96-33104. Airworthiness Directives; Boeing Model 737 Series Airplanes  

  • [Federal Register Volume 62, Number 1 (Thursday, January 2, 1997)]
    [Rules and Regulations]
    [Pages 15-16]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 96-33104]
    
    
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    DEPARTMENT OF TRANSPORTATION
    14 CFR Part 39
    
    [Docket No. 96-NM-266-AD; Amendment 39-9871; AD 96-26-07]
    RIN 2120-AA64
    
    
    Airworthiness Directives; Boeing Model 737 Series 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 all Boeing Model 737 series airplanes. This action 
    requires revising the FAA-approved Airplane Flight Manual (AFM) to 
    include procedures that will enable the flight crew to take appropriate 
    action to maintain control of the airplane during an uncommanded yaw or 
    roll condition, and to correct a jammed or restricted flight control 
    condition. This amendment is prompted by an FAA determination that such 
    procedures currently are not defined adequately in the AFM for these 
    airplanes. The actions specified in this AD are intended to ensure that 
    the flight crew is advised of the potential hazard associated with a 
    jammed or restricted flight control condition and of the procedures 
    necessary to address it.
    
    DATES: Effective January 17, 1997.
        Comments for inclusion in the Rules Docket must be received on or 
    before March 3, 1997.
    
    ADDRESSES: Submit comments in triplicate to the Federal Aviation 
    Administration (FAA), Transport Airplane Directorate, ANM-103, 
    Attention: Rules Docket No. 96-NM-266-AD, 1601 Lind Avenue, SW., 
    Renton, Washington 98055-4056.
        The information concerning this amendment may be obtained from or 
    examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, 
    SW., Renton, Washington.
    
    FOR FURTHER INFORMATION CONTACT: Les Berven, Flight Test Pilot, Flight 
    Test Branch, ANM-160S, Seattle Aircraft Certification Office, FAA, 
    Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
    Washington 98055-4056; telephone (206) 227-2666; fax (206) 227-1181.
    
    SUPPLEMENTARY INFORMATION: As part of its Continuing Operational Safety 
    Program, the FAA has become aware of new information related to the 
    safety of Boeing Model 737 series airplanes. Recent tests of the main 
    rudder power control unit (PCU), conducted at Boeing, demonstrated a 
    potential failure scenario that was previously unknown. These tests 
    revealed that, if the secondary slide of the PCU jams in certain 
    positions, rudder pedal input can cause deformation in the linkage 
    leading to the primary and secondary slides of the servo valve of the 
    main rudder PCU. This situation could result in rudder deflection in 
    the opposite direction of the rudder command, and a jammed rudder.
    
    Other Relevant Rulemaking
    
        The conditions described previously were addressed previously in AD 
    96-23-51, amendment 39-9818 (61 FR 59317, November 22, 1996), which is 
    applicable to all Boeing Model 737 series airplanes. That AD requires 
    repetitive tests to verify proper operation of the rudder power control 
    unit (PCU), and replacement of the PCU, if necessary. The actions 
    specified by that AD are intended to prevent rudder motion in the 
    opposite direction of the rudder command.
    
    FAA's Findings
    
        As a result of analysis related to the previously prescribed tests, 
    the FAA finds that certain procedures should be included in the FAA-
    approved Airplane Flight Manual (AFM) for Model 737 series airplanes to 
    enable the flight crew to take appropriate action to maintain control 
    of the airplane during an uncommanded yaw or roll condition, and to 
    correct a jammed or restricted flight control condition. The FAA has 
    determined that such procedures currently are not defined adequately in 
    the AFM for these airplanes.
    
    Explanation of the Requirements of the Rule
    
        Since an unsafe condition has been identified that is likely to 
    exist or develop on other Boeing Model 737 series airplanes of the same 
    type design, this AD is being issued to ensure that the flight crew is 
    advised of the potential hazard associated with a jammed or restricted 
    flight control condition and of the procedures necessary to address it. 
    This AD requires revising the AFM to include procedures that will 
    enable the flight crew to take appropriate action to maintain control 
    of the airplane during an uncommanded yaw or roll condition, and to 
    correct a jammed or restricted flight control condition.
    
    Determination 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 an 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, 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-266-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
    
    [[Page 16]]
    
    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, 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:
    
    96-26-07 BOEING: Amendment 39-9871. Docket 96-NM-266-AD.
    
