In this file photo taken May 31, 2011, a Serbian government Falcon plane prepares for take off at a Belgrade International Airport, Serbia. An investigation shows that a sudden plunge of the Serbian president's plane last week which triggered panic among passengers and an emergency return to Belgrade was caused by the co-pilot who spilled coffee on the instruments panel. (AP Photo/Darko Vojinovic, File)
In this May 15, 2012 photo, Serbian President Tomislav Nikolic applauds during a pre-election rally in Belgrade, Serbia. An investigation shows that a sudden plunge of the Serbian president's plane last week which triggered panic among passengers and an emergency return to Belgrade was caused by the co-pilot who spilled coffee on the instruments panel. (AP Photo/Darko Vojinovic)
BELGRADE, Serbia — An investigation into the sudden plunge of the Serbian president's plane has shown that it was because the co-pilot spilled coffee on the instruments panel, aviation authorities said Tuesday.
The investigation results show that the co-pilot accidentally activated the emergency slat extension when trying to clean the coffee from the panel. That reportedly caused the plane to dive and the brief shutdown of one of the engines. Unsurprisingly, there was panic among passengers.
The captain then stabilized the aircraft and returned to the capital, Belgrade. Slats are located on leading edges of the wings and are used by pilots to change the aircrafts' angle of descent.
Initially, President Tomislav Nikolic's press office said last Friday that the plane made an emergency return because of engine failure. Nikolic was en route to the Vatican for an official visit, which was canceled.
Nikolic's associates then spoke of the plane shaking violently and being tossed all over the cabin. They said the president will use only commercial flights, because the 34-year-old government Falcon 50 has a history of inflight problems.
Serbia's aviation authorities say that the co-pilot has been suspended.