99-47. Airworthiness Directives; Aerospatiale Model ATR72 Series Airplanes  

  • [Federal Register Volume 64, Number 2 (Tuesday, January 5, 1999)]
    [Proposed Rules]
    [Pages 438-441]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 99-47]
    
    
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    DEPARTMENT OF TRANSPORTATION
    
    Federal Aviation Administration
    
    14 CFR Part 39
    
    [Docket No. 98-NM-240-AD]
    RIN 2120-AA64
    
    
    Airworthiness Directives; Aerospatiale Model ATR72 Series 
    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 Aerospatiale Model ATR72 
    series airplanes. This proposal would require initial and repetitive 
    inspections to detect fatigue cracking in certain areas of the 
    fuselage, and corrective actions, if necessary. This proposal is 
    prompted by issuance of mandatory continuing airworthiness information 
    by a foreign civil airworthiness authority. The actions specified by 
    the proposed AD are intended to prevent fatigue cracking of the 
    fuselage and the passenger and service doors, which could result in 
    reduced structural integrity of the airplane.
    
    DATES: Comments must be received by February 4, 1999.
    
    ADDRESSES: Submit comments in triplicate to the Federal Aviation 
    Administration (FAA), Transport Airplane Directorate, ANM-114, 
    Attention: Rules Docket No. 98-NM-240-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 Aerospatiale, 316 Route de Bayonne, 31060 Toulouse, Cedex 
    03, France. This information may be examined at the FAA, Transport 
    Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.
    
    FOR FURTHER INFORMATION CONTACT: Norman B. Martenson, Manager, 
    International Branch, ANM-116, FAA, Transport Airplane Directorate, 
    1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
    227-2110; fax (425) 227-1149.
    
    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 98-NM-240-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-114, Attention: Rules 
    Docket No. 98-NM-240-AD, 1601 Lind Avenue, SW., Renton, Washington 
    98055-4056.
    
    Discussion
    
        The Direction Generale de l'Aviation Civile (DGAC), which is the 
    airworthiness authority for France, notified the FAA that an unsafe 
    condition may exist on certain Aerospatiale Model ATR72 series 
    airplanes. The DGAC advises that, during full-scale fatigue testing of 
    the airplane, cracks were detected between 12,000 and 36,000 flight 
    cycles. The cracks originated in the following areas:
         At the attachment holes at the hinge fitting of the cargo 
    compartment door outer skin;
         At the positioning holes of both the lower and upper parts 
    of the fuselage main frames;
         At the stop holes of the plug door stop fittings on the 
    forward and aft left passenger doors, and the forward and aft right 
    service doors;
         At the fastener holes in the outboard stringer at frames 
    24 and 28; and
         At the fastener holes in the area of stringer 11 at frame 
    26.
        Such fatigue cracking, if not detected and corrected in a timely 
    manner, could result in reduced structural integrity of the airplane.
    
    Explanation of Relevant Service Information
    
        The manufacturer has issued the following Avions de Transport 
    Regional Service Bulletins:
         ATR72-52-1018, dated May 18, 1995, which describes 
    procedures for a preliminary inspection of the existing fasteners to 
    determine if the fasteners are out of tolerance, and follow-on 
    corrective actions, if necessary. The follow-on corrective actions 
    include removal of existing fasteners and hinges, an inspection of the 
    fastener holes to determine if they are out of tolerance or cracked, a 
    visual inspection of holes for correct tolerance, a high frequency eddy 
    current inspection for cracking; and replacement of the cargo 
    compartment door hinges with new hinges, and repair, if necessary.
         ATR72-53-1013, Revision 2, dated March 22, 1993, which 
    describes procedures for a one-time visual inspection to determine that 
    all rivets are installed in all affected key holes located on main 
    frames 25 and 27 of the fuselage, between stringers 14 and 15; 
    installation of rivets in affected key holes; and an eddy current 
    inspection of the affected key holes to detect cracks.
         ATR72-53-1019, Revision 2, dated October 15, 1996, which 
    describes procedures for a one-time visual inspection to determine that 
    all rivets are installed in the tooling and key holes located on the 
    standard frames of the fuselage; installation of rivets in affected 
    tooling and key holes; a visual inspection to detect cracks of the 
    tooling and key holes that are missing rivets; and installation of new 
    rivets, if necessary.
         ATR72-52-1028, dated July 5, 1993, which describes 
    procedures for repetitive eddy current inspections to detect cracks in 
    the plug door stop fittings of the forward and aft left passenger 
    doors, and the forward and aft right service doors; and replacement of 
    any cracked stop fittings.
    
