Almost lost my Phantom 3 Pro

PVFlyer · Feb 3, 2016

smclark21 said:
I almost lost my beloved Phantom 3 on Saturday night. I had a couple of drinks and then decided to fly an auto pilot mission using the FPV camera app (which I love by the way). I quickly typed in a few targets, entered about 15 waypoints, and let the bird loose. The mission was planned for 10 min's; 30 seconds but it never returned It was terrible. I jumped in the car and drove towards the flight path hoping to get a signal of it's last location, nothing. Luckily, my brother came down the next morning and we found it with minimal damage. Even though I have read hundreds of posts about maintaining altitude, I was flying too low and it clipped some trees. The battery fell out on impact thus making a signal impossible to discover. Yes, I was also flying over private property which made the recovery effort a bit more tricky. My altitude at the time of the crash was 102 feet but now my minimum will be 150. I consider myself very lucky so please don't make the same mistake I did. The drone is just fine and I'm up in the air again. Here's a copy of the flight, crash happens at 4:59.

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Happy Flying, I have really enjoyed this forum.

Sorry for not chiming in here sooner, and I'm glad to know you managed to recover it. Mission Planner Important Notes section indicates altimeter discrepancy below:

• Aircraft height (altimeter) may easily vary 15-20m (50-66ft) off the actual height after aircraft flying and heating up several minutes. You are recommended to let IMU warn up properly on the ground especially in cold weather, and set waypoint height minimum 25m (82ft) above any obstacles. Cold IMU calibration trick is NOT recommended which might incur more discrepancy in altimeter reading.

For example, if there is a tree 30m height and you set the first waypoint to 40m above that tree to maintain a 10m gap and the last waypoint is also set to 40m above the same tree after 10 minutes mission flight. The aircraft might reach the first waypoint well above the tree, but when it reaches the last waypoint 10 minutes later, it might hit the tree due to discrepancy of barometer though the altimeter is still reporting 40m height.

Your 102 ft altitude reading might be only 30+ ft actually. For testing such discrepancy, you may turn off VPS, then check the altitude after a 15-20 minutes flight by hovering in front of you (say 6 ft) right before landing.

DownUnder · Feb 3, 2016

Love the video. Kept trying to guess what you were going to hit. A few near misses. Been there too with trees.

Illina · Feb 3, 2016

The thing I see is that you set the height to drop down and fly between the trees of what looks like a grass runway or pathway and then back up. I don't think I could trust everything to be that accurate as to clear everything.

The building looked to be a small hanger, not sure. Good thing that you're not using the Geofence beta or that whole area would have a big yellow circle around it.

smclark21 · Feb 4, 2016

Illina said:
The thing I see is that you set the height to drop down and fly between the trees of what looks like a grass runway or pathway and then back up. I don't think I could trust everything to be that accurate as to clear everything.

The building looked to be a small hanger, not sure. Good thing that you're not using the Geofence beta or that whole area would have a big yellow circle around it.

Wow, that is a very keen observation you made Illina! You are correct on everything you said. It is an old runway (no longer in operation) owned by one of our neighbors. The owner died in an ultralight plane crash in that very field about a decade ago. You are also right about my flight plan, I had dropped down to 49 feet while cruising along the runway so I could get a good look around. You can easily see all the surrounding trees are taller than my craft during that stretch.

I was just too aggressive on this flight. I do like lower altitude because I can always pull up Google Earth if I want a nice overview. I want to see things up close!

ELHEAPO · Feb 4, 2016

Tim_alabim said:
This post is a joke or a troll. Between the drinks, a night flight, crash, then hop in the car... Good one!

Thats a normal friday night for me,whats the problem!!

smclark21 · Feb 4, 2016

PVFlyer said:
Sorry for not chiming in here sooner, and I'm glad to know you managed to recover it. Mission Planner Important Notes section indicates altimeter discrepancy below:

• Aircraft height (altimeter) may easily vary 15-20m (50-66ft) off the actual height after aircraft flying and heating up several minutes. You are recommended to let IMU warn up properly on the ground especially in cold weather, and set waypoint height minimum 25m (82ft) above any obstacles. Cold IMU calibration trick is NOT recommended which might incur more discrepancy in altimeter reading.

For example, if there is a tree 30m height and you set the first waypoint to 40m above that tree to maintain a 10m gap and the last waypoint is also set to 40m above the same tree after 10 minutes mission flight. The aircraft might reach the first waypoint well above the tree, but when it reaches the last waypoint 10 minutes later, it might hit the tree due to discrepancy of barometer though the altimeter is still reporting 40m height.

Your 102 ft altitude reading might be only 30+ ft actually. For testing such discrepancy, you may turn off VPS, then check the altitude after a 15-20 minutes flight by hovering in front of you (say 6 ft) right before landing.

