SURPRISE!!

[lkjohnson1950]

Ultimate lack of traffic control.

[Scott]

The guys lucky he still has his hand...and his head for that matter.  Someone seriously screwed up. 

[Steve A.]

Ouch, lucky man.

[cosworth151]

It sounds like the pilot that got hit, and the ground crew, did what they should have. It looks like the plane that the camera was in konked out on the runway. It also looks like it was during an air show. The red flag being up means that the runway is closed. Checking the flag is the last thing a pilot should do before beginning the takeoff roll.

Another thing to remember. The plane that hit him (It looked like it might be an Extra 300) is a tail dragger. That is an aircraft that has a small tail wheel & sits nose high on the ground. The front of the plane really blocks the pilot's forward view until the tail lifts during the takeoff run. The pilot of the plane that was moving might not have been able to see the stationary aircraft.

[Ian]

Lucky bloke, how he never lost his hand or arm is nothing short of miraculous.   

[cosworth151]

What saved him was his vertical stabilizer. The wing of the other plane hit it and was lifted upward.

[lkjohnson1950]

Took place at the Reno air races during the F1 event. F1 planes are very similar to Extras.

http://airrace.org/portfolio-item/formula-one-class/

[cosworth151]

There's a difference between cars & planes - when did you last hear the words "relatively inexpensive" in connection with F1 cars? 

To give you an idea of what the article is talking about, this is a picture of a Cessna 150 like the ones that provide the engines for the F1 race planes. This one used to be one of the rental planes here at Fairfield County airport. I logged many, many hours in this particular 150.