94-31182. Airworthiness Directives; Jetstream Model ATP Airplanes  

  • [Federal Register Volume 59, Number 243 (Tuesday, December 20, 1994)]
    [Unknown Section]
    [Page 0]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 94-31182]
    
    
    [[Page Unknown]]
    
    [Federal Register: December 20, 1994]
    
    
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    DEPARTMENT OF TRANSPORTATION
    14 CFR Part 39
    
    [Docket No. 94-NM-168-AD]
    
     
    
    Airworthiness Directives; Jetstream Model ATP Airplanes
    
    AGENCY: Federal Aviation Administration, DOT.
    
    ACTION: Notice of proposed rulemaking (NPRM).
    
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    SUMMARY: This document proposes the adoption of a new airworthiness 
    directive (AD) that is applicable to certain Jetstream Model ATP 
    airplanes. This proposal would require installation of modified engine 
    de-ice timers, modification of the electrical wiring for the duct heat 
    of the engine air intake, and installation of a time delay for the de-
    ice system in the air intake duct of the right engine. This proposal 
    would also require associated revisions to the Airplane Flight Manual. 
    This proposal is prompted by reports of ice that accreted in the engine 
    air intake ducts and was ingested into the engine; this resulted in 
    engine power rollback (loss of engine power). The actions specified by 
    the proposed AD are intended to prevent loss of multiple engine power 
    during flight in icing conditions.
    
    DATES: Comments must be received by January 31, 1995.
    
    ADDRESSES: Submit comments in triplicate to the Federal Aviation 
    Administration (FAA), Transport Airplane Directorate, ANM-103, 
    Attention: Rules Docket No. 94-NM-168-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-168-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-168-AD, 1601 Lind Avenue, SW., Renton, Washington 
    98055-4056.
    
    Discussion
    
        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 ATP airplanes. 
    The CAA advises that probable ingestion of accreted ice, shed from the 
    inner surfaces of the engine air intake ducts, has resulted in engine 
    power rollbacks (loss of engine power) during flight in icing 
    conditions. Five reports have been received: three reports of power 
    rollback on two engines simultaneously, and two reports of power 
    rollback on one engine. Ingestion of accreted ice, if not prevented, 
    could result in multiple engine power rollback during flight in 
    freezing precipitation conditions.
        Jetstream has issued Service Bulletin ATP-30-39-30146A 
    (Modification 30146A), dated July 29, 1994, which describes procedures 
    for installing modified de-ice timers for the left and right engines. 
    The modified de-ice timers will provide additional electric power 
    directly to the engine air intake flange heater. This additional 
    electric load requires revision of electric load shedding procedures in 
    the event of electrical system failure. These procedures are included 
    in the Jetstream Aircraft ATP Airplane Flight Manual (AFM), Temporary 
    Revision T/41, Issue 1, dated November 15, 1994.
        Jetstream has also issued Service Bulletin ATP-30-37-30143A 
    (Modification 30143A), dated August 1, 1994, and Revision 1, dated 
    September 5, 1994, which describe procedures for installation of 
    modified electrical wiring for flexible ducts and lips of the engine 
    air intake. This modification automates turning on the de-ice heaters 
    in the flexible duct of the engine air intake when the lip heat is on. 
    The modification continues to allow pilots to select the de-ice systems 
    of the engine air intake manually, via the ``All On'' switch of the 
    anti-ice system.
        The CAA classified these service bulletins as mandatory, in order 
    to assure the continued airworthiness of these airplanes in the United 
    Kingdom.
        Jetstream has also issued Service Bulletin ATP-30-30-35285A, dated 
    July 15, 1994, which describes procedures for installation of a system 
    that automates a 20-second delay between the time that the left engine 
    intake de-ice systems are turned on and the time that the right engine 
    intake de-ice systems are turned on. This modification also reduces 
    pilot workload by automatically turning on the engine de-ice system at 
    an interval 20 seconds apart for the left and right engines when the 
    engine intake de-ice is selected to ``on.'' The automated 20-second 
    time delay ensures that the de-ice system for the left and right engine 
    intakes will be turned on in such a way as to prevent simultaneous 
    rollbacks of the engines in icing conditions. The CAA has not 
    classified this service bulletin as mandatory. However, the FAA has 
    determined that the pilot could easily neglect to heed the necessary 
    20-second delay if manually turning on the second flexible duct de-ice 
    system; this could cause accumulated ice in the air intake ducts of 
    both engines to dislodge simultaneously and be ingested into the 
    engines, which then could result in rollback of both engines at the 
    same time. In light of this, the FAA considers that the modification 
    described in this service bulletin is necessary.
        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 require installation of new 
    de-ice timers and an associated revision to the AFM; installation of a 
    system that automates a 20-second delay between turning on the left 
    engine intake de-ice system and turning on the right engine intake de-
    ice system; and installation of modified electrical wiring for the 
    flexible ducts and lips of the engine air intake. These actions would 
    be required to be accomplished in accordance with the service bulletins 
    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 requirement.
        The FAA estimates that 10 airplanes of U.S. registry would be 
    affected by this proposed AD, that it would take approximately 72 work 
    hours per airplane to accomplish the proposed actions, and that the 
    average labor rate is $60 per work hour. Required parts would be 
    provided by the manufacturer at no cost to the operators. Based on 
    these figures, the total cost impact of the proposed AD on U.S. 
    operators is estimated to be $43,200, or $4,320 per airplane.
        The total cost impact figure discussed above is based on 
    assumptions that no operator has yet accomplished any of the proposed 
    requirements of this AD action, and that no operator would accomplish 
    those actions in the future if this AD were not adopted.
        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 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
    106(g); and 14 CFR 11.89.
    