PV Flyer, I appreciate your reply. I actually keep my VPS turned off at all times because I never fly indoors. The app has really performed flawlessly for me so far, no major deviations from what I can tell. I've sent it out several times before and it has always returned safely. I will still run through these test that you mention to see what it does.

My only 2 suggestions for the app are:
I would still like to control altitude, if needed, during a mission. Right now you can speed up or slow down using the right stick but you can't increase/decrease altitude unless you cancel and assume control of the aircraft. This feature would not have helped in this situation because it was out of range anyway.
Second, It's hard to plan missions ahead of time in far away locations based on the map view. It shows the surrounding area where my Phantom is located. Let's say I'm traveling to Florida and I want to plan missions in advance. I would have to physically scroll around on the tiny map until I find my areas of interest. I wish I could enter a starting address to save a bunch of time.

Overall, the app has been fantastic and I will continue using it for many higher altitude missions to come.

PVFlyer · Feb 4, 2016

smclark21 said:
PV Flyer, I appreciate your reply. I actually keep my VPS turned off at all times because I never fly indoors. The app has really performed flawlessly for me so far, no major deviations from what I can tell. I've sent it out several times before and it has always returned safely. I will still run through these test that you mention to see what it does.

My only 2 suggestions for the app are:
I would still like to control altitude, if needed, during a mission. Right now you can speed up or slow down using the right stick but you can't increase/decrease altitude unless you cancel and assume control of the aircraft. This feature would not have helped in this situation because it was out of range anyway.
Second, It's hard to plan missions ahead of time in far away locations based on the map view. It shows the surrounding area where my Phantom is located. Let's say I'm traveling to Florida and I want to plan missions in advance. I would have to physically scroll around on the tiny map until I find my areas of interest. I wish I could enter a starting address to save a bunch of time.

Overall, the app has been fantastic and I will continue using it for many higher altitude missions to come.

Thank you for your suggestions.
(1) Due to DJI waypoint limitation and safety concern, altitude cannot be changed after mission started as stated in Mission Planer FAQ
Q12. Can I use RC throttle stick to control aircraft altitude (left stick up/down) or roll stick to control left/right (right stick left/right) during waypoint mission?
A12. NO. This is by design and safety concerns of DJI flight controller and firmware. Once you upload and start a waypoint mission, you cannot change aircraft altitude nor fly left/right during mission. It ensures consistent flight path regardless when you fly the same mission repeatedly, or how you yaw (left stick left/right) and speed up/down (right stick up/down) the aircraft. However, you may switch to P-mode on RC at any given time to abort a mission and take over control.
(2) If you are on FPV Camera v2.1, you can maximize the map to almost full screen (as below) by hiding unnecessary components. You may zoom out the map and pan to Florida, then zoom in to your specified location.

Manoel · Feb 6, 2016

smclark21 said:
I almost lost my beloved Phantom 3 on Saturday night. I had a couple of drinks and then decided to fly an auto pilot mission using the FPV camera app (which I love by the way). I quickly typed in a few targets, entered about 15 waypoints, and let the bird loose. The mission was planned for 10 min's; 30 seconds but it never returned It was terrible. I jumped in the car and drove towards the flight path hoping to get a signal of it's last location, nothing. Luckily, my brother came down the next morning and we found it with minimal damage. Even though I have read hundreds of posts about maintaining altitude, I was flying too low and it clipped some trees. The battery fell out on impact thus making a signal impossible to discover. Yes, I was also flying over private property which made the recovery effort a bit more tricky. My altitude at the time of the crash was 102 feet but now my minimum will be 150. I consider myself very lucky so please don't make the same mistake I did. The drone is just fine and I'm up in the air again. Here's a copy of the flight, crash happens at 4:59.

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Happy Flying, I have really enjoyed this forum.

This also happened to me. I hit a tree 50 meters above ground. I managed to locate because the camera was turned on and through the remote control could see where he was. He spent the night on the tree. Thankfully it not rained. The next day early I hired a tree pruning team. They went up and 03 hours my drone was with me in perfect condicoes.Apesar all I charged the battery and it flew away as if nothing had happened.

Albert D · Feb 6, 2016

I have been planning a similar mission. Initially, I set the altitude to about 250' then used the video as a preview of potential obstacles. In my area, the treetops are about 90-100 feet, to my south I have a set of power lines that are about 120'. Based on all this I set my RTH at 130' and planned my mission based on this. On about my third test run, running about 150', i noticed a white pole off to one side. Upon investigation, it turned out to be a 150' antenna of some kind, off to the southeast. Now my RTH is set to 160' for that one random flight path possibility, but i know that i can safely run about 120' in all the other directions. I use my p3p to measure the heights by comparing the altitude to the camera view at 0 gimbal.

MaineRC · Feb 6, 2016

Just want to let you know polarpro sells graduated neutral density filters, which would allow you to expose for the ground without blowing out the sky