98-3921. Airworthiness Directives; Sabreliner Model 40, 60, 70, and 80 Series Airplanes  

  • [Federal Register Volume 63, Number 32 (Wednesday, February 18, 1998)]
    [Rules and Regulations]
    [Pages 8086-8089]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 98-3921]
    
    
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    DEPARTMENT OF TRANSPORTATION
    
    Federal Aviation Administration
    
    14 CFR Part 39
    
    [Docket No. 97-NM-171-AD; Amendment 39-10349; AD 98-04-37]
    RIN 2120-AA64
    
    
    Airworthiness Directives; Sabreliner Model 40, 60, 70, and 80 
    Series Airplanes
    
    AGENCY: Federal Aviation Administration, DOT.
    
    ACTION: Final rule.
    
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    SUMMARY: This amendment adopts a new airworthiness directive (AD), 
    applicable to certain Sabreliner Model 40, 60, 70, and 80 series 
    airplanes, that requires revising the Airplane Flight Manual (AFM) to 
    specify procedures that would prohibit flight in severe icing 
    conditions (as determined by certain visual cues), limit or prohibit 
    the use of various flight control devices while in severe icing 
    conditions, and provide the flight crew with recognition cues for, and 
    procedures for exiting from, severe icing conditions. This amendment 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 this AD are intended to minimize the potential 
    hazards associated with operating the airplane in severe icing 
    conditions by providing more clearly defined procedures and limitations 
    associated with such conditions.
    
    EFFECTIVE DATE: March 25, 1998.
    
    ADDRESSES: Information pertaining to this rulemaking action may be 
    examined at the Federal Aviation Administration (FAA), Transport 
    Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
    Washington; or at the FAA, Small Airplane Directorate, Wichita Aircraft 
    Certification Office, 1801 Airport Road, Room 100, Mid-Continent 
    Airport, Wichita, Kansas.
    
    FOR FURTHER INFORMATION CONTACT: Charles Riddle, Program Manager, 
    Flight Test and Program Management, ACE-117W, FAA, Small Airplane 
    Directorate, Wichita Aircraft Certification Office, 1801 Airport Road, 
    Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 
    946-4144; fax (316) 946-4407.
    
    SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
    Aviation Regulations (14 CFR part 39) to include an airworthiness 
    directive (AD) that is applicable to certain Sabreliner Model 40, 60, 
    70, and 80 series airplanes was published in the Federal Register on 
    September 16, 1997 (62 FR 48556). That action proposed to require 
    revising the Limitations Section of the FAA-approved Airplane Flight 
    Manual (AFM) to specify procedures that would:
         Require flight crews to immediately request priority 
    handling from Air Traffic Control to exit severe icing conditions (as 
    determined by certain visual cues);
         Prohibit flight in severe icing 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 wing inspection lights be operative 
    prior to flight into known or forecast icing conditions at night.
        That action also proposed to require revising the Normal Procedures 
    Section of the FAA-approved 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.
    
    Comments
    
        Interested persons have been afforded an opportunity to participate 
    in the making of this amendment. Due consideration has been given to 
    the comments received.
        In addition to the proposed rule described previously, in September 
    1997, the FAA issued 24 other similar proposals that address the 
    subject unsafe condition on various airplane models (see below for a 
    listing of all 24 proposed rules). These 24 proposals also were 
    published in the Federal Register on September 16, 1997. This final 
    rule contains the FAA's responses to all relevant public comments 
    received for each of these proposed rules.
    