    
    Sec. 39.13  [Amended]
    
        2. Section 39.13 is amended by adding the following new 
    airworthiness directive:
    
    Jetstream Aircraft Limited (Formerly British Aerospace Commercial 
    Aircraft, Limited) Docket 94-NM-158-AD
    
        Applicability: Model ATP airplanes; having constructor numbers 
    2002 through 2063, 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 
    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 (c) 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 engine power rollback during flight in icing 
    conditions, due to ingestion of accreted ice, accomplish the 
    following:
        (a) For airplanes having constructor numbers 2002 through 2056, 
    inclusive: Within 90 days after the effective date of this AD, 
    install modified de-ice timers for the left and right engines 
    (Modification 30146A), in accordance with Jetstream Aircraft Limited 
    Service Bulletin ATP-30-39-30146A, dated July 29, 1994; and revise 
    the FAA-approved Airplane Flight Manual (AFM) to include the 
    information specified in Temporary Revision T/41, Issue 1, dated 
    November 15, 1994.
    
        Note 2: The revision of the AFM required by this paragraph may 
    be accomplished by inserting a copy of Temporary Revision T/41 in 
    the AFM. When this temporary revision has been incorporated into 
    general revisions of the AFM, the general revisions may be inserted 
    in the AFM, provided that the information contained in the general 
    revision is identical to that specified in Temporary Revision T/41.
    
        (b) For airplanes having constructor numbers 2002 through 2063, 
    inclusive: Within 90 days after the effective date of this AD, 
    accomplish paragraphs (b)(1) and (b)(2) of this AD:
        (1) Install the modified electrical wiring for the flexible 
    ducts and lips of the engine air intake (Modification 30143A) in 
    accordance with Jetstream Aircraft Limited Service Bulletin ATP-30-
    37-30143A, dated August 1, 1994, or Revision 1 dated September 5, 
    1994.
        (2) Install the automated 20-second delay system (Modification 
    35285A), to ensure that the left engine de-ice systems are turned on 
    prior to turning on the right engine de-ice systems, in accordance 
    with Jetstream Aircraft Limited Service Bulletin ATP-30-30-35285A, 
    dated July 15, 1994; and revise the FAA-approved AFM to include the 
    information specified in Temporary Revision T/40, Issue 1, dated 
    August 3, 1994.
    
        Note 3: The revision of the AFM required by this paragraph may 
    be accomplished by inserting a copy of Temporary Revision T/40 in 
    the AFM. When this temporary revision has been incorporated into 
    general revisions of the AFM, the general revisions may be inserted 
    in the AFM, provided the information contained in the general 
    revision is identical to that specified in Temporary Revision T/40.
    
        (c) 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 4: Information concerning the existence of approved 
    alternative methods of compliance with this AD, if any, may be 
    obtained from the Standardization Branch, ANM-113.
    
        (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.
    
        Issued in Renton, Washington, on December 14, 1994.
    Darrell M. Pederson,
    Acting Manager, Transport Airplane Directorate, Aircraft Certification 
    Service.
    [FR Doc. 94-31182 Filed 12-19-94; 8:45 am]
    BILLING CODE 4910-13-U
    
    
    

Document Information

Published:
12/20/1994
Department:
Transportation Department
Entry Type:
Uncategorized Document
Action:
Notice of proposed rulemaking (NPRM).
Document Number:
94-31182
Dates:
Comments must be received by January 31, 1995.
Pages:
0-0 (1 pages)
Docket Numbers:
Federal Register: December 20, 1994, Docket No. 94-NM-168-AD
CFR: (1)
14 CFR 39.13