[Federal Register Volume 60, Number 174 (Friday, September 8, 1995)]
[Proposed Rules]
[Pages 46792-46794]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-22302]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 94-NM-237-AD]
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 supersedure of an existing
airworthiness directive (AD), applicable to certain Jetstream Model
4101 airplanes, that currently requires repetitive purging of the
hydraulic system and installation of a spoiler actuator that has been
previously certified. That AD was prompted by a report of damage to the
locking mechanisms on some pistons of the spoiler actuators. The
actions specified by the AD are intended to prevent uncommanded
extension of the lift spoiler in the event of loss of hydraulic
pressure in the spoiler actuator. This action would establish an
increased life limit for certain spoiler actuators, and provide an
optional terminating action for the requirements of the AD. It would
also limit the applicability of the rule to fewer airplanes.
DATES: Comments must be received by October 16, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 94-NM-237-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) 227-1320.
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 94-NM-237-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. 94-NM-237-AD, 1601 Lind Avenue, SW., Renton, Washington
98055-4056.
Discussion
On August 12, 1994, the FAA issued AD 94-17-12, amendment 39-9007
(59 FR 43025, August 22, 1994), applicable to certain Jetstream Model
4101 airplanes, to require repetitive purging of the hydraulic system
and repetitive installation of an actuator that has been previously
certified. That action was prompted by a report of damage to the
locking mechanisms on some pistons of the spoiler actuators. The cause
of this damage has been attributed to inadequate purging of the spoiler
hydraulic system. In some instances, the spoiler operation was out of
sequence and may have caused damage to the locking mechanisms on the
pistons of the spoiler actuators. The requirements of that AD are
intended to prevent uncommanded extension of the lift spoiler in the
event of loss of hydraulic pressure in the spoiler actuator.
Since the issuance of that AD, the Civil Aviation Authority (CAA),
which is the airworthiness authority for the United Kingdom, has
advised the FAA that a standard life limit has been established for
Lucas Aerospace spoiler actuators having part numbers TY1763-01A and
TY1763-01B. The new life limit has been established at the current
declaration of design performance (DDP) life of 5,000 hours time-in-
service since new. Therefore, unless a spoiler actuator would fail to
perform correctly beforehand, these actuators are permitted to remain
installed on the airplane for an interval not to exceed 5,000 hours
time-in-service, at which time they must be replaced. The CAA also has
advised that compliance with this 5,000-hour life limit on these
particular spoiler actuators terminates the need for the currently
required repetitive purging of the actuators' hydraulic system and
repetitive installation of newly-certified actuators (those marked with
an ``R'' after the serial number) each 500 hours time-in-service.
Additionally, the CAA has advised that, based on further review,
fewer airplanes are subject to the identified unsafe condition than
previously considered.
Jetstream has issued Service Bulletin J41-A27-034, Revision 1,
dated October 28, 1994, which describes procedures for a one-time
removal of the left and
[[Page 46793]]
right spoiler actuators, purging the hydraulic system, and installation
of a previously certified spoiler actuator. This revised service
bulletin specifies a life limit of 5,000 hours time-in-service for
certain Lucas Aerospace spoiler actuators; if these spoiler actuators
are replaced at this life limit, the need for repetitive purging of the
hydraulic system and repetitive installation of newly-certified
actuators is eliminated. Additionally, the effectivity listing of the
revised service bulletin eliminates certain airplanes that were
specified in the original issue of the service bulletin; these
airplanes have been eliminated because they have been determined not to
be subject to the addressed unsafe condition. The CAA classified this
revised service bulletin as mandatory in order to assure the continued
airworthiness of these airplanes in the United Kingdom.
Jetstream has also issued Service Bulletin J41-27-037, dated
November 7, 1994, which describes the installation of Modification JM
41381. This modification involves the installation of improved spoiler
actuators (having improved purging capability) on the left and right
wings. Installation of these improved actuators eliminates: (1) the
need for repetitive purging of the hydraulic system and repetitive
installation of newly-certified actuators; and (2) the need for a 5,000
hour time-in-service life limit on the (Lucas Aerospace) actuators. The
CAA classified this revised service bulletin as optional.
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.
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 supersede AD 94-17-12. It
would continue to require repetitive purging of the hydraulic system
and installation of an actuator that has been previously certified
marked with an ``R'' after the serial number. These actions are
required to be performed every 500 landings.
This proposal would revise the existing AD by requiring that
certain Lucas Aerospace spoiler actuators be replaced at intervals of
5,000 hours time-in-service (on the actuator). Such replacement would
terminate the current requirement to repetitively purge the hydraulic
system and install newly-certified actuators every 500 landings. It
would also revise the applicability of the existing rule to delete
certain airplanes. The actions would be required to be accomplished in
accordance with Jetstream Service Bulletin J41-A27-034, Revision 1,
described previously.