    [[Page 439]]
    
         ATR72-52-1033, dated April 28, 1995, and ATR72-52-1029, 
    Revision 1, dated November 16, 1994, which describe procedures for 
    replacement of the plug door stop fittings of the forward and aft left 
    passenger doors, and the forward and aft right service doors, with new, 
    improved fittings. Accomplishment of this replacement would eliminate 
    the need for the repetitive inspections specified in Avions de 
    Transport Regional Service Bulletin ATR72-52-1028.
         ATR72-53-1021, Revision 1, dated February 20, 1995, which 
    describes procedures for a one-time eddy current inspection to detect 
    cracks in the rivet holes of the door surround corners of the forward 
    and aft left passenger doors; and the forward and aft right service 
    doors; modification of the rivet holes, and replacement of the door 
    surround corners with modified corners.
         ATR72-53-1014, Revision 2, dated October 15, 1992, which 
    describes procedures for a one-time eddy current inspection to detect 
    cracks of the rivet holes located on the left and right sides of 
    external stringer 4 at frames 24 and 28 of the fuselage, and 
    installation of reinforcement angles.
         ATR72-53-1020, dated October 6, 1992, which describes 
    procedures for a one-time eddy current inspection to detect cracks of 
    the rivet holes located on stringer 11 of frame 26 of the fuselage, and 
    installation of doublers and stringer clips on the left and right sides 
    of frame 26 on stringer 11.
        Accomplishment of the actions specified in these service bulletins 
    is intended to adequately address the identified unsafe condition. The 
    DGAC classified these service bulletins as mandatory and issued French 
    airworthiness directive 92-046-012(B)R4, dated November 5, 1997, in 
    order to assure the continued airworthiness of these airplanes in 
    France.
    
    FAA's Conclusions
    
        This airplane model is manufactured in France 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 DGAC has kept the FAA informed 
    of the situation described above. The FAA has examined the findings of 
    the DGAC, 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.
    
    Explanation of Requirements of Proposed Rule
    
        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 accomplishment of 
    the actions specified in the service bulletins described previously, 
    except as discussed below.
    
    Differences Between the Proposed Rule and Service Bulletins
    
        Operators should note that, unlike the procedures described in 
    Avions de Transport Regional Service Bulletins ATR72-52-1018, original 
    issue; ATR72-53-1013, Revision 2; ATR72-53-1019, Revision 2; ATR72-52-
    1028; ATR72-52-1021, Revision 1; ATR72-53-1014, Revision 2; and ATR72-
    52-1020, original issue; this proposed AD would not permit further 
    flight if cracking is detected in any section of the fuselage. The FAA 
    has determined that, because of the safety implications and 
    consequences associated with such cracking, any portion of the fuselage 
    that is found to be cracked must be repaired or modified prior to 
    further flight, in accordance with the applicable service bulletin, 
    except as discussed in the next paragraph.
        Operators also should note that, although Avions de Transport 
    Regional Service Bulletins ATR72-53-1013, Revision 2; ATR72-53-1019, 
    Revision 2; ATR72-53-1021, Revision 1; ATR72-53-1014, Revision 2; and 
    ATR72-53-1020, original issue; specify that the manufacturer may be 
    contacted for disposition of certain repair conditions, this proposed 
    AD would require the repair of those conditions to be accomplished in 
    accordance with a method approved by either the FAA or the DGAC (or its 
    delegated agent).
    
