Journal / 26 October 2026
The nose and the switch
Sideways moves swung the camera, a fix for that made it worse, and the log showed a voice order taking control back from the transmitter 0.4 seconds after I selected Land. Two of those are fixed. The third was the design.
Written from the logs of 26 October.
Two sessions, two-phone hotspot, aircraft on open-ish grass. Orders dispatched in a tenth of a second, moves arriving in four to six, the stream holding in the air. Good enough that the problems left were the interesting kind.
The nose
Every sideways move turned the aircraft to face where it was going, and the camera with it. The log makes it plain: a left move took the heading from 206 to 128 degrees, a right move from 129 to 230. Forward moves did not. PX4 does that by default when a reposition arrives without a yaw: it faces the waypoint.
So I told moves to hold the current heading. The next session, “turn around” happened during “move right”, which I had not asked for. The heading I was holding came from telemetry over the radio, and telemetry lags. Mid-turn, “current heading” was the old heading, so the move re-commanded it and the aircraft swung back. The second version holds the heading Hawk last commanded, set at liftoff and updated by every turn, and never reads the measured one for that purpose. Turning is its own order now, and I watched the aircraft turn around in place, which answered the question of whether PX4 yaws at all on a hold-position command.
The switch
Reading the same log for the yaw, I found this sequence: pilot selects Land, 0.4 seconds later a voice “move left” is executed, aircraft moves two metres. It happened twice more in that flight.
That was the design, not a bug. The override latch from the 13th stopped every running routine when the transmitter took over, and a new voice order cleared it, on the reasoning that a new order is a new intent. In the field, with a friend talking and me narrating, “a new order” arrives whether I meant it or not. The latch now clears only when the aircraft disarms. Any motion order while the switch is away from Position is refused out loud. To hand control back, you land.
The rule was always “the transmitter wins”. It took three sessions of logs to make the code mean it.
The drop
Between sessions, a manual flight ended with the kill switch from height. The battery tray survived this time; a landing leg did not, and the camera’s zip ties went with it. Tape held for a hover. Kill is for a person about to be hit. Land is for everything else, and it has been perfect in every override the log holds.