Hundreds of passengers, dozens of emergency personnel and a situation everyone hopes will never be more than just a training exercise - this is Operation Blue Sky.
It's held every two years at Auckland International Airport as a practice run for the worst case scenario, a crash at our country's busiest airport.
Newshub was given exclusive access to the massive exercise when it took place last week.
The operation is held right in the middle of the busy airport tarmac. With over 20 million passengers passing through it every year, closing the airport for training is not an option.
Anil Varma from Auckland Airport was overseeing the exercise to make sure everything that needed to be checked and practised was ticked off.
"Under CAA rules, we have to undertake an exercise of this nature - which is a full-blown exercise simulating an aviation incident - every two years," he said.
"Any learnings from this exercise are then put into place so we are better prepared to ensure we have all the right capabilities to respond to a real event. We just hope it never happens."
Directed from the airport's Emergency Operations Centre, police, fire and ambulance crews from across Auckland raced to the scene with the highest of urgency as the exercise kicked off.
Craig Monrad from Fire and Emergency NZ says speed is critical.
"It's very important to practice to get it right so when we need to do it, we get it right the first time," he said.
A full triage area was set up as volunteers acted as passengers that needed treatment for a wide range of injuries.
Mass casualty training is an essential part of the exercise, said Mat Delaney from St John's Ambulance.
"Our guys are out there treating patients every day on the road, on the front line. But to do an exercise like this just gives us that little bit more experience, and a chance to work with our partners to make sure we are delivering our services effectively in these sorts of instances," he said.
The scenario played out during the operation was based on an event that took place late last year in San Francisco and came close to being the worst aviation disaster in history.
An inbound Air Canada flight was seconds away from landing on the wrong runway, which would have seen it collide with four fully loaded flights ready to depart. There were more than 1000 people onboard the flights, all just moments away from disaster.
Should the worst happen, Auckland Airport could be shut for a long period of time. It currently only has one runway - so if it was out of action, the airport would essentially be unusable.
Not far from where the exercise was taking place is the location of one of Auckland's few fatal airline accidents.
In 1982, Air New Zealand 4374 - from Gisborne to Auckland - crashed into the Manukau Harbour, just short of the runway. There were just four people onboard, two of whom were killed.
The worst accident to happen at Auckland Airport was in 1989 when a Convair freighter crashed, killing all three onboard.
The people involved in Operation Blue Sky will hope that statement will never have to be updated.