Ok, so I took the SSS APM 2.5 up again this weekend once on Saturday and once today (Sunday) and the flights taught me important lessons in why we should read the documentation that is available for our equipment.

The Saturday flight was just stupid. It was windy and my pilot (I just man the computer and let a professional RC buddy do the take offs, lame, I know, but I'll learn later) put her down after a few loops and didn't want to take her up again. At several points you could cut the throttle and SSS would just hang in the air like a vulture and every time she banked I held my breadth as the wind caught the 2.4 meter wing and hurled her across the field. When he landed her we almost decided to catch it because the wind just held her steady and still a few feet above the ground. Gentle wind the manual says. Gentle.

You can see here how the surfer almost remains still as the red GPS readings clump together as she heads west (right of image) near the path).



Ok this was a biggie mistake. Nice weather, warm, perfect day for testing out a mission using the autopilot. I plotted out a mission like this using mission planner, my pilot launched her, took her out to the middle of the field and I hit "auto". I expected brilliance. 

The Plan (note in the real plan I moved "home" to the middle of the field).


So it's in the middle of the field and I inform my pilot that I'm going "auto" he says good luck. I engage. The SSS promptly turns away from the assigned grid area and heads straight back toward us. Like sailors watching the torpedo they launched coming back at them I start freaking out as it heads over us and the highway behind us (a decreed no-fly zone for us). I return it to manual and check my mission.  I get her over the field and again inform my pilot that I'm taking control. Again she turns and begins to charge us down. Again, I switch to manual and cry silent, dry, tears as my pilot brings her in to land. 

What happened? I had a "compass error" earlier so I thought it might be a north south issue (no, not the civil war) and that it was heading "north" instead of "south" to the first waypoint (yes, that makes no sense considering it was displaying direction fine during manual mode). I packed my gear and came home.

What happened?

Well, I can't be 100% until I get it back up in the air but it might have something to do with the fact that I didn't "write" waypoints in Mission planner. I'm fairly certain that when I hit auto the APM detected no mission and just went into RTL mode. Which, given the default "home" position" would put her in a circle over me and, in part, the highway behind. 

Moral of the story: Skipping steps is bad. Don't do it. 

Safe flying folks.


Bonus map of my failed "Auto" attempts. Green and Pink are Auto tracks. 


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  • Moderator

    I usually refer to my ground station operator as "Safety officer" as that is her prime responsibility. keeping the pilot aware of approaching aircraft, people, dogs , horses, bears etc. The PC side of things is generally monitoring progress and battery levels etc. We use our Safety officer to agree with the pilot that the systems are operating correctly before she will switch to Auto. Then she will pass on any information requested by the pilot.

    As Justin says the switch to TAKE manual control is always on the Tx. We have used this system now for a long time. 

  • We use Ground Station Operator, or Ground Station Commander.  Also the pilot should always have a switch that allows them to go back to manual without involving the GSO.

  • Thanks again all for your tips and warnings. As an aside I now feel a bit sexist for referring to the "computer" person as "computer guy". I think we should come up with a name. Maverick had Goose as his R.I.O. (Radio Intercept Officer). Since we don't have R.I.O.s can we come up an appropriate acronym for the autopilot operator (A.O.? "Ayy-Ohh", sing it with me, "Ayy-Ohh") or do we just call them "Goose"?

  • Moderator

    All great advice! One more to add is to click the "Restart Mission" button in the MP whenever a mission is changed and re-'written' just to make sure it does actually start the new mission and is 'Going to WP1'.

  • Moderator

    Well said Gary. I run almost the same method as you and it works well, three modes on the Tx Man, Stab. and FBW-A for testing. I switch to Auto on the PC. I am also traditional RC (for 30 yrs) and do my takeoffs and landings in Manual (because its FUN). we DO need more traditional RC guys. 

    I do think that communication between the Flying guy and the computer guy (girl in my case) is important. I did lose one plane to a mix up that can happen.

    I took off in MAN after checking the APM, telemetry and GPS etc. flew around then asked my partner to select AUTO. just as she did that I see a GPS warning come on the screen, I selected Man on the Tx to take back control but I DID NOT tell my partner, She saw the Head up display change to auto and then immediately back to MAN and so she thinks she did not do something correctly, so she presses AUTO again and did not tell me. 

    So now I think I'm flying my plane in MAN when its actually in Auto with no GPS. The plane is flying in a crazy way and not doing what its told. the resulting crash was spectacular. 

    I normally use the voice feature so I hear everything that is happening but on this occasion it was turned off. 

