Airworthiness Directives; Jetstream Model 4101 Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-199-AD; Amendment 39-8924; AD 94-11-08]

Airworthiness Directives; Jetstream Model 4101 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 Jetstream Model 4101 airplanes, that requires

modification of the aileron drive quadrant support structure. This

amendment is prompted by results of a stress analysis check, which

revealed that the factor of safety of the aileron drive quadrant

support structure on Model 4101 airplanes does not meet the tail-to-

wind gust load design case strength requirements specified in the

Federal Aviation Regulations. The actions specified by this AD are

intended to prevent cracking of the support structure, which could

result in reduced controllability of the airplane.

DATES: Effective July 7, 1994. The incorporation by reference of

certain publications listed in the regulations is approved by the

Director of the Federal Register as of July 7, 1994.

ADDRESSES: The service information referenced in this AD may be

obtained from Jetstream Aircraft, Inc., P.O. Box 16029, Dulles

International Airport, Washington, DC 20041-6029. 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: William Schroeder, Aerospace Engineer,

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

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

227-2148; 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 Jetstream 4101 airplanes was published in the

Federal Register on February 4, 1994 (59 FR 5359). That action proposed

to require modification of the aileron drive quadrant support structure

below the flight compartment floor.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. No comments were submitted in response

to the proposal or the FAA's determination of the cost to the public.

The FAA has determined that air safety and the public interest require

the adoption of the rule as proposed.

The FAA estimates that 4 airplanes of U.S. registry will be

affected by this AD, that it will take approximately 20 work hours per

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

rate is $55 per work hour. Required parts will be supplied by the

manufacturer at no cost to operators. Based on these figures, the total

cost impact of the AD on U.S. operators is estimated to be $4,400, or

$1,100 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 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:

94-11-08 Jetstream Aircraft Limited: Amendment 39-8924. Docket 93-

NM-199-AD.

Applicability: Model 4101 airplanes; constructors numbers 41004

through 41018 inclusive, certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent reduced controllability of the airplane, accomplish

the following:

(a) Within 3 months after the effective date of this AD, modify

the aileron drive quadrant support structure below the flight

compartment floor in accordance with Jetstream Service Bulletin J41-

53-011, dated October 15, 1993.

(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.

(d) The modification shall be done in accordance with Jetstream

Service Bulletin J41-53-011, dated October 15, 1993. 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 Jetstream Aircraft, Inc., P.O. Box

16029, Dulles International Airport, Washington, DC 20041-6029.

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.

(e) This amendment becomes effective on July 7, 1994.

Issued in Renton, Washington, on May 25, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-13237 Filed 6-6-94; 8:45 am]

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