Airworthiness Directives: British Aerospace, Regional Aircraft Limited, HP 137 Mk1, Jetstream Models 200, 3101, and 3201 Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-CE-02-AD]

Airworthiness Directives: British Aerospace, Regional Aircraft

Limited, HP 137 Mk1, Jetstream Models 200, 3101, and 3201 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to supersede two existing AD's that

require repetitively inspecting the universal joints and universal

rivets on British Aerospace (BAe), Regional Aircraft Limited, HP 137

Mk1, Jetstream Models 200, 3101, and 3201 airplanes, and replacing any

damaged part, and limiting the in-service life of the torque tube shaft

assembly. Jetstream Aircraft Limited has introduced an improved flap

torque shaft assembly that includes universal joints that are not life

limited. The Federal Aviation Administration's policy on aging

commuter-class aircraft is to eliminate or, in certain instances,

reduce the number of certain repetitive short-interval inspections when

improved parts or modifications are available. The proposed action

would require installing this improved flap torque shaft assembly in

place of the repetitive inspection and life limit requirements of the

two existing AD's. The actions specified by the proposed AD are

intended to prevent failure of the flap torque shaft assembly, which

could result in asymmetric flap deployment and loss of control of the

airplane.

DATES: Comments must be received on or before September 26, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Central Region, Office of the Assistant Chief

Counsel, Attention: Rules Docket No. 94-CE-02-AD, room 1558, 601 E.

12th Street, Kansas City, Missouri 64106. Comments may be inspected at

this location between 8 a.m. and 4 p.m., Monday through Friday,

holidays excepted.

Service information that applies to the proposed AD may be obtained

from Jetstream Aircraft Limited, Manager Product Support, Prestwick

Airport, Ayrshire, KA9 2RW Scotland; telephone (44-292) 79888;

facsimile (44-292) 79703; or Jetstream Aircraft Inc., Librarian, P.O.

Box 16029, Dulles International Airport, Washington, DC 20041-6029;

telephone (703) 406-1161; facsimile (703) 406-1469. This information

also may be examined at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. Raymond A. Stoer, Program Officer,

Brussels Aircraft Certification Office, FAA, Europe, Africa, and Middle

East Office, c/o American Embassy, B-1000 Brussels, Belgium; telephone

(322) 513.3830; facsimile (322) 230.6899; or Mr. John P. Dow, Sr.,

Project Officer, Small Airplane Directorate, Airplane Certification

Service, FAA, 1201 Walnut, suite 900, Kansas City, Missouri 64106;

telephone (816) 426-6932; facsimile (816) 426-2169.

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 should 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 that summarizes 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 No. 94-CE-02-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, Central Region, Office of the Assistant Chief Counsel,

Attention: Rules Docket No. 94-CE-02-AD, Room 1558, 601 E. 12th Street,

Kansas City, Missouri 64106.

Discussion

The FAA has determined that reliance on critical repetitive

inspections on aging commuter-class airplanes carries an unnecessary

safety risk when a design change exists that could eliminate or, in

certain instances, reduce the number of those critical inspections. In

determining what inspections are critical, the FAA considers (1) the

safety consequences of the airplane if the known problem is not

detected by the inspection; (2) the reliability of the inspection such

as the probability of not detecting the known problem; (3) whether the

inspection area is difficult to access; and (4) the possibility of

damage to an adjacent structure as a result of the problem.

These factors have led the FAA to establish an aging commuter-class

aircraft policy that requires incorporating a known design change when

it could eliminate, or, in certain instances, reduce the number of

critical repetitive inspections.

In 1991, the FAA issued a notice of proposed rulemaking (NPRM) to

amend part 39 of the Federal Aviation Regulations (14 CFR part 39) with

an airworthiness directive (AD) that would apply to BAe, Regional

Aircraft Limited, HP 137 Mk1, Jetstream Models 200, 3101, and 3201

airplanes. This NPRM (56 FR 11976, March 21, 1991) proposed inspecting

the flap torque shaft to identify all Type ``F'' universal joints, and

replacing these universal joints with Type ``M'' or part number A16123

universal joints.

Since issuance of the notice of proposed rulemaking (NPRM),

Jetstream Aircraft Limited has introduced an improved flap torque shaft

assembly that includes universal joints that are not life limited, and

that incorporates the actions proposed in the referenced NPRM and

required by the following AD's:

AD 87-04-04, Amendment 39-5529, which requires limiting

the in-service life of the torque tube shaft assembly on BAe HP 137

Mk1, Jetstream Models 200, 3101, and 3201 airplanes; and

AD 89-16-02, Amendment 39-6273, which requires

repetitively inspecting the universal joints and universal joint rivets

on BAe HP 137 Mk1, Jetstream Models 200, 3101, and 3201 airplanes, and

replacing any damaged part.

Jetstream Aircraft Limited has issued Service Bulletin (SB) No. 27-

JA 920340, which incorporates the following pages:

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Revision

Pages level Date

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1 through 6 and 9 through 16........ 2........... Dec. 21, 1993.

7, 8, and 17 through 28............. Original Sept. 2, 1992.

issue.

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This service information specifies procedures for installing the

improved flap torque shaft assembly.

