Airworthiness Directives; Jetstream Aircraft Limited (Formerly British Aerospace, Regional Airlines Limited) HP137 Mk1, Jetstream Series 200, and Jetstream Models 3101 and 3201 Airplanes

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-CE-13-AD]

Airworthiness Directives; Jetstream Aircraft Limited (Formerly

British Aerospace, Regional Airlines Limited) HP137 Mk1, Jetstream

Series 200, and Jetstream Models 3101 and 3201 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking.

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SUMMARY: This document proposes to adopt a new airworthiness directive

that would apply to Jetstream Aircraft Limited (JAL) HP137 Mk1,

Jetstream series 200 and Jetstream Models 3101 and 3201 airplanes. The

proposed action would require repetitively inspecting the left and

right pilot windscreens for poly vinyl butyrate (PVB) interlayer

cracks, and replacing any windscreen that has a crack that exceeds

certain limits. Several reports of varying degrees of PVB interlayer

cracking of pilot windscreens on the affected airplanes prompted the

proposed action. The proposed actions are intended to prevent such

windscreen cracking, which, if not detected and corrected, could result

in decompression injuries.

DATES: Comments must be received on or before December 19, 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-13-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.

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.,

Program 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-13-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-13-AD, Room 1558, 601 E. 12th Street,

Kansas City, Missouri 64106.

Discussion

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 JAL HP137 Mk1, Jetstream series 200, and

Jetstream Models 3101 and 3201 airplanes. The CAA reports several

incidents of varying degrees of PVB interlayer cracking of pilot

windscreens on the affected airplanes.

Jetstream Aircraft Limited has issued SB 56-JA 920843, Revision 1,

dated December 16, 1993, which specifies procedures for inspecting the

left and right windscreens for PVB interlayer cracks. This document

also introduces Pilkington Aerospace (the windscreen manufacturer) SB

No. 037-56-1001, Issue Date: October 21, 1992, Revision 1: March 31,

1993. The latter document includes a figure that shows a cross section

of the windscreen from where cracking can originate and also sets in-

service cracking limits for the affected windscreens. The CAA

classified Jetstream SB 56-JA 92-843 as mandatory in order to assure

the continued airworthiness of these airplanes in the United Kingdom.

The CAA classifying a service bulletin as mandatory in the United

Kingdom is equivalent to the FAA issuing an airworthiness directive in

the United States.

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 in other JAL HP137 Mk1, Jetstream series 200, and

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

proposed AD would require repetitively inspecting the left and right

pilot windscreens for PVB interlayer cracks, and replacing any

windscreen that has a crack that exceeds certain limits. The proposed

actions would be accomplished in accordance with the service

information described above.

The FAA estimates that 160 airplanes in the U.S. registry would be

affected by the proposed AD, that it would take approximately 1

workhour per airplane to accomplish the proposed modification, and that

the average labor rate is approximately $55 an hour. Based on these

figures, the total cost impact of the proposed AD on U.S. operators is

estimated to be $8,800. This figure does not take into account for any

possible window replacements nor repetitive inspections. The FAA has no

way of determining how many windscreens may have PVB interlayer cracks

that exceed the limitations and would require replacement, or the

number of repetitive inspections each owner/operator may incur.

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 adding a new AD to read as follows:

Jetstream Aircraft Limited: Docket No. 94-CE-13-AD.

Applicability: HP137 Mk1, Jetstream Series 200, and Jetstream

Models 3101 and 3201 airplanes (all serial numbers), certificated in

any category.

Compliance: Required within the next 300 hours time-in-service

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

accomplished, and thereafter as indicated.

To prevent pilot windscreen poly vinyl butyrate (PVB) interlayer

cracking, which, if not detected and corrected, could result in

decompression injuries, accomplish the following:

(a) Visually inspect the left and right windscreens for PVB

interlayer cracks in accordance with the ACCOMPLISHMENT INSTRUCTIONS

section of Jetstream Service Bulletin (SB) 56-JA 92-843, Revision

No. 1, dated December 16, 1993.

(1) If any crack is found that is within the limits specified in

Pilkington Aerospace SB No. 037-56- 1001, Issue Date: October 21,

1992, Revision 1: March 31, 1993, reinspect within the next 300

hours TIS, and replace or reinspect the windscreen thereafter as

applicable.

(2) If any crack is found that exceeds the limits specified in

Pilkington Aerospace SB No. 037-56-1001, Issue Date: October 21,

1992, Revision 1: March 31, 1993, prior to further flight, replace

the windscreen with a new windscreen and reinspect within the next

2,400 hours TIS, and replace or reinspect the windscreen thereafter

as applicable.

(3) If no cracks are found, reinspect the windscreen within the

next 2,400 hours TIS, and replace or reinspect the windscreen

thereafter as applicable.

(b) 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.

(c) An alternative method of compliance or adjustment of the

initial or repetitive compliance times 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.

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

the documents referred to herein upon request to Jetstream Aircraft

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

2RW Scotland; telephone (44-292) 79888; or Jetstream Aircraft Inc.,

Librarian, P.O. Box 16029, Dulles International Airport, Washington,

DC, 20041-6029; or may examine these documents at the FAA, Central

Region, Office of the Assistant Chief Counsel, Room 1558, 601 E.

12th Street, Kansas City, Missouri 64106.

Issued in Kansas City, Missouri, on October 7, 1994.

John R. Colomy,

Acting Manager, Small Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-25441 Filed 10-13-94; 8:45 am]

BILLING CODE 4910-13-U