Watching airline activity live via social media can have interesting consequences. Last week, I happened to see the #7700 tweet [which are tweets that are auto generated that go out any time an aircraft in coverage squawks 7700] from Planefinder.net as soon as it was posted and went to check out what was happening. Normally when you catch these emergencies, not much happens immediately, and the aircraft either continues on to its destination, or diverts to another airport.
This time I noticed that the aircraft immediately entered a very rapid descent [see an image of normal descent]. In my experience, something like that is usually caused by a loss of cabin pressure, where the pilots level off at 10,000 feet to asses the situation. However, this aircraft passed 10,000 and continued to rapidly descent, which was worrying. Was this a huge emergency, website error or just standard procedure for some issue on the flight?