Based on its aging commuter-class aircraft policy and after

reviewing all available information, the FAA has determined that (1)

installing the new improved flap torque shaft assemblies incorporates

the actions proposed in the previously referenced NPRM and AD 87-04-04

and AD 89-16-02, and replaces critical repetitive inspections with a

design modification; and (2) AD action should be taken to prevent

failure of the flap torque shaft assembly, which could result in

asymmetric flap deployment and loss of control of the airplane. With

this in mind, the FAA issued a document, withdrawing the previously

referenced NPRM, on February 14, 1994 (59 FR 8878, February 24, 1994).

Since an unsafe condition has been identified that is likely to

exist or develop in other BAe, Regional Aircraft Limited, HP 137 Mk1,

Jetstream Models 200, 3101, and 3201 airplanes of the same type design,

the proposed AD would supersede both AD 87-04-04 and AD 89-16-02 with a

new AD that would require installing this improved flap torque shaft

assembly in place of the repetitive inspection and life limit

requirements of the two existing AD's. The proposed actions would be

accomplished in accordance with Jetstream Aircraft Limited SB No. 27-JA

920340.

The subsequent final rule action (if promulgated) would have an

effective date of 12 months after publication in the Federal Register

and a compliance time of 50 hours time-in-service after the effective

date. This would allow operators time to schedule the flap torque shaft

assembly replacement. The requirements of AD 87-04-04 and AD 89-16-02

would remain in effect until this date.

The FAA estimates that 245 airplanes in the U.S. registry would be

affected by the proposed AD, that it would take approximately 31

workhours per airplane to accomplish the proposed action, and that the

average labor rate is approximately $55 an hour. Parts cost

approximately $1010 per airplane. Based on these figures, the total

cost impact of the proposed AD on U.S. operators is estimated to be

$665,175. This figure is based on the assumption that none of the

affected airplane operators have accomplished the proposed actions. In

addition, this action would eliminate the repetitive inspections

required by AD 87-04-04 and AD 89-16-02. The FAA has no way of

determining the operation levels of each individual operator of the

affected airplanes, and subsequently cannot determine the repetitive

inspections costs that would be eliminated by the proposed action. The

FAA estimates these costs to be substantial over the long-term.

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 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) 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 has been placed 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 removing both AD 87-04-04, Amendment

39-5529, and AD 89-16-02, Amendment 39-6273, and by adding a new

airworthiness directive to read as follows:

British Aerospace, Regional Aircraft Limited: Docket No. 94-CE-02-

AD; Supersedes AD 87-04-04, Amendment 39-5529, and AD 89-16-02,

Amendment 39-6273.

Applicability: HP 137 Mk1, Jetstream Models 200, 3101, and 3201

airplanes (all serial numbers), certificated in any category.

Compliance: Required within the next 50 hours time-in-service

(TIS) after the effective date of this AD, unless already

accomplished.

To prevent failure of the flap torque shaft assembly, which

could result in asymmetric flap deployment and loss of control of

the airplane, accomplish the following:

(a) Install an improved torque shaft assembly in accordance with

Part 1 of the ACCOMPLISHMENT INSTRUCTIONS section of Jetstream

Aircraft Limited Service Bulletin (SB) No. 27-JA 920340; or modify

the existing torque shaft assembly in accordance with Part 2 of the

ACCOMPLISHMENT INSTRUCTIONS section of Jetstream Aircraft Limited SB

No. 27-JA 920340, which incorporates the following pages:

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Revision

Pages level Date

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1 through 6 and 9 through 16........ 2........... Dec. 21, 1993.

7, 8, and 17 through 28............. Original Sept. 2, 1992.

issue.

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(b) The life limit requirements of the torque tube shaft

assembly required by AD 87-04-04, and the repetitive inspections of

the universal joints and universal joint rivets required by AD 89-

16-02 remain mandatory until the effective date of this AD or upon

accomplishing the installation or modification referenced by

paragraph (a) of this AD, whichever occurs first.

(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) An alternative method of compliance or adjustment of the

compliance time that provides an equivalent level of safety may be

approved by the Manager, Brussels Aircraft Certification Office,

Europe, Africa, Middle East office, FAA, c/o American Embassy, 1000

Brussels, Belgium. The request should be forwarded through an

appropriate FAA Maintenance Inspector, who may add comments and then

send it to the Manager, Brussels Aircraft Certification Office.

Note: Information concerning the existence of approved

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

obtained from the Brussels Aircraft Certification Office.

(e) All persons affected by this directive may obtain copies of

the document referred to herein upon request to Jetstream Aircraft

Limited, Manager Product Support, Prestwick Airport, Ayrshire, KA9

2RW Scotland; or Jetstream Aircraft Inc., Librarian, P.O. Box 16029,

Dulles International Airport, Washington, DC; or may examine this

document at the FAA, Central Region, Office of the Assistant Chief

Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.

(f) This amendment supersedes both AD 87-04-04, Amendment 39-

5529, and AD 89-16-02, Amendment 39-6273.

Issued in Kansas City, Missouri, on July 6, 1994.

Henry A. Armstrong,

Acting Manager, Small Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-16814 Filed 7-11-94; 8:45 am]

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