[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