AD 97-04-05

[Federal Register Volume 62, Number 33 (Wednesday, February 19, 1997)]
[Rules and Regulations]
[Pages 7340-7343]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-3535]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-234-AD; Amendment 39-9929; AD 97-04-05]
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 certain Jetstream Model 4101 airplanes. This action 
requires a one-time inspection of the airplane records to determine the 
modification status of the elevator trim servo, and, if necessary, 
inspections to determine the serial number of the servo, and repetitive 
inspections for looseness or movement of the motor housing of the 
servo. This action also requires replacement of certain elevator trim 
servos with a serviceable assembly. This

[[Page 7341]]

amendment is prompted by reports of the motor housing separating from 
the elevator trim servo and the consequent release of certain component 
parts, due to inadequate locking of screws that were installed during 
assembly of the servos. The actions specified in this AD are intended 
to prevent the motor housing of the elevator trim servo from separating 
and releasing component parts that could lodge in and jam the elevator 
controls, and result in reduced pitch control of the airplane.

DATES: Effective March 6, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 6, 1997.
    Comments for inclusion in the Rules Docket must be received on or 
before April 21, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-234-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 certain Jetstream Model 
4101 airplanes The CAA advises that it has received reports indicating 
that separation of the motor housing from the elevator trim servo and 
consequent release of motor gearbox components has occurred on a 
Jetstream Model 4101 airplane. Investigation revealed that certain 
elevator trim servo units manufactured by Honeywell were assembled 
using screws with inadequate locking capability. Certain of these 
screws fasten the servo motor inner gear casing to the mounting flange 
and some screws fasten the motor cap/sleeve to the inner gear casing. 
The inadequate locking of those screws caused the separation of the 
motor housing from the servo unit, and resulted in the release of the 
motor gearbox components. Those released components could lodge in the 
elevator controls and result in an elevator jam. This condition, if not 
corrected, could result in reduced control of the primary pitch control 
of the airplane.

Explanation of Relevant Service Information

    Jetstream has issued Alert Service Bulletin J41-A22-008, Revision 
1, dated November 21, 1996, which describes the following procedures:
    1. A one-time inspection of the airplane records or a visual 
inspection of the servo to determine if the elevator trim servo is at 
Modification B standard or greater.
    2. For those airplanes on which the elevator trim servo is not at 
Modification B or greater, the alert service bulletin describes 
procedures for an inspection of the airplane records or a visual 
inspection of the elevator trim servo to determine the serial number of 
the elevator trim servo, procedures for repetitive visual and tactile 
inspections of the motor housing of the elevator trim servo to 
determine if the motor housing is loose or moves, and repair of 
replacement of the elevator trim servo with a serviceable servo, if 
necessary. Replacement of the servo with a serviceable assembly would 
eliminate the need for repetitive inspections of the motor housing. The 
alert service bulletin also describes procedures for replacement of 
certain servos specified in the alert service bulletin with a servo at 
Modification B or later standard.
    The CAA classified this service bulletin as mandatory 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 the motor 
housing of the elevator trim servo from separating from the servo 
assembly and releasing component parts that could lodge in and jam the 
elevator control, and result in reduced pitch control of the airplane. 
This AD requires the following:
    1. A one-time inspection of the airplane records or a visual 
inspection of the servo to determine if the elevator trim servo is at 
Modification B standard or greater.
    2. For those airplanes on which the elevator trim servo is not at 
Modification B standard or greater, an inspection of the airplane 
records to determine the serial number of the elevator trim servo, 
repetitive visual and tactile inspections of the motor housing of the 
elevator trim servo to determine if the motor housing is loose or 
moves, and replacement of the elevator trim servo with a serviceable 
servo, as necessary.
    3. Replacement of certain elevator trim servos with a serviceable 
assembly.
    The actions are required to be accomplished in accordance with the 
alert service bulletin described previously.

Determine of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this 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 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

[[Page 7342]]

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-234-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:

97-04-05 Jetstream: Amendment 39-9929. Docket 96-NM-234-AD.

