6,300 ft up with 5% battery

[Skywatcher2001]

Sar104 you are a GEM my man. What an asset to have. I have a serious question for your skill set: If you were given all of the info out there on Flight MH370 . . . all the logs and handshakes from the comsat, would you try to find that bird or are there just too many variables?

 

[sar104]

Sar104 you are a GEM my man. What an asset to have. I have a serious question for your skill set: If you were given all of the info out there on Flight MH370 . . . all the logs and handshakes from the comsat, would you try to find that bird or are there just too many variables?

Thanks. I looked at some of those analyses – very fine detective efforts based on very little data. I'm accustomed to having much more to work with. The problem was the size and inaccessibility of the resulting probable search area. It's there somewhere.

 

[Skywatcher2001]

Thanks. I looked at some of those analyses – very fine detective efforts based on very little data. I'm accustomed to having much more to work with. The problem was the size and inaccessibility of the resulting probable search area. It's there somewhere.

Yeah . . . it's a compliment non the less. Isn't it amazing that a drone lost at sea yields more information, telemetry and flight data than a $130 million dollar Boeing 777?

 

[sar104]

Yeah . . . it's a compliment non the less. Isn't it amazing that a drone lost at sea yields more information, telemetry and flight data than a $130 million dollar Boeing 777?

Yes - that surprised many people. Of course it was mostly due to the telemetry having been deliberately switched off by someone in the cockpit, but that shouldn't be an option.

 

[AMann]

Was it involved in some way with a manned aircraft ?
If so, I didn't pick that up, but yeah altitude wise it may well be of interest to FAA or whoever anyway.
Being a drone, if nothing else was involved bar the drone crashing, then the NTSB might not be interested in it based on that alone . . . or maybe they do look at illegal flights of unmanned aircraft there ?
Are they a branch of the FAA ?

There was no aircraft mentioned, I was only pointing out that at the altitude it flew, it could have encountered one. The US National Transportation Safety Board is an independent investigative agency that investigates transportation accidents and makes recommendations and findings available for other agencies such as FAA.

 

[AMann]

Yeah . . . it's a compliment non the less. Isn't it amazing that a drone lost at sea yields more information, telemetry and flight data than a $130 million dollar Boeing 777?

...and a Boeing that has satellite telemetry directly from every critical part such as engines?

 

[Peter Hughes]

Just to clarify - this was not in the US. But agreed - flying at that altitude certainly risks conflict with regular traffic. The location was only 5 km or so from the local airport, although not a busy one.

You say “....although not a busy one” like that makes it alright....very strange.

 

[EricJT]

Yes - that surprised many people. Of course it was mostly due to the telemetry having been deliberately switched off by someone in the cockpit, but that shouldn't be an option.

I agree....there should not be an option to switch off the telemetry. If the data were fed to a satellite like another poster suggested, there at least might be some closure for family and relatives. Even if the telemetry was recorded to the black box and it was still recording, recovery is difficult at times.

 

[sar104]

You say “....although not a busy one” like that makes it alright....very strange.

My statement was entirely factual and does not support your inference, which also requires you to have ignored the rest of my post.

 

[DanMan32]

Toast at least would be a tasty snack. That's just nasty.

Moldy toast?

 

[DanMan32]

Wouldn't a Mavic lose speed on freefall as it reaches denser air?
Burn up on reentry? [emoji3]

 

[anotherlab]

Can you tell from the telemetry if the Mavic was tumbling while it was in free fall? I'm wondering if a tumbling body would sustain less damage at impact.

 

[Thomas B]

Can you tell from the telemetry if the Mavic was tumbling while it was in free fall? I'm wondering if a tumbling body would sustain less damage at impact.

Per Murphy’s third law: the probability that a piece of toast will land with jelly side down is directly proportional to the cost of carpet below it.

 

[DanMan32]

ROFL!

 

[sar104]

Can you tell from the telemetry if the Mavic was tumbling while it was in free fall? I'm wondering if a tumbling body would sustain less damage at impact.

At the end of the log it was spinning and wobbling significantly, but not tumbling. I'd expect a transition to fully chaotic behavior soon afterwards.

 

[anotherlab]

At the end of the log it was spinning and wobbling significantly, but not tumbling. I'd expect a transition to fully chaotic behavior soon afterwards.

Followed immediately afterwards by a relative lack of movement on all axis.

 

[Ray the drone guy]

I recently received a request to try to determine the location a lost Mavic Pro that lost power and shut down in mid-air. The logs were interesting from several perspectives. Firstly - the summary graph, which tells the basic story:

View attachment 85162

The aircraft ran out of battery and lost flight control and propulsion at just under 5,000 ft AGL, but the logs continued for another 6 seconds or so. The log data showed a consistent and steady wind field (~ 30 mph out of the west), but when I ran the usual numerical simulations of the resulting descent it became apparent that the drag coefficient was wrong - at the end of the log it had already exceeded the predicted terminal velocity by around 2 m/s.

View attachment 85165

Anyway - averaging a number of simulations, varying wind speed/direction and drag, yielded a likely crash location with an uncertainty circle of around 150 meters radius. The crash site was found around 50 meters from the center of the circle, which is reasonable, but in confirming the log data it also confirmed that the variation of drag with altitude is not negligible. Drag scales with fluid density and the square of the velocity, and at 5,000 ft AMSL the air is significantly less dense than at sea level, making my previous constant drag coefficient significantly wrong at higher altitudes. Adding a density-dependent drag, based on altitude in a standard atmosphere, shows the size of the variation:

View attachment 85167

That shows a 15% variation over 5,000 ft altitude change. Implementing that directly in the numerical simulation fixed the problem quite well - it yielded a match to both the vertical descent speed at the end of the log and the actual impact point to within a few meters:

View attachment 85168

View attachment 85169

While it's only matched to one data set, since we don't often see 5,000 ft free fall events, I'm fairly confident that the altitude-dependent form of the drag is pretty close, and I'll use that for future incidents.

As for the flight itself - don't try that at home.

That’s one complicated result

 

[strdr]

The pilot, not surprisingly, is not keen to be identified. The aircraft had clearly been in the sea, but when is uncertain.

View attachment 85186

View attachment 85188

****, that's hard to look at. /weep

 

[PTBperegrine]

blasted thermals they will get you every time especially if you have changed,the max altitude geo fence parameter

????

 

[old man mavic]

????

glad you liked it keep soaring