 Another hazard in the use of overwing exits is them being improperly opened (usually a result of passengers in these seats not paying attention to the verbal briefing provided pre-departure, or not observing the opening instructions on the safety card and on the exit).The majority of overwing exits involve the passenger physically removing the hatch from its frame and disposing of it outside on the wing without blocking the exit.Research conducted at the Cranfield Institute in the UK  showed that many passengers are prone to leaving the exit hatch on the seat next to the exit, thereby hindering other passengers' egress through the exit.