Was flying my mini 2 in a very common area for me.  Started a RTH with 31% battery remaining at about 1 mile (1.6km) from home.  Drone was very high so that I had line of sight on it (which I have done often).  Battery started dropping -way- faster than I have ever experienced before, and I got the 20% critical low battery 75 seconds later (ie: I lost 11% battery in 75 seconds).  Anyway the upshot is that the drone fell from the sky about 100 metres (300 feet) above me, landed (conveniently?) on a highly sloped roof rather than pavement.  With some careful use of superglue and bits of plastic, I actually got the drone flying again.  It could probably use a new gimbal, but given this is my backup drone I will probably just keep it as is until it dies.

SO... was it me or not??  The battery had only 8 cycles on it.  When I looked at the logs, other than the fast dropping voltage, all I could see that surprised me was that the two cells started to drain quite differently at the end (ie after 0%).  When it hit 0%, it switched to forced landing.  At that point, the batteries were 3.44V and 3.52V (delta of .08V).  It stayed aloft for around another 90 seconds.  By the time it died, one cell drained to a low of 3.06V, but the other one went all the way down to 1.35V.  I thought that the BMS would have just turned off power below around 3.1V.  The battery pack is non-responsive now.

It's shocking that the thing actually went as long as it did given the low voltages, but for the life of me I don't understand why the voltage dropped so fast.

Well, if nothing else, looking at the anatomy of a crash is interesting... Here's the log for everyone's amusement.  The GPS was reporting wonky info by the end, but amazingly the drone continued to transmit all of this info to the controller right up to (and after) the crash:  https://www.phantomhelp.com/LogViewer/39KQ9PW577H97EGVT45N/

It also recorded video up until the end.  Even got a picture of myself standing in the street as it glanced off the neighbour's roof!

Just had a very quick skim through the replay of the flight on Phantomhelp.
I would suggest you have a look at
a) the artificial horizon and the angle of pitch/roll of the drone
b) the position of the horizontal movement stick (elevator and aileron)
c) where applicable, the indicated ground speed
during
1) the out bound flight
2) the short flight 'parallel' to the ?ship
3) the inbound flight.
Do you see a pattern?
It seems to me that this flight was flown it a fair/strongish, off-shore, high altitude, wind that burnt battery on the way home. As far as I remember from my flights, where the drone starts an RTH whilst in sports mode it is possible, with the Mini 2, to 'push' the drone significantly above the nominal 10.5m/s, 23.5mph, RTH speed by, as you were doing, giving the drone full forward stick/elevator. Yet, your drone was struggling to make the nominal speed in places, though holding the throttle closed to lose 1480ft of height may have reduced the available forward thrust.

I would ask
1) Are you aware of the legal height limits of a drone in Canada? 400ft AGL?
2) Are you saying you can see a Mini 2 at a range of 5369ft and a height of 1482ft? If so you have VERY VERY good eyes.
3) is a height of 1482ft AGL not in manned aircraft airspace and HIGHLY dangerous? Especially given your seeming proximity to several airports.

Was it you? Unless there is something else that can be found from an analysis of the the logs I would say it is ENTIRELY down to you and that's just considering the distances, vertical and horizontal and the wind and ignoring legal aspects.
If you consider the latter I suspect that Transport Canada would consider this a reckless and dangerous flight if they see it.

Hi,

Your battery died in flight....But battery did very good job !  
at 0% level still both cell values above 3.3 volt, actuall cell1 = 3.435 and cell2 = 3.515.

At 9m18s mode change from GoHome to AutoLanding, this to try to land form 310 meters baro height with 14% battery level.
last part, below 0% the batt cell values got really worse, see my chart of your data. (not strange, asking full power at 0 %)

At the end of your flight with low batt level in autolanding : 100% UP and 100% forward flying at 300 meters height....uh?Why not only forward input....
Autolanding started with 14% batt level, so it will land with some juice left in the battery.

Didn`t you want to try to land safely instead of flying to HP at that height with less than 7% battery ?
3 m/s down speed at 300 meter height = 100 seconds = approx 7% battery ussage.....

Your drone lost precious time not flying direct to home in autolanding/forcedlanding. see the green to home line and your heading line.

cheers
JJB

SO... was it me or not??
No question ... it was you.
You made just about every mistake possible.
There was nothing surprising about the battery "failure".

Here's my assessment.

You had an easy flight out in SPort Mode with the wind behind the drone, so your return trip was going to be pushing against a headwind.
Halfway out, you started climbing and took the drone up to almost 1500 ft.
Shortly after reaching this height, the drone went into RTH because of the low battery level and the distance from home.
But the battery/distance calculation does not take wind into account, so things were going to be tricky.
In gusts, the drone had to tilt to Sport Mode angles to make progress against the wind and not surprisingly, this ran the battery down fast.

On the way back you reduced the height to just under 1000 ft, but then took it back up higher.
It never occurred to you that the winds up that high are almost always stronger than down at low levels.
The first thing to do if battling a headwind at high levels, is to reduce altitude and so reduce the strength of the wind you have to fight.

The drone reached critical low voltage with 3100 feet still to go and autolanding commenced with 2100 feet to go.
After autolanding started, you pushed the left stick hard up to keep attempting to keep the drone up at 1000 feet.
This only burnt battery even faster and couldn't maintain altitude anyway as the flight controller had to reduce power to prevent you draining the battery and the drone would crash down from high up.

