Inspire 2 Flyaway

NickU · Jun 28, 2017

Oddly enough, this popped up on my FB feed just now... might help some of you appreciate why you don't need to calibrate every flight, and why to try moving your home point if your aircraft demands a calibration (see his point #2) ...

DJI Owners group - Compass Calibration

It's not about distance, it's about where you are in the world, and what direction you've moved since the last calibration you did.

ianwood · Jun 28, 2017

deltalimatango said:
Maybe. Who's to say? This is a perplexing situation. However, for sure the boat/ship didn't blast the drone as someone suggested. I would not rule out RF interference coming from the ships and surrounding area.

Failsafe. All drones since forever have it. If the link is lost, the system enters its failsafe state, and for DJI drones, unless the default configuration is changed or GPS knocked out, it will RTH. Signal loss due to interference is a normal and recoverable event.

The only condition that could kill the radio but not enter failsafe would be something frying the actual RX/TX with a concentrated and powerful signal similar to the microwave/radar I described earlier. And it would have to kill it without the rest of the system being able to recognize a loss of link in order to get it to drift away like that. I am still not sure this is at all likely.

Roar said:
We did do a compass calibration before take/off because it physically wouldn’t let us take off without doing one. Could be because we updated the software earlier that morning? Since the incident I've read plenty of articles stating that you should only do a compass cal in a wide open area and only once every few weeks/months if you fly in the same area a lot.

This is an important detail. The compass is the most implicated sensor in erratic and uncontrolled flight or what some people call "flyaways". I wrote a primer on it back in the Phantom days but I've kept it up-to-date and it is equally relevant to the I2: Compass Calibration, A Complete Primer.

Roar said:
That screenshot up above isn’t completely accurate in regards to where the drone actually was at the time we lost connection. We continued flying for a few minutes from where that log says the drone was, before it went out towards sea.

At the time of the connection loss we were flying in ATTI mode but tried to switch back to GPS and it was unresponsive. We attempted RTH multiple times too without any response.

It seems like it was reasonable distance from you when this all went down. It is hard to tell how the drone is responding at such distances. Flying in ATTI without good spatial orientation would be tricky at best. It is easy to think a drone is either unresponsive or flying in a direction different to the one being commanded when it is far away from you. Not saying this is the case but it has been known to happen.

Can you post a video of the entire flight from the app? It would be useful to see the lost link messages and RTH inputs. Be sure to turn on the stick viewer.

NickU said:
Oddly enough, this popped up on my FB feed just now... might help some of you appreciate why you don't need to calibrate every flight, and why to try moving your home point if your aircraft demands a calibration (see his point #2) ...

DJI Owners group - Compass Calibration

Not a bad summary but I like mine better!

Just be aware that there is A LOT of bogus information out there on the compass including from DJI.

johnmont250 · Jun 28, 2017

ive been pretty close to some ship com equipment running with no effects.

lake_flyer · Jun 29, 2017

I concur with Editor. You should never calibrate the compass on a steel ship. Or any ship. Even 5 meters away from the magnetic backup compass on my polyester yacht I get interference. The radar should/must have been on minimal power as it was not on open sea, so I don't expect that to have been the issue.
[edit] updating firmware without proper testing procedure is also quite a gamble.

lake_flyer · Jun 29, 2017

Wifi interference can also have been the culprit. Powerful hotspots can be found in harbour areas nowadays.

sailor · Jun 29, 2017

I have considerable experience flying around steel ships with Phantoms and Inspires. I agree that you should not calibrate aboard. I've traveled hundreds of miles on ships without calibration and flown from them without incident. I've also had flyaways similar to what you describe and by switching to Atti mode been able to recover the craft. I've been flying an Inspire 2 for several months now with hundreds of flights and never calibrated the compass! It hasn't asked for it, so I've not done it. In several cases where it has asked for a calibration I've moved a bit farther from metal till the compass calibration warning goes away and all is well. Another word of caution: be sure that you have the multiple flights modes option set in the menu or you won't be able to switch to atti when you need it most. If you have a flyaway I believe the first thing you need to do is switch to Atti mode. Get a little farther form the steel and you should be able to go back to GPS. I've flown close to lots of strong radars without incident but military radar might be different. I believe bad compass calibrations have been the cause of most flyaways.

