Airworthiness Directives; Fokker Model F28 Mark 0100 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-58-AD]

Airworthiness Directives; Fokker Model F28 Mark 0100 Series

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness

directive (AD) that is applicable to certain Fokker Model F28 Mark 0100

series airplanes. This proposal would require modification of the

thrust reverser doors, and replacement of the Collins multifunction

display units (MFDU) with new MFDU's. This proposal would also require

installation of a placard, for certain airplanes. This proposal is

prompted by a report that cracks were found in the flanges of the main

hinge fittings of the horizontal stabilizer due to higher than

anticipated loads induced during thrust reverser operation. The actions

specified by the proposed AD are intended to ensure structural

integrity of the horizontal stabilizer by reducing the thrust reverser

loads on the horizontal stabilizer.

DATES: Comments must be received by January 16, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 95-NM-58-AD, 1601 Lind Avenue SW., Renton,

Washington 98055-4056. Comments

[[Page 62052]]

may be inspected at this location between 9 a.m. and 3 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: 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 95-NM-58-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-58-AD, 1601 Lind Avenue SW., Renton, Washington 98055-

4056.

Discussion

The Rijksluchtvaartdienst (RLD), which is the airworthiness

authority for the Netherlands, recently notified the FAA that an unsafe

condition may exist on certain Fokker Model F28 Mark 0100 series

airplanes. The RLD advises that, during full scale fatigue testing of

the horizontal and vertical stabilizers, cracks were found in the

flanges of the left- and right-hand main hinge fittings of the

horizontal stabilizer on a Model F28 Mark 0100 test article.

Investigation revealed that such cracking is the result of higher than

anticipated loads induced on the tail of the airplane during thrust

reverser operation. This condition, if not corrected, could lead to a

deteriorated fatigue life of the main hinge fitting structure on the

horizontal stabilizer and reduced structural integrity of the

horizontal stabilizer.

Fokker has issued Service Bulletin SBF100-78-010, Revision 1, dated

April 26, 1994, which describes procedures for modification of the

thrust reverser doors. This modification involves installation of

extended bumper fittings on the thrust reverser doors. Accomplishment

of this modification will reduce the reverse thrust at a given engine

pressure ratio by increasing the spillage gap.

Fokker has also issued Service Bulletin SBF100-31-036, dated

February 7, 1994, which describes procedures for replacement of the

Collins multifunction display units (MFDU) having part number (P/N)

622-8047-412 or 622-8047-422 with new MFDU's having P/N 622-8047-414 or

622-8047-423, respectively. Accomplishment of this replacement will

reduce thrust reverser loads on the horizontal stabilizer.

Additionally, Fokker has issued Service Bulletin SBF100-31-038,

dated April 26, 1994, which describes procedures for installation of a

placard on the main instrument panel, if the replacement of the MFDU is

accomplished prior to modification of the thrust reverser door. The

placard provides current engine limits for these airplanes.

The RLD classified these service bulletins as mandatory and issued

Netherlands airworthiness directive BLA 94-062(A), dated April 29,

1994, in order to assure the continued airworthiness of these airplanes

in the Netherlands.

This airplane model is manufactured in the Netherlands and is 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.

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 require modification of the

thrust reverser doors. The proposed AD would also require replacement

of certain Collins multifunction display units (MFDU) with certain new

MFDU's, and installation of a placard, if the replacement of the MFDU

is accomplished prior to modification of the thrust reverser door. The

actions would be required to be accomplished in accordance with the

service bulletins described previously.

The FAA estimates that 102 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 127 work

hours per airplane to accomplish the proposed actions, and that the

average labor rate is $60 per work hour. Required parts would cost

approximately $19,000 per airplane. Based on these figures, the cost

impact of the proposed AD on U.S. operators is estimated to be

$2,715,240, or $26,620 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.

[[Page 62053]]

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), 40101, 40113, 44701.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new

airworthiness directive:

Fokker: Docket 95-NM-58-AD.

Applicability: Model F28 Mark 0100 series airplanes; serial

numbers 11244 through 11460 inclusive, 11463 through 11469

inclusive, 11471, 11474, 11476, 11478, and 11479; 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 use the authority

provided in paragraph (d) of this AD to request approval from the

FAA. This approval may address either no action, if the current

configuration eliminates the unsafe condition; or different actions

necessary to address the unsafe condition described in this AD. Such

a request should include an assessment of the effect of the changed

configuration on the unsafe condition addressed by this AD. In no

case does the presence of any modification, alteration, or repair

remove any airplane from the applicability of this AD.

Compliance: Required as indicated, unless accomplished

previously.

To ensure structural integrity of the horizontal stabilizer by

reducing the thrust reverser loads on the horizontal stabilizer,

accomplish the following:

(a) Prior to the accumulation of 15,000 total flight cycles, or

within 1 year after the effective date of this AD, whichever occurs

later, accomplish the requirements of paragraphs (a)(1) and (a)(2)

of this AD concurrently, except as provided by paragraph (b) of this

AD.

(1) Modify the thrust reverser doors in accordance with Fokker

Service Bulletin SBF100-78-010, Revision 1, dated April 26, 1994;

and

(2) Replace the Collins multifunction display units (MFDU)

having part number (P/N) 622-8047-412 or 622-8047-422 with new

MFDU's having P/N 622-8047-414 or 622-8047-423, respectively; as

applicable; in accordance with Fokker Service Bulletin SBF100-31-

036, dated February 7, 1994.

(b) Paragraph (a)(2) of this AD may be accomplished prior to

paragraph (a)(1) of this AD provided that a placard is installed on

the main instrument panel in accordance with Fokker Service Bulletin

SBF100-31-038, dated April 26, 1994, and removed, prior to further

flight, after accomplishment of the requirements of paragraph (a)(1)

of this AD.

(c) For airplanes that have been modified in accordance with

paragraphs (a)(1) and (a)(2) of this AD: No person may install a

Grumman Aerospace aft engine cowling having part number 1159P41440

on any airplane unless it has been previously modified in accordance

with Fokker Component Service Bulletin P41440-78-02, dated December

17, 1993, as revised by Fokker Component Service Bulletin Change

Notification P41440-78-02/001, dated February 25, 1995.

(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, 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 November 28, 1995.

S. R. Miller,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 95-29443 Filed 12-1-95; 8:45 am]

BILLING CODE 4910-13-U