Airworthiness Directives; Fokker Model F-28 Mark 0100 Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-165-AD; Amendment 39-8885; AD 94-08-13]

Airworthiness Directives; Fokker Model F-28 Mark 0100 Series

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD),

applicable to certain Fokker Model F-28 Mark 0100 series airplanes,

that requires the installation of modified Flight Warning Computers and

Flight Augmentation Computers. This amendment is prompted by reports of

nuisance yaw-damper fault warnings and undetected horizontal trim

motion, and the development of improved computers that eliminate these

problems. The actions specified by this AD are intended to prevent

nuisance warnings in the cockpit and undetected trim motion, both of

which could compromise the safe takeoff of the airplane.

DATES: Effective May 20, 1994.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of May 20, 1994.

ADDRESSES: The service information referenced in this AD may be

obtained from Fokker Aircraft USA, Inc., 1199 North Fairfax Street,

Alexandria, Virginia 22314. This information may be examined at the

Federal Aviation Administration (FAA), Transport Airplane Directorate,

Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the

Office of the Federal Register, 800 North Capitol Street, NW., suite

700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mark Quam, Aerospace Engineer,

Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,

1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (206)

227-2145; fax (206) 227-1320.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations to include an airworthiness directive (AD) that is

applicable to certain Fokker Model F-28 Mark 0100 series airplanes was

published in the Federal Register on November 12, 1993 (58 FR 59968).

That action proposed to require the installation of modified Flight

Warning Computers (FWC) and Flight Augmentation Computers (FAC).

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the comments received.

One commenter supports the proposed rule.

Another commenter requests that the proposed rule be revised to

include an additional part-numbered FWC as an acceptable alternative

part for compliance. This commenter states that it has installed FWC's

having part number 80-0610-3-31, in accordance with Fokker Service

Bulletin SBF100-31-033, dated June 23, 1993, on its fleet of affected

airplanes. The FAA has reviewed this data and finds that FWC's having

part number 80-0610-3-31 are acceptable alternatives to those called

out in the proposal. The FAA has revised the final rule to indicate

that this.

This same commenter requests that the proposed rule be revised to

include the words ``or subsequent'' for all part numbers, so that

future designs of the components would be permitted to be installed as

alternatives to the specific part numbered components called out in the

AD. The FAA does not concur, since there would be no way to establish

that the inclusion of these words would prevent the installation of

incompatible components. For example, the ``Material Information''

portion of the referenced Fokker Service Bulletin SBF100-22-037,

concerning the replacement of FAC's, indicates that specific equipment

combinations (those having similar part numbers in the component

series) may not be compatible. For this reason, the FAA considers it

inappropriate to permit the indiscriminate installation of any future

component designs.

This same commenter requests that the proposed rule not require

accomplishment of the actions specifically in accordance with the

service bulletins; the service bulletins should be for reference only.

Although the commenter does not specify a particular reason for this

request, the FAA infers that (1) the commenter would like to install

improved or modified equipment versions of the same basic part number

series that may or may not be called out in a service bulletin; or (2)

the commenter would prefer that the rule permit installation of the

subject components in accordance with an operator's own methods. The

FAA does not concur. As for the first inference, the FAA has addressed

this in the previous paragraph. As for the second inference, the FAA

points out that the referenced service bulletins contain specific

wiring procedures necessary for installation of the components; the FAA

has determined that these procedures must be followed in order to

ensure proper installation.

After careful review of the available data, including the comments

noted above, the FAA has determined that air safety and the public

interest require the adoption of the rule with the change previously

described. The FAA has determined that this change will neither

increase the economic burden on any operator nor increase the scope of

the AD.

The FAA estimates that 27 airplanes of U.S. registry will be

affected by this AD.

Installation of the new FWC will require approximately 46 work

hours to accomplish, at an average labor charge of $55 per work hour.

Required parts will cost approximately $450 per airplane. Based on

these figures, the total cost impact of the FWC installation on U.S.

operators is estimated to be $2,980 per airplane.

The requirement to replace the FAC will vary, depending upon the

configuration of the FAC installed. Additionally, operators have a

choice of two different FAC's to use as replacement installations:

Should an operator elect to install an FAC having part number 622-

7478-401MOD11, it will require approximately 1 work hour to accomplish,

at an average labor charge of $55 per work hour. Required parts will be

provided at no cost to the operator. Based on these figures, the total

cost impact of this specific installation requirement on U.S. operators

would be $55 per airplane.

Should an operator elect to install an FAC having part number 622-

7478-411, it will require approximately 52 work hours to accomplish, at

an average labor charge of $55 per work hour. Required parts will cost

approximately $2,515 per airplane. Based on these figures, the total

cost impact of this specific FAC installation requirement on U.S.

operators is estimated to be $5,375 per airplane.

