Preheat oven to 350F. Place rack in middle position. Spray 9x5 inch loaf pan with nonstick baking spray and line in parchment paper, leaving 2-inch overhand on the long sides. Spray parchment paper.
In medium bowl, whisk together flour, baking soda, salt, and cinnamon. Set aside.
In the bowl of a stand mixer with a paddle attachment, combine butter and brown sugar. Mix on medium-high until light, fluffy, and doubled in volume, about 3 to 5 minutes. Scrape down sides and bottom of mixing bowl with spatula as necessary.
Reduce speed to low and add eggs, one at a time, adding the next after the first has been fully incorporated. Scrape down sides of bowl as necessary.
Add sour cream and vanilla and mix on low until combined. Gradually add the dry ingredients and mix until just combined. Add bananas, pineapple, and pecans and mix until evenly distributed, about 1 minute. Scrape down sides of bowl and mix an additional 30 seconds.
Pour batter into prepared pan and smooth top. Bake until a toothpick inserted in center comes out with a few moist crumbs attached, about 70-75 minutes.
Remove from oven. Cool in pan on wire rack for 15 minutes, then invert onto wire rack and continue cooling. Serve warm or at room temperature.