MDA is a man-made (synthetic) recreational drug noted for its stimulant and psychedelic properties that has been used since the 1960s as a clubbing and sex-enhancing substance, with some similarities to LSD and MDMA (ecstasy). Sought after effects.
The soaring temperatures that Las Vegas is experiencing this week could cause grief for pilots at other airports, because heat thins the air and makes it more difficult for aircraft to lift at take-off. To deal with that, pilots need to gain more momentum as they roll down the runway before reaching liftoff speed.
Pilot error was the primary cause. Owing to a communication misunderstanding, the KLM captain thought he had clearance for takeoff. Another cause was dense fog, meaning the KLM flight crew was unable to see the Pan Am aircraft on the runway until immediately prior to the collision. 2007 study by Popular Mechanics found passengers sitting at the back of a plane are 40% more likely to survive a crash than those sitting in the front. Although this article quotes Boeing, the FAA and a website on aircraft safety, all claim there is no safest seat.