If you’ve been flying for a while, you probably know of at least one person in your circle of friends who has made a very expensive mistake — starting up the engine with the towbar attached. It is a simple error but one that could cost you a new propeller and an engine overhaul.
There have even been images posted on social media of airplanes taking off with the towbar still attached. Imagine taking a stroll with your dog only to have a towbar suddenly drop from the skies. The NIMBYs trying to shut down your precious local airport would have a heyday!