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

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]

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