AD 2021-24-22 Requires Inspecting And Modifying The Rudder, Elevator, And Right-Hand (RH) Aileron Hinge Bolt

The FAA is superseding Airworthiness Directive (AD) 2012-06-16, which applied to all Pilatus Aircraft Ltd. (Pilatus) Model PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC6/350-H2, PC-6/A, PC-6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C-H2, and PC-6/C1-H2 airplanes.

AD 2012-06-16 required installing a new rudder and elevator locking screw and modifying the installation of the rudder and elevator hinge bolt. Since the FAA issued AD 2012-06-16, the European Union Aviation Safety Agency (EASA) superseded its mandatory continuing airworthiness information (MCAI) to correct an unsafe condition on these products. This AD does not retain any actions required by AD 2012-06-16 and requires inspecting and modifying the rudder, elevator, and right-hand (RH) aileron hinge bolt installations. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective January 25, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2012-06-16, Amendment 39-16997 (77 FR 19061, March 30, 2012) (AD 2012-06-16). AD 2012-06-16 applied to all Pilatus Model PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC6/350-H2, PC-6/A, PC-6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C-H2, and PC-6/C1-H2 airplanes and required installing a new elevator and rudder locking screw and modifying the installation of the elevator and rudder hinge bolt. The NPRM published in the Federal Register on September 17, 2021 (86 FR 51835).

The NPRM was prompted by AD 2021-0098, dated April 9, 2021 (referred to after this as “the MCAI”), issued by EASA, which is the Technical Agent for the Member States of the European Union.

The MCAI states:

• Occurrences were reported where, on certain PC-6 aeroplanes, the elevator or the rudders was lost or partially detached during flight. All the occurrences happened on PC-6 aeroplanes in CONFIG 1.
• This condition, if not corrected, could lead to in-flight failure of the elevator or rudder attachment, possibly resulting in reduced control of the aeroplane.
• To address this potential unsafe condition, Pilatus issued SB 55-001 (original issue and Revision 1) to provide rework instructions for the elevator and rudder hinge bolt locking. Consequently, EASA published AD 2011-0230 to require this rework. Subsequently, Pilatus issued recommended SB 55-003 (later revised) to provide instructions to modify the hinge bolt installation of the elevator and rudder. This [service bulletin] SB, being recommended only, had no impact on the existing EASA AD.
• Since that [EASA] AD and the recommended Pilatus SB 55-003 were published, the latest risk assessment determined that the modification of the hinge bolt installation of the elevator, rudder and right-hand (RH) aileron installation must be required to reach an acceptable level of safety for the affected aeroplanes. Consequently, Pilatus issued the SB, as defined in this [EASA] AD, to provide instructions to modify the affected aeroplanes into CONFIG 2 standard.
• For the reasons described above, this [EASA] AD supersedes EASA AD 2011-0230 and requires, for certain aeroplanes, a one-time inspection of the elevator and rudder installation, followed by repetitive inspections of the elevator and rudder, and, depending on findings, accomplishment of applicable corrective action(s). This [EASA] AD also requires modification of the elevator, rudder and RH aileron hinge bolt installations into CONFIG 2, which is the terminating action for the repetitive inspections required by this [EASA] AD. Finally, this [EASA] AD prohibits (re)installation of affected parts.

You may examine the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0786.

FMI: www.regulations.gov