Quads - be careful - don't take it for granted!!

[jarflyer]

With all the easy installation & configuration of Quad controllers like Naza, Phantom etc.. we also need to understand that these are all hobby components and can just not perform the way they are supposed to perform.

I have been flying quads for about 3+years now - started with the first Gaui 330x.. used Fiyutec FY90Q, then to DJI Naza.. which is the best.. I have two Naza's on two different size quads. All was well till what happened yesterday.. I was shocked!!

Normally to keep my batteries from dying, I charge them & do very low hovering in our condo basement parking OR in broad walkways in our condo. When I have time on weekends, I prefer to go Tampines and fly with complete set-up (gopro etc). When I don't have somuch time, I fly in a open ground around my area - all four sides surrounded with HDB blocks. I never had any problems in last few years with regard to my quad crashing OR going out of control - although I have seen a couple of instances with others who fly in that area. To be safe I always fly in the middle of the ground and don't go vertically so high that incase something goes wrong, the quad should not reach the HDB blocks before I take corrective action.

Yesterday in this ground, I was flying my F450 quad at just 12-15ft high in GPS mode (got the GPS lock as well) - my battery was at 11.8v and I wanted to hover for few minutes and use-up the battery before I load fully charged batteries - hence was just flying low. exactly at 2 minutes in to hovering, my quad started to wobble.. I realized something was about to happen and started to slowly reduce the throttle to land.. imagine what happened next !! The quad went crazy and within fraction of seconds, it just tilted towards the side and headed directly towards me with full speed - may be about 30-40kmph and flew past my head.. and went directly in direction of HDB blocks.... I could see it was headed directly towards a window - where I could see baby cloths hanged for drying (imagine my quad heading into a home which had an infant baby!!! )

Two lucky things happened.. I was in middle of the ground.. the battery was already low, so the quad lost power before it reached the window and altitude reduced by couple of feet... it went directly into the void deck below that window...!! But there were children playing over there!!! Lucky again my quad crashed into one of the pillars... and did not reach the children.. although a few pieces of the props reached the children - did not hit them...

I was shocked!! not for my broken quad - but what would have happened if it had hit the window of that house OR did not collide with the pillar - it would have hit the children in the void deck!!

I promise, I will never again fly in any open ground near residential blocks nor inside my condo nor in the basement car park. If I cannot make it to Tampines, I will not fly. But I will not endanger other people & myself by flying in populated areas!!!

I would especially advise this to all Phantom owners as well... as I see a lot of inexperienced Phantom flyers around my area flying very close to the residential blocks and that too very high.. they try to go over the 12floor HDB blocks...

My whole perspective of safety & reliability has changed. Its all in our hands to be safe & understand that all these are hobby stuff and can dramatically go wrong anytime.

Lets fly safe!!

[mave]

That is a very scary event.
Have you done a post mortem? can share your findings?

[feudallordcult]

Thanks for sharing. Even more thanks for being responsible which I seldom see in new flyers. Really dare not imagine the consequences if the quad had struck either the children or worse, an infant.

[Nicholas]

Interesting, i'd actually like to know what actually happened which caused this awkward and bizarre behavior. Was it the Naza? or simply electronics failing in flight? It would be good for the community here if you can find the cause and the solution!

[Aramid]

It sounds like a classic Naza flyaway. This is why all multirotor pilots, particularly those flying DJI ones, need to learn how to fly in manual mode. Flipping the switch to manual would most likely stopped the quad from its suicide mission and instead obey your controls.

[feudallordcult]

It sounds like a classic Naza flyaway. This is why all multirotor pilots, particularly those flying DJI ones, need to learn how to fly in manual mode. Flipping the switch to manual would most likely stopped the quad from its suicide mission and instead obey your controls.

Classic naza flyaway?wat causes it? Sounds dangerous. It's like dsm2 where low voltage can cause a brownout/reset of rx. But this is an entirely different ball game.

[wanna_be_pilot]

Classic naza flyaway?wat causes it? Sounds dangerous. It's like dsm2 where low voltage can cause a brownout/reset of rx. But this is an entirely different ball game.

There can be several reasons for flyaways. GPS module is bad. Too much electromagnetic interference. Not getting enough GPS locks. Its hard to diagnose the problems with the whole DJI franchise since the user can't review logged data after the flight.

As for dsm2, just a word of caution, DO NOT use dsm2 or below at CD field. There is a jammer suspected to be on the Civil Defence building which literally shoots down airplanes.

[feudallordcult]

There can be several reasons for flyaways. GPS module is bad. Too much electromagnetic interference. Not getting enough GPS locks. Its hard to diagnose the problems with the whole DJI franchise since the user can't review logged data after the flight.

As for dsm2, just a word of caution, DO NOT use dsm2 or below at CD field. There is a jammer suspected to be on the Civil Defence building which literally shoots down airplanes.