NickU · Jun 29, 2017

They didn't calibrate onboard the ship, Roar got the message on the quayside and did the cal there. Unfortunately for them, they did exactly what DJI Go and the Inspire asked for, without realising that they were stood over a load of iron and what the message was really saying

Unless we've directly experienced it ourselves, most of us could easily fall into the same trap.

teecee · Jun 29, 2017

That is terrifying! We had an I2 go down due to "abnormal compass data" around a giant piece of steel we were shooting. Different problem. Same result - No more I2...

rmb · Jul 1, 2017

Roar said:
I agree with not knowing conclusively but unfortunately without the drone being sent to DJI I don't think I'll ever know exactly what caused it. As for landing to determine the cause before resuming that's a painful lesson learnt... All fully insured though so not the end of the world.

Sorry for this trivial question around your serious loss. I am just about to get commercial insurance for my I2. I have DJI refresh, but acknowledge that that is probably not enough. May I ask what company you went with and what sort of premium I can expect? Thanks and again sorry for the flyaway. I can't imagine!

SanCap · Jul 1, 2017

rmb said:
Sorry for this trivial question around your serious loss. I am just about to get commercial insurance for my I2. I have DJI refresh, but acknowledge that that is probably not enough. May I ask what company you went with and what sort of premium I can expect? Thanks and again sorry for the flyaway. I can't imagine!

DJI Refresh will not help you if you do not have the remains of the Inspire. Expect to pay $1000 to $1500 for a million in liability and @ $6000 in hull insurance.

Buzz In California · Jul 3, 2017

My question is;

When you finally realized that you lost your drone, how long did it take for the uneasiness in the pit of your stomach to go away????

I had a similar feeling when I crashed my drone and it stayed with me until I sent the drone off for repair....sob....

dkotinsky · Jul 5, 2017

deltalimatango said:
Please explain: "threw a fake GPS at your drone." Are you asserting that someone maliciously send a GPS jamming signal to the drone? If so, that signal is omni-directional and would most likely disrupt all other GPS receivers in the area unless they were SAASM enabled and the proper keys loaded.

Know your drone no-fly zones, says store owner

"Naval vessels also have their own rolling no-fly zones to keep drones away, according to Habib."

"Habib said that military installations such as the Canadian Forces Ammunition Depot in Bedford maintain active no-fly zones and any drone entering such areas will be jammed and forced to land."

Buzz In California · Jul 5, 2017

dkotinsky said:
Know your drone no-fly zones, says store owner

"Naval vessels also have their own rolling no-fly zones to keep drones away, according to Habib."

"Habib said that military installations such as the Canadian Forces Ammunition Depot in Bedford maintain active no-fly zones and any drone entering such areas will be jammed and forced to land."

You neglected to post the funniest advice the store owner offered to us

And Dr Drone store owner Edward Habib has some simple advice for Halifax’s drone operators.

“Stay away from airports and don’t be an idiot.”

deltalimatango · Jul 8, 2017

dkotinsky said:
Know your drone no-fly zones, says store owner

"Naval vessels also have their own rolling no-fly zones to keep drones away, according to Habib."

"Habib said that military installations such as the Canadian Forces Ammunition Depot in Bedford maintain active no-fly zones and any drone entering such areas will be jammed and forced to land."

Yes that may be all well and good but jamming signals aren't selective. They would affect everything in the area to include civilian and other naval vessels. Not to mention any other civilian applications. I don't think they threw a jamming signal at the OP's drone as it would cause too much collateral damage.

ATU · Jul 24, 2017

deltalimatango said:
Yes that may be all well and good but jamming signals aren't selective. They would affect everything in the area to include civilian and other naval vessels. Not to mention any other civilian applications. I don't think they threw a jamming signal at the OP's drone as it would cause too much collateral damage.

Not selective but can be highly directional depending on the type of antenna system used and effective range depending on radiating power. Even if there are no report of other parties being affected, it does not mean it did not happen, it was a military vessel afterall. Unless the shoot was officially commissioned by the military and the ship was part of the shoot then we can possibly rule out jamming. Likely it was new firmware and compass calibration that caused it though.