This proposal would also provide for an optional action to
terminate both the repetitive purging and installation requirements, as
required by the existing AD; and the 5,000 hour time-in-service life
limit on certain actuators, as required by this new AD. This optional
terminating action consists of installing improved actuators
(Modification JM 41381) in accordance with Jetstream Service Bulletin
J41-27-037, described previously.
As a result of recent communications with the Air Transport
Association (ATA) of America, the FAA has learned that, in general,
some operators may misunderstand the legal effect of AD's on airplanes
that are identified in the applicability provision of the AD, but that
have been altered or repaired in the area addressed by the AD. The FAA
points out that all airplanes identified in the applicability provision
of an AD are legally subject to the AD. If an airplane has been altered
or repaired in the affected area in such a way as to affect compliance
with the AD, the owner or operator is required to obtain FAA approval
for an alternative method of compliance with the AD, in accordance with
the paragraph of each AD that provides for such approvals. A note has
been included in this notice to clarify this long-standing requirement.
The FAA estimates that 17 airplanes of U.S. registry would be
affected by this proposed AD.
The repetitive purging and installation actions that are currently
required by AD 94-17-12 take approximately 6 work hours per airplane to
accomplish, at an average labor rate of $60 per work hour. Based on
these figures, the total cost impact on U.S. operators of the actions
currently required is estimated to be $6,120, or $360 per airplane.
Replacement of the spoiler actuator at the newly established life
limit would add no new costs to affected operators. In fact, it would
reduce the economic burden for most operators, since: (1) Repetitive
purging of the actuators would be eliminated, and (2) replacement of
the actuators will not have to be accomplished as often as was
previously required. Additionally, some of the replacement actuators
would be provided to operators free of charge by the manufacturer.
Further, since this proposed AD would be applicable to fewer
airplanes than was AD 94-17-12, the total cost impact of the AD would
be reduced by the amount of labor and parts costs that would previously
have been applied to those additional airplanes.
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 USC 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-9007 (59 FR
[[Page 46794]]
43025, August 22, 1994), and by adding a new airworthiness directive
(AD), to read as follows:
Jetstream Aircraft, Limited: Docket 94-NM-237-AD. Supersedes AD
94-17-12, Amendment 39-9007.
Applicability: Model 4101 airplanes; having constructors numbers
41004 through 41015 inclusive, 41018 through 41026 inclusive, 41028
through 41030 inclusive, and 41032; 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 use the authority
provided in paragraph (d) of this AD to request approval from the
FAA. This approval may address either no action, if the current
configuration eliminates the unsafe condition; or different actions
necessary to address the unsafe condition described in this AD. Such
a request should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any airplane from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent uncommanded extension of the lift spoiler in the
event of loss of hydraulic pressure in the spoiler actuator,
accomplish the following:
(a) Within 21 days after September 6, 1994 (the effective date
of AD 94-17-12, amendment 39-9007), remove the spoiler actuators in
accordance with Jetstream Alert Service Bulletin J41-A27-034, dated
June 9, 1994, or Revision 1, dated October 28, 1994. Following
removal of the actuators, accomplish the requirements of paragraphs
(a)(1) and (a)(2) of this AD, in accordance with the service
bulletin. Thereafter, repeat the requirements of this paragraph at
intervals not to exceed 500 landings.
(1) Prior to further flight, purge the hydraulic system to
ensure that there is no contamination.
(2) Prior to further flight, install a spoiler actuator that has
been previously certified and marked with an ``R'' after the serial
number on the nameplate of the actuator.
(b) For spoiler actuators having Lucas Aerospace part number (P/
N) TY1763-01A or P/N TY1763-01B: Prior to the accumulation of 5,000
total hours time-in-service on the spoiler actuator, or within 30
days after the effective date of this AD, whichever occurs later,
replace the actuator with a new or serviceable part, in accordance
with Jetstream Service Bulletin J41-A27-034, Revision 1, dated
October 28, 1994. Thereafter, prior to the accumulation of 5,000
hours time-in-service on the spoiler actuator, replace the actuator
with a new or serviceable part, in accordance with the service
bulletin. Such replacement constitutes terminating action for the
repetitive purging and repetitive installation requirements of
paragraph (a) of this AD.
(c) Installation of improved spoiler actuators (Modification JM
41381) on the left and right wings, in accordance with Jetstream
Service Bulletin J41-27-037, dated November 7, 1994, constitutes
terminating action for the requirements of paragraphs (a) and (b) of
this AD.
(d) 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.
(e) 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 September 1, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-22302 Filed 9-7-95; 8:45 am]
BILLING CODE 4910-13-O
