Cut the potato lengthwise into 1/4 inch thin slices; then cut each slice into 1/4 inch fries. (A mandolin is helpful here).
In a medium bowl toss the potatoes and oil. Season with salt, garlic powder and black pepper to taste; toss to coat.
Place the potatoes in the air fryer basket in an even layer without overlapping or crowding, cook the potatoes 380°F 12 to 15 minutes, turning halfway until crisp.
Note: If you have a Cuisinart Toaster Style Fryer, cook 350F 12 minutes.