    ------------------------------------------------------------------------
                                Manufacturer/airplane     Federal Register  
            Docket No.                  model                 citation      
    ------------------------------------------------------------------------
    97-CE-49-AD...............  Aerospace              62 FR 48520          
                                 Technologies of                            
                                 Australia, Models                          
                                 N22B and N24A.                             
    97-CE-50-AD...............  Harbin Aircraft Mfg.   62 FR 48513          
                                 Corporation, Model                         
                                 Y12 IV.                                    
    97-CE-51-AD...............  Partenavia             62-FR 48524          
                                 Costruzioni                                
                                 Aeronauticas,                              
                                 S.p.A., Models P68,                        
                                 AP68TP 300, AP68TP                         
                                 600.                                       
    97-CE-52-AD...............  Industrie              62 FR 48502          
                                 Aeronautiche                               
                                 Meccaniche Rinaldo                         
                                 Piaggio S.p.A.,                            
                                 Model P-180.                               
    97-CE-53-AD...............  Pilatus Aircraft       62 FR 48499          
                                 Ltd., Models PC-12                         
                                 and PC-12/45.                              
    97-CE-54-AD...............  Pilatus Britten-       62 FR 48538          
                                 Norman Ltd., Models                        
                                 BN-2A, BN-2B, and BN-                      
                                 2T.                                        
    97-CE-55-AD...............  SOCATA--Groupe         62 FR 48506          
                                 Aerospatiale Model                         
                                 TBM-700.                                   
    97-CE-56-AD...............  Aerostar Aircraft      62 FR 48481          
                                 Corporation Models                         
                                 PA-60-600, -601, -                         
                                 601P, -602P, and -                         
                                 700P.                                      
    97-CE-57-AD...............  Twin Commander         62 FR 48549          
                                 Aircraft Corporation                       
                                 Models 500, -500-A, -                      
                                 500-B,-500-S, -500-                        
                                 U, -520, -560, -560-                       
                                 A, -560-E, -560-F, -                       
                                 680, -680-E, -                             
                                 680FL(P), -680T, -                         
                                 680V, -680W, -681,-                        
                                 685, -690, -690A, -                        
                                 690B, -690C, -690D, -                      
                                 695, -695A, -695B,                         
                                 and 720.                                   
    97-CE-58-AD...............  Raytheon Aircraft      62 FR 48517          
                                 Company (formerly                          
                                 known as Beech                             
                                 Aircraft                                   
                                 Corporation) Models                        
                                 E55, E55A, 58, 58A,                        
                                 58P, 58PA, 58TC,                           
                                 58TCA, 60 series, 65-                      
                                 B80 series, 65-B-90                        
                                 series, 90 series,                         
                                 F90 series, 100                            
                                 series, 300 series,                        
                                 and B300 series.                           
    97-CE-59-AD...............  Raytheon Aircraft      62 FR 48531          
                                 Company (formerly                          
                                 known as Beech                             
                                 Aircraft                                   
                                 Corporation) Model                         
                                 2000.                                      
    97-CE-60-AD...............  The New Piper          62 FR 48542          
                                 Aircraft, Inc.                             
                                 Models PA-46 -310P                         
                                 and PA-46-350P.                            
    
    [[Page 8087]]
    
