AD 2023-26-05 Requires Periodic Replacement Of Affected Titanium Threaded Bolts...

The FAA is adopting a new airworthiness directive (AD) for certain Pilatus Aircraft Ltd. (Pilatus) Model PC–24 airplanes. 

This AD was prompted by a determination that the titanium threaded bolts at the forward end of the short rudder trim tab actuating rods could be subject to unexpectedly high oscillating loads due to aerodynamic forces acting on the rudder trim tab. This AD requires periodic replacement of affected titanium threaded bolts, a one-time inspection of the rudder mass balance arm and other elements of the rudder trim tab installation for correct attachment, damage (gouges), cracks, deformation, surface finish, and corrosion on any surrounding parts and, depending on findings, accomplishment of applicable corrective actions, as specified in a European Union Aviation Safety Agency (EASA) emergency AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.

This AD is effective January 3, 2024.

Background: EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA Emergency AD 2023–0219–E, dated December 19, 2023 (EASA Emergency AD 2023–0219–E) (also referred to as the MCAI), to correct an unsafe condition on certain Pilatus Model PC–24 airplanes. The MCAI states it was determined that the titanium threaded bolts at the forward end of the short rudder trim tab actuating rods could be subject to unexpectedly high oscillating loads due to aerodynamic forces acting on the rudder trim tab. If not corrected, this condition could lead to failure of the bolt with consequent damage to the rudder and rudder trim tab, which could result in loss of rudder control and reduced or loss of control of the airplane. The MCAI identifies the affected parts as titanium threaded bolts, part number (P/N) 527.20.24.489, installed on the rudder trim tab short control rods. 

The MCAI identifies the serviceable part as any threaded titanium bolt, having P/N 527.20.24.489 that is new and not previously installed. To address the unsafe condition, Pilatus, pending the development of a new design installation, issued Pilatus PC–24 Service Bulletin 27–009, dated December 18, 2023, which specifies instructions to replace the affected part and a one-time inspection of the rudder mass balance arm and other elements of the rudder trim tab installation for correct attachment, damage, cracks, deformation, surface finish, and corrosion on any surrounding parts. The MCAI requires periodic replacement of affected parts, a one-time inspection of the rudder mass balance arm and other elements of the rudder trim tab installation and, depending on findings, accomplishment of applicable corrective actions. 

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA–2023–2404.

FMI: www.regulations.gov