My P3P crashed, DJI not cooperating

[Chris_P]

I have learnt quite a bit from reading this thread and looking at Chris's log myself, thanks to those expert members here.

Anyway, a few mistakes have contributed to this crash - (1) Didn't turn off Smart return home. (2) Didn't update the home point during the flight. (3) Missed cancelling the RTH button on the screen. Means the flight is doomed. The inaccuracy in altitude reading is known to myself as I have noted it can vary by 10ft when I landed my P3A from my experience. The fact is even if your drone did clear those short trees (as shown in the photo), it may not have enough battery to fly back to its original home point and crashed anyway. And if it did have enough battery to return to its original home point, which is in the middle of the river from the look of the log map, your drone is still doomed. Chris, I think you have to take this as a very expensive lesson. If you want to pull off another one of these flights in the future when you plan to fly the battery down to such low level, you better check and double-check all your settings before hand. I doubt you are going to receive anymore discount or compensation than the 20% they are offering you now.

Best of luck.

I accept the things that I failed to do. I've owned that from the beginning. My big issue is that if the Phantom had performed properly based on proper altitude readings, It would have afforded me more time to realize what was happening and have a fighting chance of avoiding the crash. In these circumstances, I had 13 seconds to assess and react. I'm still a new inexperienced operator so more time would have been to my advantage.

 

[Noodle]

I accept the things that I failed to do. I've owned that from the beginning. My big issue is that if the Phantom had performed properly based on proper altitude readings, It would have afforded me more time to realize what was happening and have a fighting chance of avoiding the crash. In these circumstances, I had 13 seconds to assess and react. I'm still a new inexperienced operator so more time would have been to my advantage.

I wonder what more can you do while you were panic? Says if you have an extra 10 seconds before it crash into the next obstacle (on its way back to its doomed original home point), do you think you can avoid it? I think DJI offering you 20% discount is a way of saying they accept 20% of the responsibility while you have to accept the other 80% responsibility of this crash.

 

[skipilot1]

I'd always assumed the cancel RTH height (via stick input) was to give the pilot the ability to maximize the remaining battery if the extra altitude wasn't needed.

RTH often causes new pilots to panic when it happens. IMO, all new pilots should practice RTH in a field so they get comfort before relying on it in a real situation.

I panicked the first time also but luckily it didn't cost me anything.

When RTH kicks in, the RC beeps and the screen has a clear message on it. Also, pushing the stick up in a panic is usually a good idea. Even if it was trying to descend, you could have raised it, has a moment to think, cancelled RTH and brought it home.

 

[skipilot1]

When RTH kicks in, the RC beeps and the screen has a clear message on it. Also, pushing the stick up in a panic is usually a good idea. Even if it was trying to descend, you could have raised it, has a moment to think, cancelled RTH and brought it home.

This is also a clear message to inexperienced users that they need to put in the time flying close to home and not out on a lake. I am often puzzled as to why folks don't buy a much cheaper drone to fly with, make mistakes with and even crash and destroy it before jumping into a drone that is expensive and so chock full of features that it takes some months to learn them all and become proficient. Also, like any good pilot, there should be a pre-takeoff check list that should be used until it is memorized. That list includes checking the props for tightness, checking the home point has been set, checking the battery stats, not just the percentage in case of a bad cell, checking the sensors so the IMU is not off by more than 1.0, that the compass has a reading between 1400 and 1600 and a check of the main setting screen for RTH altitude, smart RTH setting and any other important info that you should know before takeoff. Lastly, you need to confirm the home point. If this user says he reset the home point, he should have checked the map to make sure that in fact the software had updated the home point. I am not trying to add to his loss. It is just a warning to those who buy this drone without previous experience. Lastly, when you are confused and don't know what is going on, climb as high as you can so you can have a few extra moments to figure out what is going on. That is what every student pilot is taught.

 

[MikeyOnline]

I wonder what more can you do while you were panic? Says if you have an extra 10 seconds before it crash into the next obstacle (on its way back to its doomed original home point), do you think you can avoid it? I think DJI offering you 20% discount is a way of saying they accept 20% of the responsibility while you have to accept the other 80% responsibility of this crash.

