In sounding rockets, avionics is a vital component. Typically for sounding rockets' avionics, apogee detection, parachute deployment, and telemetry are essential functions. Any issues with avionics can pose multiple threats, potentially resulting in the loss of the entire rocket itself, if not worse. Series 3 Flight Computer (S3FC), a flight computer designed by thrustMIT, takes multiple considerations to prevent catastrophic failures, such as - neither parachute ejection event happens without ensuring that the rocket has successfully launched from the ground, the code ignores rapid fluctuations in sensor readings to avoid unintentional ejections, the Global Positioning System (GPS) location of the rocket sent to the ground station aids in avoiding contact with people during descent, telemetry uses Cyclic Redundancy Check (CRC) so that the ground station could detect if the data received is faulty, and the fabrication of the circuit board happens through commercial Printed Circuit Board (PCB) manufacturing facilities, ensuring the quality is up to the mark. The quality check during manufacturing includes verifying the usage of a suitable temperature gradient-rated material, short-circuit protection, and necessary trace tolerance. This paper aims to outline the development of a low-cost flight computer (S3FC) to achieve the above-mentioned tasks.