A fatal mid-air collision occurred between Hawker Siddeley HS-121 Trident 3B and McDonnell Douglas DC-9-32 aircraft near Vrobec, Turkey, following a scheduled flight from London-Heathrow to Istanbul-Yesilk”y. Both aircraft crashed, resulting in the deaths of all 176 passengers and crew. The DC-9, operated by Inex-Adria Aviopromet, was on a flight to return tourists to Cologne. The Trident, operated by British Airways, was en route to Istanbul with a passenger and crew of 9. Initial contact with Zagreb Area Control was established at 10:04 GMT, and the flight was requested to pass the Zagreb VOR. At 2 minutes and 50 seconds, the Trident changed heading to 115ø to head back towards the airway centerline, while the DC-9 switched to the Zagreb Area Control Centre lower sector east frequency. The crew switched to the middle sector controller’s frequency, which instructed the flight to climb to FL350. A beam and westward observation revealed the Trident was at FL330, while the DC-9 was at FL180. At 10:14:04 GMT, the crew radioed the Upper Sector controller, reporting a climb to FL325. The controller then requested the DC-9 to maintain its altitude and report passing the Zagreb VOR. At 10:14:38, the crew switched to the middle sector controller’s frequency, requesting flight JP550 to maintain its altitude and report passing the Zagreb VOR. The controller instructed the flight to maintain its current altitude and report passing the Zagreb VOR. The collision occurred at 10:14:38, with the DC-9’s left wing striking the Trident’s cockpit. The fuselage disintegrated, and the DC-9 tumbled down, impacting the ground tail-first. The primary cause was the direct impact of the DC-9 wing into the Trident’s cockpit, resulting in uncontrollable flight and a catastrophic crash.A fatal mid-air collision occurred between Hawker Siddeley HS-121 Trident 3B and McDonnell Douglas DC-9-32 aircraft near Vrobec, Turkey, following a scheduled flight from London-Heathrow to Istanbul-Yesilk”y. Both aircraft crashed, resulting in the deaths of all 176 passengers and crew. The DC-9, operated by Inex-Adria Aviopromet, was on a flight to return tourists to Cologne. The Trident, operated by British Airways, was en route to Istanbul with a passenger and crew of 9. Initial contact with Zagreb Area Control was established at 10:04 GMT, and the flight was requested to pass the Zagreb VOR. At 2 minutes and 50 seconds, the Trident changed heading to 115ø to head back towards the airway centerline, while the DC-9 switched to the Zagreb Area Control Centre lower sector east frequency. The crew switched to the middle sector controller’s frequency, which instructed the flight to climb to FL350. A beam and westward observation revealed the Trident was at FL330, while the DC-9 was at FL180. At 10:14:04 GMT, the crew radioed the Upper Sector controller, reporting a climb to FL325. The controller then requested the DC-9 to maintain its altitude and report passing the Zagreb VOR. At 10:14:38, the crew switched to the middle sector controller’s frequency, requesting flight JP550 to maintain its altitude and report passing the Zagreb VOR. The controller instructed the flight to maintain its current altitude and report passing the Zagreb VOR. The collision occurred at 10:14:38, with the DC-9’s left wing striking the Trident’s cockpit. The fuselage disintegrated, and the DC-9 tumbled down, impacting the ground tail-first. The primary cause was the direct impact of the DC-9 wing into the Trident’s cockpit, resulting in uncontrollable flight and a catastrophic crash.