99-33166. Airworthiness Directives; The New Piper Aircraft, Inc. J-2 Series Airplanes That Are Equipped With Wing Lift Struts  

  • [Federal Register Volume 64, Number 248 (Tuesday, December 28, 1999)]
    [Rules and Regulations]
    [Pages 72524-72528]
    From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
    [FR Doc No: 99-33166]
    
    
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    DEPARTMENT OF TRANSPORTATION
    
    Federal Aviation Administration
    
    14 CFR Part 39
    
    [Docket No. 99-CE-13-AD; Amendment 39-11479; AD 99-26-19]
    RIN 2120-AA64
    
    
    Airworthiness Directives; The New Piper Aircraft, Inc. J-2 Series 
    Airplanes That Are Equipped With Wing Lift Struts
    
    AGENCY: Federal Aviation Administration, DOT.
    
    ACTION: Final rule.
    
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    SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
    applies to certain The New Piper Aircraft, Inc. (Piper) J-2 series 
    airplanes equipped with wing lift struts. This AD requires repetitively 
    inspecting the wing lift struts for dents and corrosion and the wing 
    lift strut forks for cracks; replacing any strut found with corrosion 
    or dents, or forks with cracks; and repetitively replacing the wing 
    lift strut forks. This AD also requires incorporating a ``NO STEP'' 
    placard on the lift strut. This AD is the result of the Federal 
    Aviation Administration (FAA) inadvertently omitting the J-2 series 
    airplanes from the applicability of AD 99-01-05. The actions specified 
    by this AD are intended to prevent in-flight separation of the wing 
    from the airplane caused by wing lift struts with dents or corrosion or 
    wing lift forks with cracks, which could result in loss of control of 
    the airplane.
    
    DATES: Effective February 14, 2000.
        The incorporation by reference of certain publications listed in 
    the regulations is approved by the Director of the Federal Register as 
    of February 14, 2000.
    
    ADDRESSES: Service information that applies to this AD may be obtained 
    from The New Piper Aircraft, Inc., Customer Services, 2926 Piper Drive, 
    Vero Beach, Florida 32960. Copies of the instructions to the F. Atlee 
    Dodge supplemental type certificate (STC) may be obtained from F. Atlee 
    Dodge, Aircraft Services, Inc., P.O. Box 190409, Anchorage, Alaska 
    99519-0409. Copies of the instructions to the Jensen Aircraft STC's may 
    be obtained from Jensen Aircraft, Inc., 9225 County Road 140, Salida, 
    Colorado 81201. This information may also be examined at the Federal 
    Aviation Administration (FAA), Central Region, Office of the Regional 
    Counsel, Attention: Rules Docket No. 99-CE-13-AD, 901 Locust, Room 506, 
    Kansas City, Missouri 64106; or at the Office of the Federal Register, 
    800 North Capitol Street, NW, suite 700, Washington, DC.
    
    FOR FURTHER INFORMATION CONTACT: Mr. William O. Herderich, Aerospace 
    Engineer, FAA, Atlanta Aircraft Certification Office, One Crown Center, 
    1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; telephone: 
    (770) 703-6084; facsimile: (770) 703-6097.
    
    SUPPLEMENTARY INFORMATION:
    
    Events Leading to the Issuance of This AD
    
        A proposal to amend part 39 of the Federal Aviation Regulations (14 
    CFR part 39) to include an AD that would apply to certain Piper J-2 
    series airplanes of the same type design that are equipped with wing 
    lift struts was published in the Federal Register as a notice of 
    proposed rulemaking (NPRM) on July 12, 1999 (64 FR 37465). The NPRM 
    proposed to require repetitively inspecting the wing lift struts for 
    dents and corrosion and the wing lift strut forks for cracks; replacing 
    any strut found with corrosion or dents, or forks with cracks; and 
    repetitively replacing the wing lift strut forks. The NPRM also 
    proposed to require installing a placard on the lift strut, and would 
    provide the option of installing certain wing lift strut and wing lift 
    strut fork assemblies, as terminating action for repetitive inspection 
    and replacement requirements. Accomplishment of the proposed action as 
    specified in the NPRM would be required in accordance with Piper 
    Service bulletin No. 528D, dated October 19,1990.
        The NPRM was the result of the Federal Aviation Administration 
    (FAA) inadvertently omitting the J-2 series airplanes from the 
    applicability of AD 99-01-05.
        Interested persons have been afforded an opportunity to participate 
    in the making of this amendment. No comments were received on the 
    proposed rule or the FAA's determination of the cost to the public.
    
