'My brother died in Lockerbie - our story changed how air disasters are handled' / Harrowing space accidents from catastrophic fires to parachute tragedy / A timeline of last month's air disaster in Washington, the deadliest in the US since 2001 / A timeline of last week's air disaster in Washington, the deadliest in the US since 2001 / Families visit crash site days after the deadliest U.S. air disaster in a generation