Canada's next fleet of fighters will be packed with high-tech gizmos but lack one comforting feature : a second engine.
For pilots who will fly patrols over Canada's vast expanses of territory in the Far North, it means no back-up.
So what happens if the sole engine in the new F-35 Lightning fails?
"It won't," Defence Minister Peter MacKay insisted on Friday. It was a bold prediction and one he will be remembered for making.
Canada chose its current fleet of CF-18s precisely because they had dual engines. As the Cold Lake Air Force Museum's website notes, Ottawa selected the Hornets "mostly because of twin-engine reliability" in case one failed during flights between Canada and Europe or sucked in a bird during low-level operations.
But today, the Harper government insists the single engine on the F-35 jets is more reliable than that of previous generations.
Ottawa has also favoured a single engine because it reduces support costs. Half of the maintenance bills for jet fighters are for their engines.
The debate about one engine or two has gone on for decades. The F-22, a fifth-generation fighter that the United States won't sell even to allies, is a faster twin-engine craft.
But government officials say a single-engine configuration will leave the F-35 lighter and more agile to manoeuvre.