You kept pushing the left stick and right forward but the flight controller no longer allowed Sport Mode tilt angles and the speed dropped while the battery went down faster.
You kept the battery running way past critical low voltage level to 0% and beyond, taking an unusual long way home rather than the straight line and crash at 12:40.

Mistakes
Starting a long flight with a partially used battery
No awareness of the wind or how it would affect your flight.
No awareness of increased wind speed at altitude.
Flying far out with a tailwind
Not returning early enough
Returning at very high altitude against a strong headwind.
Not lowering altitude to have less wind to fight.
Wasting battery trying to stay high when not necessary
Not making an emergency landing after reaching land
Not taking the shortest path home

There was no problem with your GPS
The GPS messages were when the drone was upside down without a proper skyview.
All data following the crash is from sensors affected by the crash.

Thanks for the quick responses.  Among the many operator mistakes, after the 0% battery point, panic set in with the expectation that the drone could just drop out of the sky.  This caused waffling on where to direct the drone for safest exit.

On the point of rules in Canada, it is worth pointing out that the actual legal rules for <250g drones are extremely light.  However Transport Canada does publish "marketing" documents that refer to things like "should stay under 400 feet" and "should maintain visual line of sight" - this can create ambiguity since the marketing documents don't match the legal documents.  It's even more confusing when people from the US and UK try to interpret Canadian rules in the context of what they are used to.  In any event, others have done a better job explaining this than me.  Here's one for example: https://colinsa.ca/blog/where-you-can-fly-a-micro-drone-in-canada

Since I am the one who commented on the rules in Canada I will say this.
Yes, prior to questioning you concerning the laws I saw that https://tc.canada.ca/sites/default/files/2020-06/2019-2020-AA-33_INFOGRAPHIC_EN_V8.pdf says "should" and yes, that is ambiguous but do you honestly, hand on heart, believe that "should" is not meant to be read as "must".
If the answer to that is ''Yes, you do honestly believe that'', don't you think it a bit strange that an advisory document, published by the relevant authority, does not specify the circumstances in which it was acceptable to fly above 400ft AGL and or BVLOS? I do. I don't think my being British presents the slightest impediment to my understanding the rules.

Would you be prepared to risk the legal fees and possible fines in trying to argue, before the relevant authority, that, in the applicable sense, "should" does not mean ''must'' and that it was perfectly legal and niether reckless nor hazardous to fly in airspace that is possibly legal airspace for manned aircraft?

More to the point, are you happy to risk the lives of the occupants of manned aircraft just to satisfy your presumed rights because of an ambiguity in the wording of a document?

This may be of interest https://mavicpilots.com/threads/ ... d-24-jun-22.127667/

You may be able to afford the legal fees of arging you 'rights' for an uneventful flight but could you afford the cost if you caused the crash of a manned aircraft? Do you think the ''should'' argument would carry any weight in such circumstances?

Could your conscience afford the cost of causing a manned aircraft to crash?

Since you did not argue that you COULD see the drone I assume that the drone was beyond the range of your eyesight.

If correct, I rhetorically ask. At those heights and distances could you have judged whether of not the drone was a threat to a manned aircraft in that general area? I would say no and guess that about all you could honestly say was that the drone was somewhere off in 'that' direction.
I have lost sight of a drone before and brought it back under, with one exception where I was metaphorically pooping myself all the way down, 400ft, either by using the screen or RTHing it and I have very rarely got it back in sight before it was well within my VLOS. Indeed, often where I was looking for it was nowhere near where it reappeared, most times I spotted it with 'peripheral' vision.

With regards to the site to which you provide the link.

I have read it, it seem very good, and will re-read it, but the impression I get is that, whilst the author thinks that it is legal to fly a micro drone above 400ft AGL in Canada, he thinks it unwise to do so.

Like wise he thinks one should keep a drone in VLOS.
And that one should not ''operate a remotely piloted aircraft system in such a reckless or negligent manner as to endanger or be likely to endanger aviation safety or the safety of any person."

All I suggest is that you think of the safety of others first and foremost.

fansb4f50ec1 Posted at 7-3 06:09
Thanks for the quick responses.  Among the many operator mistakes, after the 0% battery point, panic set in with the expectation that the drone could just drop out of the sky.  This caused waffling on where to direct the drone for safest exit.

On the point of rules in Canada, it is worth pointing out that the actual legal rules for

Hello,

Writer of the article you linked on Where You Can Legally Fly a Micro Drone in Canada. I had a few people reach to me to comment here.
I checked your post and your DJI Flight logs, and also behaviour around this flight.

You need to more clearly read the post I wrote---as I think you're trying to find loopholes in the "what you can do" vs. "what you should do".
You absolutely cannot just fly up into aviation airspace. Class F (CYR), Class A, and Class B are highly controlled and can get you into very serious trouble. In the article I don't even mention Class A and B because they are so high above where drones should ever be.

Either way--you're in Missisauga and near some of the busiest air traffic in Canada, you most certainly should not be flying anywhere near 1500ft AGL. Transport Canada requires 400ft AGL for a reason. Stick to it and please follow my suggested guidelines to fly safely.