                                                                            
    97-CE-61-AD...............  The New Piper          62 FR 52294          
                                 Aircraft, Inc.                             
                                 Models PA-23, PA-23-                       
                                 160, PA-23-235, PA-                        
                                 23-250, PA-E23-250,                        
                                 PA-30, PA-39, PA-40,                       
                                 PA-31, PA-31-300, PA-                      
                                 31-325, PA-31-350,                         
                                 PA-34-200, PA-34-                          
                                 200T, PA-34-220T, PA-                      
                                 42, PA-42-720, PA-42-                      
                                 1000.                                      
    97-CE-62-AD...............  Cessna Aircraft        62 FR 48535          
                                 Company, Models                            
                                 P210N, T210N, P210R,                       
                                 and 337 series.                            
    97-CE-63-AD...............  Cessna Aircraft        62 FR 48528          
                                 Company, Models                            
                                 T303, 310R, T310R,                         
                                 335, 340A, 402B,                           
                                 402C, 404, F406,                           
                                 414, 414A, 421B,                           
                                 421C, 425, and 441.                        
    97-CE-64-AD...............  SIAI-Marchetti S.r.I.  62 FR 48510          
                                 (Augusta), Models                          
                                 SF600 and SF600A.                          
    97-NM-170-AD..............  Cessna Aircraft        62 FR 48560          
                                 Company, Models 500,                       
                                 501, 550, 551, and                         
                                 560 series.                                
    97-NM-171-AD..............  Sabreliner             62 FR 48556          
                                 Corporation, Models                        
                                 40, 60, 70, and 80                         
                                 series.                                    
    97-NM-172-AD..............  Gulfstream Aerospace,  62 FR 48563          
                                 Model G-159 series.                        
    97-NM-173-AD..............  McDonnell Douglas,     62 FR 48553          
                                 Models DC-3 and DC-4                       
                                 series.                                    
    97-NM-174-AD..............  Mitsubishi Heavy       62 FR 48567          
                                 Industries, Model YS-                      
                                 11 and YS-11A series.                      
    97-NM-175-AD..............  Frakes Aviation,       62 FR 48577          
                                 Model G-73 (Mallard)                       
                                 and G-73T series.                          
    97-NM-176-AD..............  Lockheed, Models L-14  62 FR 48574          
                                 and L-18 series.                           
    97-NM-177-AD..............  Fairchild, Models F27  62 FR 48570          
                                 and FH227 series.                          
    ------------------------------------------------------------------------
    
    Comment 1. Unsubstantiated Unsafe Condition for This Model
    
        One commenter suggests that the AD's were developed in response to 
    a suspected contributing factor of an accident involving an airplane 
    type unrelated to the airplanes specified in the proposal. The 
    commenter states that these proposals do not justify that an unsafe 
    condition exists or could develop in a product of the same type design. 
    Therefore, the commenter asserts that the proposal does not meet the 
    criteria for the issuance of an AD as specified in the Federal Aviation 
    Regulations (14 CFR part 39 ).
        The FAA does not concur. As stated in the Notice of Proposed 
    Rulemaking (NPRM), the FAA has identified an unsafe condition 
    associated with operating the airplane in severe icing conditions. As 
    stated in the preamble to the proposal, the FAA has not required that 
    airplanes be shown to be capable of operating safely in icing 
    conditions outside the certification envelope specified in Appendix C 
    of part 25 of the Federal Aviation Regulations (14 CFR part 25). This 
    means that any time an airplane is flown in icing conditions for which 
    it is not certificated, there is a potential for an unsafe condition to 
    exist or develop and the flight crew must take steps to exit those 
    conditions expeditiously. Further, the FAA has determined that flight 
    crews are not currently provided with adequate information necessary to 
    determine when an airplane is operating in icing conditions for which 
    it is not certificated or what action to take when such conditions are 
    encountered. The absence of this information presents an unsafe 
    condition because without that information, a pilot may remain in 
    potentially hazardous icing conditions. This AD addresses the unsafe 
    condition by requiring AFM revisions that provide the flight crews with 
    visual cues to determine when icing conditions have been encountered 
    for which the airplane is not certificated, and by providing procedures 
    to safely exit those conditions.
        Further, in the preamble of the proposed rule, the FAA discussed 
    the investigation of roll control anomalies to explain that this 
    investigation was not a complete certification program. The testing was 
    designed to examine only the roll handling characteristics of the 
    airplane in certain droplets the size of freezing drizzle. The testing 
    was not a certification test to approve the airplane for flight into 
    freezing drizzle. The results of the tests were not used to determine 
    if this AD is necessary, but rather to determine if design changes were 
    needed to prevent a catastrophic roll upset. The roll control testing 
    and the AD are two unrelated actions.
        Additionally, in the preamble of the proposed rule, the FAA 
    acknowledged that the flight crew of any airplane that is certificated 
    for flight icing conditions may not have adequate information 
    concerning flight in icing conditions outside the icing envelope. 
    However, in 1996, the FAA found that the specified unsafe condition 
    must be addressed as a higher priority on airplanes equipped with 
    pneumatic deicing boots and unpowered roll control systems. These 
    airplanes were addressed first because 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. The FAA also placed a 
    priority on airplanes that are used in regularly scheduled passenger 
    service. The FAA has previously issued AD's to address those airplanes. 
    Since the issuance of those AD's, the FAA has determined that similar 
    AD's should be issued for similarly equipped airplanes that are not 
    used in regularly scheduled passenger service.
    
