Airworthiness Directives; Fokker Model F28 Mark 0100 Series Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-113-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 fixed

engine cowling at the forward and aft crane beam attachment; and an

inspection of the forward and aft crane beam to detect surface damage,

and repair, if necessary. This proposal is prompted by several reports

of rear cabin noise (engine rumble) during flight and while taxiing,

which may have been caused by the interference between the forward and

aft crane beams and the fasteners in the fixed engine cowling. The

actions specified by the proposed AD are intended to prevent chafing

due to normal engine vibration, which could result in structural damage

to the engine mount and possible separation of the engine from the

airplane.

DATES: Comments must be received by November 10, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 94-NM-113-AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056. Comments 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) 227-1320.

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 94-NM-113-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. 94-NM-113-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 it has received several reports of rear

cabin noise (engine rumble) experienced on these airplanes during

flight and while taxiing. Investigation revealed that one possible

cause was interference between the forward and aft crane beams and the

fasteners in the fixed engine cowling. Such interference could result

in chafing due to normal engine vibration. This condition, if not

corrected, could result in structural damage to the engine mount and

possible separation of the engine from the airplane.

Fokker has issued Service Bulletin SBF100-71-016, dated February

18, 1994, which describes procedures for modification of the fixed

engine cowling at the forward and aft crane-beam attachment; and a

visual inspection of the forward and aft crane beam to detect surface

damage, and repair, if necessary. This modification entails replacing

fasteners of the fixed engine cowling with fasteners of a different

type. This modification will ensure the structural integrity of the

engine mount. The RLD classified this service bulletin as mandatory and

issued Netherlands Airworthiness Directive BLA 94-038 (A), dated

February 21, 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

fixed cowl at the forward and aft crane-beam attachment; and performing

a visual inspection of the forward and aft crane beam to detect surface

damage, and repair, if necessary. The actions would be required to be

accomplished in accordance with the service bulletin described

previously.

The FAA estimates that 83 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 90 work

hours per airplane to accomplish the proposed inspection and

modification, and that the average labor rate is $55 per work hour.

Required parts would cost approximately $75 per airplane. Based on

these figures, the total cost impact of the proposed AD on U.S.

operators is estimated to be $417,075, or $5,025 per airplane.

The total 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 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.

106(g); and 14 CFR 11.89.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new

airworthiness directive:

Fokker: Docket 94-NM-113-AD.

Applicability: Model F28 Mark 0100 series airplanes, serial

numbers 11244 through 11438 inclusive, certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent structural damage to the engine mount and possible

separation of the engine from the airplane, accomplish the

following:

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

within 3 months after the effective date of this AD, whichever

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

(a)(2) of this AD in accordance with Fokker Service Bulletin SBF100-

71-016, dated February 18, 1994.

(1) Modify the fixed engine cowling at the forward and aft

crane-beam attachment in accordance with the service bulletin.

(2) Perform a visual inspection of the forward and aft crane

beam to detect surface damage, in accordance with the service

bulletin.

(i) If no surface damage is found, no further action is required

by paragraph (a)(2) of this AD.

(ii) If any surface damage is found, prior to further flight,

repair the crane beam in accordance with the service bulletin.

(b) 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: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Standardization Branch, ANM-113.

(c) 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 September 26, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-24202 Filed 9-29-94; 8:45 am]

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