    Cost Impact
    
        The FAA estimates that 39 airplanes of U.S. registry would be 
    affected by this proposed AD.
        For airplanes identified in Avions de Transport Regional Service 
    Bulletin ATR72-53-1018 (14 U.S.-registered airplanes), it would take 
    approximately 250 work hours per airplane to accomplish the proposed 
    actions, at an average labor rate of $60 per work hour. Required parts 
    would cost approximately $9,880 per airplane. Based on these figures, 
    the cost impact of these actions proposed by this AD on U.S. operators 
    is estimated to be $348,320, or $24,880 per airplane.
        For airplanes identified in Avions de Transport Regional Service 
    Bulletin ATR72-52-1013, Revision 2, (2 U.S.-registered airplanes), it 
    would take approximately 3 work hours per airplane to accomplish the 
    proposed actions, at an average labor rate of $60 per work hour. Based 
    on these figures, the cost impact of these actions proposed by this AD 
    on U.S. operators is estimated to be $360, or $180 per airplane.
        For airplanes identified in Avions de Transport Regional Service 
    Bulletin ATR72-52-1019, Revision 2, (2 U.S.-registered airplanes), it 
    would take approximately 100 work hours per airplane to accomplish the 
    proposed actions, at an average labor rate of $60 per work hour. Based 
    on these figures, the cost impact of these actions proposed by this AD 
    on U.S. operators is estimated to be $12,000, or $6,000 per airplane.
        For airplanes identified in Avions de Transport Regional Service 
    Bulletin ATR72-52-1028, (2 U.S.-registered airplanes), it would take 
    approximately 5 work hours per airplane to accomplish the proposed 
    actions, at an average labor rate of $60 per work hour. Based on these 
    figures, the cost impact of these actions proposed by this AD on U.S. 
    operators is estimated to be $600 or $300 per airplane, per inspection 
    cycle.
        For airplanes identified in Avions de Transport Regional Service 
    Bulletin ATR72-52-1033, and ATR72-52-1029, Revision 1, (2 U.S.-
    registered airplanes), it would take approximately 145 work hours per 
    airplane to accomplish the proposed door stop fitting replacement, at 
    an average labor rate of $60 per work hour. Required parts would be 
    provided by the manufacturer at no cost to the operators. Based on 
    these figures, the cost impact of the stop fittings replacement 
    proposed by this AD on U.S. operators is estimated to be $17,400 or 
    $8,700 per airplane.
        For airplanes identified in Avions de Transport Regional Service 
    Bulletin ATR72-53-1021, Revision 1, (2 U.S.-registered airplanes) it 
    would take approximately 30 work hours per airplane to accomplish the 
    proposed actions, at an average labor rate of $60 per work hour. Based 
    on these figures, the cost impact of these actions proposed by this AD 
    on U.S. operators is estimated to be $3,600, or $1,800 per airplane.
        For airplanes identified in Avions de Transport Regional Service 
    Bulletin ATR72-53-1014, Revision 2, (2 U.S.-registered airplanes), it 
    would take approximately 8 work hours per airplane to accomplish the 
    proposed actions, at an average labor rate of $60 per work hour. Based 
    on these figures, the cost impact of these actions proposed by this AD 
    on U.S. operators
    
    [[Page 440]]
    
    is estimated to be $960, or $480 per airplane.
        For airplanes identified in Avions de Transport Regional Service 
    Bulletin ATR72-53-1020, (14 U.S.-registered airplanes), it would take 
    approximately 6 work hours per airplane to accomplish the proposed 
    actions, at an average labor rate of $60 per work hour. Based on these 
    figures, the cost impact of these actions proposed by this AD on U.S. 
    operators is estimated to be $5,040, or $360 per airplane.
        The cost impact figures discussed above are 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.
    
    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 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. 106(g), 40113, 44701.
    
    
    Sec. 39.13  [Amended]
    
        2. Section 39.13 is amended by adding the following new 
    airworthiness directive:
    Aerospatiale: Docket 98-NM-240-AD.
    
        Applicability: Model ATR72 series airplanes, certificated in any 
    category, and listed in the following Avions de Transport Regional 
    Service Bulletins:
         ATR72-52-1018, dated May 18, 1995;
         ATR72-53-1013, Revision 2, dated March 22, 1993;
         ATR72-53-1019, Revision 2, dated October 15, 1996;
         ATR72-52-1028, dated July 5, 1993;
         ATR72-52-1033, dated April 28, 1995;
         ATR72-52-1029, Revision 1, dated November 16, 1994;
         ATR72-53-1021, Revision 1, dated February 20, 1995;
         ATR72-53-1014, Revision 2, dated October 15, 1992; and
         ATR72-53-1020, dated October 6, 1992.
    
