HOWEVER, he now tells me that he has lost confidence in it because it had to have the recalibration. I explained to him that any precision instrument needs to be recalibrated at times, but he is adamant that the Phantom is now unreliable. So... I'm short on reasons why IMU would need to be recalibrated.
The National Highway Traffic Safety Administration estimates that drowsy driving was responsible for 72,000 crashes, 44,000 injuries, and 800 deaths in 2013.4 However, these numbers are underestimated and up to 6,000 fatal crashes each year may be caused by drowsy drivers.5-7.
On average, more than 100 people per day died in car crashes in the U.S. The death toll for a single day can range from 45 to 252 people, say the researchers.  July Fourth had the highest number of crash deaths (161). It had an average of 12 more deaths than any other day of the year.