Complex sentence: The collision resulted in the deaths of all 349 people on board both aircraft--the deadliest mid-air collision on record and the deadliest aviation disaster in India, as well as the third-deadliest aviation disaster of all time.
Split into simpler sentences: The collision resulted in the deaths of all 349 people on board both aircraft. It was the deadliest mid-air collision on record and the deadliest aviation disaster in India, as well as the third-deadliest aviation disaster of all time.