What happened
A certificated commercial pilot departed on a short VFR cross-country flight after receiving a weather briefing two hours prior. The briefing had indicated the potential for rain and thunderstorms along the intended route. During the flight, the pilot and a passenger encountered heavy rain upon arrival at their destination. The intensity of the rain was such that it was difficult to hear communications from air traffic control.
The pilot attempted an initial landing but was forced to execute a go-around because visibility through the front windshield was obscured by the heavy rain. During this maneuver, the pilot pushed the throttles to the full forward position, but reported that the aircraft would not climb.
A witness, a flight instructor with over 17,000 hours of flight time, observed the aircraft in a climb over the runway. Shortly after this observation, the weather at the airport deteriorated significantly, characterized by lightning, heavy rain, hail, and wind gusts reaching 50 miles per hour.