During warm-up for the 1975 Austrian Grand Prix, tyre failure at the flat out first corner sent Mark Donohue's Penske March 751 through rows of catch fencing, over a barrier and through an advertising hoarding. Debris seriously injured several trackside workers, and Donohue was struck in the head by a post. Tragic news came On This Day fifty years ago - Daytona 24 Hours and Indy 500 winner Mark Donohue and marshal Manfred Schaller both succumbed to their injuries. 😔 [📸 1975 Austrian Grand Prix 1975 Spanish Grand Prix 1969 Daytona 24 Hours 1973 Indianapolis 500] . . . .   #F1 #OnThisDay #RIP #MarkDonohue #Penske #Rolex24 #Indy500 #FormulaOne #AustrianGP #Osterreichring #70sF1 #ClassicF1 #Formula1 #GrandPrix #F1History #PhotographyHistory #MotorsportHistory #MotorsportPhotography #GettyImages #GettySport #LATImages #RainerSchlegelmilch #SuttonImages #DavidPhipps