The time from the instant the AC switched to RTH and impact was 12.2 seconds. But by the time RTH was initiated until it canceled the ascent due to stick movement, turned, and then started flying toward the home point was another 5 seconds. So from when it took off toward that rock until impact was a little over 7 seconds. So an extra 10 seconds, more than doubling the reaction time... I'd say that could make quite a difference. So I know most would like to believe we're experienced pilots but think about what you are asking. You're in a noisy environment about to hand catch so you're watching the AC, not your screen. It takes 5 seconds to discern you're no longer in control (assuming it's obvious), and then you have about 6 of the final 7 seconds to decide what to do. Your AC is flying toward an obstacle. Do you look down at your device to try to see if it's in RTH mode and what to swipe, taking your eyes of the AC to do so (one that is seconds from impact)? Do you just assume it's in RTH and hit the RTH button on the RC, potentially putting it into RTH when potentially that wasn't really the problem? It wouldn't be obvious that it's in RTH just by watching the AC because it's supposed to raise to at least 20m first regardless of stick movement (it didn't). Some of us could have avoided it. But I'd venture that a good number would find 6 seconds not long enough to react.

Two more points I think DJI should consider. First, if the baro really isn't accurate for about 3 minutes, then make that part of the warmup time. If people complain about a 3 minute warmup, just pop up a warning "Really take off before altitude is fully calibrated?" The second point is, Chris, did your device have GPS enabled? If so, the AC should have seen that you were decending to the point where the RC was located. In such a circumstance, it should never fly off toward the takeoff point, knowing that you are just a few feet from the controller.

Mike

 

[MikeyOnline]

This is also a clear message to inexperienced users that they need to put in the time flying close to home and not out on a lake. I am often puzzled as to why folks don't buy a much cheaper drone to fly with, make mistakes with and even crash and destroy it before jumping into a drone that is expensive and so chock full of features that it takes some months to learn them all and become proficient. Also, like any good pilot, there should be a pre-takeoff check list that should be used until it is memorized. That list includes checking the props for tightness, checking the home point has been set, checking the battery stats, not just the percentage in case of a bad cell, checking the sensors so the IMU is not off by more than 1.0, that the compass has a reading between 1400 and 1600 and a check of the main setting screen for RTH altitude, smart RTH setting and any other important info that you should know before takeoff. Lastly, you need to confirm the home point. If this user says he reset the home point, he should have checked the map to make sure that in fact the software had updated the home point. I am not trying to add to his loss. It is just a warning to those who buy this drone without previous experience. Lastly, when you are confused and don't know what is going on, climb as high as you can so you can have a few extra moments to figure out what is going on. That is what every student pilot is taught.

I think most of us do that. Maybe Chris did, I can't speak for him. I do all that and more, and probably like Chris, I know that my altitude shows 0 ft on takeoff (as his did). I must have missed the part in the manual where it says you should take a spare battery just to warm up the barometer for 3 minutes or your altitude can be off by as much as 40ft or more during parts of a flight, causing you to run into obstacles that you think should be cleared on the RTH. There are always ways to improve a product and as long as we all take the attitude that there's no room for improvement in the "smart features" and everything must be pilot error, they will continue to contribute to crashes. No one is saying problems can't be avoided, but I sure see a lot of room for improvement on DJI's part. I'd put the culpability at 50/50 on this one. Not 20/80 pilot/DJI. But that's just one man's opinion.

Mike

 

[impilot51]

I think though we can all agree that when one says they are an inexperienced pilot, flying over water, taking it down to low battery levels, hand catching from the back of a boat, loud environment where you can't hear your transmitter, don't fully understand how RTH works, or how to stop it, thinks he has reset home point twice yet neither are in the log, etc. etc. etc, it is a recipe for disaster. The environment in question is challenging for an experienced pilot. I don't thing DJI will offer more considering the situation. Expensive lesson learned, and one that I would hope would prompt you to spend considerable time in an open field practicing RTH, cancelling it, etc. until you fully understand it. Of course DJI has some responsibility here, and they, as others have said, feel its about 20% worth. Is that the fair number? Maybe, maybe not. Yes, things could operate a bit differently. But in hind site, a couple of simple changes would have totally alleviated this situation.

