96-1220. Airworthiness Directives; Cessna Aircraft Company Models 208 and 208B Airplanes  

  • [Federal Register Volume 61, Number 17 (Thursday, January 25, 1996)]
    [Proposed Rules]
    [Pages 2178-2180]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 96-1220]
    
    
    
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    DEPARTMENT OF TRANSPORTATION
    14 CFR Part 39
    
    [Docket No. 96-CE-05-AD]
    
    
    Airworthiness Directives; Cessna Aircraft Company Models 208 and 
    208B 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 all Cessna Aircraft Company (Cessna) Models 
    208 and 208B airplanes. This proposal would require revising the 
    Airplane Flight Manual (AFM) to specify procedures that would prohibit 
    flight in freezing rain or freezing drizzle conditions (as determined 
    by certain visual cues), limit or prohibit the use of various flight 
    control devices, and provide the flight crew with recognition cues for, 
    and procedures for exiting from, severe icing conditions. This proposal 
    is prompted by results of a review of the requirements for 
    certification of the airplane in icing conditions, new information on 
    the icing environment, and icing data provided currently to the flight 
    crews. The actions specified by the proposed AD are intended to 
    minimize the potential hazards associated with operating the airplane 
    in freezing rain or freezing drizzle conditions by providing more 
    clearly defined procedures and limitations associated with such 
    conditions.
    
    DATES: Comments must be received on or before March 7, 1996.
    
    ADDRESSES: Submit comments in triplicate to the Federal Aviation 
    Administration (FAA), Central Region, Office of the Assistant Chief 
    Counsel, Attention: Rules Docket No. 96-CE-05-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.
        Information that relates to the proposed AD may be examined at the 
    Rules Docket at the address above.
    
    FOR FURTHER INFORMATION CONTACT: Mr. Bennett L. Sorensen, Flight Test 
    Pilot, Wichita Aircraft Certification Office, FAA, 1801 Airport Road, 
    Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4122; 
    facsimile (316) 946-4407.
    
    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. 96-CE-05-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 Assistant Chief Counsel, 
    Attention: Rules Docket No. 96-CE-05-AD, Room 1558, 601 E. 12th Street, 
    Kansas City, Missouri 64106.
    
    Discussion
    
        In October 1994, a transport category airplane was involved in an 
    accident in which severe icing conditions (believed to be composed of 
    freezing drizzle size droplets) were reported in the area. Although the 
    National Transportation Safety Board (NTSB) has not yet made a finding 
    of probable cause of the accident, loss of control of the airplane may 
    have occurred because ice accretion on the upper surface of the wing 
    aft of the area protected by the ice protection system caused airflow 
    separation, which resulted in the ailerons being forced to a right-
    wing-down control position. There also is concern that the autopilot, 
    which was engaged, may have masked the unusual control forces generated 
    by the ice accumulation. On the accident aircraft, these conditions, if 
    not corrected, could result in a roll upset from which the flight crew 
    may be unable to recover.
        The atmospheric conditions (freezing drizzle) that may have 
    contributed to the accident are outside the icing envelope specified in 
    Appendix C of part 25 of the Federal Aviation Regulations (14 CFR part 
    25) for certification of any airplane. Section 23.1419 of the Federal 
    Aviation Regulations (14 CFR 23.1419) cross-references Appendix C of 
    part 25 of the Federal Aviation Regulations (14 CFR part 25). Freezing 
    rain is an atmospheric condition that also is outside the icing 
    envelope. Such icing conditions are not defined in Appendix C of part 
    25 of the Federal Aviation Regulations (14 CFR part 25) for 
    certification of any airplane, and the FAA has not required that 
    airplanes be shown to be capable of operating safely in those icing 
    conditions.
        The FAA finds that flight crews are not currently provided with 
    adequate information necessary to determine when the airplane is 
    operating in icing conditions for which the airplane is not 
    certificated or what action to take when such conditions are 
    encountered. Therefore, the FAA has determined that flight crews must 
    be provided with such information and must be made aware of certain 
    visual cues that may indicate the airplane is operating in atmospheric 
    conditions that are outside the icing envelope.
        Since such information is not available to flight crews, and no 
    airplane is certificated for operation in freezing drizzle conditions, 
    the FAA finds that the potentially unsafe condition (described 
    previously as control difficulties following operation of the airplane 
    in icing conditions outside of the icing envelope) is not limited to 
    airplanes having the same type design as that of the accident airplane.
        The FAA recognizes that the flight crew of any airplane that is 
    certificated for flight in icing conditions may not have adequate 
    information concerning flight in icing conditions outside the icing 
    envelope. However, the FAA finds that the specified unsafe condition 
    must be addressed as a higher priority on airplanes that are 
    turbopropeller-powered and have unpowered control systems. Many of 
    these airplanes carry passengers in regularly scheduled revenue service 
    in the United States. Since turbopropeller-powered airplanes 
    
