RTH emergency

[Jeff watson]

The other day RTH signal came on. Aircraft returned to home. I tried to cancel RTH. No luck. Aircraft moved off home position and commenced landing. Aircraft hit object on the way to the ground. It crashed. Could I have saved the aircraft from crashing in the autonomous,RTH mode with a hand catch?

 

[msinger]

RTH can always be cancelled as long as the remote controller is connected to the Phantom. It would be safest to cancel the RTH and manually land.

 

[Jeff watson]

I tried canceling. Battery critically low. Would not cancel. It hit post and flipped over on props. Motors then started spinning at high speed on ground. Controller would not stop motors. I had to, carefully remove battery. It was my fault. I was showing my friend how the DJI worked. He was interested in buying one. I was not watching the battery and low battery came on and RTH commenced. By the time it got home to land the battery was critically low. Canceling was not an option. What do you do in an emergency like that?

 

[msinger]

I tried canceling. Battery critically low.

Ah, the battery was critically low. That's an important point

Canceling was not an option. What do you do in an emergency like that?

When the battery reaches the critically low level, the Phantom will auto land at its current location. There is no way to stop that auto landing. The only thing you can do is move the throttle stick to the full up position just long enough for you to steer the Phantom to a better landing spot. You don't want to hold the throttle up too long though since that would eventually cause the battery to shut off mid-flight.

 

[BigAl07]

I tried canceling. Battery critically low. Would not cancel.

That's VERY key in the overall conversation here.

As stated you still have "some guidance" as to speed and general location as the aircraft is descending so you should be able to get it down safely in most instances.

Keep in mind when it hits "Critically Low" you're playing with fire. The battery is indeed getting close to the point of doing internal battery damage and trying to prolong the flight can push it beyond safe limits. It's even possible to TRY and push it to the point of the aircraft shutting the battery down for preservation although I think that feature "might" have been disabled a while back.

 

[MapMaker53]

This points out the importance of having in mind a few emergency landing locations should a forced landing situation arise. I had the same situation occur recently with a critically low battery situation. I was assigned to film a school bus arriving and students getting off the bus during a field trip -- but it was taking FOREVER for them to get off the bus and line up. My focus was on the bus doorway and not on my battery level and it suddenly went into auto land mode over trees. Once I realized what was happening, I had to get to my closest safe landing area. With people, cars and light poles in the area, it was a bit of a challenge and I could only hope no one was standing on the asphalt area I had in mind. Wasn't sure I'd make it there so I quickly scanned for something closer -- but spotted nothing acceptable. With only lateral control as I descended, I felt like Neil Armstrong looking for that perfect spot to land the Lunar Module as fuel ran out. This is how quickly things can go wrong.

Dropbox - emergency landing.wmv

btw.. I was actually located in the far parking lot due to the fact that I thought the bus was going to arrive and off-load there. I didn't want to emergency land in the roadway because I figured my bird would be roadkill by the time I could make my way over to it. To make matters worse, the last 5 feet of decent was blind as I suddenly lost video feed.

 

[Jeff watson]

Great news. Sent my drone in. DJI fixed it for next to nothing!