Don't be alarmed if you hear a loud rumbling in the sky on Tuesday and Wednesday nights. It's just helicopters from Canada's 427 Special Operations Aviation Squadron conducting counter-terrorism training sessions over Stelco Tower for the next two days.

The 427 Special Operations Aviation Squadron is an Air Force tactical helicopter squadron that falls under the jurisdiction of the Canadian Special Operations Forces Command, which includes the Joint Task Force 2 (JTF2).

"These pilots fly in support of very specific missions," said Major Douglas MacNair.

A significant part of their mandate is counter-terrorism measures, he added. As a result, Tuesday and Wednesday's training sessions will simulate a response to a counter-terrorism threat.

"They will simulate dropping off troops on the roof of Stelco Tower," said MacNair.

Helicopters will be flying low and hovering over Stelco Tower as a way of simulating a response to a real urban threat. And yes, it will be "noisy" confirmed MacNair.

Don't expect to see any fatigue-clad soldiers rappelling from the aircraft and onto the roof of the King Street West tower, however. The effort is just a training exercise.

MacNair stressed the importance of preparing pilots to fly difficult maneuvers in an urban environment in the dark as this is the most likely scenario for a real situation.

"The point is to deal with the challenges of an urban environment," he said. 

Training will start at 8 p.m both nights and will end at midnight.

Hurricane Sandy may force the choppers to reconsider their flight plan, though.

We're pushing ahead now but the big storm can have an impact," said MacNair. If the storm is too much, the flights will take place Wednesday and Thursday of this week instead, he added.  

The training sessions are largely counter-terrorism exercises, but MacNair joked that the city of Hamilton was chosen as a location for its skyline and urban environment not because of any perceived security issue.

"We haven't identified a threat in Hamilton", he said jokingly. "It's just a city of the right size and skyline."

Last year, similar training took place in Windsor.

Major Doug MacNair stresses the training is weather permitting at the moment. If Hurricane Sandy proves too powerful the training will take place Wednesday and Thursday night rather than Tuesday and Wednesday.