        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 (i) 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 prevent fatigue cracking of the fuselage and the passenger 
    and service doors, which could result in reduced structural 
    integrity of the airplane, accomplish the following:
        (a) For airplanes on which Aerospatiale Modification 03191 
    (reference Avions de Transport Regional Service Bulletin ATR72-52-
    1018, dated May 18, 1995) has not been accomplished: Perform a 
    preliminary inspection of the existing fasteners to determine if the 
    fasteners are out of tolerance in accordance with paragraph 2.C.(1) 
    of the Accomplishment Instructions of Avions de Transport Regional 
    Service Bulletin ATR72-52-1018, dated May 18, 1995. Depending on the 
    results of the inspection, prior to further flight, accomplish the 
    requirements in paragraphs (a)(1) and (a)(2), or (a)(2) and (a)(3) 
    of this AD, as applicable.
        (1) Remove the fasteners and inspect the fastener holes to 
    determine if they are out of tolerance or cracking, in accordance 
    with Part A of the Accomplishment Instructions of the service 
    bulletin. Perform a visual inspection of the holes for correct 
    tolerance, and a high frequency eddy current (HFEC) inspection for 
    cracking.
        (i) If any discrepancy is detected, prior to further flight, 
    repair in accordance with Part C of the Accomplishment Instructions 
    of the service bulletin.
        (ii) If no discrepancy is detected, prior to further flight, 
    replace the cargo compartment door hinges with new hinges in 
    accordance with Part A of the Accomplishment Instructions of the 
    service bulletin.
        (2) Remove the existing fasteners and inspect the fastener holes 
    for correct tolerance in accordance with Part B of the 
    Accomplishment Instructions of the service bulletin.
        (i) If any discrepancy is detected, prior to further flight, 
    repair in accordance with a method approved by the Manager, 
    International Branch, ANM-116, Transport Airplane Directorate; or 
    the Direction Generale de l'Aviation Civile (DGAC) or its delegated 
    agent.
        (ii) If no discrepancy is detected, prior to further flight, 
    replace the cargo compartment door hinges with new hinges in 
    accordance with Part B of the Accomplishment Instructions of the 
    service bulletin.
        (3) Remove the existing fasteners, repair, and replace the cargo 
    compartment door hinges with new hinges in accordance with Part C of 
    the Accomplishment Instructions of the service bulletin.
        (b) For airplanes having serial numbers 108 through 210 
    inclusive: Prior to the accumulation of 36,000 total flight cycles, 
    or within 1 month after the effective date of this AD, whichever 
    occurs later, perform a one-time visual inspection to determine if 
    rivets are installed in the key holes located on main frames 25 and 
    27 of the fuselage, between stringers 14 and 15, in accordance with 
    Avions de Transport Regional Service Bulletin ATR72-53-1013, 
    Revision 2, dated March 22, 1993.
        (1) If all rivets are installed, no further action is required 
    by paragraph (b) of this AD.
        (2) If any rivet is missing, prior to further flight, perform an 
    eddy current inspection of the affected key holes to detect cracks, 
    in accordance with the service bulletin.
        (i) If no crack is detected during the inspection required by 
    paragraph (b)(2) of this AD, prior to further flight, install rivets 
    in all affected key holes, in accordance with the service bulletin. 
    If installation of rivets is not possible, prior to further flight, 
    repair in accordance with a method approved by the Manager, 
    International Branch, ANM-116; or the DGAC (or its delegated agent).
        (ii) If any crack is detected during the inspection required by 
    paragraph (b)(2) of this AD, prior to further flight, repair in 
    accordance with a method approved by the Manager, International 
    Branch, ANM-116; or the DGAC (or its delegated agent).
        (c) For airplanes having serial numbers 108 through 207 
    inclusive: Prior to the accumulation of 36,000 total flight cycles, 
    or within 1 month after the effective date of this AD, whichever 
    occurs later, perform a one-time visual inspection to determine if 
    rivets are installed in the tooling and key holes located on the 
    standard frames of the fuselage, in accordance with Avions de 
    Transport Regional Service Bulletin ATR72-53-1019, Revision 2, dated 
    October 15, 1996.
        (1) If all rivets are installed, no further action is required 
    by paragraph (c) of this AD.
        (2) If any rivet is missing, prior to further flight, perform a 
    visual inspection of the
    
