EASA SIB NE-17-26
Avidyne TAS600A, TAS600, and 9900BX Traffic Advisory System (TAS) - Misleading Intruder Aircraft Vertical Trend
Summary
The Special Airworthiness Information Bulletin NE-17-26 titled "Avidyne TAS600A, TAS600, and 9900BX Traffic Advisory System (TAS) - Misleading Intruder Aircraft Vertical Trend" informs owners and operators of aircraft equipped with these Avidyne TAS units about a defect affecting the display of intruder aircraft vertical trend indications. This issue does not impact traffic alerting or other intruder data such as range, altitude, and bearing. The bulletin applies specifically to the Avidyne TAS600A, TAS600, and 9900BX Traffic Advisory Systems.
What Changed
This bulletin introduces awareness of a defect in the Avidyne TAS600A, TAS600, and 9900BX TAS units where the vertical trend of intruder aircraft may be misleading due to rapid ownship altitude changes. Avidyne has issued a software update for the TAS600A series to correct this behavior but does not plan updates for TAS600 or 9900BX series. The FAA does not consider this defect an unsafe condition warranting an airworthiness directive at this time.
Why It Matters
This information is important for aviation professionals because the misleading vertical trend display could affect situational awareness during flight operations. Operators and maintenance teams need to understand that while traffic alerting remains reliable, the vertical trend indication cannot be fully trusted until software updates are applied where available. This helps ensure proper risk management and informed decision-making in the cockpit.
What To Do
Owners and operators of aircraft with TAS600 or 9900BX systems should remain aware of the defect and not rely on vertical trend indications. For TAS600A systems, operators are recommended to comply with Avidyne Service Bulletin 601-00185-009 to update the software and correct the issue. No mandatory compliance deadlines are specified in the bulletin.