Airworthiness Directives; Jetstream Model HS 748 Series 2A and 2B Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 94-NM-125-AD; Amendment 39-9071; AD 94-23-08]

Airworthiness Directives; Jetstream Model HS 748 Series 2A and 2B

Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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

applicable to all Jetstream Model HS 748 Series 2A and 2B airplanes.

This action requires repetitive replacement of the structurally

significant items (SSI) on the nose landing gear (NLG) and main landing

gear (MLG) with serviceable SSI's. This amendment is prompted by

fatigue testing which revealed that the SSI's on the NLG and the MLG

have a limited service life. The actions specified in this AD are

intended to ensure the replacement of the SSI's that have reached the

maximum life limit; SSI's that are not replaced could fail and lead to

the failure of the NLG and MLG during taxi, take-off, or landing.

DATES Effective: December 6, 1994.

The incorporation by reference of certain publications listed in

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

of December 6, 1994.

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

before January 20, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 94-NM-125-AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056.

The service information referenced in this AD may be obtained from

Dowty Aerospace, Customer Support Center, P.O. Box 49, Sterling,

Virginia 20166. 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) 227-2141; fax (206) 227-1100.

SUPPLEMENTARY INFORMATION: The Civil Aviation Authority (CAA), which is

the airworthiness authority for the United Kingdom, recently notified

the FAA that an unsafe condition may exist on all Jetstream Model HS

748 series 2A and 2B airplanes. The CAA advises that results of fatigue

testing, conducting by Dowty [the manufacturer of the nose landing gear

(NLG) and main landing gear (MLG) components], revealed that certain

components in the NLG and MLG specified as structurally significant

items (SSI) have a limited service life. Investigation revealed that

these SSI's, upon attaining or exceeding a certain number of landings,

can fail due to fatigue-related stress. If not replaced in a timely

manner, the SSI's could fail and lead to the failure of the NLG and MLG

during taxi, take-off, or landing.

Dowty has issued Service Bulletin 32-104E, dated January 20, 1993,

which describes procedures for determining the number of landings

accumulated on the SSI's on the NLG and MLG, and repetitively replacing

these SSI's with serviceable SSI's at regulator intervals. The CAA

classified this service bulletin as mandatory.

This airplane model is manufactured in the United Kingdom and is

type certificated for operation in the United States under the

provisions of section 21.29 of the Federal Aviation Regulations (14 CFR

21.29) 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 an unsafe condition has been identified that is likely to

exist or develop on other airplanes of the same type design registered

in the United States, this AD is being issued to ensure the replacement

of the SSI's that have reached the maximum life limit. This AD requires

initially determining the number of landings accumulated on the SSI's

currently installed in the NLG and MLG, and repetitively replacing the

SSI's with serviceable SSI's, upon the accumulation of a certain number

of landings. The actions would be required to be accomplished in

accordance with the service bulletin described previously.

There currently are no Jetstream Model HS 748 series 2A and 2B

airplanes on the U.S. Register. All airplanes included in the

applicability of this rule currently are operated by non-U.S. operators

under foreign registry; therefore, they are not directly affected by

this AD action. However, the FAA considers that this rule is necessary

to ensure that the unsafe condition is addressed in the event that any

of these subject airplanes are imported and placed on the U.S. Register

in the future.

Should an affected airplane be imported and placed on the U.S.

Register in the future, it would require approximately 40 work hours to

accomplish the required actions, at an average labor charge of $60 per

work hour. Based on these figures, the total cost impact of this AD

would be $2,400 per airplane, per replacement cycle.

Since this AD action does not affect any airplane that is currently

on the U.S. register, it has no adverse economic impact and imposes no

additional burden on any person. Therefore, notice and public

procedures hereon are unnecessary and the amendment may be made

effective in less than 30 days after publication in the Federal

Register.

Comments Invited

Although this action is in the form of a final rule and was not

preceded by notice and 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 rule must submit a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket Number 94-NM-125-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.

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:

94-23-08 Jetstream Aircraft Limited (Formerly British Aerospace

Commercial Aircraft, Limited): Amendment 39-9071. Docket 94-NM-125-

AD.

Applicability: All Model Jetstream Model HS 748 series 2A and 2B

airplanes, certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To ensure replacement of the SSI's that have reached the maximum

life limit, accomplish the following:

(a) Within 60 days after the effective date of this AD,

determine the number of landings accumulated on each structurally

significant item (SSI) currently installed in the nose landing gear

(NLG) and main landing gear (MLG), in accordance with Dowty

Aerospace Landing Gear Service Bulletin 32-104E, dated January 20,

1993.

(1) If the number of landings accumulated on an SSI is equal to

or greater than the number of landings specified in the ``Life

Limitations'' column of the applicable table in the service

bulletin, prior to further flight, replace the SSI with a

serviceable SSI, in accordance with the service bulletin.

Thereafter, replace the SSI at intervals not to exceed the

accumulation of the number of landings specified in the ``Life

Limitations'' column of the applicable table in the service

bulletin.

(2) If the number of landings accumulated on the SSI is less

than the number of landings specified in the ``Life Limitations''

column of the applicable table in the service bulletin, replace the

SSI with a serviceable SSI prior to or upon the accumulation of the

number of landings specified in the ``Life Limitations'' column of

the applicable table in the service bulletin. Thereafter, replace

the SSI at intervals not to exceed the accumulation of the number of

landings specified in the ``Life Limitations'' column of the

applicable table in the service bulletin.

(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 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.

(d) The replacement shall be done in accordance with Dowty

Aerospace Landing Gear Service Bulletin 32-104E, dated January 20,

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 Dowty Aerospace, Customer

Support Center, P.O. Box 49, Sterling, Virginia 20166. 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 December 6, 1994.

Issued in Renton, Washington, on November 7, 1994.

S.R. Miller,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-27966 Filed 11-18-94; 8:45 am]

BILLING CODE 4910-13-U