    [[Page 441]]
    
    affected tooling and key holes to detect cracks, in accordance with 
    the service bulletin.
        (i) If no crack is detected during the inspection required by 
    paragraph (c)(2) of this AD, prior to further flight, install new 
    rivets in all affected tooling and key holes, in accordance with the 
    service bulletin.
        (ii) If any crack is detected during the inspection required by 
    paragraph (c)(2) of this AD, prior to further flight, repair in 
    accordance with a method approved by the Manager, International 
    Branch, ANM-116; or the DGAC (or its delegated agent).
        (d) For airplanes on which Aerospatiale Modification 03775 
    (reference Avions de Transport Regional Service Bulletin ATR72-52-
    1029, Revision 1, dated November 16, 1994) or Aerospatiale 
    Modification 03776 (reference Avions de Transport Regional Service 
    Bulletin ATR72-52-1033, dated April 28, 1995) has not been 
    accomplished: Prior to the accumulation of 12,000 total flight 
    cycles, or within 1 month after the effective date of this AD, 
    whichever occurs later, perform an eddy current inspection to detect 
    cracks in the plug door stop fittings of the forward and aft 
    passenger and service doors, in accordance with Avions de Transport 
    Regional Service Bulletin ATR72-52-1028, dated July 5, 1993.
        (1) If no crack is detected, repeat the eddy current inspection 
    required by paragraph (d) of this AD thereafter at intervals not to 
    exceed 6,000 flight cycles.
        (2) If any crack is detected, prior to further flight, replace 
    the cracked stop fittings with new, improved fittings, in accordance 
    with Avions de Transport Regional Service Bulletin ATR72-52-1033, 
    dated April 28, 1995, or ATR72-52-1029, Revision 1, dated November 
    16, 1994; as applicable. Accomplishment of the replacement 
    constitutes terminating action for the repetitive inspection 
    requirements of paragraph (d)(1) of this AD for that fitting.
        (e) For airplanes on which Aerospatiale Modification 03775 or 
    Aerospatiale Modification 03776 has not accomplished: Prior to the 
    accumulation of 18,000 total flight cycles, or within 1 month after 
    the effective date of this AD, whichever occurs later, replace the 
    plug door stop fittings of the forward and aft passenger and service 
    doors with new, improved fittings, in accordance with Avions de 
    Transport Regional Service Bulletin ATR72-52-1033, dated April 28, 
    1995; or ATR72-52-1029, Revision 1, dated November 16, 1994; as 
    applicable. Accomplishment of the replacement constitutes 
    terminating action for the repetitive inspection requirements of 
    paragraph (d)(1) of this AD.
        (f) For airplanes on which Aerospatiale Modification 02986 
    (reference Avions de Transport Regional Service Bulletin ATR72-53-
    1021, Revision 1, dated February 20, 1995) has not been 
    accomplished: Prior to the accumulation of 18,000 total flight 
    cycles, or within 1 month after the effective date of this AD, 
    whichever occurs later, perform a one-time eddy current inspection 
    to detect cracks in the rivet holes of the door surround corners of 
    the forward and aft passenger and service doors, in accordance with 
    Avions de Transport Regional Service Bulletin ATR72-53-1021, 
    Revision 1, dated February 20, 1995.
        (1) If no crack is detected during the inspection required by 
    paragraph (f) of this AD, prior to further flight, modify the rivet 
    holes, and replace the door surround corners with modified corners, 
    in accordance with the service bulletin.
        (2) If any crack is detected during the inspection required by 
    paragraph (f) of this AD, prior to further flight, repair and modify 
    in accordance with a method approved by the Manager, International 
    Branch, ANM-116; or the DGAC (or its delegated agent).
        (g) For airplanes on which Aerospatiale Modification 02397 
    (reference Avions de Transport Regional Service Bulletin ATR72-53-
    1014, Revision 2, dated October 15, 1992) has not been accomplished: 
    Prior to the accumulation of 12,000 total flight cycles, or within 1 
    month after the effective date of this AD, whichever occurs later, 
    perform a one-time eddy current inspection to detect cracks of the 
    rivet holes located on the left and right sides of external stringer 
    4 at frames 24 and 28 of the fuselage, in accordance with Avions de 
    Transport Regional Service Bulletin ATR72-53-1014, Revision 2, dated 
    October 15, 1992.
        (1) If no crack is detected during the inspection required by 
    paragraph (g) of this AD, prior to further flight, install 
    reinforcement angles on the left and right sides of external 
    stringer 4 at frames 24 and 28 of the fuselage, in accordance with 
    the service bulletin.
        (2) If any crack is detected during the inspection required by 
    paragraph (g) of this AD, prior to further flight, repair in 
    accordance with a method approved by the Manager, International 
    Branch, ANM-116; or the DGAC (or its delegated agent).
        (h) For airplanes on which Aerospatiale Modification 03185 
    (reference Avions de Transport Regional Service Bulletin ATR72-53-
    1020, dated October 6, 1992) has not been accomplished: Prior to the 
    accumulation of 12,000 total flight cycles, or within 1 month after 
    the effective date of this AD, whichever occurs later, perform a 
    one-time eddy current inspection to detect cracks of the rivet holes 
    located on stringer 11 of frame 26 of the fuselage, in accordance 
    with Avions de Transport Regional Service Bulletin ATR72-53-1020, 
    dated October 6, 1992.
        (1) If no crack is detected during the inspection required by 
    paragraph (h) of this AD, prior to further flight, install doublers 
    and stringer clips on the left and right sides on stringer 11 of 
    frame 26 of the fuselage, in accordance with the service bulletin.
        (2) If any crack is detected during the inspection required by 
    paragraph (h) of this AD, prior to further flight, repair in 
    accordance with a method approved by the Manager, International 
    Branch, ANM-116; or the DGAC (or its delegated agent).
    
