[Federal Register Volume 62, Number 93 (Wednesday, May 14, 1997)]
[Proposed Rules]
[Pages 26456-26457]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-12681]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-214-AD]
RIN 2120-AA64


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 all Jetstream Model 4101 
airplanes. This proposal would require repetitive inspections of the 
structure associated with the engine nacelle fairing that is attached 
to the left and right flaps of the wings for damage, and repair of any 
damage found. This proposed AD would also require drilling a new drain 
hole in each engine nacelle fairing and applying a sealant to the gap 
between the wing flap and engine nacelle fairing. This proposal is 
prompted by reports indicating that fatigue cracks were found in the 
structure that attaches the engine nacelle fairing to the wing flaps on 
the affected airplanes. The actions specified by the proposed AD are 
intended to detect and correct such fatigue cracking, which could 
result in the engine nacelle fairing partially or completely separating 
from the wing flap, and consequent additional structural damage to the 
airframe and/or reduced controllability of the airplane.

DATES: Comments must be received by June 23, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-214-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 (425) 
227-2148; fax (425) 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 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 96-NM-214-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-214-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Civil Aviation Authority (CAA), which is the airworthiness 
authority for the United Kingdom, notified the FAA that an unsafe 
condition may exist on all Jetstream Model 4101 airplanes. The CAA 
advises it has received reports of cracks in the fairing attachment 
angles of the engine nacelle and in the wing flap skins associated with 
the engine nacelle fairing attached to the left and right flap of the 
wings. In one of these incidents, a loose fairing caused vibration of 
the wing and fuselage. Investigation revealed that the cause of such 
cracks was attributed to structural fatigue induced by repetitive loads 
from the wake of the propeller. Such fatigue cracking, if not detected 
and corrected in a timely manner, could result in the engine nacelle 
fairing partially or completely separating from the wing flap, and 
consequent additional structural failure of the airframe and/or reduced 
controllability of the airplane.

Explanation of Relevant Service Information

    Jetstream has issued Alert Service Bulletin J41-A57-015, dated May 
27, 1996, which describes the following procedures:

--Performing repetitive visual inspections of the structure associated 
with the engine nacelle fairing that is attached to the left and right 
flaps of the wings for damage;
--Drilling a new drain hole in each engine nacelle fairing;
--Applying a new sealant to the gap between the wing flap and engine 
nacelle fairing; and
--Repairing any damaged fairing.

    The CAA classified this alert service bulletin as mandatory and 
issued British airworthiness directive 006-05-96 in order to assure the 
continued airworthiness of these airplanes in the United Kingdom.

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 repetitive visual 
inspections of the structure associated with the engine nacelle fairing 
that is attached to the left and right flaps of the wings for damage, 
and repair of any damage found. The proposed AD also would require 
drilling a new drain hole in each fairing and applying a sealant to the 
gap between the wing flap and engine nacelle fairing. The actions would 
be required to be

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accomplished in accordance with the alert service bulletin described 
previously.

Cost Impact

    The FAA estimates that 51 Jetstream Model 4101 airplanes of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 3 work hours per airplane to accomplish the proposed 
initial inspection, and that the average labor rate is $60 per work 
hour. (The FAA has no way of determining how many repetitive 
inspections the owners/operators would incur over the life of the 
affected airplanes.) Required parts (sealant) would be provided by the 
manufacturer at no cost to operators. Based on these figures, the cost 
impact of the proposed AD on U.S. operators is estimated to be $9,180, 
or $180 per airplane.
    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.

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 Limited: Docket 96-NM-214-AD.

    Applicability: All Model 4101 airplanes, 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 (b) 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 detect and correct fatigue cracking in the structure 
associated with the engine nacelle fairings attached to the left and 
right flaps of the wings, which could result in the engine nacelle 
fairing partially or completely separating from the wing flap, and 
consequent additional structural damage to the airframe and/or 
reduced controllability of the airplane, accomplish the following:

    (a) Prior to the accumulation of 1,500 hours time-in-service 
(TIS), or within 60 days after the effective date of this AD, 
whichever occurs later, visually inspect the structure associated 
with the engine nacelle fairing that is attached to the left and 
right flaps of the wings for damage; drill a new drain hole in each 
engine nacelle fairing; and apply a sealant to the gap between the 
wing flap and engine nacelle fairing; in accordance with Jetstream 
Alert Service Bulletin J41-A57-015, dated May 27, 1996. Repeat the 
visual inspection thereafter at intervals not to exceed 1,500 hours 
TIS.
    (1) If any damage is found and the damage is within the limits 
specified in the alert service bulletin, prior to further flight, 
repair it in accordance with the alert service bulletin.
    (2) If any damage is found and the damage is outside the limits 
specified in the alert service bulletin, prior to further flight, 
repair it in accordance with a method approved by the Manager, 
Standardization Branch, ANM-113, FAA, Transport Airplane 
Directorate.
    (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. 
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.

    (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.

    Issued in Renton, Washington, on May 8, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-12681 Filed 5-13-97; 8:45 am]
BILLING CODE 4910-13-P