Airworthiness Directive · Amendment 39-17169 · Flight controls
Piper Aircraft, Inc. Airplanes
This AD applies to the following Piper Aircraft, Inc. airplanes, certificated in any category:
(1) Model PA-24, serial numbers (S/Ns) 24-1 through 24-3687, with horn part number (P/N) 20397-00 (assembly P/N 20399) installed;
(2) Model PA-24-250, S/Ns 24-1 and 24-103 through 24-3687, with horn P/N 20397-00 (assembly P/N 20399) installed; and
(3) Model PA-24-260, S/Ns 24-3642 and 24-4000 through 24-5034, with horn P/N 20397-00 (assembly P/N 20399) installed.
We are adopting a new airworthiness directive (AD) for certain Piper Aircraft, Inc. Models PA-24, PA-24-250, and PA-24-260 airplanes. This AD was prompted by reports of cracks developing in the stabilator horn assembly. This AD requires replacement of the stabilator horn assembly and/or repetitive inspections of the stabilator horn assembly for corrosion or cracks, as applicable. Corrosion or cracks could lead to failure of the stabilator horn. Consequently, failure of the stabilator horn could lead to a loss of pitch control in flight. We are issuing this AD to correct the unsafe condition on these products.
Comply with this AD following Piper Aircraft, Inc. Service Bulletin No. 1189, dated April 29, 2010, within the compliance times specified in this AD, unless already done (does not eliminate the repetitive actions of this AD).
(1) When a new stabilator horn assembly has been installed (during production or replacement) and the stabilator horn assembly reaches a total of 1,000 hours time-in-service (TIS) or 10 years after installation, or within the next 100 hours TIS after October 22, 2012 (the effective date of this AD), whichever occurs later, do one of the following actions:
(i) Initially inspect the stabilator horn assembly for corrosion or cracks. Repetitively thereafter inspect at intervals not to exceed 500 hours TIS or 5 years, whichever occurs first.
(ii) Replace the stabilator horn assembly with a new stabilator horn assembly. When the new stabilator horn assembly reaches a total of 1,000 hours TIS after replacement or within 10 years after replacement, whichever occurs first, you must do one of the actions in paragraph (g)(1) of this AD.
(iii) Replace the stabilator horn assembly with a used serviceable stabilator horn assembly that has been inspected before installation and found free of cracks or corrosion. Repetitively thereafter inspect at intervals not to exceed 500 hours TIS or 5 years, whichever occurs first.
(2) When a used serviceable stabilator horn assembly that has been inspected before installation and found free of cracks or corrosion has been installed and the stabilator horn assembly reaches a total of 500 hours TIS or 5 years after installation, or within the next 100 hours TIS after October 22, 2012 (the effective date of this AD), whichever occurs later, do one of the following actions:
(i) Initially inspect the stabilator horn assembly for corrosion or cracks. Repetitively thereafter inspect at intervals not to exceed 500 hours TIS or 5 years, whichever occurs first.
(ii) Replace the stabilator horn assembly with a new stabilator horn assembly. When the new stabilator horn assembly reaches a total of 1,000 hours TIS after replacement or within 10 years after replacement, whichever occurs first, you must do one of the actions in paragraph (g)(1) of this AD.
(iii) Replace the stabilator horn assembly with a used serviceable stabilator horn assembly that has been inspected before installation and found free of cracks or corrosion. Repetitively thereafter inspect at intervals not to exceed 500 hours TIS or 5 years, whichever occurs first.
(3) If you do not know the total hours TIS on the stabilator horn assembly, within the next 100 hours TIS after October 22, 2012 (the effective date of this AD) do one of the actions required in paragraph (g)(1)(i), (g)(1)(ii), (g)(1)(iii), (g)(2)(i), (g)(2)(ii), or (g)(2)(iii) of this AD.
(4) If any corrosion or cracks are found during any of the inspections required in paragraph (g)(1)(i), (g)(1)(iii), (g)(2)(i), or (g)(2)(iii) of this AD, before further flight, you must replace the stabilator horn assembly as specified in paragraph (g)(1)(ii), (g)(1)(iii). (g)(2)(ii), or (g)(2)(iii) of this AD, as applicable.
(5) For the bolts common to the torque tube and stabilator horn, install the nuts using a torque of 120-145 in.-lbs. for the actions required by paragraphs (g)(1), (g)(2), or (g)(3) of this AD.
Note 1 to paragraph (g) of this AD: The stated torque value of 120-145 in.-lbs. includes friction drag from the nut's locking element, which is assumed to be 60 in.-lbs. The installation torque can be adjusted according to the actual, measured friction drag. For example, if the friction-drag torque is measured to be 40 in.-lbs. (20 in.-lbs. less than the assumed value of 60 in.-lbs.), then the installation torque will be adjusted to be 100-125 in.-lbs. of torque.
(6) You may at any time replace the stabilator horn assembly with a new stabilator horn assembly, provided no corrosion or cracks were found during an inspection that would require replacement before further flight. When the new stabilator horn assembly reaches a total of 1,000 hours TIS after replacement or within 10 years after replacement, whichever occurs first, you must do one of the actions in paragraph (g)(1) of this AD.
Note 2 to paragraph (g) of this AD: Piper Aircraft, Inc. Service Bulletin No. 1160, dated December 26, 2005; Special Airworthiness Information Bulletin CE-04-88, dated September 15, 2004, at http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSAIB.nsf/0/77fc29bb15c8a85b8625721f0052ecb4/$FILE/CE-04-88.pdf; and AD 74-13-03, Amendment 39-2588 (41 FR 17371, April 26, 1976), are related to this AD action. For the attached torque tube, you may consider combining that inspection with the requirements of this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