        Applicability: All Model 737 series airplanes, 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 (b) 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 ensure that the flight crew is advised of the potential 
    hazard associated with jammed or restricted flight controls and of 
    the procedures necessary to address it, accomplish the following:
        (a) Within 30 days after the effective date of this AD, 
    accomplish paragraphs (a)(1) and (a)(2) of this AD.
        (1) Revise the Emergency Procedures Section of the FAA-approved 
    Airplane Flight Manual (AFM) to include the following recall item, 
    which will enable the flight crew to take appropriate action to 
    maintain control of the airplane during an uncommanded yaw or roll 
    condition. This may be accomplished by inserting a copy of this AD in 
    the AFM.
    
    ``UNCOMMANDED YAW OR ROLL
    
    RECALL
    
        Maintain control of the airplane with all available flight 
    controls. If roll is uncontrollable, immediately reduce angle of 
    attack and increase airspeed. Do not attempt to maintain altitude 
    until control is recovered. If engaged, disconnect autopilot and 
    autothrottle.''
        (2) Revise the section entitled ``JAMMED FLIGHT CONTROLS'' of 
    the Normal Procedures Section (for Model 737-100 and -200 series 
    airplanes) or the Non-Normal Procedures Section (for Model 737-300, 
    -400, and -500 series airplanes), as applicable, of the FAA-approved 
    AFM to include the following procedures, which will enable the 
    flight crew to take appropriate action to maintain control of the 
    airplane and to correct a jammed or restricted flight control 
    condition. This may be accomplished by inserting a copy of this AD 
    in the AFM.
    
    ``JAMMED FLIGHT CONTROLS
    
    JAMMED OR RESTRICTED ELEVATOR OR AILERON:
    
        In the event of a jammed elevator or aileron, do not hesitate to 
    apply additional force to maintain control of the airplane. Do not 
    turn off any flight control switches unless the faulty control is 
    positively identified. Manual trim may be used to offload control 
    forces.
    
    JAMMED OR RESTRICTED RUDDER:
    
        If the rudder pedals will not move to the pilot commanded 
    position, or if the pedals are deflected in one direction and 
    jammed, maintain control of the airplane with all available flight 
    controls. Disengage the autopilot and autothrottle. Use maximum 
    force (combined effort by both pilots) to overpower the rudder 
    system.
        After establishing control of the aircraft, check rudder pedal 
    position. If the rudder pedals have centered, accomplish a normal 
    descent, approach, and landing. If the rudder pedals remain jammed 
    and are deflected to a degree that significantly affects the 
    controllability of the airplane, select System B flight control 
    switch to STBY RUD. If this action clears the jam/deflection, make a 
    normal approach and landing, noting that rudder control may be 
    limited. If moving the System B flight control switch to STBY RUD 
    does not clear the jam, select System A flight control switch to 
    off. If pedals do not center, select System B flight control switch 
    to off. Make approach and landing with flaps 15 at VREF flaps 
    15. The crosswind capability of the airplane will be greatly 
    reduced.
    
    YAW DAMPER:
    
        The yaw damper is a separate control and provides a limited 
    rudder movement in opposition to the yaw rate of the airplane. 
    Rudder (yaw damper) indicator displacement indicates yaw damper 
    operation. Yaw damper light illuminates amber when the yaw damper is 
    not engaged.
        (b) 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, Seattle Aircraft Certification 
    Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
    submit their requests through an appropriate FAA Principal 
    Operations Inspector, who may add comments and then send it to the 
    Manager, Seattle ACO.
    
        Note 2: Information concerning the existence of approved 
    alternative methods of compliance with this AD, if any, may be 
    obtained from the Seattle ACO.
    
        (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) This amendment becomes effective on January 17, 1997.
    
        Issued in Renton, Washington, on December 23, 1996.
    S.R. Miller,
    Acting Manager, Transport Airplane Directorate, Aircraft Certification 
    Service.
    [FR Doc. 96-33104 Filed 12-30-96; 10:25 am]
    BILLING CODE 4910-13-U
    
    
    

Document Information

Effective Date:
1/17/1997
Published:
01/02/1997
Department:
Transportation Department
Entry Type:
Rule
Action:
Final rule; request for comments.
Document Number:
96-33104
Dates:
Effective January 17, 1997.
Pages:
15-16 (2 pages)
Docket Numbers:
Docket No. 96-NM-266-AD, Amendment 39-9871, AD 96-26-07
RINs:
2120-AA64: Airworthiness Directives
RIN Links:
https://www.federalregister.gov/regulations/2120-AA64/airworthiness-directives
PDF File:
96-33104.pdf
CFR: (1)
14 CFR 39.13