Turkey's decision to shoot down a Russian warplane on Tuesday could have "huge political consequences,' a Canadian military expert says, but some key details about the incident remain unconfirmed.

"Sometimes immediately after [an incident] accounts differ," said Stéfanie von Hlatky, director of the Centre for International and Defence Policy at Queen's University in Kingston, Ont.

Turkey said the Russian Su-24 bomber flying over Syria ignored 10 warnings that it was nearing, then intruding, on Turkish airspace. Russia insisted its plane stayed in Syrian territory.

Every NATO country, including Turkey, has its own rules of engagement for dealing with airspace violations, von Hlatky said, but standard operating procedures for Turkey would be similar to those of other countries.

Those operating procedures would dictate that Turkey should first "attempt to open channels of communication with the aircraft" from the ground if it enters a "buffer zone," she said. In this case, the buffer zone would start in Syrian territory about eight kilometres away from the Turkish border.

If the aircraft didn't respond after several attempts, von Hlatky said, the next step would be to scramble military jets to try to make contact in the air. That could include sending signals recognized by pilots, she said.

If communication still isn't established with the offending plane, military aircraft would try to "escort" it to the ground — essentially forcing it to land.

'Huge political consequences'

When asked if the Russian bomber could have accidentally strayed into Turkish airspace, von Hlatky said that military aircraft are equipped with GPS and "they would know where they are."

One of the key questions that needs to be definitively answered, she said, is whether the Russian plane was in the buffer zone or clearly in Turkish airspace — something that will likely be determined by radar images in the coming days.

The other critical question is whether the Russian plane dropped a bomb on Turkmen rebels fighting against the Bashar al-Assad regime in Syria, as a Turkmen commander has claimed.

Russia is providing air support to Assad. It has also joined the bombing campaign against the Islamic State of Iraq and Syria (ISIS) in Syria.

On Tuesday, the Russian military plane appeared to be targeting the rebels in Syria, not ISIS militants, von Hlatky said.

Turkish President Recep Tayyip Erdogan on Tuesday criticized Russian actions in the Turkmen regions, saying there were no Islamic State group fighters in the area. (Kayhan Ozer/Associated Press)

If Turkey shot down the plane to help the Turkmen rebels in Syria, von Hlatky said, that opens up a "broader dynamic here … in the context of a war zone."

Another factor adding to the complexity of the situation, she said, are reports that the Turkmen rebels shot the two Russian pilots after they ejected from the plane and parachuted to the ground.

If that happened, she said, it would be a breach of United Nations laws governing military conflict.

"For sure we need to ask these questions," von Hlatky said. "[There are] huge political consequences."