    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 except for 
    minor editorial corrections. The FAA has determined that these minor 
    corrections will not change the meaning of the AD and will not add any 
    additional burden upon the public than was already proposed.
    
    [[Page 72525]]
    
    Cost Impact
    
        The FAA estimates that 91 airplanes in the U.S. registry will be 
    affected by this AD.
        It will take approximately 8 workhours per airplane to accomplish 
    the initial inspection, and the average labor rate is approximately $60 
    an hour. Based on these figures, the total cost impact of the initial 
    inspection on U.S. operators is estimated to be $43,680, or $480 per 
    airplane. These figures are based only on the cost of the initial 
    inspection and do not take into account the costs of any repetitive 
    inspections. The FAA has no way of determining how many repetitive 
    inspections each owner/operator will incur over the life of the 
    airplane.
        It will take approximately 4 workhours per airplane to accomplish 
    the initial wing lift strut fork replacements, and the average labor 
    rate is approximately $60 an hour. Fork assemblies cost approximately 
    $110 each and four are required for each airplane. Based on these 
    figures, the total cost impact of the initial wing lift strut fork 
    replacements on U.S. operators is estimated to be $61,880, or $680 per 
    airplane.
        Airplane operators who do not incorporate the improved design wing 
    lift strut assemblies will have to repetitively replace the wing lift 
    strut forks. The FAA has no way of determining how many airplanes do 
    not have the improved design wing lift strut assemblies installed and 
    will need repetitive strut fork replacements.
    
    Regulatory Impact
    
        The regulations adopted herein will not have a substantial direct 
    effect 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, it 
    is determined that this final rule does not have federalism 
    implications under Executive Order 13132.
        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) 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 final 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, Incorporation by 
    reference, 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 a new airworthiness directive 
    (AD) to read as follows:
    
    99-26-19 The New Piper Aircraft, Inc.: Amendment 39-11479; Docket 
    No. 99-CE-13-AD.
    
        Applicability: J-2 series airplanes, serial numbers 500 through 
    1975, certificated in any category; that are equipped with wing lift 
    struts.
    
        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 (f) 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 in the body of this AD, unless 
    already accomplished.
        To prevent in-flight separation of the wing from the airplane 
    caused by wing lift struts with dents or corrosion or wing lift 
    forks with cracks, which could result in loss of control of the 
    airplane, accomplish the following:
    
        Note 2: The paragraph structure of this AD is as follows:
        Level 1: (a), (b), (c), etc.
        Level 2: (1), (2), (3), etc.
        Level 3: (i), (ii), (iii), etc.
        Level 4: (A), (B), (C), etc.
    
    Level 2, Level 3, and Level 4 structures are designations of the 
    Level 1 paragraph they immediately follow.
    