 

[henick]

Take it out of context man if my barometer sticks on my 1800$ toy and I can prove it was stuck they'll have a hard time getting rid of me is all I'm saying. Especially if VPS says higher and their interface wasn't programmed to warn me of the discrepancy as a compass error would. That's 100% a hardware failure slice it any way you want. Not to sound callous or disagreeable to their 20% offer but for 1800 bucks my barometer better work for the entire time they agreed to warranty it or I'll see them in court.

Problem selling expensive toys is I can pay to defend what they sold me. They seem to be nice to me so far

Use the ideas here I'm sure they have better than 20% hiding in there for you.

 

[impilot51]

Proving it is the tough part. There is a lot of head scratching here. Yet simply turning off RTH when in a moving situation and this whole thing never happens. It will be interesting to see if DJI moves beyond this.

 

[skipilot1]

I think though we can all agree that when one says they are an inexperienced pilot, flying over water, taking it down to low battery levels, hand catching from the back of a boat, loud environment where you can't hear your transmitter, don't fully understand how RTH works, or how to stop it, thinks he has reset home point twice yet neither are in the log, etc. etc. etc, it is a recipe for disaster. The environment in question is challenging for an experienced pilot. I don't thing DJI will offer more considering the situation. Expensive lesson learned, and one that I would hope would prompt you to spend considerable time in an open field practicing RTH, cancelling it, etc. until you fully understand it. Of course DJI has some responsibility here, and they, as others have said, feel its about 20% worth. Is that the fair number? Maybe, maybe not. Yes, things could operate a bit differently. But in hind site, a couple of simple changes would have totally alleviated this situation.

There is still the issue of the pilot saying he change the home point twice without ever checking the map! Even in RTH mode you can change the altitude and the answer is when you are confused GO UP. I don't understand why we are talking about altitude. I adjust altitude while in RTH mode. Sometimes I come home in Atti mode and forget to put it in P mode when it gets close. The other day the wind was strong, the drone was in Atti and not reacting as expected and was close to tree tops and a gust pushed it back behind the line of sight. That was reason for panic. Guess what. I hit the altitude switch before doing anything else. This should be an automatic reaction. It was then I realized I was in Atti mode and the wind had picked up. Had I not raised the quad it would have hit the trees. It rose up and I could now see it again. That gave me time to check my settings and realize I was still in Atti mode. Altitude improves sight and transmission.

 

[msinger]

did your device have GPS enabled? If so, the AC should have seen that you were decending to the point where the RC was located. In such a circumstance, it should never fly off toward the takeoff point, knowing that you are just a few feet from the controller.

It will always fly off toward the home point (no matter where the GPS-enabled mobile device is located). The only exception is if the Phantom is within 20m of the home point. In that case, it'll auto land at its current location.

 

[flyNfrank]

The good news and bad news is....I compared the .TXT Flight Log and .DAT Flight Log height readings with each another, and at the point when the a/c was called to go home both log's show the exact same height reading which is 63.2ft.

A good thing I came across was that the .DAT Flight Log recorded more data after the fact. Actually to the point in which the a/c was recovered and lifted an additional 14.1ft from it's lowest point it reached. The .DAT also displays the elevation reading down to -55.1ft below "0" elevation, in this case. So if you add the point in which the .TXT version stops which is at 10.5ft to the -55.1ft you of course end up around 65.6ft additional data to work with.

And your final recorded coordinates 44.9007459, -79.8558077

 

[GadgetGuy]

I redid my very unscientific test, but this time I let it set with motors running at idle for 3 minutes before taking off. I then hovered at eye level again (6 feet), confirmed I had both the barometer and the VPS reading 6 feet. Then ascended to 400 feet, came back down, went back up, came back down. Now I only have about 1 foot of error in the barometer (read 5 feet when hovering at eye level) while VPS said 6. So there is obviously something to be said for allowing the barometer to calibrate before taking off. I only lost 1% of indicated battery life while letting it idle for 3 minutes. Might be a worthy trade off for less altimeter drift. YMMV.

It isn't necessary to idle the motors to calibrate the barometer before lift off. You just need to turn the battery on, so you'll sacrifice less battery power that way, if you don't have a spare battery to swap out before takeoff.

