Airworthiness Directives; Jetstream Aircraft Limited Model 4101 Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-NM-223-AD; Amendment 39-8849; AD 93-25-10]

Airworthiness Directives; Jetstream Aircraft Limited Model 4101

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: This document publishes in the Federal Register an amendment

adopting Airworthiness Directive (AD) 93-25-10 that was sent previously

to all known U.S. owners and operators of certain Jetstream Model 4101

airplanes by individual letters. This AD requires inspections to detect

damage of the bearings in the aileron quadrants, replacement of damaged

bearings with new bearings, and adjustment to the secondary stops. This

amendment is prompted by a report that an in-flight failure of a

bearing in a quadrant in the pilot's aileron control system caused

abnormal backlash of the pilot's aileron control. The actions specified

by this AD are intended to prevent reduced controllability of the

airplane.

DATES: Effective March 28, 1994, to all persons except those persons to

whom it was made immediately effective by priority letter AD 93-25-10,

issued on December 16, 1993, which contained the requirements of this

amendment.

The incorporation by reference of certain publications listed in

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

of March 28, 1994.

Comments for inclusion in the Rules Docket must be received on or

before May 10, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 93-NM-223-AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056.

The applicable service information 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 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.

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: On December 16, 1993, the FAA issued

priority letter AD 93-25-10, which is applicable to certain Jetstream

Model 4101 airplanes. That action was prompted by a report indicating

that an in-flight failure of a bearing in a quadrant in the pilot's

aileron control system had caused abnormal backlash of the pilot's

aileron control. In this incident, the co-pilot assumed control and

landed the airplane. A subsequent fleet inspection revealed damage to

two other bearings. This condition, if not corrected, could result in

reduced controllability of the airplane.

Jetstream Aircraft Limited has issued Alert Service Bulletin J41-A-

27-026, Revision 1, dated December 7, 1993, that describes procedures

for performing repetitive detailed visual inspections to detect damage

of the bearings in the aileron quadrants, replacing damaged bearings

with new bearings, and adjusting the secondary stops. The Civil

Aviation Authority (CAA), which is the airworthiness authority for the

United Kingdom, classified this alert service bulletin as mandatory in

order to assure the continued airworthiness of these airplanes in the

United Kingdom.

This airplane model is manufactured in the United Kingdom and is

type certificated for operation in the United States under the

provisions of Sec. 21.29 of the Federal Aviation Regulations and the

applicable bilateral airworthiness agreement. Pursuant to this

bilateral airworthiness agreement, the CAA has kept the FAA informed of

the situation described above. The FAA has examined the findings of the

CAA, 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 the unsafe condition described is likely to exist or develop

on other airplanes of the same type design registered in the United

States, the FAA issued priority letter AD 93-25-10 to require

repetitive detailed visual inspections to detect damage of the bearings

in the aileron quadrants, replacement of damaged bearings with new

bearings, and adjustment to the secondary stops. The actions are

required to be accomplished in accordance with the alert service

bulletin previously described.

Since it was found that immediate corrective action was required,

notice and opportunity for prior public comment thereon were

impracticable and contrary to the public interest, and good cause

existed to make the AD effective immediately by individual letters

issued on December 16, 1993, to all known U.S. owners and operators of

certain Jetstream Model 4101 airplanes. These conditions still exist,

and the AD is hereby published in the Federal Register as an amendment

to Sec. 39.13 of part 39 of the Federal Aviation Regulations (FAR) to

make it effective as to all persons.

Comments Invited

Although this action is in the form of a final rule that involves

requirements affecting flight safety and, thus, was not preceded by

notice and an opportunity for public comment, comments are invited on

this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All

communications received on or before the closing date for comments will

be considered, and this rule may be amended in light of the comments

received. Factual information that supports the commenter's ideas and

suggestions is extremely helpful in evaluating the effectiveness of the

AD action and determining whether additional rulemaking action would be

needed.

Comments are specifically invited on the overall regulatory,

economic, environmental, and energy aspects of the rule that might

suggest a need to modify the 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 that

summarizes each FAA-public contact concerned with the substance of this

AD 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 93-NM-223-AD.'' The postcard will be date stamped and

returned to the commenter. -

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.

The FAA has determined that this regulation is an emergency

regulation that must be issued immediately to correct an unsafe

condition in aircraft, and is not a ``significant regulatory action''

under Executive Order 12866. It has been determined further that this

action involves an emergency regulation under DOT Regulatory Policies

and Procedures (44 FR 11034, February 26, 1979). If it is determined

that this emergency regulation otherwise would be significant under DOT

Regulatory Policies and Procedures, a final regulatory evaluation will

be prepared and placed in the Rules Docket. A copy of it, if filed, 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:

93-25-10 Jetstream Aircraft Limited: Amendment 39-8849. Docket 93-

NM-223-AD.

Applicability: Model 4101 airplanes, having constructor numbers

41004 and subsequent, certificated in any category. -

Compliance: Required as indicated, unless accomplished

previously.

To prevent reduced controllability of the airplane, accomplish

the following:

(a) Within 7 days after the effective date of this AD, perform a

detailed visual inspection to detect damage of the bearings in the

aileron quadrant in the pilot's and co-pilot's aileron control, in

accordance with Jetstream Aircraft Limited Alert Service Bulletin

J41-A-27-026, Revision 1, dated December 7, 1993.

(1) If no damaged bearing is found, repeat the inspection,

thereafter, at intervals not to exceed 7 days.

(2) If any damaged bearing is found, prior to further flight,

replace the damaged bearing with a new bearing in accordance with

the service bulletin, and repeat the inspection, thereafter, at

intervals not to exceed 7 days.

(b) Within 7 days after the effective date of this AD, adjust

the aileron secondary stop in the pilot's and co-pilot's aileron

control system in accordance with Jetstream Aircraft Limited Alert

Service Bulletin J41-A-27-026, Revision 1, dated December 7, 1993.

(c) Within 7 days after the effective date of this AD, revise

the Abnormal Procedures Section of the FAA-approved Airplane Flight

Manual (AFM) to include the following. This may be accomplished by

inserting a copy of this AD in the AFM.

``Where abnormal aileron control backlash is experienced by one

pilot, the other pilot should assume control of the aircraft without

using the disconnect facility. The disconnect facility should only

be used in accordance with published procedures in cases of control

restrictions or jamming.''

(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: 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 inspections, replacement, and adjustment shall be done

in accordance with Jetstream Aircraft Limited Alert Service Bulletin

J41-A-27-026, Revision 1, dated December 7, 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.

-

(g) This amendment becomes effective on March 28, 1994, to all

persons except those persons to whom it was made immediately

effective by priority letter AD 93-25-10, issued on December 16,

1993, which contained the requirements of this amendment.

Issued in Renton, Washington, on March 3, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-5405 Filed 3-10-94; 8:45 am]

BILLING CODE 4910-13-U