        Note 2: Inspections and repairs accomplished prior to the 
    effective date of this AD in accordance with Avions de Transport 
    Regional Service Bulletins ATR72-53-1013, dated June 10, 1991, or 
    Revision 1, dated June 12, 1992; ATR72-53-1019, dated May 13, 1993, 
    or Revision 1, dated November 11, 1994; ATR72-52-1029, dated July 
    20, 1994; or ATR72-53-1014, Revision 1, dated June 30, 1992; are 
    considered acceptable for compliance with the applicable actions 
    specified in this amendment.
    
        (i) 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, International Branch, ANM-116. 
    Operators shall submit their requests through an appropriate FAA 
    Principal Maintenance Inspector, who may add comments and then send 
    it to the Manager, International Branch, ANM-116.
    
        Note 3: Information concerning the existence of approved 
    alternative methods of compliance with this AD, if any, may be 
    obtained from the International Branch, ANM-116.
    
        (j) 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.
    
        Note 4: The subject of this AD is addressed in French 
    airworthiness directive 92-046-012(B)R4, dated November 5, 1997.
    
        Issued in Renton, Washington, on December 29, 1998.
    Darrell M. Pederson,
    Acting Manager, Transport Airplane Directorate, Aircraft Certification 
    Service.
    [FR Doc. 99-47 Filed 1-4-99; 8:45 am]
    BILLING CODE 4910-13-P
    
    
    

Document Information

Published:
01/05/1999
Department:
Federal Aviation Administration
Entry Type:
Proposed Rule
Action:
Notice of proposed rulemaking (NPRM).
Document Number:
99-47
Dates:
Comments must be received by February 4, 1999.
Pages:
438-441 (4 pages)
Docket Numbers:
Docket No. 98-NM-240-AD
RINs:
2120-AA64: Airworthiness Directives
RIN Links:
https://www.federalregister.gov/regulations/2120-AA64/airworthiness-directives
PDF File:
99-47.pdf
CFR: (1)
14 CFR 39.13