AD 2022-19-03 Requires Incorporating New Revisions To The ALS Of The Existing Airplane Maintenance Manual

The FAA is superseding Airworthiness Directive (AD) 2016-26-08, which applied to all Pilatus Aircraft Ltd. Model PC-12, PC-12/45, PC-12/47, and PC-12/47E airplanes.

AD 2016-26-08 required incorporating revisions into the airworthiness limitations section (ALS) of the maintenance program and inspecting the main landing gear (MLG) attachment bolts for cracks and corrosion. Since the FAA issued AD 2016-26-08, the European Union Aviation Safety Agency (EASA) superseded its mandatory continuing airworthiness information (MCAI) to add a new life limit for certain MLG actuator bottom attachment bolts and then superseded it again to add new life limits for the rudder bellcrank. This AD requires incorporating new revisions to the ALS of the existing airplane maintenance manual (AMM) or Instructions for Continued Airworthiness (ICA) to establish a 5-year life limit for certain MLG actuator bottom attachment bolts and new life limits for the rudder bellcrank. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective October 27, 2022.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2016-26-08, Amendment 39-18766 (82 FR 1172, January 5, 2017; corrected February 16, 2017, 82 FR 10859) (AD 2016-26-08). AD 2016-26-08 applied to all Pilatus Aircraft Ltd. (Pilatus) Model PC-12, PC-12/45, PC-12/47, and PC-12/47E airplanes. AD 2016-26-08 required incorporating revisions into the ALS of the existing FAA-approved maintenance program and inspecting the MLG attachment bolts for cracks and corrosion.

The NPRM published in the Federal Register on March 14, 2022 (87 FR 14187). The NPRM was prompted by reports of failure of MLG actuator bottom attachment bolts, part number 532.10.12.218, identified with “VLG” on the bolt head. These parts are from a specific vendor and are subject to hydrogen embrittlement. Accordingly, EASA, which is the Technical Agent for the Member States of the European Union, superseded its prior AD on this condition and issued EASA AD 2021-0005, dated January 7, 2021, corrected January 14, 2021, to require a new 5-year life limit for the MLG actuator bottom attachment bolt identified with “VLG.” Pilatus subsequently added new life limits for the rudder bellcrank. As a result, EASA superseded its AD again and issued AD 2021-0214, dated September 17, 2021 (referred to after this as “the MCAI”).

The MCAI states:

• The airworthiness limitations and certification maintenance instructions for Pilatus PC-12 aeroplanes, which are approved by EASA, are currently defined and published in Pilatus PC-12 AMM Chapter 04-00-00. These instructions have been identified as mandatory for continued airworthiness.
• Failure to accomplish these instructions could result in an unsafe condition.
• Previously, EASA issued [EASA] AD 2021-0005, requiring the actions described in the Pilatus PC-12 AMM Chapter 04-00-00, Document Number 02049 Issue 01 Revision 40, Document Number 02300 Issue 01 Revision 24 and Document Number 02436 Issue 01 Revision 02.
• Since that [EASA] AD was issued, Pilatus published the applicable ALS, as defined in this [EASA] AD, which contains new and/or more restrictive tasks and limitations, as specified in the Component Limitations section, to introduce a new life limit for the rudder bellcrank. Due to the introduction of this life limit, the repetitive eddy current inspections are no longer required and deleted from the Supplemental Structural Inspection section.
• For the reason described above, this [EASA] AD retains the requirements of EASA AD 2021-0005, which is superseded, and requires accomplishment of the actions as specified in the applicable ALS.

You may examine the MCAI at regulations.gov by searching for and locating Docket No. FAA-2022-0153.

In the NPRM, the FAA proposed to require incorporating new revisions to the ALS of the existing AMM or ICA to establish a 5-year life limit for certain MLG actuator bottom attachment bolts and new life limits for the rudder bellcrank. The FAA is issuing this AD to prevent MLG collapse during all phases of airplane operations, including take-off and landing, and also to prevent rudder bellcrank failure, which could lead to loss of airplane control.

FMI: www.regulations.gov