    [[Page 2179]]
    are more likely to operate at low altitudes and to make more frequent 
    landings, they are more likely to encounter icing conditions that are 
    outside the icing envelope. Additionally, the flight crew of an 
    airplane having an unpowered roll control system must rely solely on 
    physical strength to counteract roll control anomalies, whereas a roll 
    control anomaly that occurs on an airplane having a powered roll 
    control system need not be offset directly by the flight crew.
        Subsequent to the accident, the FAA, in conjunction with certain 
    foreign airworthiness authorities and airplane manufacturers, conducted 
    reviews of certain transport and small category airplanes to determine 
    if any airplanes might experience control difficulty should a ridge of 
    ice form aft of the deicing boots and forward of the ailerons. The 
    review focused on turbopropeller-powered airplanes having unpowered 
    roll control systems, since those airplanes are similar in design to 
    the accident airplane and because they are frequently exposed to icing 
    conditions.
        During the reviews of these airplanes, an artificial ice shape was 
    used in the demonstration of roll control characteristics. This ice 
    shape was chosen as representative of a shape that might form if an 
    airplane were operated in freezing drizzle. Results of these reviews 
    revealed that certain airplanes demonstrated acceptable roll control 
    forces. However, the dynamics of ice accretion in freezing drizzle are 
    not well understood, and the FAA recognizes that such airplanes could 
    develop ice shapes other than those tested during the review. Upon 
    further review, the FAA may consider additional rulemaking.
        Following examination of all relevant information, the FAA has 
    determined that certain limitations and procedures should be included 
    in the FAA-approved Airplane Flight Manual (AFM) for the affected 
    airplanes, as follows:
         Cessna Models 208 and 208B airplanes must be prohibited 
    from flight in freezing rain or freezing drizzle conditions (as 
    determined by certain visual cues); and
         flight crews must be provided with information that would 
    minimize the potential hazards associated with operating the airplane 
    in freezing rain or freezing drizzle conditions.
        The FAA has determined that such limitations and procedures 
    currently are not defined adequately in the AFM for these airplanes.
    
    Explanation of the Provisions of the Proposed AD
    
        Since an unsafe condition has been identified that is likely to 
    exist on airplanes of the same type design, the proposed AD would 
    require revising the Limitations Section of the AFM to specify 
    procedures that would:
         prohibit flight in freezing rain or freezing drizzle 
    conditions (as determined by certain visual cues);
         prohibit use of the autopilot when ice is formed aft of 
    the protected surfaces of the wing, or when an unusual lateral trim 
    condition exists; and
         require that all icing detection lights be operative prior 
    to flight into icing conditions at night.
        The prohibition on flight in freezing rain or freezing drizzle is 
    not intended to prohibit purely inadvertent encounters with the 
    specified atmospheric conditions. However, pilots should make all 
    reasonable efforts to avoid such encounters and must immediately exit 
    the conditions if they are encountered.
        This proposed AD also would require revising the Normal Procedures 
    Section of the AFM to specify procedures that would:
         limit the use of the flaps and prohibit the use of the 
    autopilot when ice is observed forming aft of the protected surfaces of 
    the wing, or if unusual lateral trim requirements or autopilot trim 
    warnings are encountered; and
         provide the flight crew with recognition cues for, and 
    procedures for exiting from, severe icing conditions.
    
