[Federal Register Volume 61, Number 156 (Monday, August 12, 1996)]
[Proposed Rules]
[Pages 41757-41759]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-20430]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-139-AD]
RIN 2120-AA64


Airworthiness Directives; Jetstream Model BAe ATP 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 BAe ATP 
airplanes. This proposal would require repetitive inspections of the 
ram air inlet ducts for structural integrity and security of fasteners, 
and repairs, if necessary. This proposal also provides an optional 
terminating modification for the repetitive inspections. This proposal 
is prompted by a report of the separation of a ram air inlet duct from 
the airplane during flight. The actions specified by the proposed AD 
are intended to prevent such separation, which could pose a hazard to 
persons or property on the ground.

DATES: Comments must be received by September 23, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-139-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, DC 20041-6029. This information may 
be examined at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington.

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) 227-1149.

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 numbers 
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 96-NM-139-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. 96-NM-139-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 BAe ATP 
airplanes. The CAA advises that the ram air inlet duct base plate 
flanges can delaminate and allow the screws fastening the ducts to the 
airplane to pull through the duct base plate. These conditions, if not 
corrected, could result in the separation of a duct from the airplane 
during flight, which poses a hazard to persons or property on the 
ground.

[[Page 41758]]

Explanation of Relevant Service Information

    Jetstream has issued Service Bulletin BAe ATP-21-36, dated January 
3, 1996, which describes procedures for inspecting the left and right 
ram air inlet ducts, to detect if the duct base plate flange has 
delaminated and the screws fastening the ducts to the airplane are 
pulling through the duct base plate; this service bulletin also 
describes procedures for repairing these discrepancies using new bolts 
and washers. The CAA classified this service bulletin as mandatory and 
issued CAA Airworthiness Directive 003-01-96 in order to assure the 
continued airworthiness of these airplanes in the United Kingdom.
    In addition, Jetstream has issued Service Bulletin BAe ATP-21-37, 
dated January 23, 1996, which describes a ram air inlet duct 
modification that terminates the need to perform required repetitive 
duct inspections and repairs. This modification, which would prevent 
the duct from separating from the airplane, requires the bolting of 
reinforcing plates to the base flange of the duct. The CAA classified 
this service bulletin as optional.

FAA's Conclusions

    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.

Explanation of Requirements of Proposed Rule

    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 the inspection of 
the airplane's left and right ram air inlet ducts to determine whether 
the duct base plate flange has delaminated and the screws fastening 
these ducts have pulled through the duct base plate; and would require 
repair, if necessary. Thereafter, the proposed AD also would require 
repetitive inspections and repairs, if necessary, unless an optional 
terminating action is performed. The actions would be required to be 
accomplished in accordance with the service bulletins described 
previously.

Cost Impact

    The FAA estimates that 10 airplanes of U.S. registry would be 
affected by this proposed AD, that it would take approximately 1 work 
hour per airplane to accomplish the proposed inspection, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the proposed AD on U.S. operators is estimated to be 
$600 per inspection, or $60 per airplane, per inspection.
    The 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.
    Should an operator elect to accomplish the optional terminating 
modification provided in this proposal, it would require approximately 
1.5 work hours to accomplish, at an average labor rate of $60 per work 
hour. (This work hour figure does not include the time necessary for 
sealant to cure.) The cost of required parts would be nominal and could 
be produced locally from standard materials. Based on these figures, 
the cost impact of the proposed optional terminating modification on 
U.S. operators is estimated to be $60 per airplane.

Regulatory Impact

    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Jetstream Aircraft, Ltd. (Formerly British Aerospace Commercial 
Aircraft, Limited): Docket 96-NM-139-AD.

    Applicability: Model BAe ATP airplanes having constructor 
numbers 2002 through 2063 inclusive, certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (c) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated unless accomplished 
previously.
    To prevent the separation of the ram air inlet duct from the 
airplane, accomplish the following:
    (a) Prior to the accumulation of 50 flight hours after the 
effective date of this AD, inspect the left and right ram air inlet 
ducts to determine whether the duct base plate flange has 
delaminated and the screws fastening the duct have pulled through 
the duct base plate, in accordance with Jetstream BAe ATP Service 
Bulletin ATP-21-36, dated January 3, 1996.
    (1) If no discrepancy is detected, repeat the inspection 
thereafter at intervals not to exceed 250 flight hours.
    (2) If any discrepancy is detected, prior to further flight, 
repair in accordance with the service bulletin. Thereafter, repeat 
the inspection at intervals not to exceed 250 flight hours.
    (b) Accomplishment of the modification of the ram air inlet 
ducts in accordance with

[[Page 41759]]

Jetstream BAe ATP Service Bulletin ATP-21-37, dated January 23 , 
1996, constitutes terminating action for the repetitive inspections 
required by paragraph (a) of this AD.
    (c) 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (d) 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.

    Issued in Renton, Washington, on August 6, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-20430 Filed 8-9-96; 8:45 am]
BILLING CODE 4910-13-U