 

[GadgetGuy]

Keep in mind I was landing the Phantom. My eyes were on the AC not on my screen. I was in an outdoor boating environment. Whatever beeps came from my iPad were most certainly lost in my surroundings.

I reiterate my strong suggestion to turn Smart Return Home OFF. This entire incident would never have occurred with Smart Return Home disabled. It is a very annoying function, when left on, and won't tell you anything you aren't aready fully aware of, if you are paying any attention to the telemetry. Now, we see that it can also lead to crashes during landing, even if only because the pilot misinterprets what is happening. Shut it OFF!

 

[GadgetGuy]

I have learnt quite a bit from reading this thread and looking at Chris's log myself, thanks to those expert members here.

Anyway, a few mistakes have contributed to this crash - (1) Didn't turn off Smart return home. (2) Didn't update the home point during the flight. (3) Missed cancelling the RTH button on the screen. Means the flight is doomed. The inaccuracy in altitude reading is known to myself as I have noted it can vary by 10ft when I landed my P3A from my experience. The fact is even if your drone did clear those short trees (as shown in the photo), it may not have enough battery to fly back to its original home point and crashed anyway. And if it did have enough battery to return to its original home point, which is in the middle of the river from the look of the log map, your drone is still doomed. Chris, I think you have to take this as a very expensive lesson. If you want to pull off another one of these flights in the future when you plan to fly the battery down to such low level, you better check and double-check all your settings before hand. I doubt you are going to receive anymore discount or compensation than the 20% they are offering you now.

Best of luck.

Smart Return Home uses a very conservative algorithm. It will ultimately result in the aircraft landing with 25% remaining power, so any assumptions based upon the inability to make it back to the set Home Point, after Smart Return Home activates, are flawed. The OP was in the process of handcatching when Smart Return Home activated, so he was not flying "the battery down to such a low level" as you imply. His primary mistake, as you and I have both pointed out, was not turning off the stupid Smart Return Home function entirely. It is a recipe for disaster.

 

[impilot51]

It isn't necessary to idle the motors to calibrate the barometer before lift off. You just need to turn the battery on, so you'll sacrifice less battery power that way, if you don't have a spare battery to swap out before takeoff.

Agreed, however it was just shy of 100 degrees with the P3 sitting on my concrete driveway. I was concerned with:
1. The camera over heating
2. This was only a test and I didn't care about my battery usage.
3 I don't tend to fly missions that are so long that I am concerned with loosing a couple percent worth of battery at take-off.


Sent from my iPhone using PhantomPilots mobile app

 

[MikeyOnline]

I think though we can all agree that when one says they are an inexperienced pilot, flying over water, taking it down to low battery levels, hand catching from the back of a boat, loud environment where you can't hear your transmitter, don't fully understand how RTH works, or how to stop it, thinks he has reset home point twice yet neither are in the log, etc. etc. etc, it is a recipe for disaster. The environment in question is challenging for an experienced pilot. I don't thing DJI will offer more considering the situation. Expensive lesson learned, and one that I would hope would prompt you to spend considerable time in an open field practicing RTH, cancelling it, etc. until you fully understand it. Of course DJI has some responsibility here, and they, as others have said, feel its about 20% worth. Is that the fair number? Maybe, maybe not. Yes, things could operate a bit differently. But in hind site, a couple of simple changes would have totally alleviated this situation.

Point taken. And well stated. This thread has been a bit of an epiphany for me. I've flown Phantoms since the P1 and thought I was pretty experienced. But these things are so complex that every time I think I've got the routine down, my pre-flight checklist is good, and I know how to react in different situations, practicing things like canceling RTH, flying in ATTI, doing two close-to-home flight tests after each firmware upgrade, etc. etc... I keep paying attention and reading more and finding more "potholes" I could potentially fall into (many of which are not covered in the manual). I still think DJI has an opportunity to patch a lot of those potholes to keep us out of those situations like at least a "sensors not yet fully calibrated" warning or longer warmup time, don't cancel RTH ascent if sticks are moved within the first 10 seconds of the ascent, don't fly off to the homepoint if you are descending within a 50m radius of the contoller, and so on. But short of that, maybe there should be a post/thread covering this and many other potential "gotchas" that might affect junior flyers. Does such a thing exist? I mean.. a GOOD one that includes things like the baro not being accurate unless you do a 3 minute warmup?

