Airworthiness Directive · Amendment 39-21855 · Horizontal stabilizer structure
Piper Aircraft, Inc. Airplanes
This AD applies to Piper Aircraft, Inc., Model PA-23-250 airplanes, serial numbers 27-7654001 through 27-7954121, certificated in any category.
The FAA is superseding Airworthiness Directive (AD) 78-02-03, which applied to all Piper Aircraft, Inc. (Piper) Model PA-23-250 airplanes. AD 78-02-03 required repetitively inspecting the stabilator tip tube and weight assemblies for cracks, inspecting for missing rivets and screws, replacing the forward rib/horn assemblies, and reinforcing the mounting. Since AD 78-02-03 was issued, Piper developed a newly-designed stabilator, which is not subject to the unsafe condition, and revised its service information. This AD retains the actions of AD 78-02-03, but reduces the applicability and requires the actions in the revised service information. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Within 50 hours time-in-service (TIS) after January 26, 1978 (the effective date of AD 78-02-03), do the following inspections and modifications.
(i) For airplanes with serial numbers 27-7654001 through 27-7754054, inspect both stabilator tip ribs for missing rivets and missing tube and weight assembly attachment screws and if necessary alter in accordance with Piper Service Bulletin (SB) 547, dated March 1, 1977.
(ii) For airplanes with serial numbers 27-7654001 through 27-7754127, 27-7754130, 27-7754131, 27-7754133 through 27-7754136, and 27-7754138 through 27-7754144, replace the right and left stabilator tab forward inboard rib/horn assemblies by installing Piper Kit 761 143 or equivalent kit in accordance with Piper SB 569, dated August 24, 1977.
(iii) For airplanes with serial numbers 27-7654001 through 27-7754041 equipped with stabilators Piper part number (P/N) 15658-2, 15658-3, 15658-22 or 15658-23, reinforce the mounting of the stabilator tube and weight assemblies by installing additional nose-ribs with Piper Kit 761 141 or equivalent kit in accordance with Piper Service Letter 807A, dated September 8, 1977.
(2) Before further flight after completing the alterations in paragraphs (g)(1)(ii) and (iii) of this AD, balance the stabilator.
Within 10 hours TIS after the effective date of this AD or within 100 hours TIS after completing the last inspection required by paragraph (a) of AD 78-02-03, whichever occurs later, and thereafter at intervals not to exceed 100 hours TIS, inspect the left and right stabilator balance weight assemblies for cracks and complete any necessary repairs by following Parts I and II of the Instructions in Piper SB No. 540B, dated February 9, 2021, except you are not required to contact Piper for repair instructions. Instead, repair in accordance with FAA-approved procedures.
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.
