Petr Vidiečan, R&D Director at SPEEL Praha.
In just six months, SPEEL Praha has designed, developed, and delivered a new avionics converter unit — ATD-39-01— to Aero Vodochody.
This compact ARINC-429-to-discretes interface enables control of up to eight discrete signals from an ARINC-429 bus, marking another step forward in modernising aircraft system integration on platforms such as the L-39.
“During those six months, we had to not only complete the development of the converter itself but also design a dedicated tester and manufacture two prototypes for testing — all during the summer holiday period,” explains Petr Vidiečan, R&D Director at SPEEL Praha.
“Coordinating all phases so that everything ran quickly and smoothly was the real challenge.”
Speed through experience and collaboration
According to Vidiečan, the key to achieving such rapid development lay in SPEEL’s accumulated know-how and agile internal processes.
“We had valuable experience with similar devices — for instance, our Discretes-to-ARINC-429 converter. But the real advantage comes from the direct and intensive communication between colleagues across development, design, and production. At SPEEL, our processes are set up to move as fast and efficiently as possible while maintaining high quality and reliability.”
Compact, configurable, and ready for integration
The ATD-39-01 is already being integrated into the L-39 SkyFox, where it replaces a mechanical speed switch controlling flap and airbrake actuation at specific airspeeds.
Its compact size and simple configuration — output contacts can be selected (make or break) by connecting to the appropriate pin — make it a versatile and user-friendly component for avionics engineers.
Czech collaboration at its best
Continuous communication with Aero Vodochody throughout the development ensured that the design remained aligned with customer requirements.
“The ongoing feedback loop with the customer helped us ensure the product met technical specifications and progressed exactly according to plan,” adds Vidiečan.
Ready for qualification and beyond
The converter will now undergo functional flight tests at Aero Vodochody, followed by environmental qualification, after which it will be eligible for use in military aviation.
SPEEL expects serial production to begin in Q1 2026 and sees significant potential for export applications in aircraft modernisation programmes and special-mission platforms.
“ATD-39-01 bridges the gap between digital data-bus systems and legacy discrete-signal equipment,” concludes Vidiečan. “It’s a small device, but it enables major integration flexibility.”
By: Katerina Urbanová
Photo credit: Katerina Urbanová, Speel Praha
