AircraftDirectives
aircraftdirectives.com · Operated by Aircraft Directives 2026
Airworthiness Directive packet

AD 98-21-14

Airworthiness Directives; British Aerospace Jetstream Model 3101 Airplanes

1 · Quick read — prepared by AircraftDirectives

Our plain-language summary — not the regulation

Requires modifying the airplane's navigational system by shortening and re-clipping the cable looms to the No.

AD number
98-21-14
Federal Register document
98-26969
Citation
63 FR 54564
Amendment
39-10823
Docket
Docket No. 98-CE-33-AD
Action
Final rule; request for comments.
Published
1998-10-13
Effective
1998-11-02
Effective (as stated in the rule)
Effective November 2, 1998.
Issued by
Transportation Department, Federal Aviation Administration
Regulation
14 CFR 39
Applies to (in our index)
British Aerospace Jetstream 31/32

2 · Official Federal Register document — government source, verbatim

Reproduced unedited from the Federal Register
[Federal Register Volume 63, Number 197 (Tuesday, October 13, 1998)]
[Rules and Regulations]
[Pages 54564-54565]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-26969]


[[Page 54564]]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-CE-33-AD; Amendment 39-10823; AD 98-21-14]
RIN 2120-AA64


Airworthiness Directives; British Aerospace Jetstream Model 3101 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to certain British Aerospace Jetstream Model 3101 airplanes. 
This AD requires modifying the airplane's navigational system by 
shortening and re-clipping the cable looms to the No. 1 and No. 2 
vertical gyroscopes, installing a warning label adjacent to the 
gyroscopes, and performing an operational check on the system. This AD 
is the result of mandatory continuing airworthiness information (MCAI) 
issued by the airworthiness authority for the United Kingdom. The 
actions specified by this AD are intended to prevent a cross connection 
in the No. 1 and No. 2 vertical gyroscopes, which could result in 
navigational errors during flight.

DATES: Effective November 2, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 2, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before November 1, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket 98-CE-33-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.
    Service information that applies to this AD may be obtained from 
British Aerospace Regional Aircraft, Prestwick International Airport, 
Ayrshire, KA9 2RW, Scotland; telephone: (01292) 479888; facsimile: 
(01292) 479703. This information may also be examined at the Federal 
Aviation Administration (FAA), Central Region, Office of the Regional 
Counsel, Attention: Rules Docket 98-CE-33-AD, Room 1558, 601 E. 12th 
Street, Kansas City, Missouri 64106; or at the Office of the Federal 
Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

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

SUPPLEMENTARY INFORMATION:

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. The CAA reports that the navigational system in these 
airplanes could malfunction with a cross connection of the No. 1 and 
No. 2 vertical gyroscopes.
    This condition, if not corrected, could result in navigational 
errors during flight.

Relevant Service Information

    British Aerospace has issued Jetstream Service Bulletin (SB) 34-JA 
891143, dated March 2, 1990, which specifies procedures for modifying 
the navigation system by shortening and re-clipping the cable looms of 
the No. 1 and No. 2 vertical gyroscopes, installing a warning label, 
part number (P/N) JA-891143-K1, next to the vertical gyroscopes, and 
performing an operational check to assure the gyroscopes are operating 
correctly.

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 This AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Jetstream Model 3101 airplanes of the same 
type design, this AD requires modifying the navigation system by 
shortening and re-clipping the cable looms on the No. 1 and No. 2 
vertical gyroscopes, installing a warning label adjacent to the 
vertical gyroscopes, and performing an operational check to assure 
correct operation of the vertical gyroscopes. The actions are to be 
done in accordance with the instructions in British Aerospace Jetstream 
SB 34-JA 891143, dated March 2, 1990.

Cost Impact

    None of the Jetstream Model 3101 airplanes affected by this action 
are on the U.S. Register. All airplanes included in the applicability 
of this rule currently are operated by non-U.S. operators under foreign 
registry; therefore, they are not directly affected by this AD action. 
However, the FAA considers this rule necessary to ensure that the 
unsafe condition is addressed in the event that any of these subject 
airplanes are imported and placed on the U.S. Register.
    Should an affected airplane be imported and placed on the U.S. 
Register, accomplishment of the required modification would take 
approximately 8 workhours at an average labor charge of $60 per 
workhour. Based on these figures, the total cost impact of this AD 
would be $480 per airplane that would become registered in the United 
States.

The Effective Date of This AD

    Since this AD action does not affect any airplane that is currently 
on the U.S. register, it has no adverse economic impact and imposes no 
additional burden on any person. Therefore, notice and public 
procedures hereon are unnecessary and the amendment may be made 
effective in less than 30 days after publication in the Federal 
Register.

Comments Invited

    Although this action is in the form of a final rule and 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 action and determining whether additional 
rulemaking action would be needed.
    Comments are specifically invited on the overall regulatory, 
economic,

[[Page 54565]]

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 No. 98-CE-33-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.
    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) 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, 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 a new airworthiness directive 
(AD) to read as follows:

98-21-14  British Aerospace: Amendment 39-10823; Docket No. 98-CE-
33-AD.

