Audio from paramedic dispatchers is shedding light on how emergency crews handled 911 calls from passengers stranded on the Ottawa airport's tarmac Monday, after their flights were diverted from Montreal due to bad weather.

The recording, provided by live radio broadcast provider Broadcastify, covers about 25 minutes, from the paramedic call centre first dispatching crews to the Ottawa International Airport, to a final report back from one of the paramedics who went to the scene.

It begins with a dispatcher announcing a "Code 4" at the airport — a potentially life-threatening emergency in which responding ambulances should turn on their lights but not necessarily their sirens.

"Looks like four planes were diverted and there were some planes that were delayed waiting for fuel," she said.

"There's a citizen that called it in saying that there's approximately 100 people in the plane, generally unwell. [There are] complaints of severe pain, cold sweats, coughing."

The call came in roughly 4½ hours after Air Transat Flight 157 from Brussels to Montreal landed in Ottawa at 5 p.m. ET. It had been scheduled to arrive in Montreal at 3:15 p.m., but was diverted due to bad weather.

Laura Mah, one of the passengers, told CBC News the aircraft lost power and the air conditioning was shut off. She said there was no food on the plane and eventually a fellow passenger called 911.

The dispatcher said security was checking in on the situation, including "multiple units." Minutes later, the dispatcher said Ottawa airport fire crews were notified of the 911 call but hadn't provided dispatch with an update.

'Doesn't look like we're having mass casualties'

Thirteen minutes after the initial call, someone asks the paramedic team at the Ottawa airport to respond on a separate radio channel.

About 25 minutes after the initial call, a paramedic responds on the main channel with his assessment of the situation.

"Doing another check of the plane. It doesn't look like we're having mass casualties, but we need a precautionary truck just to come on scene. One possible patient with anxiety," the paramedic said.

"Have the security truck pick them up and take them to my location."

Mah said staff from the Ottawa International Airport eventually began to hand out bottles of water, and the plane's doors were opened to let air circulate. Passengers spent a total of 15 hours in the plane, both in the air and on the ground.

I'm sorry to hear that - it's up to the airline to determine whether to deplane or wait it out when a flight diverts. —@FlyYOW

Inquiry deadline Friday

The Canadian Transportation Agency has now given Air Transat until 5 p.m. ET Friday to provide an explanation as to why passengers on flight 157 and a second plane were stranded inside those aircraft for hours, without being allowed off the plane.

In addition to flight 157, Air Transat flight 507 from Rome to Montreal was also diverted to Ottawa due to bad weather and stayed on the tarmac for four hours. Again, passengers were not allowed to leave the aircraft.

The Canadian Transportation Agency is conducting an inquiry into how Air Transat handled the lengthy delay of two flights that were diverted to Ottawa's Macdonald-Cartier International Airport. (Mike Hillman/CBC)

In a written statement Wednesday, the transportation agency said it was launching an inquiry to determine whether Air Transat respected its tariff — a document that sets out, among other things, an airline's rights and responsibilities toward its passengers.

According to that tariff, in the case of an on-board delay more than 90 minutes, Air Transat promises to offer passengers the option of getting off the plane.

The transportation agency could require Air Transat to compensate passengers, change its policies or do additional training for staff. It can also compel the airline to participate in the inquiry.

Disagreement over cause of delay

Air Transat issued a statement saying "nearly 30" planes were diverted to Ottawa Monday night, creating a host of "exceptional" congestion issues that resulted in the tarmac delay.

The airline said the airport staff were unable to provide bridges to allow the plane to be unloaded and there were delays both in refuelling the aircraft and refilling the drinking water reservoir.

The Ottawa International Airport Authority disputes those claims, saying closer to 20 planes were diverted and all other planes were refuelled and on their way within three hours, most within the first hour or two.

The airport authority said there was both a gate and air stairs available, and they were prepared to bring supplies beyond just bottled water to the stranded passengers — but never received clearance from Air Transat.