        (a) Within 1 calendar month after the effective date of this AD 
    or within 24 calendar months after the last inspection accomplished 
    per AD 93-10-06, whichever occurs later, remove the wing lift struts 
    in accordance with Piper Service Bulletin (SB) No. 528D, and 
    accomplish one of the following (the actions in either paragraph 
    (a)(1), (a)(2), (a)(3), or (a)(4), including subparagraphs, of this 
    AD):
        (1) Inspect the wing lift struts for perceptible dents (as 
    defined in the service bulletin referenced below) and corrosion in 
    accordance with the ``INSTRUCTIONS'' section in part I of Piper SB 
    No. 528D, dated October 19, 1990.
        (i) If no perceptible dents are found in the wing lift strut and 
    no corrosion is externally visible, prior to further flight, apply 
    corrosion inhibitor to each strut in accordance with the SB 
    referenced above. Reinspect the lift struts at intervals not to 
    exceed 24 calendar months.
        (ii) If a perceptible dent is found in the wing lift strut or 
    external corrosion is found, prior to further flight, accomplish one 
    of the installations (and subsequent actions presented in each 
    paragraph) specified in paragraph (a)(3) or (a)(4) of this AD.
        (2) Inspect the wing lift struts for corrosion in accordance 
    with the Appendix to this AD. The inspection procedures in this 
    Appendix must be accomplished by a Level 2 inspector certified using 
    the guidelines established by the American Society for Non-
    destructive Testing, or MIL-STD-410.
        (i) If no corrosion is found that is externally visible and all 
    requirements in the Appendix to this AD are met, prior to further 
    flight, apply corrosion inhibitor to each strut in accordance with 
    the SB referenced above. Reinspect the lift struts at intervals not 
    to exceed 24 calendar months.
        (ii) If external corrosion is found or if any of the 
    requirements in the Appendix of this AD are not met, prior to 
    further flight, accomplish one of the installations (and subsequent 
    actions presented in each paragraph) specified in paragraph (a)(3) 
    or (a)(4) of this AD.
        (3) Install original equipment manufacturer (OEM) part number 
    wing struts (or FAA-approved equivalent part numbers) that have been 
    inspected in accordance with the specifications presented in either 
    paragraph (a)(1) or (a)(2) of this AD, and are found to be airworthy 
    according to the inspection requirements included in these 
    paragraphs. Thereafter, inspect these wing lift struts at intervals 
    not to exceed 24 calendar months in accordance with the 
    specifications presented in either paragraph (a)(1) or (a)(2) of 
    this AD.
        (4) Install new sealed wing lift strut assemblies, part numbers 
    as specified in Piper SB No. 528D (or FAA-approved equivalent part 
    numbers), on each wing as specified in the INSTRUCTIONS section in 
    part II of the above-referenced SB. These sealed wing lift strut 
    assemblies also include the wing lift strut forks. Installation of 
    these assemblies constitutes terminating action for the inspection 
    and replacement requirements of both paragraphs (a) and (b) of this 
    AD.
        (b) Within the next 100 hours time-in-service (TIS) after the 
    effective date of this AD or within 500 hours TIS after the last 
    inspection, whichever is later, remove the wing lift strut forks and 
    accomplish one of the following (the actions in either paragraph 
    (b)(1), (b)(2) or (b)(3); including subparagraphs, of this AD):
    
    [[Page 72526]]
    
        (1) Inspect the wing lift strut forks for cracks using FAA-
    approved magnetic particle procedures.
        (i) If no cracks are found, reinspect at intervals not to exceed 
    500 hours TIS provided that the replacement requirements of 
    paragraphs (b)(1)(ii)(B) and (b)(1)(ii)(C) of this AD have been met.
        (ii) Replace the wing lift strut forks at whichever of the 
    following is applicable:
        (A) If cracks are found on any wing lift strut fork: Prior to 
    further flight;
        (B) If the airplane is equipped with floats or has been equipped 
    with floats within the last 2,000 hours TIS and no cracks are found 
    during the above inspections: Upon accumulating 1,000 hours TIS on 
    the wing lift strut forks or within the next 100 hours TIS after the 
    effective date of this AD, whichever occurs later; or
        (C) If the airplane has not been equipped with floats within the 
    last 2,000 hours TIS and no cracks are found during the above 
    inspections: Upon accumulating 2,000 hours TIS on the wing lift 
    strut forks or within the next 100 hours TIS after the effective 
    date of this AD, whichever occurs later.
        (iii) Replacement parts shall be of the same part numbers of the 
    existing part (or FAA-approved equivalent part numbers) and shall be 
    manufactured with rolled threads. Lift strut forks manufactured with 
    machined (cut) threads shall not be utilized.
        (iv) The 500-hour TIS interval repetitive inspections are still 
    required when the above replacements are accomplished.
        (2) Install new OEM part number wing lift strut forks (or FAA-
    approved equivalent part numbers). Reinspect and replace these wing 
    lift strut forks at the intervals specified in paragraphs (b)(1)(i), 
    (b)(1)(ii), (b)(1)(iii), and (b)(1)(iv), including all 
    subparagraphs, of this AD.
        (3) Install new sealed wing lift strut assemblies, part numbers 
    as specified in Piper SB No. 528D (or FAA-approved equivalent part 
    numbers), on each wing as specified in the INSTRUCTIONS section in 
    part II of the above-referenced SB.
        (i) This installation may have ``already been accomplished'' 
    through the actions specified in paragraph (a)(4) of this AD.
        (ii) No repetitive inspections are required after installing 
    these sealed wing lift strut assemblies.
        (c) If holes are drilled in wing lift strut assemblies installed 
    in accordance with (a)(4) or (b)(3) of this AD to attach cuffs, door 
    clips, or other hardware, inspect the wing lift struts at intervals 
    not to exceed 24 calendar months using the procedures specified in 
    paragraph (a)(1) or (a)(2), including all subparagraphs, of this AD.
        (d) Within 1 calendar month after the effective date of this AD 
    and thereafter prior to further flight after the installation of any 
    lift strut assembly, accomplish one of the following:
        (1) Install ``NO STEP'' decal, Piper part number (P/N) 80944-02, 
    on each wing lift strut approximately 6 inches from the bottom of 
    the struts in a way that the letters can be read when entering and 
    exiting the aircraft; or
        (2) Paint the statement ``NO STEP'' approximately 6 inches from 
    the bottom of the struts in a way that the letters can be read when 
    entering and exiting the aircraft. Use a minimum of 1-inch letters 
    utilizing a color that contrasts with the color of the airplane.
        (e) 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.
        (f) An alternative method of compliance or adjustment of the 
    initial and repetitive compliance times that provides an equivalent 
    level of safety may be approved by the Manager, FAA, Atlanta Aircraft 
    Certification Office (ACO), One Crown Center, 1895 Phoenix Boulevard, 
    suite 450, Atlanta, Georgia 30349. The request shall be forwarded 
    through an appropriate FAA Maintenance Inspector, who may add comments 
    and then send it to the Manager, Atlanta ACO.
    