    Applicability: Jetstream Model 3101 airplanes, serial numbers 703, 
705, and 707, 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 (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 prior to further flight after the effective 
date of this AD, unless already accomplished.
    To prevent a cross connection in the No. 1 and No. 2 vertical 
gyroscopes, which could result in navigational errors during flight, 
accomplish the following:
    (a) Modify the navigation system by shortening and re-clipping 
the cable looms on the No. 1 and No. 2 vertical gyroscope in 
accordance with the Accomplishment Instructions section of Jetstream 
Service Bulletin No. 34-JA 891143, dated March 2, 1990.
    (b) Install a warning label, part number JA-891143-K1 or an FAA-
approved equivalent part number, adjacent to the No. 1 and No. 2 
vertical gyroscope in accordance with the Accomplishment 
Instructions section of Jetstream Service Bulletin No. 34-JA 891143, 
dated March 2, 1990.
    (c) Perform an operational check of the No. 1 and No. 2 vertical 
gyroscope in accordance with the Accomplishment Instructions section 
of Jetstream Service Bulletin No. 34-JA 891143, dated March 2, 1990. 
If the vertical gyroscopes do not operate correctly, prior to 
further flight, correct any discrepancies in accordance with the 
Accomplishment Instructions section of Jetstream Service Bulletin 
No. 34-JA 891143, dated March 2, 1990.
    (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) 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.

    (f) Questions or technical information related to British 
Aerospace Jetstream SB 34-JA 891143, dated March 2, 1990, 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.
    (g) The modification and operational check required by this AD 
shall be done in accordance with British Aerospace Jetstream Service 
Bulletin 34-JA 891143, dated March 2, 1990. 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 British Aerospace Regional Aircraft, Prestwick 
International Airport, Ayrshire, KA9 2RW, Scotland. Copies may be 
inspected at the FAA, Central Region, Office of the Regional 
Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at 
the Office of the Federal Register, 800 North Capitol Street, NW, 
suite 700, Washington, DC.

    Note 3: The subject of this AD is addressed in British Aerospace 
Jetstream SB 34-JA 891143, dated March 2, 1990. This service 
bulletin is classified as mandatory by the United Kingdom Civil 
Aviation Authority (CAA).

    (h) This amendment becomes effective on November 2, 1998.

    Issued in Kansas City, Missouri, on September 30, 1998.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-26969 Filed 10-9-98; 8:45 am]
BILLING CODE 4910-13-P

Sources. Section 1 is written by AircraftDirectives from the record below and is a reading aid only. Section 2 is the United States Government's own text, reproduced without edit.

Federal Register: https://www.federalregister.gov/documents/1998/10/13/98-26969/airworthiness-directives-british-aerospace-jetstream-model-3101-airplanes

Official PDF: https://www.govinfo.gov/content/pkg/FR-1998-10-13/pdf/98-26969.pdf

Packet generated 2026-08-18 08:14 UTC.

This packet is not an airworthiness determination and not legal or maintenance advice. AircraftDirectives reproduces official records and condenses their wording for easier reading. It does not decide, certify or imply whether any aircraft, engine, appliance or part is airworthy, compliant, affected by this directive, or eligible for return to service. No inspection, approval, or determination of any kind is performed or implied by this document.

Section 1 is a reading aid, not the rule. It is our own plain-language condensation, written to help a reader find the relevant directive quickly. It is NOT a substitute for the regulation, it may omit conditions, exceptions, compliance times, alternative methods of compliance (AMOCs) and applicability limits, and it has no legal force whatsoever. Only the official text governs. Where Section 1 and Section 2 differ in any respect, Section 2 - and the official source it was retrieved from - controls absolutely.

Responsibility remains with the owner/operator. Under 14 CFR §91.403 and §91.417 the owner or operator is responsible for maintaining airworthiness and for required records; under §39.7 no person may operate a product to which an airworthiness directive applies except in accordance with that directive. Determining applicability to a specific serial number and configuration, and performing or supervising any required action, is the responsibility of the owner/operator and appropriately certificated personnel.

Accuracy and currency. Section 2 was retrieved at the time stamped above and is reproduced without edit; Federal Register material is a work of the United States Government. Directives are amended, corrected and superseded over time, and this sheet is a snapshot, not a live record - it does not update after printing. Re-check the official sources before acting on it. This packet is provided without warranty of any kind, express or implied, including fitness for a particular purpose. We do not sell parts and have no commercial interest in any action a directive may require.

AircraftDirectives · AD 98-21-14 · Section 1 is our plain-language reading aid; Section 2 is the official Federal Register text and controls where the two differ. Not an airworthiness determination — 14 CFR §91.403 / §91.417 responsibility remains with the owner/operator. Retrieved 2026-08-18 08:14 UTC.