EASA AD 2026-0149
Integrated Modular Avionics – Primus APEX DFZ Build 6.0 Software – Modification
Summary
EASA Airworthiness Directive 2026-0149 is an airworthiness directive affecting Pilatus PC-24 aeroplanes with manufacturer serial numbers 101 to 337 and 501 to 600. It mandates a software modification to the Integrated Modular Avionics Primus APEX DFZ system, updating from Build 5.3 or earlier to Build 6.0. This directive ensures continued safe operation by addressing flight director calculation errors during approach.
What Changed
EASA Airworthiness Directive 2026-0149 supersedes AD 2024-0240 and requires installation of the updated Primus APEX DFZ Build 6.0 software on affected PC-24 aircraft. It also mandates amendments to the Aircraft Flight Manual (AFM) with specific technical revisions and prohibits installation of the older affected software on any aircraft. The directive introduces a permanent software fix replacing the interim abnormal procedures previously required.
Why It Matters
This directive is critical for operators and maintenance organizations as it addresses a safety issue where inaccurate flight director calculations could increase pilot workload and reduce safety margins during approach. Compliance ensures the aircraft avionics function correctly, maintaining operational safety and regulatory conformity. It also prevents installation of outdated software that could reintroduce the unsafe condition.
What To Do
Operators of affected PC-24 aeroplanes must implement the AFM technical revision 02371-075 within 30 days after 24 December 2024 and update to Primus APEX DFZ Build 6.0 software within 9 months after 11 August 2026. After software installation, the AFM must be further amended with revision 02371-081 before the next flight. Installation of older software versions on any affected aircraft is prohibited from the effective date.
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