        Note 3: Information concerning the existence of approved 
    alternative methods of compliance with this AD, if any, may be 
    obtained from the Atlanta ACO.
    
        (g) The removals, inspections, modifications, and installations 
    required by this AD shall be done in accordance with Piper Service 
    Bulletin No. 528D, dated October 19, 1990. This incorporation by 
    reference was approved by the Director of the Federal Register in 
    accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be 
    obtained from The New Piper Aircraft, Inc., Customer Services, 2926 
    Piper Drive, Vero Beach, Florida 32960. Copies may be inspected at 
    the FAA, Central Region, Office of the Regional Counsel, 901 Locust, 
    Room 506, Kansas City, Missouri, or at the Office of the Federal 
    Register, 800 North Capitol Street, NW, suite 700, Washington, DC.
    
    Appendix to Docket No. 99-CE-13-AD--Procedures and Requirements for 
    Ultrasonic Inspection of Piper Wing Lift Struts
    
    Equipment Requirements
    
        1. A portable ultrasonic thickness gauge or flaw detector with 
    echo-to-echo digital thickness readout capable of reading to 0.001-
    inch and an A-trace waveform display will be needed to accomplish 
    this inspection.
        2. An ultrasonic probe with the following specifications will be 
    needed to accomplish this inspection: 10 MHz (or higher), 0.283-inch 
    (or smaller) diameter dual element or delay line transducer designed 
    for thickness gauging. The transducer and ultrasonic system shall be 
    capable of accurately measuring the thickness of AISI 4340 steel 
    down to 0.020-inch. An accuracy of +/-0.002-inch throughout a 0.020-
    inch to 0.050-inch thickness range while calibrating shall be the 
    criteria for acceptance.
        3. Either a precision machined step wedge made of 4340 steel (or 
    similar steel with equivalent sound velocity) or at least three shim 
    samples of same material will be needed to accomplish this 
    inspection. One thickness of the step wedge or shim shall be less 
    than or equal to 0.020-inch, one shall be greater than or equal to 
    0.050-inch, and at least one other step or shim shall be between 
    these two values.
        4. Glycerin, light oil, or similar non-water based ultrasonic 
    couplants are recommended in the setup and inspection procedures. 
    Water-based couplants, containing appropriate corrosion inhibitors, 
    may be utilized, provided they are removed from both the reference 
    standards and the test item after the inspection procedure is 
    completed and adequate corrosion prevention steps are then taken to 
    protect these items.
    
         Note: Couplant is defined as ``a substance used between 
    the face of the transducer and test surface to improve transmission 
    of ultrasonic energy across the transducer/strut interface.''
         Note: If surface roughness due to paint loss or 
    corrosion is present, the surface should be sanded or polished 
    smooth before testing to assure a consistent and smooth surface for 
    making contact with the transducer. Care shall be taken to remove a 
    minimal amount of structural material. Paint repairs may be 
    necessary after the inspection to prevent further corrosion damage 
    from occurring. Removal of surface irregularities will enhance the 
    accuracy of the inspection technique.
    
