[Federal Register Volume 63, Number 116 (Wednesday, June 17, 1998)]
[Proposed Rules]
[Pages 33018-33019]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-16024]



[[Page 33018]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-CE-32-AD]
RIN 2120-AA64


Airworthiness Directives; British Aerospace Jetstream Model 3101 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to certain British Aerospace Jetstream Model 3101 
airplanes. The proposed AD would require replacing the elevator trim 
servo motor with a new motor of improved design and inspecting the 
cable tension and electrical operation of the elevator and trim tab for 
proper operation and making any necessary adjustments. The proposed AD 
is the result of mandatory continuing airworthiness information (MCAI) 
issued by the airworthiness authority for the United Kingdom. The 
actions specified by the proposed AD are intended to prevent the 
elevator trim servo motor drive gear assembly from remaining engaged 
when the autopilot is disengaged, which could result in the pilot 
having to manually overpower the elevator trim control and possibly 
lose directional control of the airplane during critical phases of 
flight.

DATES: Comments must be received on or before July 24, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 98-CE-32-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106. Comments may be inspected at this location 
between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted.
    Service information that applies to the proposed AD may be obtained 
from British Aerospace Regional Aircraft, Prestwick International 
Airport, Ayrshire, KA9 2RW, Scotland; telephone: (01292) 479888; 
facsimile: (01292) 479703. This information also may be examined at the 
Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Mr. S.M. Nagarajan, Aerospace 
Engineer, FAA, Small Airplane Directorate, Aircraft Certification 
Service, 1201 Walnut, suite 900, Kansas City, Missouri 64106; 
telephone: (816) 426-6932; facsimile: (816) 426-2169.

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 should 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 that summarizes 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 No. 98-CE-32-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, Central Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 98-CE-32-AD, Room 1558, 601 E. 12th Street, Kansas 
City, Missouri 64106.

Discussion

    The Civil Airworthiness Authority (CAA), which is the airworthiness 
authority for the United Kingdom, notified the FAA that an unsafe 
condition may exist on certain British Aerospace Jetstream Model 3101 
airplanes that are equipped with an autopilot. The CAA reports that an 
elevator trim servo motor in the autopilot failed on a Jetstream Model 
3101 airplane, causing the pilot to use extreme force to manually 
rotate the elevator trim control handwheel. The investigation showed 
that the leaf spring in the solenoid assembly of the elevator trim 
servo motor fractured. This fracture caused the servo motor drive gear 
assembly to remain engaged, even with the solenoid de-energized and the 
autopilot disengaged. This condition occurs from residual magnetism in 
the solenoid core, which keeps the armature depressed.
    These conditions, if not corrected, could result in loss of 
directional control of the airplane during critical phases of flight.

Relevant Service Information

    British Aerospace has issued Jetstream Service Bulletin 22-A-JA 
860413, dated April 16, 1986, which specifies procedures for replacing 
the elevator trim servo motor; and Jetstream Alert Service Bulletin 22-
A-JA 851231, dated April 9, 1986, which specifies procedures for 
inspecting the cable tension and electrical operation of the elevator 
trim, along with testing and adjusting, if necessary, the friction and 
the electric trim manual override loads after the installation of the 
new elevator trim servo motor.
    The CAA classified these service bulletins as mandatory in order to 
assure the continued airworthiness of these airplanes in the United 
Kingdom. The CAA classifying a service bulletin as mandatory is the 
same in the United Kingdom as the FAA issuing an AD in the United 
States.

The FAA's Determination

    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, including the service information referenced 
above; and determined that AD action is necessary for products of this 
type design that are certificated for operation in the United States.

Explanation of the Provisions of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other British Aerospace Jetstream Model 3101 
airplanes of the same type design registered in the United States, the 
FAA is proposing AD action. The proposed AD would require replacing the 
elevator trim servo motor with one of improved design, inspecting the 
cable tension and electrical operation, testing the friction and the

[[Page 33019]]

electric trim manual override loads after the new motor is installed, 
and making any necessary adjustments. Accomplishment of the proposed 
modification would be in accordance with the service bulletins 
previously referenced.

Cost Impact

    The FAA estimates that 25 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 6 
workhours per airplane to accomplish the proposed action, and that the 
average labor rate is approximately $60 an hour. The manufacturer will 
provide parts at no cost to the owner/operator. Based on these figures, 
the total cost impact of the proposed AD on U.S. operators is estimated 
to be $9,000, or $360 per airplane.

Regulatory Impact

    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 action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under 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 has been placed 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 U.S.C. 106(g), 40113, 44701.

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
(AD) to read as follows:

British Aerospace: Docket No. 98-CE-32-AD.
    Applicability: Jetstream Model 3101 airplanes, certificated in 
any category, with the following serial numbers, that are equipped 
with an autopilot:

Serial Numbers

601   603   604   606   607   609
610   612   614   616   620   621
622   626   629   634   637   641
645   648   649   655   665   686
690

    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 (d) 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 within the next 100 hours time-in-service 
(TIS) after the effective date of this AD, unless already 
accomplished.
    To prevent the elevator trim servo motor drive gear assembly 
from remaining engaged when the autopilot is disengaged, which could 
result in the pilot having to manually overpower the elevator trim 
control, and possibly lose directional control of the airplane 
during critical phases of flight, accomplish the following:
    (a) Replace the elevator trim servo motor with a new elevator 
trim servo motor of improved design at fuselage station (F.S.) 421, 
aft of the rear bulkhead, in accordance with the ACCOMPLISHMENT 
INSTRUCTIONS section in JETSTREAM Alert Service Bulletin (SB) 22-A-
JA 860413, ORIGINAL ISSUE: April 16, 1986.
    (b) Inspect the cable tension, system friction, and electric 
trim manual override and make any necessary adjustments in 
accordance with the ACCOMPLISHMENT INSTRUCTIONS section in JETSTREAM 
SB No. 22-A-JA 851231, ORIGINAL ISSUE: April 9, 1986.
    (c) 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.
    (d) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Small Airplane Directorate, Aircraft 
Certification Service, 1201 Walnut, suite 900, Kansas City, Missouri 
64106. The request shall be forwarded through an appropriate FAA 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Small Airplane Directorate.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Small Airplane Directorate.

    (e) Questions or technical information related to British 
Aerospace Jetstream Service Bulletin 22-A-JA 851231, dated April 9, 
1986, and Jetstream Alert Service Bulletin 22-A-JA 860413, dated 
April 16, 1986, should be directed to British Aerospace Regional 
Aircraft, Prestwick International Airport, Ayrshire, KA9 2RW, 
Scotland; telephone: (01292) 479888; facsimile: (01292) 479703. This 
service information may be examined at the FAA, Central Region, 
Office of the Regional Counsel, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

    Note 3: The subject of this AD is addressed in British Aerospace 
Jetstream Service Bulletin 22-A-JA 851231, dated April 9, 1986, and 
British Aerospace Jetstream Service Bulletin 22-A-JA 860413, dated 
April 16, 1998. These service bulletins are classified as mandatory 
by the United Kingdom Civil Aviation Authority (CAA).

    Issued in Kansas City, Missouri, on June 9, 1998.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-16024 Filed 6-16-98; 8:45 am]
BILLING CODE 4910-13-U