Question: Assuming RTH was selected as failsafe, if the craft knows it's currrent GPS coordinate and the home point GPS coordinate, does it still need compass data? In theory, the craft can just estimate a heading and fly towards the HP. If the compass was in error and the new GPS coordinate goes in the wrong direction, then the craft can just turn and "home" in on the home point by trial and error. Thoughts?

jonathan Atkin · Mar 13, 2020

Roar said:
Hi guys, posting this to hopefully help out others. I was on a job the other day photographing and filming a navel ship with an Inspire 2 + X5S. Managed to get some good footage of the ship but after about 5 minutes had a warning saying 'magnetic interference, switch to ATTI if aircraft changes behaviour'. The aircraft seemed fine but I switched to ATTI mode anyway just incase. We continued to take photos and then a few minutes later lost full connection of the drone on the iPad and the controller itself. Every failsafe failed. The drone did not return to home and did not make any attempt to land. It went out to sea, probably never to been seen again...

After researching and speaking to various people in the industry, it seems that the radars and satellite dishes on the ship completely fried the insides of the Inspire causing complete loss of connection and control.

In the UK you are required to write an 'Operations Manual' when you apply for your CAA SUA licence. Our Ops manual was roughly around 11,000 words and after writing so much about all the failsafes that are in place if something was to ever go wrong, it was truly terrifying when nothing worked.

I couldn't find much on the internet about flying drones near vessels/ships. So just a word of caution to anyone planning to do something similar in the future.

Good Day. I fly around cargo ships and tugboats and to simply say: I always have permission from the vsl. As a USCG Licensed captain myself I carry a VHF to talk with the bridge. I NEVER EVER FLY near a military vessel whatsoever unless I have acknowledgement.

USCG regulations permit the Captain to turn off radar at his discretion. In close maneuvers with no real need for radar, I request radar to be shut off.

Military vessels emit RF far and above most civilian vsls. Marine radar and satellite technicians supplied me with a list of radio frequencies common to US Naval ships. I sent those frequencies to DJI Support asking if there was any shielding from the frequencies. There was no specific response other than to say, don't fly near ships. LOL. The same advice re: Microwave antennas.

That said, most large ships of any size, radar is but one set of RF interference as ships are transmitting on radios of various frequencies from VHF to otherwise, use massive broadband capabilities, and other transmitting devices that we may not know about. I stay at least 75 feet away from any antenna. And certainly do NOT fly directly in front of a radar dish. One can research the expanding radius of its signal. And stay clear...as much as one can.

The US Navy -- Fact File: AN/SPS-48G

Fact sheet for: AN/SPS-48G

www.navy.mil

As you can read, military systems are exceptionally complex to detect incoming at almost 360 degrees and at low and high altitude. Not your every day Garmin Radar on a tugboat.

"The processor supports contact processing rates of non-coherent and coherent detections per 4-second scan. Doppler filtering is utilized to make coherent detections. The radar has been designed to function in two separate scan modes: Low Elevation (LOW-E) and Equal Angle Coverage (EAC) mode. LOW-E is designed to detect and track low flying anti-ship missiles utilizing Moving Target Indicator (MTI). EAC mode is designed for high angle volume search and to track both high and low altitude targets. Either scan mode can be selected for all 360 degrees in azimuth coverage (Background Mode) or can be entered as scan mode gates in sectors not smaller than 5.6 degrees and as large as 360 degrees."

Dobmatt · Mar 13, 2020

jonathan Atkin said:
As you can read, military systems are exceptionally complex to detect incoming at almost 360 degrees and at low and high altitude. Not your every day Garmin Radar on a tugboat.

And even these "every day Garmin radars" can mess with DJI drone. Last summer I was filming a little tugboat towing a lumber on Arrow Lake BC, get too close and my usually very reliable Phantom 4 Pro went crazy. Compass Error warning message was followed by entering ATTI Mode flight, which I was able to manage safely. P-Mode returned shortly after escape to a safe distance away from this vessel.

Bottom line: flying DJI drone within marina environment must be carried cautiously.

mmarian · Mar 13, 2020

Bottom line: flying DJI drone within marina environment must be carried cautiously.
[/QUOTE/]
So true! When I was photographing this yacht I asked the captain to switch the radar off, to eliminate any possibility of RF interference. It was a hair raising gig but I encountered zero issues, thanks god. The biggest challenge was to land the drone safely in strong wind on sloping canopy/suite roof near the small square window next to the passage to the bow. I was standing in that passage when flying and photoshoped out myself and my assistant/spotter from the final photos.

Douglas Bader · Mar 14, 2020

How far were you away from this Naval ship? Also how far away was the drone from the Ship? And finally how far was the drone from you when it went AWOL?