    Instrument Setup
    
        1. Set up the ultrasonic equipment for thickness measurements as 
    specified in the instrument's user's manual. Because of the variety 
    of equipment available to perform ultrasonic thickness measurements, 
    some modification to this general setup procedure may be necessary. 
    However, the tolerance requirement of step 13 and the record keeping 
    requirement of step 14, must be satisfied.
        2. If battery power will be employed, check to see that the 
    battery has been properly charged. The testing will take 
    approximately two hours. Screen brightness and contrast should be 
    set to match environmental conditions.
        3. Verify that the instrument is set for the type of transducer 
    being used, i.e. single or dual element, and that the frequency 
    setting is compatible with the transducer.
        4. If a removable delay line is used, remove it and place a drop 
    of couplant between the transducer face and the delay line to assure 
    good transmission of ultrasonic energy. Reassemble the delay line 
    transducer and continue.
        5. Program a velocity of 0.231-inch/microsecond into the 
    ultrasonic unit unless an alternative instrument calibration 
    procedure is used to set the sound velocity.
        6. Obtain a step wedge or steel shims per item 3 of the 
    Equipment Requirements. Place the probe on the thickest sample using 
    couplant. Rotate the transducer slightly back and forth to ``ring'' 
    the transducer to the sample. Adjust the delay and range settings to 
    arrive at an A-trace signal display with the first backwall echo 
    from the steel near the left side of the screen and the second 
    backwall echo near the right of the screen. Note that when a single 
    element transducer is used, the initial pulse and the delay line/
    steel interface will be off of the screen to the left. Adjust the 
    gain to place the amplitude of the first backwall signal at 
    approximately 80% screen height on the A-trace.
    
    [[Page 72527]]
    
        7. ``Ring'' the transducer on the thinnest step or shim using 
    couplant. Select positive half-wave rectified, negative half-wave 
    rectified, or filtered signal display to obtain the cleanest signal. 
    Adjust the pulse voltage, pulse width, and damping to obtain the 
    best signal resolution. These settings can vary from one transducer 
    to another and are also user dependent.
        8. Enable the thickness gate, and adjust the gate so that it 
    starts at the first backwall echo and ends at the second backwall 
    echo. (Measuring between the first and second backwall echoes will 
    produce a measurement of the steel thickness that is not affected by 
    the paint layer on the strut). If instability of the gate trigger 
    occurs, adjust the gain, gate level, and/or damping to stabilize the 
    thickness reading.
        9. Check the digital display reading and if it does not agree 
    with the known thickness of the thinnest thickness, follow your 
    instrument's calibration recommendations to produce the correct 
    thickness reading. When a single element transducer is used this 
    will usually involve adjusting the fine delay setting.
        10. Place the transducer on the thickest step of shim using 
    couplant. Adjust the thickness gate width so that the gate is 
    triggered by the second backwall reflection of the thick section. If 
    the digital display does not agree with the thickest thickness, 
    follow your instruments calibration recommendations to produce the 
    correct thickness reading. A slight adjustment in the velocity may 
    be necessary to get both the thinnest and the thickest reading 
    correct. Document the changed velocity value.
        11. Place couplant on an area of the lift strut which is thought 
    to be free of corrosion and ``ring'' the transducer to surface. 
    Minor adjustments to the signal and gate settings may be required to 
    account for coupling improvements resulting from the paint layer. 
    The thickness gate level should be set just high enough so as not to 
    be triggered by irrelevant signal noise. An area on the upper 
    surface of the lift strut above the inspection area would be a good 
    location to complete this step and should produce a thickness 
    reading between 0.034-inch and 0.041-inch.
        12. Repeat steps 8, 9, 10, and 11 until both thick and thin shim 
    measurements are within tolerance and the lift strut measurement is 
    reasonable and steady.
        13. Verify that the thickness value shown in the digital display 
    is within +/-0.002-inch of the correct value for each of the three 
    or more steps of the setup wedge or shims. Make no further 
    adjustments to the instrument settings.
        14. Record the ultrasonic versus actual thickness of all wedge 
    steps or steel shims available as a record of setup.
    
