Wait, then come home

A valid receiver pulse has to sit between the minimum and the maximum. The demo minimum is 885 µs and the maximum is 2115 µs. Both step by 5, from 750 to 2250. A pulse outside that window is not a live stick.

Guard time starts at 0.5 seconds, from 0 to 20, in steps of 0.1. The procedure does not start until that guard has passed. Recovery time also starts at 0.5 seconds, over the same range. After the link returns, roll, pitch and yaw must move at least the stick threshold from centre. That threshold starts at 50 µs, from 0 to 500, in steps of 10. The hint says 0 means the link alone ends the failsafe.

Drop if throttle was low for starts at 0 seconds, from 0 to 90. The hint says a throttle that sat at zero for that long disarms immediately. The picture waits the demo guard, half a second, and only then runs the procedure. It does not write the board.

The procedure starts on Return to home. Land brings the craft down. Drop disarms. Do nothing does not fly a return or a landing. The footer says return to home needs a GPS fix with home set, and that without one INAV falls back to landing.

The picture follows that. Lose the signal and the lamp stays on Guard for half a second. With the fix on, Return to home then climbs and moves to the home mark. Turn the fix off and the same procedure lands where it is, instead of coming home. Land does that descent too. Drop shows Disarmed. Do nothing stays put.

Near home within starts at 0 m, from 0 to 650, and the hint says 0 turns it off. Closer than a non-zero distance, the procedure near home is used instead. That choice stays hidden while the distance is 0. The value behind it starts on Drop.

Choosing Land reveals two more fields. Landing throttle starts at 1000 µs, from 1000 to 2000, in steps of 5. Motors off after starts at 20 seconds, from 0 to 200. They stay hidden while the procedure is Return to home.

The return card footer says these fields are used by failsafe return and by the NAV return mode. Return altitude mode starts at At least the return altitude. The other choices are Current altitude, Current altitude plus extra, Fixed altitude, and Highest altitude this flight. The return altitude starts at 10 m, from 0 to 650, in steps of 1 m.

Climb before turning home starts On. Off skips that climb. On, planes climb in a spiral is the third choice. Climb even in emergency starts off. Fly home tail first starts off, and its hint says it is multirotor only.

Hover altitude at home starts at 0 m. The hint says 0 stays at the return altitude. Land immediately within starts at 5 m, from 0 to 50. The hint says that is too close to home to bother returning. Abort if moving away by starts at 500 m, from 0 to 650, and the hint says 0 turns that abort off. Maximum altitude starts at 0, and the hint says 0 means no limit.

Land at home starts on Always. Never and Failsafe only are the other choices. Wait before failsafe landing starts at 0 seconds, from 0 to 1800, in steps of 10. The hint says 0 lands straight away, and that a low battery warning lands at once even when you set a wait. Start slowing the descent at 20 m. The final slow descent is below 5 m. Descent speed up high starts at 2 m/s, and the final descent at 0.5 m/s. Emergency landing speed starts at 5 m/s.

The two-stage climb, the descent on the way and path retrace are on Advanced nav, not on this card. Safehomes can replace the arming point as the place a return aims at. This card is the procedure and the basic altitude.

Fixed-wing emergency landing is shown for an airplane, and also when the firmware sends no platform list. A multirotor hides it. The footer says it is used when a plane must land without a usable altitude or position estimate: it holds the pitch and circles with the bank and yaw rate.

Pitch starts at 10 degrees, from 80 below to 80 above, in steps of 1. The hint says positive dives and negative climbs. Bank starts at 20 degrees to the left, over the same range. The hint says negative banks left. Yaw rate starts at 45 degrees per second to the left, from 1000 either way, in steps of 5. The hint says negative turns left.

Failsafe lights appear only when the flash period is not zero. Channel fallback sits under the procedure. For the sticks, Auto centres roll, pitch and yaw and drops the throttle, and Hold keeps the last position. For a switch, Hold keeps the last position or Set picks one.

Open Failsafe on INAV. Chrome or Edge connects over USB or Bluetooth. Android adds Wi-Fi. iPhone uses Bluetooth or Wi-Fi and has no USB host.

Leave the props off for the first check. Arm, switch the transmitter off, and watch the procedure on the ground before you trust it in the air.