Flight controllers and ESCs: what the rules require of the electronics.

What the FAI requires of an F9U model

The FAI's F9U rules, F9 Drone Sports volume, 2025 edition (effective 1 May 2025), article C.1, set functions every racing model must have and functions it must not have. The 2026 edition was not read; its effective date is reported as 1 January 2026 and as 1 June 2026, both from search summaries.

The fail-safe matters to the FAI's helper rule. Every F9U pilot has one mandatory helper beside them, and in an emergency the helper may switch off the pilot's transmitter to trigger the model's fail-safe. Under rule C.4, the organiser may check each registered model's fail-safe and motor cut-off device, battery voltage, and radio and video equipment.

Earlier FAI texts

The 2019 edition (effective 1 May 2019) had the same fail-safe requirement and the same ban on automatic positioning and path correction, and named "anti turtle" and "anti crash" as permitted pilot-activated recovery modes. The FAI's 2024 World Drone Racing Championship Sporting Rules (June 2024, article 2) used the names "Flip over after crash" and "Crash recovery" for the permitted modes. Pit mode is recorded here from the 2025 edition.

An association's rule: the MAAA (Australia)

The Model Aeronautical Association of Australia's policy MOP066 (revision of 19 August 2019, section 9.2) applies to its members racing at MAAA clubs and affiliated sites. It requires a switch-based arm switch that stops all motors when disarmed, and a radio failsafe that stops all motors immediately on loss of signal, with no two-stage failsafe allowed. Failsafe settings are checked by the event coordinator or flight line director before racing. MOP066 also bans Return to Home on racing aircraft, citing extra safety concerns on smaller tracks. These are association rules, not law.

Flight-control software

The Betaflight project describes itself, in its GitHub README read on 30 October 2026, as free, open-source flight control software for drones, licensed under GPL-3.0. It lists support for STM32 F4, F7, G4, H5 and H7 processors, AT32F435, APM32 and RP2350, with ESP32 and others experimental. Those are the project's own statements.

MultiGP, an organiser, names Betaflight in two classes on its Race Class Specifications page (read 30 October 2026; its Rule Book was not read). Pro Spec allows any Betaflight flight controller, and Freedom Spec requires Betaflight with what MultiGP calls the "FreedomSpec" 18,000 RPM limit. These are MultiGP class rules for MultiGP races.

A maker, Caddx, claims in a blog post of 24 March 2023 that its Walksnail Avatar digital video system works with Betaflight, INAV and KISS flight-controller firmware.

Electronic speed controllers (ESCs)

No regulator or standards body page describing ESCs was found, so this section rests on the trade press and MultiGP. Hackaday (7 June 2024) describes ESCs as translating flight-controller commands into motor responses, and reported that:

• BLHeli_32, a closed-source 32-bit firmware for FPV drone ESCs, was stopped by its Norwegian developer, BLHeli AS, which cited illegal use of its firmware by sanctioned countries, including for warfare;
• the earlier BLHeli and BLHeli_S firmwares are open source, with forks such as Bluejay for BLHeli_S;
• AM32 is an open-source 32-bit ESC firmware alternative.

Forum and reviewer sources (an ArduPilot forum thread and the trade reviewer Oscar Liang), seen only as search summaries, report that BLHeli_32's licence servers were shut down and new flashing blocked, one dating it to June 2024. BLHeli AS's own statement was not read, so the details are unconfirmed.

MultiGP's rules name ESC firmware too. Its Pro Spec class permits only official release versions of BLHeli32 and AM32 and does not allow BLHeli_S-based firmware such as Bluejay. That is MultiGP's class rule, as its class page and Pro Spec page state it.

The FCC Covered List

In the United States, the FCC's fact sheet of 7 January 2026 names flight controllers among the drone "critical components" covered by its December 2025 Covered List additions, along with motors and batteries. It also says parts that never needed FCC authorisation do not newly need it. See the FCC Covered List.

What this page leaves out

Setting up a fail-safe, flashing firmware, choosing settings and wiring a board are configuration and building tasks, and this site does not describe them. The rules above say what a model must do at a race; under rule C.4 the organiser may check whether a particular model does it.