    Inspection Procedure
    
        1. Clean the lower 18 inches of the wing lift struts using a 
    cleaner that will remove all dirt and grease. Dirt and grease will 
    adversely affect the accuracy of the inspection technique. Light 
    sanding or polishing may also be required to reduce surface 
    roughness as noted in the Equipment Requirements section.
        2. Using a flexible ruler, draw a \1/4\-inch grid on the surface 
    of the first 11 inches from the lower end of the strut as shown in 
    Piper Service Bulletin No. 528D or 910A, as applicable. This can be 
    done using a soft (#2) pencil and should be done on both faces of 
    the strut. As an alternative to drawing a complete grid, make two 
    rows of marks spaced every \1/4\-inch across the width of the strut. 
    One row of marks should be about 11 inches from the lower end of the 
    strut, and the second row should be several inches away where the 
    strut starts to narrow. Lay the flexible ruler between respective 
    tick marks of the two rows and use tape or a rubber band to keep the 
    ruler in place. See Figure 1.
        3. Apply a generous amount of couplant inside each of the square 
    areas or along the edge of the ruler. Re-application of couplant may 
    be necessary.
        4. Place the transducer inside the first square area of the 
    drawn grid or at the first \1/4\-inch mark on the ruler and ``ring'' 
    the transducer to the strut. When using a dual element transducer, 
    be very careful to record the thickness value with the axis of the 
    transducer elements perpendicular to any curvature in the strut. If 
    this is not done, loss of signal or inaccurate readings can result.
        5. Take readings inside each square on the grid or at \1/4\-inch 
    increments along the ruler and record the results. When taking a 
    thickness reading, rotate the transducer slightly back and forth and 
    experiment with the angle of contact to produce the lowest thickness 
    reading possible. Pay close attention to the A-scan display to 
    assure that the thickness gate is triggering off of maximized 
    backwall echoes.
    
         Note: A reading shall not exceed .041-inch. If a 
    reading exceeds .041-inch, repeat steps 13 and 14 of the Instrument 
    Setup section before proceeding further.
    
        6. If the A-trace is unsteady or the thickness reading is 
    clearly wrong, adjust the signal gain and/or gate setting to obtain 
    reasonable and steady readings. If any instrument setting is 
    adjusted, repeat steps 13 and 14 of the Instrument Setup section 
    before proceeding further.
        7. In areas where obstructions are present, take a data point as 
    close to the correct area as possible.
    
         Note: The strut wall contains a fabrication bead at 
    approximately 40% of the strut chord. The bead may interfere with 
    accurate measurements in that specific location.
    
        8. A measurement of 0.024-inch or less shall require replacement 
    of the strut prior to further flight
        9. If at any time during testing an area is encountered where a 
    valid thickness measurement cannot be obtained due to a loss of 
    signal strength or quality, the area shall be considered suspect. 
    These areas may have a remaining wall thickness of less than 0.020-
    inch, which is below the range of this setup, or they may have small 
    areas of localized corrosion or pitting present. The latter case 
    will result in a reduction in signal strength due to the sound being 
    scattered from the rough surface and may result in a signal that 
    includes echoes from the pits as well as the backwall. The suspect 
    area(s) shall be tested with a Maule ``Fabric Tester'' as specified 
    in Piper Service Bulletin No. 528D or 910A.
        10. Record the lift strut inspection in the aircraft log book.
    
    [[Page 72528]]
    
    [GRAPHIC] [TIFF OMITTED] TR28DE99.022
    
    
    
        (h) This amendment becomes effective on February 14, 2000.
    
        Issued in Kansas City, Missouri, on December 16, 1999.
    James Jackson,
    Acting Manager, Small Airplane Directorate, Aircraft Certification 
    Service.
    [FR Doc. 99-33166 Filed 12-27-99; 8:45 am]
    BILLING CODE 4910-13-U
    
    
    

Document Information

Effective Date:
2/14/2000
Published:
12/28/1999
Department:
Federal Aviation Administration
Entry Type:
Rule
Action:
Final rule.
Document Number:
99-33166
Dates:
Effective February 14, 2000.
Pages:
72524-72528 (5 pages)
Docket Numbers:
Docket No. 99-CE-13-AD, Amendment 39-11479, AD 99-26-19
RINs:
2120-AA64: Airworthiness Directives
RIN Links:
https://www.federalregister.gov/regulations/2120-AA64/airworthiness-directives
PDF File:
99-33166.pdf
CFR: (1)
14 CFR 39.13