After entering service with the United States Army aviation units, the aircraft quickly received the reputation of a "widowmaker" due to the early models' high accident rate during takeoffs and landings. This was due to the fact that the Marauder had to be flown at exact airspeeds, particularly on final runway approach or when one engine was out. The unusually high 150 mph (241 km/h) speed on short final runway approach was intimidating to many pilots who were used to much slower approach speeds, and whenever they slowed down to speeds below what the manual stipulated, the aircraft would often stall and crash. The B-26 became a safer aircraft once crews were re-trained, and after aerodynamics modifications (an increase of wingspan and wing angle-of-incidence to give better takeoff performance, and a larger vertical stabilizer and rudder). The Marauder ended World War II with the lowest loss rate of any USAAF bomber.