Thank you Flushvision, that has cleared up all my questions. Thank you again for taking the time to reply. Glad to here that I will be able to progress with this drone.
Auto land and transmitter failure
- Thread starter MattClark
- Start date
Also the thing that the H is "waiting" instead of landing immediately is extremely good in situations like starting off of a boat (even though it is not the safest idea). Because in an event of a lost connection between the ST16 and the H, instead of landing in the water it gives us a chance to reacquire control over the bird. BUT of course as others have pointed it, if the pilot is not quick enough, the bird will take an unpleasant bath eventually 
The only time I tried this (accidently) mine flew off, luckily, I was in the process of bringing it back to me and landing it was about 10' off the ground, and flew past me and into a soft cedar tree about 50' behind me.
Mr. T&N and all,
Whenever I hear/read of instances describing an unexpected location for “home,” I wonder if adequate satellite acquisition (almanac, et al) was in place before take-off. In other words, was the true “home location” locked and stored before it was needed?
Food for thought?
Jeff
Not 100% sure on this flight, but.
My property,I fly there all the time
always 16-19 sats, this was about the 14-16th flight of the day.
Close to 2 hours of flight time.
H flew in a direction I have never flown from.
rdonson
Premium Pilot
Here's what Jeff was talking about:
The reason you wait 15 min initially is NOT to get SAT lock. It is to populate the GPS almanac in your H. After that you only need to repeat the practice if you haven't flown the H in quite some time or if you're getting some weird GPS behavior. The GPS data in the almanac is maintained by a small rechargeable battery on the GPS module. Should the voltage in that battery drop below a certain level the data may deteriorate. Also, the GPS SATs themselves update their information periodically.
BTW, you simply sit on the ground without props running for the 15 min to perform this. This uses a small amount of the battery capacity to accomplish this.
Also consider that your ST-16 has a GPS module in it. It populates its almanac as well. Otherwise how would it know where home was?
This is NOT in the Yuneec manuals. Their marketing people like to sell that the H is easy for anyone to fly. It is but their manuals don't fully educate pilots on how they work or best practices.
There are individual efforts to fill in the deficiencies in the Yuneec manuals. This link may help.
Want to help make a better manual?
Another potential explanation is that you had a flyaway. These are fairly rare but they do happen. This can only be determined by looking at your telemetry files on the ST16.
In the stated 2 hrs flight-time I am sure the almanac was properly filled.
Can't imagine the updating stops as soon as the H takes off. Might take a bit longer while it is moving tho.
And I also stated “whenever I read something about return to home did not go as planned”... wasn’t trying to explain this particular incident but rather the topic in general.
Jeff
rdonson
Premium Pilot
@Dr Delta, you may be entirely correct.
I have not been able to learn much about how Yuneec implements the u-blox M8Q GPS. There are a few options in implementation that "might" affect its ability to update the almanac while in flight. Since I have no hands on knowledge of the GPS beyond replacing one and reading the spec sheets I can't honestly say. I am very conservative in expecting unknown electronics to behave in a specific manner that isn't documented somewhere.
https://www.u-blox.com/sites/default/files/MAX-M8-FW3_DataSheet_(UBX-15031506).pdf
Is this something new? I never got briefed to allow for a Tx failure for my flight assessment. (PfCO Nov 2016)
Don't get me wrong, I see the sense of it and I wrote just such an emergency for my Ops Manual but the most likely in-flight failure would be loss of GPS signal so expect to turn off the GPS and able to control the UAV with a degree of competence. I also had to demonstrate the RTH function, in case I get incapacitated, then asked to regain control of the craft and land it.
In no way was the aircraft under flight assessment to show that it was safe, it was the operator.
Just a thought but I'm wondering if the examiner is going over and above (pun intended) their remit.
Good luck anyway.
Don't get me wrong, I see the sense of it and I wrote just such an emergency for my Ops Manual but the most likely in-flight failure would be loss of GPS signal so expect to turn off the GPS and able to control the UAV with a degree of competence. I also had to demonstrate the RTH function, in case I get incapacitated, then asked to regain control of the craft and land it.
In no way was the aircraft under flight assessment to show that it was safe, it was the operator.
Just a thought but I'm wondering if the examiner is going over and above (pun intended) their remit.
Good luck anyway.
