Almost Crashed my Phantom 2 V2 Transmitter (issue?)

[ThePhantom]

Ok so I was flying early, because my phantom fixed its horizontal gimbal issue (posted somewhere in the forums). I have a P2 v.20 with the new Tx. The new fx on the Tx Throttle Down and lock is supposed to make my Phantom go down at a steady level right? However when I locked it (thankfully a few feet above ground), the Phantom turned off. It seems to do this too when the Phantom is at idle mode on the ground. Throttle Lock (lever all the way down) and bam, Phantom turns off. Anyone experienced this?

Thanks.

 

[QYV]

holding the throttle full down for like, 4-5 seconds does indeed turn the props off, but that's only supposed to happen if the Phantom senses that is is no longer descending. internal barometer & GPS are supposed to keep an eye on that. I almost always have the throttle full down when I'm descending now due to the 2m/s descent limit and it's never shut the props off while it's up in the air, only after I catch it (I always catch, never "land")

If you locked your throttle full down "only a few feet off the ground"... then it would have almost immediately settled on the ground, sensed it wasn't descending, and turned off the props as designed... is that what happened?

 

[d4ddyo]

I was told NOT to lock the throttle down until landed. I was told the reason why they put that lock in there was because people were dropping their phantoms out of the sky by full downstick and the phantom sensed it was ground level when it wasn't.

 

[N017RW]

Have you somehow changed the MOTOR Cut Off Type to immediate via the Phantom 2 Assistant s/w?
It should be in the upper right side of the 'View" tab.

Sometime f/w updates do things like this and has been reported to change the Tx Mode from 2 to 1 also.

 

[SteveMann]

I was told NOT to lock the throttle down until landed. I was told the reason why they put that lock in there was because people were dropping their phantoms out of the sky by full downstick and the phantom sensed it was ground level when it wasn't.

That makes no sense. That advice didn't come from here, did it? The Phantom uses the internal barometric altimeter to decide if it's on the ground. If the pressure doesn't change for, I think, 3-seconds, (and the throttle is all the way down) then the motors are turned off.

 

[d4ddyo]

I was told NOT to lock the throttle down until landed. I was told the reason why they put that lock in there was because people were dropping their phantoms out of the sky by full downstick and the phantom sensed it was ground level when it wasn't.

That makes no sense. That advice didn't come from here, did it? The Phantom uses the internal barometric altimeter to decide if it's on the ground. If the pressure doesn't change for, I think, 3-seconds, (and the throttle is all the way down) then the motors are turned off.

A lot of things don't make sense. Calibrating in RC assistant before Phantom 2 Assistant to fix gimbal control issues doesn't make sense. but it works.

I was told by a distributor... because I was curious why put a lock. Putting a lock doesn't make sense either to me.

 

[d4ddyo]

We are not speaking of massive altitude.

 

[ThePhantom]

I did a bit more testing and can confirm that throttle down lock while descending will not turn the phantom off. I guess that was just a glitch? It was only 5 feet off the ground. Cut-off was in "intelligent" mode, though I don't know if that one can be changed at all. Though now, I just let it go down without locking and when it has landed, I just lock the throttle down and it safely turns off.

 

[Hughie]

Let's not call it a glitch. There must be an explanation for what happened.

 

[jason]

For those who may not have seen a demo of the new Phantom 2 check it out.
[youtube]https://www.youtube.com/watch?v=QI5ESz-i4yA[/youtube]

 

[bho]

As a new P2 user I have a similar problem. When I take it up to say 100' AGL and start bringing it down, if I start descending too rapidly it seems to go into an idle mode. Up throttle has no effect. I read in the posts that it can go it the idle mode if the stick is completely back (down) but it's not suppose to do this unless it close to the ground. It can happen to me at 50' AGL. Is this operator error on my part or some equipment malfunction. We have two P2's and both show the same characteristics so I'm thinking it operator error?? P2 is about five months old...

 

[QYV]

As a new P2 user I have a similar problem. When I take it up to say 100' AGL and start bringing it down, if I start descending too rapidly it seems to go into an idle mode. Up throttle has no effect. I read in the posts that it can go it the idle mode if the stick is completely back (down) but it's not suppose to do this unless it close to the ground. It can happen to me at 50' AGL. Is this operator error on my part or some equipment malfunction. We have two P2's and both show the same characteristics so I'm thinking it operator error?? P2 is about five months old...

you're saying that you're just flying normally... and you start to descend, let's say you give it full stick descend for a couple seconds, and then... what is "an idle mode" ? it just hovers? it continues descending at the same steady rate and moving the throttle stick up or down does nothing? if it keeps descending, when does it stop? when it lands / hits something?