    Cost Impact
    
        The FAA estimates that 728 airplanes in the U.S. registry would be 
    affected by the proposed AD, that it would take approximately 1 
    workhour per airplane to accomplish the proposed action, and that the 
    average labor rate is approximately $60 an hour. Since an owner/
    operator who holds at least a private pilot's certificate as authorized 
    by sections 43.7 and 43.11 of the Federal Aviation Regulations (14 CFR 
    43.7 and 43.11) can accomplish the proposed action, the only cost 
    impact upon the public is the time it would take the affected airplane 
    owner/operators to incorporate the proposed AFM revisions.
    
    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 USC 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:
    
    Cessna Aircraft Company: Docket No. 96-CE-05-AD.
    
        Applicability: Models 208 and 208B airplanes (all serial 
    numbers), 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 (c) 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.
    
    
    [[Page 2180]]
    
        Compliance: Required as indicated, unless already accomplished.
        To minimize the potential hazards associated with operating the 
    airplane in freezing rain or freezing drizzle icing conditions by 
    providing more clearly defined procedures and limitations associated 
    with such conditions, accomplish the following:
        (a) Within 30 days after the effective date of this AD, 
    accomplish the requirements of paragraphs (a)(1) and (a)(2) of this 
    AD.
    
        Note 2: Operators must initiate action to notify and ensure that 
    flight crewmembers are apprised of this change.
    
        (1) Revise the FAA-approved Airplane Flight Manual (AFM) by 
    incorporating the following into the Limitations Section of the AFM. 
    This may be accomplished by inserting a copy of this AD in the AFM.
        `` Flight in meteorological conditions described as 
    freezing rain or freezing drizzle, as determined by the following 
    visual cues, is prohibited:
    
    --Unusually extensive ice accreted on the airframe in areas not 
    normally observed to collect ice
    --Accumulation of ice on the upper surface (for low-wing airplanes) 
    or lower surface (for high-wing airplanes) of the wing aft of the 
    protected area
    --Accumulation of ice on the propeller spinner farther back than 
    normally observed
    
        If the airplane encounters conditions that are determined to 
    contain freezing rain or freezing drizzle, the pilot must 
    immediately exit the freezing rain or freezing drizzle conditions by 
    changing altitude or course.
    
        Note: The prohibition on flight in freezing rain or freezing 
    drizzle is not intended to prohibit purely inadvertent encounters 
    with the specified meteorological conditions. However, pilots should 
    make all reasonable efforts to avoid such encounters and must 
    immediately exit the conditions if they are encountered.
    
         Use of the autopilot is prohibited when any ice is 
    observed forming aft of the protected surfaces of the wing, or when 
    unusual lateral trim requirements or autopilot trim warnings are 
    encountered.
    
        Note: The autopilot may mask tactile cues that indicate adverse 
    changes in handling characteristics. Therefore, the pilot should 
    consider not using the autopilot when any ice is visible on the 
    airplane.
    
         All icing detection lights must be operative prior to 
    flight into icing conditions at night. This supersedes any relief 
    provided by the Master Minimum Equipment List (MMEL).''
        (2) Revise the FAA-approved AFM by incorporating the following 
    into the Normal Procedures Section of the AFM. This may be 
    accomplished by inserting a copy of this AD in the AFM.
    
    ``WARNING
    
        ``If ice is observed forming aft of the protected surfaces of 
    the wing, or if unusual lateral trim requirements or autopilot trim 
    warnings are encountered:
         If the flaps are extended, do not retract them until 
    the airframe is clear of ice.
         The flight crew should reduce the angle-of-attack by 
    increasing speed as much as the airplane configuration and weather 
    allow, without exceeding design maneuvering speed.
         If the autopilot is engaged, hold the control wheel 
    firmly and disengage the autopilot. Do not re-engage the autopilot 
    until the airframe is clear of ice.
         Exit the icing area immediately by changing altitude or 
    course.
         Report these weather conditions to Air Traffic Control.
    
    CAUTION
    
        Severe icing comprises environmental conditions outside of those 
    for which the airplane is certificated. Flight in freezing rain, 
    freezing drizzle, or mixed icing conditions (supercooled liquid 
    water and ice crystals) may result in extreme ice build-up on 
    protected surfaces exceeding the capability of the ice protection 
    system, or may result in ice forming aft of the protected surfaces. 
    This ice may not be shed using the ice protection systems, and may 
    seriously degrade the performance and controllability of the 
    airplane.
    
