After reading all the pages on this topic I would like to share a few thoughts and opinions. After all, that is one of the benefits of a forum. I agree with most of the suggestions stated so far. Especially the idea of using a checklist, and refraining from doing an IMU calibration until its warranted by a firmware upgrade or a hardware change. That said, I do not agree with the idea of refraining from doing a compass calibration. To me, that's as important as making sure your props are on correctly. I don't understand "The Editors" point about doing it somewhere else and not doing it at the flying field. I am not sure what his source is on defining a new location as "thousands of miles". My reading from DJI in the days I flew the Phantom and now the Inspire is that it is closer to 20 miles rather than thousands. Besides, it has to get done at some point, why not just before you fly. And if its done at some "safe location" lets say, free from underground pipes and wires, what's to prevent the settings to be altered while driving to the flying site. Car speakers, or other outside interference could cause the calibration to be altered. To me, doing a calibration at the field, then checking the sensors is cheap insurance. I hope I am not pissing TE off here because that is not my intention. He has come to my rescue before with advice and I am sure the same holds true with others. But like I said, this is my opinion based on my experiences.
So, to continue my story: Just last week, 3 of us got together to fly at a "not so local beach". We all flew in our respective fields about 50 miles from the beach site without issues a day earlier. As I calibrated my compass, one of the pilots asked why I was calibrating the compass. I said we need to because we are in a different location. I took off after calibrating. No issues. Another pilot did the same, and took off without issues. The third did not calibrate the compass, took off, lost control immediately and ended up in the Atlantic ocean. $3 grand down the drain. He swears now that he will re-calibrate the compass before each flight.
The video referenced in this post does not show the bird having issues until well into the flight. If there were issues with the calibration before the flight, wouldn't the problem surface immediately. Just like my fellow pilot at the beach? My opinion, and we are entitled to our own opinions, is that something happened to the machine during the flight as someone else suggested. Radar emissions perhaps, but who knows.
One last, and final comment: The missing landing footage is probably still on the SD card. What I think happened is we are seeing the first 4GB section of the video. The second, piece which probably has the landing, was not closed properly because the Inspires power was shut off before the camera was turned off. The Inspires stores the video in a FAT32 (file allocation table - 32 bit) format which has a 4GB maximum size. The second, third etc. files are automatically created and the previous one closed automatically by the operating system. There are steps that can be taken to reclaim most of that video if it still exists.
