitot heating system: Accomplish the replacement within 
9 months after the effective date of this AD.
    (2) For airplanes that are equipped either with an FWS speed 
comparator that is activated, or with a Rosemount type 853KK No. 1 
pitot heating system: Accomplish the replacement within 18 months 
after the effective date of this AD. 

[[Page 5331]]

    (c) 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.

    (d) 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 February 6, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-2997 Filed 2-9-96; 8:45 am]
BILLING CODE 4910-13-U