Airworthiness Directives; Fokker Model F28 Mark 0100 Series Airplanes

14 CFR Part 39

[Docket No. 94-NM-38-AD; Amendment 39-9025; AD 94-19-03]

Airworthiness Directives; Fokker Model F28 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 F28 Mark 0100 series airplanes, that

requires replacement of the autopilot disconnect switches with modified

units. This amendment is prompted by several incidents in which the

flight crew did not depress both halves of the autopilot disconnect

switch during the LAND 2 or LAND 3 approach and, as a result, one

autopilot remained engaged. This condition resulted in unanticipated

movements of the stabilizer trim and higher than anticipated control

forces of the flight controls. The actions specified by this AD are

intended to prevent the flight crew from inadvertently disconnecting

only one autopilot when both autopilots are engaged, which could result

in unanticipated control surface movements.

DATES: Effective October 21, 1994.

The incorporation by reference of certain publications listed in

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

of October 21, 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: 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: A proposal to amend part 39 of the Federal

Aviation Regulations (14 CFR part 39) to include an airworthiness

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

series airplanes was published in the Federal Register on May 11, 1994

(59 FR 24383). That action proposed to require replacement of the

autopilot disconnect switches with modified units.

Interested persons have been afforded an opportunity to participate

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

the comments received.

Both commenters support the proposed rule.

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 as proposed.

The FAA estimates that 19 airplanes of U.S. registry will be

affected by this AD, that it will take approximately 8 work hours per

airplane to accomplish the required actions, and that the average labor

rate is $55 per work hour. Required parts will cost approximately

$2,500 per airplane. Based on these figures, the total cost impact of

the AD on U.S. operators is estimated to be $55,860, or $2,940 per

airplane.

The total cost impact figure discussed above is 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.

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 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:

94-19-03 Fokker: Amendment 39-9025. Docket 94-NM-38-AD.

Applicability: Model F28 Mark 0100 series airplanes; serial

numbers 11244 through 11286 inclusive, 11289 through 11293

inclusive, 11295 through 11297 inclusive, 11300, 11303, 11306,

11308, 11310, 11312, and 11313; certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent the flight crew from inadvertently disconnecting only

one autopilot when both autopilots are engaged, which could result

in unanticipated control surface movements, accomplish the

following:

(a) Within 6 months after the effective date of this AD, replace

the autopilot disconnect switches with modified units, in accordance

with Fokker Service Bulletin SBF100-22-020, dated September 25,

1990.

(b) As of 6 months after the effective date of this AD, no

person shall install an autopilot disconnect switch, part number

A47007-401 or A47007-403, on any airplane.

(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: 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

Secs. 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.

(e) The replacement shall be done in accordance with Fokker

Service Bulletin SBF100-22-020, dated September 25, 1990. 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.

(f) This amendment becomes effective on October 21, 1994.

Issued in Renton, Washington, on September 14, 1994.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-23221 Filed 9-20-94; 8:45 am]

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