[Federal Register Volume 59, Number 135 (Friday, July 15, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-17194]


[[Page Unknown]]

[Federal Register: July 15, 1994]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-66-AD]

 

Airworthiness Directives; Jetstream Model 4101 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Jetstream Model 4101 
airplanes. This proposal would require installation of additional 
venting between the flight deck and the passenger compartment. This 
proposal is prompted by results of an engineering analysis that 
revealed there was insufficient venting in the forward stowage and 
wardrobe assembly. The actions specified by the proposed AD are 
intended to prevent injury to the crew resulting from structural 
failure of the bulkhead between the flight deck and the passenger 
compartment in the event of windshield failure and subsequent rapid 
decompression.

DATES: Comments must be received by September 20, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-66-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056. Comments may be inspected at this location 
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal 
holidays.
    The service information referenced in the proposed rule may be 
obtained from Jetstream Aircraft, Inc., P. O. Box 16029, Dulles 
International Airport, Washington, D.C. 20041-6029. This information 
may be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Bud 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:

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 shall 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 summarizing 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 Number 94-NM-66-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, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 94-NM-66-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

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 certain Jetstream Model 4101 airplanes. 
The CAA advises that results of an engineering analysis have revealed 
that there is insufficient venting in the left and right forward 
stowage and the right forward wardrobe assembly between the flight deck 
and the passenger compartment. This condition, if not corrected, could 
result in injury to the crew due to structural failure of the bulkhead 
between the flight deck and the passenger compartment in the event of 
windshield failure and subsequent rapid decompression. Although the 
forward flight attendant seat is attached to this bulkhead, integrity 
of the airplane hull is not a risk factor in this situation.
    Jetstream Aircraft Limited has issued Service Bulletin J41-25-018, 
dated March 15, 1994, that describes procedures for installing 
additional venting in the left and right forward stowage and the right 
forward wardrobe assembly. This additional venting would provide faster 
pressure equalization between the flight deck and the passenger 
compartment in the event of a sudden depressurization of the pilots' 
compartment. Faster pressure equalization will prevent structural 
failure of the bulkhead in the event of rapid depressurization. The CAA 
classified this 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 (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, the proposed AD would require installation of 
additional venting between the flight deck and the passenger 
compartment. The actions would be required to be accomplished in 
accordance with the service bulletin described previously.
    The FAA estimates that 10 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 40 work 
hours per airplane to accomplish the proposed actions, and that the 
average labor rate is $55 per work hour. Required parts would be 
provided by the manufacturer at no cost to the operators. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $22,000, or $2,200 per airplane.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    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 proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the 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 is contained 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 the following new 
airworthiness directive:

Jetstream Aircraft Limited: Docket 94-NM-66-AD.

    Applicability: Model 4101 airplanes; constructors numbers 41005 
through 41015 inclusive, 41019 through 41024 inclusive, 41028, and 
41029; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent injury to the crew resulting from structural failure 
of the bulkhead between the flight deck and the passenger 
compartment in the event of windshield failure and subsequent rapid 
decompression, accomplish the following:
    (a) Within 525 hours time-in-service after the effective date of 
this AD, install additional decompression vents in the left and 
right stowage and the right forward wardrobe assembly bulkhead 
between the flight deck and passenger compartment, in accordance 
with Jetstream Service Bulletin J41-25-018, dated March 15, 1994.
    (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 
Sec. Sec.  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.

    Issued in Renton, Washington, on July 11, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-17194 Filed 7-14-94; 8:45 am]
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