PHOENIX -- A US Airways ( LCC) jet briefly caught fire at its gate at the Phoenix airport during maintenance tests.US Airways spokeswoman Michelle Mohr says crews were conducting routine maintenance tests when the fire broke out Monday night on the plane's auxiliary power unit. She described it as a small motor under the plane's tail that supplies additional power. Mohr says no injuries were reported and the fire was quickly extinguished. Phoenix Sky Harbor International Airport spokeswoman Kris Commerford says no passengers were on board at the time. She says the plane had arrived from California and was headed next to Vancouver, Canada. Mohr says 101 passengers were put on a different plane and would be delayed by about two hours.