Flights have resumed today but passengers have been urged to check the status of their flight with their airline before travelling to airport
The AAIB said their team are currently enroute to the airport, with the update coming as flights resume at the site.
An Aer Lingus Regional ATR aircraft skidded down the runway at around 4pm yesterday.
Four crew members were on board but no-one was seriously hurt.
In a statement this morning, an AAIB spokesperson said: “An investigation has begun into an accident involving a fixed-wing aircraft which occurred at Belfast City Airport on 22 December 2024.
“AAIB inspectors have commenced the on-site investigation to gather evidence and make enquiries.”
The runway was closed for the rest of Sunday, throwing Christmas travel plans into chaos.
It has reopened, the airport said this morning, however some delays are expected.
A spokesperson said: “The runway at Belfast City Airport has now reopened and normal operations will resume today.
“Passengers impacted by yesterday’s runway closure, or those due to travel today should check the status of their flight with the airline before making their way to the airport.”
The airplane slammed nose first onto the tarmac as the nose gear collapsed, prompting emergency services to rush to the scene.
Aer Lingus, KLM, British Airways and easyJet flights due to depart the airport last night were cancelled, impacting passengers trying to get to cities including Amsterdam, London, Birmingham, Manchester and Liverpool.
Some flights due to arrive at the location were diverted to Belfast International Airport which warned it was operating “close to capacity”.
Five flights were also diverted to Dublin Airport.
The plane got into trouble while touching down at the city airport with four crew members onboard.
A special team with aircraft recovery equipment travelled from Dublin to Belfast after the hard landing during strong gusts of wind as the flight arrived from Edinburgh.
Images from the scene also show the turboprop plane on the side of a runway with two fire appliances positioned nearby.
Northern Ireland Fire and Rescue Service (NIFRS) said it attended the scene at 4.15pm when it despatched four appliances and a specialist rescue team in addition to a command support unit and three supervisory officers.
“On attending crews encountered an aircraft which had experienced a nose wheel collapse on landing,” a spokesperson confirmed.
“At 4:34pm NIFRS scaled back our response.
“We had 24 personnel in total in attendance and assisted Belfast City Airport Fire Service to make the scene safe.
“We currently have one appliance and three officers on scene, all other appliances have been stood down.”
Hilary Bratton, who was travelling from Leeds Bradford Airport, was among the passengers affected as flights were diverted.
“During the flight the captain came on to say there was a problem at Belfast City,” she told the BBC’s Good Morning Ulster programme.
“So we then circled Belfast City until they said that we could divert to the International Airport.”
She added: “It was very tense. We were just circling Belfast City for a long time and to be honest, it was just very quiet… everybody was just a bit nervous of what was going to happen.”
Sarah O’Connell (67) was on an Emerald Air flight from Southampton with her husband Stephen Hanks to visit their daughter who has been living in Northern Ireland and working here as a doctor.
Suddenly the pilot announced “there had been an incident at Belfast City and that we were being diverted to Belfast International”.
“Then a couple of minutes later he came back to say that Belfast International was at capacity so we would land in Dublin,” she recalled.
Despite the inconvenience, the excited mother said everything “has gone very smoothly”.
“Coaches were outside and the roads have been clear,” Ms O’Connell added.
“We are looking forward to seeing our daughter who has been working in Belfast for the last 18 months.”
Graeme McQueen, media relations manager at DAA, the operator of Dublin Airport, said it was “happy to accommodate five diverted aircraft from Belfast City Airport this evening”.
“Members of Dublin Airport’s airfield operations team are currently travelling to Belfast with aircraft recovery equipment,” he added.
“We are happy to help our neighbouring airport.”
A number of flights were diverted to Belfast International Airport as a result of the incident, including a British Airways flight from London City and an Aer Lingus flight from Leeds Bradford.
But the travel hub at Aldergrove has warned it has limited capacity during what is a busy time of the year.
A Belfast International Airport spokesperson confirmed it had taken in four diverted flights last night.
“As we have a heavier schedule than usual we are now, with these additional flights, close to capacity so we are limited in how many more redirected flights we can take this evening but we will continue to support where possible,” they said.
“Our website will carry the most up to date information for arrivals and departures and passengers should contact their airline directly.
“Given the circumstances, our teams on the ground are working to help these additional flights as quickly as possible.
“We would ask for passengers’ patience as we support each additional flight.”
Last night a spokesperson for Belfast City Airport there said no passengers were on the aircraft involved in the incident.
“At around 4pm today, Sunday, an Aer Lingus regional flight, operated by Emerald Airlines, had an incident on landing at Belfast City Airport,” they said.
“This was a positioning flight with no passengers but four crew members onboard.
“The airport’s emergency procedures were enacted.”
It added: “Passengers are asked to contact their airline.”
A spokesperson from Emerald Airlines said the “positioning flight, EA701P, with no passengers on board, flying from Edinburgh to Belfast City Airport … experienced a hard landing upon arriving into Belfast City Airport due to adverse weather conditions.”
Millions of travellers in the UK faced disruption during the busiest weekend of the year as 82mph winds wreaked havoc on transport services.
The Met Office yellow warning for wind came into force at 7am on Saturday and remained in place until 9pm last night.
London Heathrow called off flights while P&O Ferries axed journeys between Larne and Cairnryan until at least 8pm last night.
Loganair flights from Glasgow Airport to the Hebridean islands and CalMac ferry routes were also affected.