On that last topic, I wonder if some of us have done ourselves a disservice by doing cold IMU calibrations? I don't put mine in the fridge but I did calibrate mine near an A/C vent to make sure it was cool. Before that, it took a good 60 seconds to warm up. Afterward, maybe 10 seconds... allowing me to complete my pre-flight faster and potentially take off before that 3 minute baro calibration. Just a thought. I don't remember seeing an altitude discrepancy when landing before I did that "cool" IMU calibration. Yesterday I launched within probably 60 seconds of turning the battery on because I had already done my pre-flight in the house on a different battery (checking all settings after I did the 1.9 FW update) and I had big discrepancies in altitude while flying and upon landing. Needless to say, I'll be waiting 3 minutes from now on.

Mike

 

[GadgetGuy]

Agreed, however it was just shy of 100 degrees with the P3 sitting on my concrete driveway. I was concerned with:
1. The camera over heating
2. This was only a test and I didn't care about my battery usage.
3 I don't tend to fly missions that are so long that I am concerned with loosing a couple percent worth of battery at take-off.


Sent from my iPhone using PhantomPilots mobile app

No problem. All good points, especially at 100°! Even hovering at 93° made my motors so hot, that they were too hot to touch after! iPad also starts acting up at those temperature with telemetry issues!

Just wanted to clarify for anyone else following along at home that the barometer just needs battery power, like the IMU, to warm up and calibrate itself. Some of us wish we had just had an extra 2%, before the battery shutoff in midair, after one of the cells dropped below 3.0V! You never know when that last 2% might be needed. This is particularly true with the P4 batteries that cannot be topped off, when at 98% remaining, unlike the P3 batteries!

 

[GadgetGuy]

Point taken. And well stated. This thread has been a bit of an epiphany for me. I've flown Phantoms since the P1 and thought I was pretty experienced. But these things are so complex that every time I think I've got the routine down, my pre-flight checklist is good, and I know how to react in different situations, practicing things like canceling RTH, flying in ATTI, doing two close-to-home flight tests after each firmware upgrade, etc. etc... I keep paying attention and reading more and finding more "potholes" I could potentially fall into (many of which are not covered in the manual). I still think DJI has an opportunity to patch a lot of those potholes to keep us out of those situations like at least a "sensors not yet fully calibrated" warning or longer warmup time, don't cancel RTH ascent if sticks are moved within the first 10 seconds of the ascent, don't fly off to the homepoint if you are descending within a 50m radius of the contoller, and so on. But short of that, maybe there should be a post/thread covering this and many other potential "gotchas" that might affect junior flyers. Does such a thing exist? I mean.. a GOOD one that includes things like the baro not being accurate unless you do a 3 minute warmup?

On that last topic, I wonder if some of us have done ourselves a disservice by doing cold IMU calibrations? I don't put mine in the fridge but I did calibrate mine near an A/C vent to make sure it was cool. Before that, it took a good 60 seconds to warm up. Afterward, maybe 10 seconds... allowing me to complete my pre-flight faster and potentially take off before that 3 minute baro calibration. Just a thought. I don't remember seeing an altitude discrepancy when landing before I did that "cool" IMU calibration. Yesterday I launched within probably 60 seconds of turning the battery on because I had already done my pre-flight in the house on a different battery (checking all settings after I did the 1.9 FW update) and I had big discrepancies in altitude while flying and upon landing. Needless to say, I'll be waiting 3 minutes from now on.

Mike

Great summary, with one minor correction. It's within 20 meters of the Home Point, not 50 meters of the controller, where it autolands instead of ascending and returning to the Home Point.

 

[MikeyOnline]

Great summary, with one minor correction. It's within 20 meters of the Home Point, not 50 meters of the controller, where it autolands instead of ascending and returning to the Home Point.

Sorry. That was supposed to be my suggestion to DJI: if it sees you descending within 50 meters of the controller, don't try to fly to the home point.

Mike