[Federal Register Volume 61, Number 191 (Tuesday, October 1, 1996)]
[Rules and Regulations]
[Pages 51212-51213]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-25039]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

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; correction.

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SUMMARY: This amendment clarifies information in an existing 
airworthiness directive (AD), applicable to all Jetstream 4101 
airplanes, that currently requires a review of maintenance records to 
determine the time-in-service of the bearings in the starter/generators 
of both engines. It also establishes a new time-in-service limit for 
the bearings, and requires replacement of the starter/generator unit 
with a serviceable unit, if necessary. The actions specified in that AD 
are intended to prevent failure of the bearings of the starter/
generator, which could cause severe vibrations and resultant in-flight 
shutdown of one or both engines. This amendment clarifies the 
requirements of the current AD by specifying the name of the 
manufacturer of the starter/generator units that are affected by the 
requirements of this AD.

DATES: Effective July 15, 1996.
    The incorporation by reference of certain publications listed in 
the regulations was approved previously by the Director of the Federal 
Register as of July 15, 1996 (61 FR 33647, June 28, 1996).

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: On June 17, 1996, the FAA issued AD 96-13-
09, amendment 39-9677 (61 FR 33647, June 28, 1996), which is applicable 
to all Jetstream Model 4101 airplanes. That AD requires a review of 
maintenance records to determine the time-in-service of the bearings in 
the starter/generators of both engines. It also establishes a new time-
in-service limit for the bearings, and requires replacement of the 
starter/generator unit with a serviceable unit, if necessary. That AD 
was prompted by reports of controlled in-flight engine shutdowns 
resulting from severe vibration caused by the failure of the bearings 
in the direct current (DC) starter/generator unit. The actions 
specified in that 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.

Actions Since Issuance of AD 96-13-09

    Since the issuance of that AD, the FAA has been advised that there 
may be confusion on the part of operators as to which specific make and 
model of starter/generator units are susceptible to the bearing problem 
and should be subject to the requirements of the AD. Additionally, 
operators of airplanes other than Jetstream Model 4101 airplanes may be 
confused as to whether starter/generator units installed on those 
airplanes are also susceptible to the bearing problem. Such confusion 
arises because the name of the manufacturer of the affected units was 
not specified in AD 96-13-09.
    The FAA notes that there are several manufacturers of starter/
generator units, but only those manufactured by Lucas Aerospace Power 
Systems for Jetstream Model 4101 airplanes are installed on the 
affected airplanes and are subject to

[[Page 51213]]

the AD. Lucas Aerospace Power Systems starter/generator units installed 
on other makes and models of airplanes are not affected by this AD. 
Likewise, other makes and models of starter/generator units installed 
on airplanes other than the Model 4101 are not affected by this AD.
    In light of the possible confusion that may have been created 
relative to this point, the FAA finds that AD 96-13-09 should be 
clarified to specify the name of the manufacturer of the affected 
starter/generator units.
    In all other respects, however, the AD is correct and adequate as 
issued.

Action Taken by FAA

    Action is taken herein to clarify AD 96-13-09 by identifying the 
name of the manufacturer of the subject starter/generators, and to 
correctly add the AD as an amendment to section 39.13 of the Federal 
Aviation Regulations (14 CFR 39.13).
    The final rule is being reprinted in its entirety for the 
convenience of affected operators. The effective date remains July 15, 
1996.
    Since this action only clarifies a current requirement, it has no 
adverse economic impact and imposes no additional burden on any person. 
Therefore, notice and public procedures hereon are unnecessary.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Correction

    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 correctly 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 Lucas Aerospace 
Power Systems 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 Lucas 
Aerospace Power Systems starter/generator units on the airplane, 
remove at least one of those 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 Jetstream Alert 
Service Bulletin J41-A24-036, dated February 26, 1996. This 
incorporation by reference was approved previously by the Director 
of the Federal Register, in accordance with 5 U.S.C. 552(a) and 1 
CFR part 51, as of July 15, 1996 (61 FR 33647, June 28, 1996). 
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.

    Issued in Renton, Washington, on September 24, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-25039 Filed 9-30-96; 8:45 am]
BILLING CODE 4910-13-U