    Comment 2. AD Is Inappropriate To Address Improper Operation of the 
    Airplane
    
        One commenter requests that the proposed AD be withdrawn because an 
    unsafe condition does not exist within the airplane. Rather, the 
    commenter asserts that the unsafe condition is the improper operation 
    of the airplane. The commenter further asserts that issuance of an AD 
    is an inappropriate method to address improper operation of the 
    airplane.
        The FAA does not concur. The FAA has determined that an unsafe 
    condition does exist as explained in the proposed notice and discussed 
    previously. As specifically addressed in Amendment 39-106 of part 39 of 
    the Federal Aviation Regulations (14 CFR part 39), the responsibilities 
    placed on the FAA statute (49 U.S.C., formerly the Federal Aviation 
    Act), justify allowing AD's to be issued for unsafe conditions however 
    and wherever found, regardless of whether the unsafe condition results 
    from maintenance, design defect, or any other reason.
        This same commenter considers that part 91 (rather than part 39) of 
    the Federal Aviation Regulations (14 CFR part 91) is the appropriate 
    regulation to address the problems of icing encounters outside of the 
    limits for which the airplane is certificated. Therefore, the commenter 
    requests that the FAA withdraw the proposal.
        The FAA does not concur. Service experience demonstrates that 
    flight in icing conditions that are outside the icing certification 
    envelope does occur. Apart from the visual cues provided in these final 
    rules, there is no existing method provided to the flight crews to 
    identify when the airplane is in a condition that exceeds the icing
    
    [[Page 8088]]
    
    certification envelope. Because this lack of awareness may create an 
    unsafe condition, the FAA has determined that it is appropriate to 
    issue an AD to require revision of the AFM to provide this information.
        One commenter asserts that while it is prudent to advise and 
    routinely remind the pilots about the hazards associated with flight 
    into known or forecast icing conditions, the commenter is opposed to 
    the use of an AD to accomplish that function. The commenter states that 
    pilots' initial and bi-annual flight checks are the appropriate 
    vehicles for advising the pilots of such hazards, and that such 
    information should be integrated into the training syllabus for all 
    pilot training.
        The FAA does not concur that substituting advisory material and 
    mandatory training for issuance of an AD is appropriate. The FAA 
    acknowledges that, in addition to the issuance of an AD, information 
    specified in the revision to the AFM should be integrated into the 
    pilot training syllabus. However, the development and use of such 
    advisory materials and training alone are not adequate to address the 
    unsafe condition. The only method of ensuring that certain information 
    is available to the pilot is through incorporation of the information 
    into the Limitations Section of the AFM. The appropriate vehicle for 
    requiring such revision of the AFM is issuance of an AD. No change is 
    necessary to the final rule.
    
