abstract: On October 7, 2008, the flight control system of Qantas flight 72 malfunctioned without warning. The failure caused the aircraft to violently pitch down with an acceleration of -0.8g, pitching passengers and crew into the roof of the cabin resulting in many injuries. In the investigation that followed, the malfunction was attributed to a software problem in the Air Data Inertial Reference Unit. These units are utilized on all modern passenger jets, but are proprietary devices not open to public scrutiny. This capstone project develops an open source Air Data Inertial Reference Unit using four redundant Arduino boards each with a microcontroller, 3D gyroscope and accelerometer. Faults are injected into the system through software and outputs are monitored over serial ports allowing the user to test effectiveness of fault-tolerant algorithms to mask fail silent and byzantine faults in the sensors. Failures in ADIRU systems are usually complex in nature and arise under very anomalous circumstances suggesting that fault-tolerant system design could benefit from the diverse testing and evaluation that can occur in an open source community. This project demonstrates the low entry-cost to building a fault-tolerant system for open-source design and experimentation.. bio: The presenters are Portland State ECE seniors: Chris Andrew, Kayla Seliner, Mark Craig, and Trang Nguyen. Their advisors are Prof. Christof Teuscher (PSU) and Dr. Lee Pike (Galois inc.).