[Federal Register Volume 61, Number 126 (Friday, June 28, 1996)]
[Rules and Regulations]
[Pages 33647-33650]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-15954]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 96-NM-129-AD; Amendment 39-9677; AD 96-13-09]
RIN 2120-AA64
Airworthiness Directives; Jetstream Model 4101 Airplanes
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to all Jetstream Model 4101
[[Page 33648]]
airplanes. This action requires a review of maintenance records to
determine the time-in-service (TIS) of the bearings in the starter/
generators of both engines. This action also establishes a new TIS
limit for the bearings, and requires replacement of the starter/
generator unit with a serviceable unit, if necessary. This amendment is
prompted by reports of controlled in-flight engine shutdowns resulting
from failure of the bearings in the starter/generator unit. The actions
specified in this AD are intended to prevent such failure of the
bearings of the starter/generator, which could cause severe vibrations
and resultant in-flight shutdown of one or both engines.
DATES: Effective July 15, 1996.
-The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 15, 1996.
Comments for inclusion in the Rules Docket must be received on or
before August 27, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 96-NM-129-AD, 1601 Lind Avenue, SW.,
Renton, Washington 98055-4056.
-The service information referenced in this AD 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; or at the Office of the Federal Register, 800 North Capitol
Street, NW., suite 700, Washington, DC.
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: 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 all Jetstream Model 4101
airplanes. The CAA advises that it has received reports of controlled
in-flight engine shutdowns. Investigation has revealed that the
bearings of the direct current (DC) starter/generator failed, which
resulted in severe vibration. The bearing failures that resulted in
engine shutdown occurred at 409, 433, and 470 hours time-in-service
(TIS). These conditions, if not corrected, could result in an in-flight
engine shutdown.
Explanation of Relevant Service Information
-Jetstream has issued Alert Service Bulletin J41-A24-036, dated
February 26, 1996, which describes procedures for reviewing the
airplane maintenance records to determine the number of hours TIS that
the bearings of the DC starter/generator have accumulated. The alert
service bulletin also describes procedures to remove and replace the
starter/generator units with serviceable units when the bearings have
reached a certain (reduced) TIS limit. Such replacement of one of the
starter/generator units (per airplane) when the bearings have reached a
certain reduced TIS limit, reduces the possibility of the bearings
failing in both of the starter/generator units on any one airplane
during the same flight. The CAA classified this service bulletin as
mandatory and issued United Kingdom airworthiness directive 002-02-96,
dated March 1, 1996, 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 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, this AD is being issued to prevent in-flight
engine shutdown of both engines on the same flight due to failure of
the bearings of the starter/generators of the engines and resultant
severe vibration. This AD requires a review of maintenance records to
determine the TIS of the bearings in the starter/generators of both
engines. This action also establishes a new TIS limit for the bearings
in one of the two starter/generator units on each airplane, and
requires replacement of the unit with a serviceable unit. The actions
are required to be accomplished in accordance with the service bulletin
described previously.
Differences Between Service Bulletin and AD
Operators should note that the requirements of this AD differ from
certain TIS recommendations in the referenced alert service bulletin.
Specifically, this AD establishes a new limit of 300 hours TIS for the
bearings of one of the starter/generators of each airplane, rather than
specifying replacement of the unit when 300 hours ``remain'' on the
unit before scheduled bearing replacement, as indicated in the alert
service bulletin. The FAA considers that replacement of a unit with 300
hours ``remaining'' on the unit could permit a unit to operate
significantly longer than 300 hours TIS if the TIS limit for the unit
had previously been extended. The FAA finds that specifying a 300-hour
TIS limit for the bearings of one of the starter/generator units per
airplane will ensure that, at no one time, will an airplane be
operating with both starter/generator units having more than 300 hours
TIS on the bearings. A review of starter/generator unit failure reports
and consideration of probability of failure requirements in the type
certification basis for Jetstream Model 4101 airplanes support the
establishment of a 300-hour TIS limit for the bearings of one of the
starter/generator units on each airplane. This limit will ensure an
acceptable level of safety, as related to continued availability of
power from both engines on Jetstream Model 4101 airplanes.
Additionally, the manufacturer has notified the FAA that the
availability of ample parts may be a problem should the AD require both
starter/generator units to be replaced if their bearings exceed the TIS
limit. The FAA has determined that limiting the bearings to 300 hours
TIS on at least one of the starter/generator units on the airplane
provides an adequate level of safety; therefore, this AD establishes a
300-hour TIS limit for the bearings of only one of the two starter/
generator units of the airplane.
Interim Action
This is considered to be interim action. The manufacturer has
advised that it currently is developing a modification that will
positively address the unsafe condition addressed by this AD. Once the
modification is developed, approved, and available, the FAA may
consider further rulemaking.
Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of
this
[[Page 33649]]
regulation, it is found that notice and opportunity for prior public
comment hereon are impracticable, and that good cause exists for making
this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the 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
AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this rule must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 96-NM-129-AD.'' The postcard will be date stamped and
returned to the commenter.
Regulatory Impact
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and that it is not a ``significant regulatory
action'' under Executive Order 12866. It has been determined further
that this action involves an emergency regulation under DOT Regulatory
Policies and Procedures (44 FR 11034, February 26, 1979). If it is
determined that this emergency regulation otherwise would be
significant under DOT Regulatory Policies and Procedures, a final
regulatory evaluation will be prepared and placed in the Rules Docket.
A copy of it, if filed, may be obtained from the Rules Docket at the
location provided under the caption ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 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:
96-13-09 Jetstream Aircraft Limited: Amendment 39-9677. Docket 96-
NM-129-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
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 severe vibration of one or both engines, which could
cause in-flight engine shutdown, accomplish the following:
(a) Within 7 days after the effective date of this AD, review
the airplane maintenance records to determine the hours time-in-
service (TIS) accumulated on the bearings in the starter/generator
units of both engines, in accordance with Jetstream Alert Service
Bulletin J41-A24-036, dated February 26, 1996.
(1) If the bearings on both of the starter/generator units have
accumulated 300 or more hours TIS: Prior to further flight, replace
at least one of the starter/generator units with a unit having
bearings with less than 300 hours TIS, in accordance with the alert
service bulletin.
(2) If the bearings on one or both starter/generator units have
bearings with less than 300 hours TIS: Prior to the accumulation of
300 hours TIS on the bearings on both starter/generator units,
remove at least one of the units and replace it with a unit having
bearings with less than 300 hours TIS, in accordance with the alert
service bulletin.
(b) As a continuing requirement thereafter: Prior to the
accumulation of 300 hours TIS on the bearings on both of the
starter/generator units on the airplane, remove at least one of the
units and replace it with a unit having bearings with less than 300
hours TIS, in accordance with Jetstream Alert Service Bulletin J41-
A24-036, dated February 26, 1996.
(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.
(e) The actions shall be done in accordance with Jetstream Alert
Service Bulletin J41-A24-036, dated February 26, 1996. This
incorporation by reference was approved by the Director of the
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part
51. Copies may be obtained from Jetstream Aircraft, Inc., P.O. Box
16029, Dulles International Airport, Washington, DC 20041-6029.
Copies may be inspected at the FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington; or at the Office of the
Federal Register, 800 North Capitol Street, NW., suite 700,
Washington, DC.
(f) This amendment becomes effective on July 15, 1996.
[[Page 33650]]
Issued in Renton, Washington, on June 17, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 96-15954 Filed 6-27-96; 8:45 am]
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