    Comment 3. Inadequate Visual Cues
    
        One commenter provides qualified support for the AD. The commenter 
    notes that the recent proposals are identical to the AD's issued about 
    a year ago. Although the commenter supports the intent of the AD's as 
    being appropriate and necessary, the commenter states that it is 
    unfortunate that the flight crew is burdened with recognizing icing 
    conditions with visual cues that are inadequate to determine certain 
    icing conditions. The commenter points out that, for instance, side 
    window icing (a very specific visual cue) was determined to be a valid 
    visual cue during a series of icing tanker tests on a specific 
    airplane; however, later testing of other models of turboprop airplanes 
    revealed that side window icing was invalid as a visual cue for 
    identifying icing conditions outside the scope of Appendix C.
        The FAA does not concur with the commenters' request to provide 
    more specific visual cues. The FAA finds that the value of visual cues 
    has been substantiated during in-service experience. Additionally, the 
    FAA finds that the combined use of the generic cues provided and the 
    effect of the final rules in increasing the awareness of pilots 
    concerning the hazard of operating outside of the certification icing 
    envelope will provide an acceptable level of safety. Although all of 
    the cues may not be exhibited on a particular model, the FAA considers 
    that at least some of the cues will be exhibited on all of the models 
    affected by this AD. For example, some airplanes may not have side 
    window cues in freezing drizzle, but would exhibit other cues, (such as 
    accumulation of ice aft of the protected area) under those conditions. 
    For these reasons, the FAA considers that no changes regarding visual 
    cues are necessary to the final rule. However, for those operators that 
    elect to identify airplane-specific visual cures, the FAA would 
    consider a request for approval of an alternative method of compliance, 
    in accordance with the provisions of this AD.
    
    Comment 4. Request for Research and Use of Wing-Mounted Ice Detectors
    
        One commenter requests that wing-mounted ice detectors, which 
    provide real-time icing severity information (or immediate feedback) to 
    flight crews, continue to be researched and used throughout the fleet. 
    The FAA infers from this commenter's request that the commenter asks 
    that installation of these ice detectors be mandated by the FAA.
        While the FAA supports the development of such ice detectors, the 
    FAA does not concur that installation of these ice detectors should be 
    required at this time. Visual cues are adequate to provide an 
    acceptable level of safety; therefore, mandatory installation of ice 
    detector systems, in this case, is not necessary to address the unsafe 
    condition. Nevertheless, because such systems may improve the current 
    level of safety, the FAA has officially tasked the Aviation Rulemaking 
    Advisory Committee (ARAC) to develop a recommendation concerning ice 
    detection. Once the ARAC has submitted its recommendation, the FAA may 
    consider further rulemaking action to require installation of such 
    equipment.
    
    Comment 5. Particular Types of Icing
    
        This same commenter also requests that additional information be 
    included in paragraph (a) of the AD that would specify particular types 
    of icing or particular accretions that result from operating in 
    freezing precipitation. The commenter asserts that this information is 
    of significant value to the flightcrew.
        The FAA does not concur with the commenter's suggestion to specify 
    types of icing or accretion. The FAA has determined that supercooled 
    large droplets (SLD) can result in rime ice, mixed (intermediate) ice, 
    and ice with glaze or clear appearance. Therefore, the FAA finds that 
    no type of icing can be excluded from consideration during operations 
    in freezing precipitation, and considers it unnecessary to cite those 
    types of icing in the AD.
    
    The FAA's Determination
    
        After careful review of all available information related to the 
    subject presented above, the FAA has determined that air safety and the 
    public interest require the adoption of the rule as proposed.
    
    Cost Impact
    
        There are approximately 283 Sabreliner Model 40, 60, 70, and 80 
    series airplanes of the affected design in the worldwide fleet. The FAA 
    estimates that 176 airplanes of U.S. registry will be affected by this 
    AD, that it will take approximately 1 work hour per airplane to 
    accomplish the required actions, and that the average labor rate is $60 
    per work hour. Based on these figures, the cost impact of the AD on 
    U.S. operators is estimated to be $10,560, or $60 per airplane.
        The cost impact figure discussed above is based on assumptions that 
    no operator has yet accomplished any of the requirements of this AD 
    action, and that no operator would accomplish those actions in the 
    future if this AD were not adopted.
        In addition, the FAA recognizes that this action may impose 
    operational costs. However, these costs are incalculable because the 
    frequency of occurrence of the specified conditions and the associated 
    additional flight time cannot be determined. Nevertheless, because of 
    the severity of the unsafe condition, the FAA has determined that 
    continued operational safety necessitates the imposition of the costs.
    
    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
    
    [[Page 8089]]
    
    ``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 final 
    evaluation has been prepared for this action and it is contained in the 
    Rules Docket. A copy of it 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:
    
    98-04-37  Sabreliner: Amendment 39-10349. Docket 97-NM-171-AD.
    
