50 years on: Remembering the air disaster that changed Croatian aviation history

Digital artwork depicting the mid-air collision (Image: Anynobody/CC BY-SA 3.0)

Fifty years ago today, one of the deadliest aviation disasters in European history unfolded in the skies above Vrbovec, near Zagreb.

On 10 September 1976, a British Airways Trident and an Inex-Adria Aviopromet DC-9 collided at an altitude of around 10,000 metres.

All 176 passengers and crew aboard the two aircraft were killed, making it the world’s deadliest mid-air collision at the time.

The tragedy involved an Inex-Adria aircraft flying from Split towards Cologne with 108 people aboard, most German holiday-makers returning home after a holiday on the Dalmatian coast, and a British Airways aircraft  travelling towards Istanbul.

Inex-Adria was a charter airline based in Slovenia.

The weather was clear and visibility was good. Both aircraft were operating normally and their crews were qualified and experienced.

The circumstances that led to the collision were instead connected to air-traffic control.

At the time, Zagreb was one of Europe’s busy aviation corridors. The investigation found serious failures in maintaining adequate separation between the aircraft and in recognising the developing danger.

The controller responsible had reportedly been working a long shift amid staff shortages, while the control centre was operating with ageing equipment.

The collision occurred shortly after 10:15am.

The consequences on the ground were devastating. Aircraft debris and personal belongings were scattered across a large area around Vrbovec. Around 1,200 police officers, medical workers, firefighters and local residents were involved in the search and recovery operation over the following days.

Route of BA476 (red) and JP550 (green) (Image: Jonathan McFly/Public domain)

Witnesses later described seeing the aircraft breaking apart in the sky and debris falling into fields and gardens.

The investigation conducted by British and Yugoslav authorities placed the majority of responsibility on failures in Zagreb’s air-traffic control system.

One air-traffic controller was eventually convicted and sentenced to seven years in prison, although he served just over two years. Other controllers later described him as a scapegoat.

The accident had a lasting impact on aviation safety and became one of the most significant disasters associated with the former Yugoslav aviation system.

Inex-Adria DC-9 (Photo credit: Philip Pain/CC BY 2.0)

British Airways Trident (Photo: British Airways Trident/CC BY 2.0)

Today, the crash remains part of the history of Vrbovec and Croatian aviation.

Its 50th anniversary is also a reminder of how a combination of human factors, workload, communication and air-traffic management can have consequences far beyond the cockpit.