Hi John,
I'm sorry to hear about your bad flight experience. It's always frustrating when something doesn't go right, but it's especially unnerving with such an expensive piece of equipment.
I've been reading through the thread and noticed some concerning points regarding your familiarity with the craft and the app. Here are the specific quotes...
"No-one takes flying these things safely more than me."
"I wasn't aware that you had to switch the option on to allow ATTI mode."
"Is there any good online instructions for calibrating the IMU? Are there any traps with doing it?"
"How do you delete old home points?"
Allowing ATTI mode via the app and calibrating the IMU are critical steps to flying the Inspire. In fact, IMU calibration is one of the first things that should be done with a new Inspire. It's difficult to reconcile your statement about flying safely while not knowing about ATTI mode in the app and how to calibrate the IMU. No one can know everything about these crafts (they are rather complicated after all), but these 2 points are fairly critical.
I had a similar "flyaway" experience shortly after acquiring my Inspire 1. After a successful flight, I landed, powered down, swapped batteries, then started up and took off. After about 20-30 seconds of flight on the 2nd battery it started to pull hard to one corner then moved erratically. It wouldn't respond to stick movements. I switched to ATTI mode and everything returned to normal (except, no GPS-assisted control, of course). I quickly landed the I1, then packed it up until I could do some research and do some test flights in a more open area. I don't know if I "fixed" the issue (I doubt it) but here's what I learned:
- It's important to stay on top of the firmware and app updates (not just performing the updates but knowing what's different and why you're updating). That said, don't necessarily jump to be the first user of the latest firmware.
- Close all other open apps on your device and power cycle it before a flying session.
- Physically inspect the craft for any issues before EVERY flight.
- Ensure the camera/gimbal is seated properly and connected securely.
- Enable multiple flight modes in the Pilot app and check that it's enabled before each flight.
- If the app isn't telling you to calibrate, don't calibrate. Simply lift off (after performing hardware and software checks mentioned above and getting GPS lock) and allow the craft to hover in place for about 30 seconds. Perform short pitch, roll, and yaw maneuvers to ensure it's responding normally. Once everything checks out, continue with your flight.
Performing these steps won't guarantee anything, of course, but they should minimize the chances of something bad occurring and help narrow down the possible causes if something does go wrong. I hope this helps a bit. Happy and safe flying!
Hopefully, your experience was an anomaly like mine appears to have been.
-dbot3000