 

[Hughie]

As a new P2 user I have a similar problem. When I take it up to say 100' AGL and start bringing it down, if I start descending too rapidly it seems to go into an idle mode. Up throttle has no effect. I read in the posts that it can go it the idle mode if the stick is completely back (down) but it's not suppose to do this unless it close to the ground. It can happen to me at 50' AGL. Is this operator error on my part or some equipment malfunction. We have two P2's and both show the same characteristics so I'm thinking it operator error?? P2 is about five months old...

No this does not happen with my P2 V2.

Are you waiting for the P2 to initialise and calibrate its barometer ?

What procedure do you go through each time on you preflight checks?

 

[bho]

I started descent (from 100' AGL), started slowly then gave it more backstick and everything looks like a normal descent then all of sudden it starts descending at a faster rate (maybe at 30-50' AGL) but I can't stop the descent by giving it full throttle (props don't spin up, seems to remain at idle). Motors don't shutoff but seems to be at idle. After it semi-crash lands I need to disarm with remote control unit (props still turning). On preflight I give it plenty of time to lockin on the GPS satellites and lights are normal.

 

[Hughie]

If this is height related you should be able to reproduce it by setting its home point and then artificially elevating it (use a hill or a building to increase its height safely whilst still holding it) and see if you can reproduce it and film it as evidence.

It should not behave in this manner.

 

[bho]

I have some video of the event but it will be several days before I could post it as I'm on travel now. Video shows what happens.

 

[Customer]

First flight with brand new Phantom V2 2.0 tried the throttle lock and my phantom began to descend rapidly toilet bowling. I released the throttle lock and now I'm afraid to try it again! My Phantom has the new 3 axis gimbal a fpv transmitter and GoPro attached. Are people using this feature without issue and is the decent very rapid?

 

[Dg661]

I started descent (from 100' AGL), started slowly then gave it more backstick and everything looks like a normal descent then all of sudden it starts descending at a faster rate (maybe at 30-50' AGL) but I can't stop the descent by giving it full throttle (props don't spin up, seems to remain at idle). Motors don't shutoff but seems to be at idle. After it semi-crash lands I need to disarm with remote control unit (props still turning). On preflight I give it plenty of time to lockin on the GPS satellites and lights are normal.

I thought I was reading about me. Same exact situation a few days ago. I'm relatively new, flying a P2 with GoPro, maybe a dozen flights with no issues, until just like bho described, I was descending with full stick back. Suddenly it started descending faster and all controls failed to function. Fortunately, it slammed into soft slightly muddy soil. Knocked camera out of its mounts, but no serious damage. Now I'm very gun shy about trying it again. Any thoughts would be greatly appreciated. I agree with the "idle" description. It was descending with motors still running, but now in an ascent or descent mode, just falling with motor still running.

 

[Dg661]

Some additional thoughts: I realized that it was the first flight with prop guards. It was a little windy. It did a kind of uncontrolled dance at altitude, which is why I was bringing it down. I've read that the prop guards can cause extra turbulence, especially when it's windy. I've also read that turbulence can mess with the altimeter. The only thing that doesn't make sense is why it just locked into a rapid descent. Does anyone have similar circumstances with similar results?

 

[QYV]

There is a danger with rotary wing aircraft called "Vortex Ring State" which it kind of sounds like one or both of you may have experienced. it's an uncontrolled free fall like Dg661 said "just falling with the motor running"... This occurs in all copters (helicopter, quad, etc) if you descend straight down too quickly into your 'prop wash' - the air that your blades have already "grabbed" and forced down to generate lift. if you descend down into that already downward moving air then the blades have no "good air" to grab and you simply lose lift and the copter will fall straight out of the sky.

This was happening quite a lot on Phantom2's with early firmware and no descent restrictions when people went full throttle straight down, so in the later firmwares DJI put in a limit to the rate you can descend... in firmware v3 (the latest) it's 2m/s. Theoretically in calm conditions, 2m/s straight down is not descending fast enough to your prop wash to cause a VRS. I personally descend straight down at full throttle all the time even though really it's wise to maintain some lateral movement when you're descending.

So there's a couple possibilities for you guys: 1) if it's a used or otherwise not brand new P2, it could possibly be on an early firmware (v1) that doesn't have the descent limit and is much more susceptible to VRS.
2) in certain wind conditions like if a strong enough breeze blows "down" onto the phantom, a VRS could be possible with the newer firmware. The rate limit is not a 100% foolproof method for protecting against VRS
3) prop guards caused it to happen or a combination of #2 and #3.

I have indeed heard from many sources that prop guards increase the chances of a VRS since they cause even more disturbed air below the Phantom than normal. Prop guards seem like a good idea, but combined with the fact that they add weight and therefore decrease flight time, IMO the only reason to run them is if you are less experienced pilot flying in a location where you have a real chance to hit something like a building or trees (or people, but you shouldn't be that careless at all ever really) . If you're just flying around up in the air not near any obstacles (again, IMO) they do more harm than good.