fix(mavlink_command): allow QGC 5 takeoff command (again)

[MaEtUgR]

Solved Problem

1. Start basic PX4 simulation (make px4_sitl sihsim_quadx) and QGC 5.0.8 stable
2. Press on Takeoff button
3. Takeoff gets "denied":
   

Bisection shows #27541 rejects even basic, commonly used commands like takeoff sent by the ground station.

Solution

1. Solve the basic takeoff case I ran into.
2. Remove the complicated per vehicle type handling that was only used to break the takeoff command.
3. Let Claude Code compare command usage in QGC 5 and PX4 main to determine if there are more such basic supported cases that newly get rejected.

Claude output

Confirmed compatibility bugs (fixed)

cmd	Issue	Fix
NAV_TAKEOFF (22)	QGC sends param1=-1 unconditionally on every guided takeoff, for all vehicle types	(first commit) override widened to all vehicle types
NAV_WAYPOINT (16)	"Pass Radius" (param3) is a plain editable field in the waypoint editor for any vehicle	mission mask 0x7B→0x7F
NAV_VTOL_TAKEOFF (84)	raw mission-command editor exposes param2 "Transition Heading"	mission mask 0x78→0x7A
NAV_VTOL_LAND (85)	raw mission-command editor exposes param3 "Approach Alt"	mission mask 0x78→0x7C
DO_CHANGE_SPEED (178)	mission-item "Offset" (Relative/Absolute) field writes param4	mission mask 0x07→0x0F
DO_LAND_START (189)	FW/VTOL Landing Pattern (a commonly-used feature) sets real lat/lon/alt in param5-7	mission mask 0x00→0x70
DO_SET_ROI_WPNEXT_OFFSET (196)	mask omitted param5-7, but PX4's own navigator_main.cpp reads them as pitch/roll/yaw offset — this was a bug in the table independent of QGC	mission+command mask 0x01→0x71
CONDITION_GATE (4501)	Survey/Corridor-Scan complex items can emit real param2 + lat/lon/alt when "condition gate" is enabled	mission mask 0x00→0x72

DO_LAND_START and NAV_WAYPOINT are the two I'd flag as most impactful — Landing Pattern is a standard FW/VTOL workflow, so that one alone must have broken most fixed-wing mission uploads from QGC.

Checked, no issue found

NAV_LOITER_UNLIM, NAV_LOITER_TIME, NAV_RETURN_TO_LAUNCH, NAV_LAND, NAV_LOITER_TO_ALT, NAV_ROI (dead/unused by QGC), NAV_DELAY, CONDITION_DELAY/CONDITION_DISTANCE (not offered by QGC for PX4 vehicles at all), DO_SET_MODE (sent as legacy SET_MODE, not validated by this table), DO_JUMP, DO_SET_HOME, DO_SET_ROI_LOCATION, DO_SET_ROI_NONE, DO_SET_ROI (unreachable for PX4), all camera/gripper/autotune/video/image commands, DO_VTOL_TRANSITION, all 5 geofence commands, NAV_RALLY_POINT, DO_WINCH (QGC has no UI for it at all).

Changelog Entry

Fix basic MAVLink commands like takeoff from QGC 5 getting rejected

Test coverage

It fixes the takeoff at least 👀 Ideally #27541 would have been tested once before merging.

Context

Last time #26408 rejected basic commands sent from QGC 5, had to be reverted in #26626 to make PX4 usable again.

[github-actions]

🔎 FLASH Analysis

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Updated: 2026-07-14T13:16:50

[julianoes]

I noticed this last night as well, thanks!

[julianoes]

So I agree that we need to be compatible with QGC, but also, we need to fix in QGC when it sends something wrong, right? And then add a note explaining it. Why would QGC send -1 for pitch?