An Air Accidents Investigation Branch heard how the Glasgow-bound plane plummeted downwards for eighteen seconds.
Details of the frightening incident from the Belfast flight have now been revealed with the investigation finding that the plane plunged 500ft with 44 passengers and four crew on board.
The incident occurred due to an error which saw autopilot accidentally set to ‘altitude zero’ during the flight in January.
An inquest heard from terrified flight crew who said that they ‘became visual with the ground’ as the plane dropped in the air.
The plane had taken off from Belfast City Airport and climbed to 1,350ft before the accident happened.
The Bombardier Dash 8 Q400 turboprop plane continued to climb to 1,500ft but then ‘pitched nose-down and descended rapidly’ after autopilot was mistakenly set with a target altitude of zero feet.
The pilot rapidly switched off autopilot as cockpit alarms sounded and corrected the descent, but not before the plane had fallen to 928ft.
Despite the incident, the flight continued on to Glasgow without any further incident.
The AAIB said selection of a particular autopilot mode before take off led to the zero altitude target.
Flybe said it has taken a number safety measures in response to the incident, including revisions to simulator training and amendments to pilots’ pre-take off checklists.