TH 480 won't land

[cbecker125]

Hi gang. This post got buried in another thread so I thought I'd start anew in hopes of getting the attention of some knowledgeable folks here. My apologies if this is redundant and you don't give a rip.
But, in case you do....

I have not been able to land intermittently/frequently. Both scary and risky. RTH has been the most successful solution, albeit, slow. I've not yet tested the low battery effects on the RTH mode :/.
SC, Thanks for your input on this matter of failure to land. Your suggestion to turn off GPS I will try today and get back with you all. Coupled with a no descent issue, GPS usually has trouble acquiring GPS lock even aftyer several minutes showing in excess of 19 satellites for base unit and 19 for aircraft. Maybe this is more than a coincidence. I can say that pairing my offending aircraft with my H Pro ST-16 base unit, turning off Real Sense, shows no improvement. The ST-16 for my Pro has no issues with the Pro H eliminating the non-real sense ST-16 as the culprit.
C
Aircraft and controller each have latest most current firmware and software applied. Controller has been calibrated numerous times, I always calibrate compass before each flight. I also have an H 480 Pro which does not have these described issues which perhaps could tend to support ruling out pilot error. As promised, since posting my reply to Steve Carr above, I retested my H 480 on several occasions. In all sessions I experienced GPS acquiring problems (this has been an historical problem and most annoying). Skip forward. Two out of three recent flight sessions the H 480 flew exceptionally well for 12-14 minutes each (I recorded the flights - countless take offs, landings, climbing, descending, all of it - no problems aside from trouble acquiring aircraft GPS experienced during the first battery; just like nothing was wrong - then problems after switching out battery - weird. The controller and aircraft each maintained around 19 satellites which seems consistent in my experience whether acquiring problems occur or not. The third flight session was very problematic: forever acquiring GPS, and would not start for an extended 5-10 minutes, unable to land properly). I was able to connect GPS, or launch. After a bunch of waiting, restarting aircraft, restarting controller, the aircraft finally acquired GPS. Once airborne, I tried to land....no go. With full down stick, the descent was slow, stalled, even lifted if I let the left stick go to neutral. As suggested, Steve, I TURNED OFF GPS on the controller and was able to promptly bring in the aircraft to land safely. Don't try that for the first time on a windy day! Drift is a real concern then without GPS. I wanted to add my confirmation to your GPS disconnect comment. I seriuosly question the health of the GPS system. Any experience linking the barometer/altimiter to such symptoms? Your thoughts?
Craig

 

[AeroJ]

Re: Failure to descend: Have you found all the other threads about this ? I'd say it's perhaps the most common problem people report with the H...
In those threads I am one of the people convinced that this problem is a result of inaccurate barometer readings interfering with the normal staged descent of the H. You can check this in the telemetry, and I suspect you will find the barometer was more than 20 ft wrong on your problem flights.

I suspect that the not acquiring GPS problem is separate to this and possibly unrelated... if you are showing 19 satellites and still not getting a solid purple / white flash I think I'd be considering trying a new compass / gps module - mine 'locks' no problem as soon as it gets more than 7 or 8 sats.

 

[AH-1G]

Why are you calibrating compass before each flight?
IMO; Not needed, in fact over kill If you are flying within the same area of 50 to 100 miles radius.
I have only done maybe 6 calibrations in the last 1½ years.
If you cross over the red or blue lines, then a calibration is needed.

 

[Ty Pilot]

Agree 100% with all the above

 

[Steve Carr]

The third flight session was very problematic: forever acquiring GPS, and would not start for an extended 5-10 minutes, unable to land properly). I was able to connect GPS, or launch. After a bunch of waiting, restarting aircraft, restarting controller, the aircraft finally acquired GPS. Once airborne, I tried to land....no go. With full down stick, the descent was slow, stalled, even lifted if I let the left stick go to neutral. As suggested, Steve, I TURNED OFF GPS on the controller and was able to promptly bring in the aircraft to land safely.

That is very good information and helps define the problem. Either the GPS module is faulty or the Flight Controller is bad. If you can get Yuneec to review the FlightLog folder they should be able to determine which one is causing the problem.
Is this H still in the warranty period?

 

[cbecker125]

Sorry Steve. I just saw your question. It was not within warranty. As it turned out, I sold it for a real low price and said ADIOS. The buyer wanted a project. Told him everything about it.