        Applicability: Model 40, 60, 70, and 80 series airplanes 
    equipped with pneumatic deicing boots, 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 already accomplished.
        To minimize the potential hazards associated with operating the 
    airplane in severe 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 should 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.
    
    ``WARNING
    
        Severe icing may result from 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 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.
         During flight, severe icing conditions that exceed 
    those for which the airplane is certificated shall be determined by 
    the following visual cues. If one or more of these visual cues 
    exists, immediately request priority handling from Air Traffic 
    Control to facilitate a route or an altitude change to exit the 
    icing conditions.
    
    --Unusually extensive ice accumulation on the airframe and 
    windshield in areas not normally observed to collect ice.
    --Accumulation of ice on the upper surface of the wing aft of the 
    protected area.
    
         Since the autopilot, when installed and operating, may 
    mask tactile cues that indicate adverse changes in handling 
    characteristics, use of the autopilot is prohibited when any of the 
    visual cues specified above exist, or when unusual lateral trim 
    requirements or autopilot trim warnings are encountered while the 
    airplane is in icing conditions.
         All wing icing inspection lights must be operative 
    prior to flight into known or forecast icing conditions at night. 
    [NOTE: 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.
    
    ``The Following Weather Conditions may be Conducive to Severe In-Flight 
    Icing
    
         Visible rain at temperatures below 0 degrees Celsius 
    ambient air temperature.
         Droplets that splash or splatter on impact at 
    temperatures below 0 degrees Celsius ambient air temperature.
    
    Procedures for Exiting the Severe Icing Environment
    
        These procedures are applicable to all flight phases from 
    takeoff to landing. Monitor the ambient 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 Limitations Section of the AFM for identifying severe icing 
    conditions are observed, accomplish the following:
         Immediately request priority handling from Air Traffic 
    Control to facilitate a route or an altitude change to exit the 
    severe icing conditions in order to avoid extended exposure to 
    flight conditions more severe than those for which the airplane has 
    been certificated.
         Avoid abrupt and excessive maneuvering that may 
    exacerbate control difficulties.
         Do not engage the autopilot.
         If the autopilot is engaged, hold the control wheel 
    firmly and disengage the autopilot.
         If an unusual roll response or uncommanded roll control 
    movement is observed, reduce the angle-of-attack.
         Do not extend flaps when holding in icing conditions. 
    Operation with flaps extended can result in a reduced wing angle-of-
    attack, with the possibility of ice forming on the upper surface 
    further aft on the wing than normal, possibly aft of the protected 
    area.
         If the flaps are extended, do not retract them until 
    the airframe is clear of ice.
         Report these weather conditions to Air Traffic 
    Control.''
        (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, Wichita Aircraft Certification 
    Office (ACO), FAA, Small Airplane Directorate. The request shall be 
    forwarded through an appropriate FAA Operations 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.
    
        (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 March 25, 1998.
    
        Issued in Renton, Washington, on February 6, 1998.
    Darrell M. Pederson,
    Acting Manager, Transport Airplane Directorate, Aircraft Certification 
    Service.
    [FR Doc. 98-3921 Filed 2-17-98; 8:45 am]
    BILLING CODE 4910-13-P
    
    
    

Document Information

Effective Date:
3/25/1998
Published:
02/18/1998
Department:
Federal Aviation Administration
Entry Type:
Rule
Action:
Final rule.
Document Number:
98-3921
Dates:
March 25, 1998.
Pages:
8086-8089 (4 pages)
Docket Numbers:
Docket No. 97-NM-171-AD, Amendment 39-10349, AD 98-04-37
RINs:
2120-AA64: Airworthiness Directives
RIN Links:
https://www.federalregister.gov/regulations/2120-AA64/airworthiness-directives
PDF File:
98-3921.pdf
CFR: (1)
14 CFR 39.13