[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]
[[Page 26456]]
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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
