Blackbox

The Blackbox tab configures flight-data logging -- which fields are recorded, logging rate, and (if fitted) onboard flash/SD storage management. Blackbox logs are the primary tool for diagnosing tuning issues after a flight, and are usually the first thing to attach when asking for tuning help.

When it logs

Device picks where logs go: onboard flash, an SD card, or an external serial logger (each only appears if actually fitted/supported). Mode then decides when logging is active: Armed (simplest -- logs every flight), Normal (logs only when armed and a Blackbox switch is active, for keeping only flights you deliberately flag), or Switch (logs whenever that switch is active, armed or not). Grace Period keeps logging briefly after disarming, specifically to catch the moments right after a crash rather than cutting off exactly at disarm.

Rate and fields

Rate of Logging is a divisor of the PID loop rate -- higher rates capture more detail (useful for chasing a specific fast oscillation) at the cost of filling storage faster; lower rates log longer flights in the same space. The field checkboxes choose which data categories are recorded at all -- turn off what you don't need to save space, but when in doubt for a tuning question, leave gyro/PID/setpoint data on since that's what most tuning advice is read from.

Debug Mode adds a further 8 extra values on top of the normal fields, for a specific diagnostic (its exact meaning depends on which mode is selected) -- leave it on NONE unless you're chasing something specific that calls for it. Modes inherited from Rotorflight that no longer record anything are named UNUSED_<n> and are left out of the list; see CLI reference → Debug modes.

Flash storage

Initial Erase guarantees a minimum amount of free space before recording starts, erasing old logs if needed -- note that erasing can take a while on some flash chips, so recording doesn't begin until it finishes. Rolling Erase instead overwrites the oldest logs once storage is full, trading guaranteed history for never running out of space -- logs can gain gaps if the chip is slow to erase mid-flight.

Reading flight-mode changes in logs

Each periodic log frame records which flight modes are active in two words, flightModeFlags and flightModeFlags2, together covering every mode. Older firmware logged only the first word, which silently dropped every mode past the 32nd -- including MANUAL -- so a MANUAL segment never showed as engaged. If you read logs with a tool that only knows flightModeFlags, modes such as MANUAL need flightModeFlags2 too. The separate flight-mode change event still carries only the first word.

Log files over USB

When the flight controller is plugged in as a USB drive (mass storage), log files are named after the craft name from your pilot settings, followed by a sequence number and timestamp. With no craft name set, the prefix is wflt (it used to be rtfl), for example wflt_002_20251012_141213.bbl.

Reviewing logs

Open a .bbl file in the WingFlight Blackbox viewer to play the flight back. Each graph stacks related fields -- here, setpoint against gyro for each axis, then the servo outputs and motor -- with the legend on the right showing every field's value at the red cursor line. The craft model and stick overlays follow the cursor, and the strip along the bottom shows the whole log so you can jump to any part of the flight. The status bar lists the firmware, loop rate, and flight modes active at the cursor (here ARM and ATTHOLD). Graph setup chooses which fields each graph shows.

The Overlay buttons add analysis views on top of the graphs. The spectrum analyser plots the frequency content of a field over the visible window, with the gyro filter cutoffs marked -- useful for finding the frequency of a vibration before changing filter settings.

The step response graph shows how quickly and cleanly the gyro follows a change in setpoint on roll, pitch and yaw, with each axis' PID gains noted alongside. A trace that overshoots well past 1.0 or keeps ringing points to gains that are too high on that axis.