    THE FOLLOWING SHALL BE USED TO IDENTIFY FREEZING RAIN/FREEZING DRIZZLE 
    ICING CONDITIONS:
    
         Unusually extensive ice accreted on the airframe in 
    areas not normally observed to collect ice.
         Accumulation of ice on the upper surface (for low-wing 
    airplanes) or lower surface (for highwing airplanes) of the wing aft 
    of the protected area.
         Accumulation of ice on the propeller spinner farther 
    back than normally observed.
    
    THE FOLLOWING MAY BE USED TO IDENTIFY POSSIBLE FREEZING RAIN/FREEZING 
    DRIZZLE CONDITIONS:
    
         Visible rain at temperatures below +5 degrees Celsius 
    [outside air temperature (OAT)].
         Droplets that splash or splatter on impact at 
    temperatures below +5 degrees Celsius OAT.
    
    PROCEDURES FOR EXITING THE FREEZING RAIN/FREEZING DRIZZLE ENVIRONMENT:
    
        These procedures are applicable to all flight phases from 
    takeoff to landing. Monitor the outside air temperature. While 
    severe icing may form at temperatures as cold as -18 degrees 
    Celsius, increased vigilance is warranted at temperatures around 
    freezing with visible moisture present. If the visual cues specified 
    in the AFM for identifying possible freezing rain or freezing 
    drizzle conditions are observed, accomplish the following:
         Exit the freezing rain or freezing drizzle severe icing 
    conditions immediately to avoid extended exposure to flight 
    conditions outside of those for which the airplane has been 
    certificated for operation. Asking for priority to leave the area is 
    fully justified under these conditions.
         Avoid abrupt and excessive maneuvering that may 
    exacerbate control difficulties.
         Do not engage the autopilot. The autopilot may mask 
    unusual control system forces.
         If the autopilot is engaged, hold the control wheel 
    firmly and disengage the autopilot.
         If an unusual roll response or uncommanded control 
    movement is observed, reduce the angle-of-attack by increasing 
    airspeed or rolling wings level (if in a turn), and apply additional 
    power, if needed.
         Avoid extending flaps during extended operation in 
    icing conditions. Operation with flaps extended can result in a 
    reduced wing angle-of-attack, with ice forming on the upper surface 
    further aft on the wing than normal, possibly aft of the protected 
    area.
         Report these weather conditions to Air Traffic Control.
        (b) Incorporating the AFM revisions, as required by this AD, may 
    be performed by the owner/operator holding at least a private pilot 
    certificate as authorized by section 43.7 of the Federal Aviation 
    Regulations (14 CFR 43.7), and must be entered into the aircraft 
    records showing compliance with this AD in accordance with section 
    43.11 of the Federal Aviation Regulations (14 CFR 43.11).
        (c) An alternative method of compliance or adjustment of the 
    compliance time that provides an equivalent level of safety may be 
    approved by the Manager, Wichita Aircraft Certification Office 
    (ACO), 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, 
    Kansas 67209. The request shall be forwarded through an appropriate 
    FAA Maintenance Inspector, who may add comments and then send it to 
    the Manager, Wichita ACO.
    
        Note 3: Information concerning the existence of approved 
    alternative methods of compliance with this AD, if any, may be 
    obtained from the Wichita ACO.
    
        (d) All persons affected by this directive may examine 
    information related to this AD at the FAA, Central Region, Office of 
    the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas 
    City, Missouri 64106.
    
        Issued in Kansas City, Missouri, on January 19, 1996.
    Michael Gallagher,
    Manager, Small Airplane Directorate, Aircraft Certification Service.
    [FR Doc. 96-1220 Filed 1-24-96; 8:45 am]
    BILLING CODE 4910-13-U
    
    

Document Information

Published:
01/25/1996
Department:
Transportation Department
Entry Type:
Proposed Rule
Action:
Notice of proposed rulemaking (NPRM).
Document Number:
96-1220
Dates:
Comments must be received on or before March 7, 1996.
Pages:
2178-2180 (3 pages)
Docket Numbers:
Docket No. 96-CE-05-AD
PDF File:
96-1220.pdf
CFR: (1)
14 CFR 39.13