Thanks for the tip. Now I'm getting an idea on WHY my skysurfer flew away so mysteriously...

[mave]

serious?!
Does that mean that it will affect also DSMX or spectrum receivers?

There can be several reasons for flyaways. GPS module is bad. Too much electromagnetic interference. Not getting enough GPS locks. Its hard to diagnose the problems with the whole DJI franchise since the user can't review logged data after the flight.

As for dsm2, just a word of caution, DO NOT use dsm2 or below at CD field. There is a jammer suspected to be on the Civil Defence building which literally shoots down airplanes.

[wanna_be_pilot]

serious?!
Does that mean that it will affect also DSMX or spectrum receivers?

I really cant say anything since i have since changed to futaba ever since my planes got shot down with the dsm2 radios.

Maybe if someone is using dsmx at CD, they can weigh in...

[Sawit]

From my past experience, GPS signal in between HDB blocks is quite unreliable.
It may be the main contributor to the failure.
Would you be able to carry out the following and share the info?

If you are able to extract the real time GPS signal from your NAZA, go back to place of incident and track your stationary NAZA module on Google map.
The position should not be shifting over time.

A typical GPS device may give you a position with a 15m error.
Differential GPS is better. The error is only 10cm..... which I think NAZA is not.
15m error here and there will cause plenty problems.

In the meantime, don't fly around HDB blocks lah..

[guile]

If you still want to fly around HDB blocks, it's better to fly in Atti. No use flying in GPS mode if you can't get a reliable GPS lock and your quad will still drift about anyway. Moreover there's bound to be a lot of interference from all the wireless routers that's inside almost all households these days and electronic magnetic interference from the metal structures of the buildings which may cause havoc to the GPS's magnetic compass. By the way, what firmware are you on? 4.02? Do you have any telemetry on IOSD installed? Those can help alert you if the compass values are out of range.

[jarflyer]

Hi All,

Thanks for the feedbacks. Few clarifications:

1. The GPS had got adequate satellites locked.. got the 5 green blinks and while on air as well, it was blinking green. Also as I mentioned, I was in middle of the field.. so not much interference I suppose.
2. Yes, I am using Spektrum DX8 and have a switch to quickly switch from GPS to Atti. The moment I saw the quad tilted and started heading towards me, immediately I flicked the switch to Atti mode.. but not sure if that really helped.. I did this exactly when the quad was drifting past my head.. then I flicked the fail safe switch as well... but may be that was of no use, as I had already moved into atti mode...
3. Yes its Naza and all electronics etc was perfect.. infact I checked the ESC's & motors - all are working perfectly and they were just warm - not even hot.
4. When I connected the Naza to assistant software - its showing everything OK.. even GPS is working.. Just connected the motors (without props) and all spinning absolutely perfect. I have an old quad frame & rebuilding. Hopefully will go Tampines this weekend and test fly.

[wanna_be_pilot]

Hi All,

Thanks for the feedbacks. Few clarifications:

1. The GPS had got adequate satellites locked.. got the 5 green blinks and while on air as well, it was blinking green. Also as I mentioned, I was in middle of the field.. so not much interference I suppose.
2. Yes, I am using Spektrum DX8 and have a switch to quickly switch from GPS to Atti. The moment I saw the quad tilted and started heading towards me, immediately I flicked the switch to Atti mode.. but not sure if that really helped.. I did this exactly when the quad was drifting past my head.. then I flicked the fail safe switch as well... but may be that was of no use, as I had already moved into atti mode...
3. Yes its Naza and all electronics etc was perfect.. infact I checked the ESC's & motors - all are working perfectly and they were just warm - not even hot.
4. When I connected the Naza to assistant software - its showing everything OK.. even GPS is working.. Just connected the motors (without props) and all spinning absolutely perfect. I have an old quad frame & rebuilding. Hopefully will go Tampines this weekend and test fly.

Sounds like your Rx had a brownout. Did you see the LED's on the rx when you picked it up after the crash...

[elmosan]

Sounds like your Rx had a brownout. Did you see the LED's on the rx when you picked it up after the crash...

1. I am not sure which part of jarflyer's incident sounded like a brownout. In fact, I don't anything in his description is even remotely suggesting a brownout. At most, a brownout is a wild guess from you.

2. I don't think checking the rx led could indicate any brownout on DSMX. The blinking led brownout indicator only works on DSM2. So jarflyer, if you are on DSMX, no use checking the led. http://www.horizonhobby.co.uk/aeroon..._dsmx_faq.html

3. A search on RCG forums and FPVlabs, suspected problems with Naza/rx consistently results in a power cut-off/deathspin and crash, NOT a flyaway as described by TS.

http://www.fpvhub.com/?topic=7287.0

http://www.multirotorforums.com/showthread.php?2247-Naza-falls-out-of-the-sky-Attitude-Mode-Intelligent-cut-off-problem

http://www.rcgroups.com/forums/showthread.php?t=2069061

Im just saying....