    All I can say is that we learn from our own mistakes as well as the mistakes of others. 


  • Moderator

    I think your waypoints are a bit close together as well. You have to remember it has to be able to make the turn and sort itself out. Its a big airframe I would think for tidy turns you need to be in the 150m swathe range. Here's a Talon with 110m between each leg and it sorts itself out pretty nicely before the leg starts again. 


    Wind does not matter to an aircraft in the air, what you are seeing is what you think matters. It will shoot off downwind and seem to stop into wind. It does make life harder for the autopilot and you should start being interested when the wind is more than half the cruise speed in my opinion. Anything above cruise and you run the risk of going backwards. There are autopilots that take advantage of a strong wind and decide to exactly hover when they can and its very cool. Easier than battling around a circle.

    When I go to fly I always upload the waypoints at home, then connect my tablet and review what I expect to happen. On scene I then brief myself on what I expect to see before taking off. If the picture starts looking wrong I throw away the flight and get home in time for tea and medals.

    I always manually take off to ensure that the aircraft is flying correctly. Put the aircraft into a loiter on my traditional RC controller and then select auto on my tablet when the aircraft is into wind. My traditional controller only has manual, stabilze and RTL on it. It stays in my hand at all times during the flight. Every flight ends with an RTL once the aircraft is doing that on the into wind part of the circle I take over control and land. Generally having flown a couple of circuits either because its not happening how I want it to or I need the practice.

    Always make mode changes into wind because if you do them downwind and things don't happen as you think at least its not being blown away whilst you try and figure it out.

    Repeating how you fly and getting heights and speed hardwired into your head really helps when you have unusual situations. At least you have a set of it works from these points in your mind as reference.

    We still have too many computer guys and not enough flying guys around here. The multirotor world is even worse.

  • Thanks for the feed back and tips all. Greg, your 100% correct on the lists and the switch. I do have "gear" assigned to manual / return to launch. The pilot didn't elect to flip it (and that's my bad, I should have told him to toggle it) but left it up to me.

    I do find the computer / pilot pair to be effective. I don't think I would want to pilot and use the computer at the same time. Plus, as computer guy, you can make sure no one else is sneaking up on your while flying. You can have friendly conversations with curious folk wile the pilot concentrates on the plane. 

    Next up: rebuild the wiring inside the plane (it is a hot mess) & come up with preflight checklists. Anyone have any checklists they can share??? 


  • OK, you have a few operational mistakes/omissions to your procedure. Not to mention it was far to windy. The pilot holding the transmiter must have a switch for manual mode selection. Even if its just a 2 position gear switch for manual and some other mode. The computer guy can always set a mode, but the pilot needs to switch to man if needed. There is no time to communicate sometimes. No mater what mode the plane is in the pilot can toggle the mode switch and put it in manual from what ever mode you have it in.

    Next. Always read the mission as part of your pre-flight checklist. That way you can see what is in the planes eeprom. This should be done before you even leave for the field, its that important.

    A successful flight does not come by accident. It comes from planing and anticipating what could go wrong, and making sure you avoid those things.

    I would say good luck, but you should depend on luck as little as possible.

    Happy flying!

  • this "computer guy" and pilot thing is quite interesting.  i am the "computer guy" on our team and will also learn to RC fly someday but not right now.  my pilot and i worked together for 30 years in the flight test business so we had learned that communications between the two functions is critical to success before starting this effort.  during my career i found that fighter pilots tended need (accept?) less input than "heavy" pilots and i am fortunate that my team pilot was not a fighter pilot because he is great at the communications "thing".  we have each saved each other from disaster by simply asking the simplest and most obvious questions just in time for the one about to make the mistake to abort the catastropy.  as the computer guy i probably drive him crazy by babbling status info constantly (along with the bitching betty of the software) as he does his "pilot" thing.  yesterday we flew an auto mission and decided to change a few things and fly it again - i made the changes and got distracted and never did a write to the autopilot.  when i said i was ready to go auto he asked me if i had updated the mission and of course i had not - he must be getting used  to my babbling and somehow caught the fact that i had not said i was writing the mission to the vehicle.  from my limited time with this stuff it seems to me that to do a "real" video shoot with live downlinked video and someone driving the mount you really still need a third person (computer guy) who watches things from that perspective.  we swore we were going to use checklists but we just don't do it and probably never will so i can see the resultant smoke from a crash in our future at some point.

  • I have been bit by the failure to write once!  I now always read the waypoints back from the APM prior to taking off to make sure they are correct.

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