    Applicability: Model 4101 airplanes having serial numbers 41004 
through 41090 inclusive, 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 (e) 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 separation of the motor housing of the elevator trim 
servo from the servo body that would allow detachment of component 
parts that could lodge in and jam the elevator control, and result 
in reduced control of the primary pitch of the airplane; accomplish 
the following:

    Note 2: Accomplishment of actions required by this AD in 
accordance with Jetstream Alert Service Bulletin J41-A22-008, dated 
July 18, 1996, is not considered acceptable for compliance with the 
applicable action specified in this AD.

    (a) Within 14 days after the effective date of this AD: Perform 
either an inspection of the airplane records or a visual inspection 
of the elevator trim servo, to determine if the elevator trim servo 
is at Modification B standard or greater, in accordance with 
Jetstream Alert Service Bulletin J41-A22-008, Revision 1, dated 
November 21, 1996.
    (b) If the inspection required by paragraph (a) of this AD 
reveals that the elevator trim servo is at Modification B standard 
or greater: No further action is required by this AD.
    (c) If the inspection required by paragraph (a) of this AD 
reveals that the elevator trim servo is not at Modification B 
standard or greater: Prior to further flight, perform either an 
inspection of the airplane records or a visual inspection of the 
elevator trim servo, to determine if the serial number of the 
elevator trim servo is specified in paragraph 1.M.(4)(b) of 
Jetstream Alert Service Bulletin J41-A22-008, Revision 1, dated 
November 21, 1996; and, regardless of the serial number, perform 
both a visual inspection and a tactile inspection of the motor 
housing of the elevator trim servo to determine if the motor housing 
is loose or moves, in accordance with the alert service bulletin.
    (1) If the motor housing does not move and is not loose, and the 
elevator trim servo does not have a serial number that is specified 
in paragraph 1.M(4)(b) of the alert service bulletin: No further 
action is required by this AD.
    (2) If the motor housing does not move and is not loose, but the 
elevator trim servo has a serial number that is specified in 
paragraph 1.M(4)(b) of the alert service bulletin: Repeat the visual 
and tactile inspections of the elevator trim servo thereafter at 
intervals not to exceed 50 hours time-in-service, until the 
requirements of paragraph (d) of this AD are accomplished.
    (3) If the motor housing moves or is loose, regardless of serial 
number: Prior to further flight, accomplish the requirements of 
either paragraph (c)(3)(i) or (c)(3)(ii) of this AD:
    (i) Secure the elevator trim servo and deactivate the autopilot 
system, in accordance with Part 3 of the Accomplishment Instructions 
of the alert service bulletin. Thereafter, repeat the visual and 
tactile inspections at intervals not to exceed 50 hours time-in-
service, until the requirements of paragraph (d) of this AD are 
accomplished. Or
    (ii) Replace the elevator trim servo with an ``acceptable 
replacement'' servo, as defined by the ``Note'' in Paragraph 2., 
Accomplishment Instructions, of Jetstream Alert Service Bulletin 
J41-A22-008, Revision 1, dated November 21, 1996. Accomplish the 
replacement in accordance with Part 4 of the Accomplishment 
Instructions of the alert service bulletin. Accomplishment of this 
replacement constitutes terminating action for the repetitive 
inspections required by this AD.
    (d) For airplanes subject to paragraph (c)(2) or (c)(3)(i) of 
this AD: Within 90 days after the effective date of this AD, replace 
the elevator trim servo with an ``acceptable replacement'' servo, as 
defined by the ``Note'' in Paragraph 2., Accomplishment 
Instructions, of Jetstream Alert Service Bulletin J41-A22-008, 
Revision 1, dated November 21, 1996. Accomplish the replacement in 
accordance with Part 4 of the Accomplishment Instructions of the 
alert service bulletin. Accomplishment of this replacement 
constitutes terminating action for the repetitive inspections 
required by this AD.
    (e) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (f) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199

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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.
    (g) The actions shall be done in accordance with Jetstream Alert 
Service Bulletin J41-A22-008, Revision 1, dated November 21, 1996, 
which contains the specificed list of effective pages:

------------------------------------------------------------------------
                                   Revision level                       
             Page No.               shown on page    Date shown on page 
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1-10, 15.........................               1  November 21,1996.    
11-14, 16, 17....................           (\1\)  July 18, 1996.       
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\1\ Original.                                                           

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.
    (h) This amendment becomes effective on March 6, 1997.

    Issued in Renton, Washington, on February 6, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-3535 Filed 2-18-97; 8:45 am]
BILLING CODE 4910-13-M