Based on the figures discussed above, the total cost impact of this

proposed AD on U.S. operators would be between $3,005 and $8,355 per

airplane, or between $81,135 and $225,585 for the entire U.S. fleet.

The total cost impact figures discussed above are based on

assumptions that no operator has yet accomplished any of the

requirements of this AD action, and that no operator would accomplish

those actions in the future if this AD were not adopted. However, the

FAA has been advised that at least one U.S. operator affected by the AD

has previously accomplished the required installations on most of its

fleet of airplanes. In light of this, the total future cost impact of

the rule is expected to be less than the figures indicated above.

The regulations adopted herein will 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 final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is

not a ``significant regulatory action'' under Executive Order 12866;

(2) is not a ``significant rule'' under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action

and it is contained in the Rules Docket. A copy of it may be obtained

from the Rules Docket at the location provided under the caption

ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends 14 CFR part

39 of the Federal Aviation Regulations 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:

94-08-13 Fokker: Amendment 39-8885. Docket 93-NM-165-AD.

Applicability: Model F-28 Mark 0100 series airplanes; serial

numbers 11244 through 11348, inclusive; equipped with Flight Warning

Computer, P/N 80-0610-2-( ); or equipped with Flight Augmentation

Computer, part number (P/N) 622-7478-321 or P/N 622-7478-401;

certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent nuisance yaw-damper fault warnings and undetected

trim motion, accomplish the following:

(a) For airplanes having serial numbers 11244 through 11321

inclusive, 11323 through 11329 inclusive, 11331, and 11333; and

equipped with Flight Warning Computer (FWC) P/N 80-0610-2-( ):

Within one year after the effective date of this AD, remove the

currently installed FWC, modify the airplane, and install FWC P/N

80-0610-3-30, in accordance with Fokker Service Bulletin SBF100-31-

020, Revision 1, dated June 12, 1993.

Note 1: Installation accomplished prior to the effective date of

this AD in accordance with Fokker Service Bulletin SBF100-31-020,

dated May 24, 1991, is considered to be in compliance with this

paragraph.

Note 2: Installation of FWC P/N 80-0610-3-31, in accordance with

Fokker Service Bulletin SBF100-31-031, dated June 23, 1993, is

considered an acceptable alternative method of compliance with this

paragraph.

(b) For airplanes having serial numbers 11244 through 11339

inclusive, 11341, and 11342; and equipped with Flight Augmentation

Computer (FAC) P/N 622-7478-321: At the same time as, or prior to

further flight after, accomplishing the requirements of paragraph

(a) of this AD, remove the currently installed FAC and replace it

with either of the following:

(1) FAC P/N 622-7478-401MOD11, in accordance with Fokker Service

Bulletin SBF100-22-032, dated September 2, 1991; or

(2) FAC P/N 622-7478-411, in accordance with Fokker Service

Bulletin SBF100-22-037, dated May 31, 1993. Equipment combinations

listed in that service bulletin must be adhered to.

(c) For airplanes having serial numbers 11244 through 11348

inclusive, and equipped with FAC P/N 622-7478-401: Within one year

after the effective date of this AD, remove the currently installed

FAC and replace it with either of the following:

(1) FAC P/N 622-7478-401MOD11, in accordance with Fokker Service

Bulletin SBF100-22-032, dated September 2, 1991; or

(2) FAC P/N 622-7478-411, in accordance with Fokker Service

Bulletin SBF100-22-037, dated May 31, 1993. Equipment combinations

listed in that service bulletin must be adhered to.

(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 3: 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

Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the

airplane to a location where the requirements of this AD can be

accomplished.

(f) The installations shall be done in accordance with Fokker

Service Bulletin SBF100-22-032, dated September 2, 1991; Fokker

Service Bulletin SBF100-22-037, dated May 31, 1993, and Fokker

Service Bulletin SBF100-31-020, Revision 1, dated June 12, 1993,

which contains the following list of effective pages:

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Revision level Date shown on

Page No. shown on page page

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1, 2, 5-12, 17, 19A, 19B, 22-24, 32, 1............... June 12, 1993.

34, 36.

3, 4, 13-16, 18, 19, 20, 21, 25-31, Original........ May 24, 1991.

33, 35.

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This incorporation by reference was approved by the Director of the

Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part

51. Copies may be obtained from Fokker Aircraft USA, Inc., 1199

North Fairfax Street, Alexandria, Virginia 22314. Copies may be

inspected at the FAA, Transport Airplane Directorate, 1601 Lind

Avenue, SW., Renton, Washington; or at the Office of the Federal

Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) This amendment becomes effective on May 20, 1994.

Issued in Renton, Washington, on April 13, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-9340 Filed 4-19-94; 8:45 am]

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