the 24th, 39th and 40th Squadons
Each air crewman was typically assigned to a particular crew and plane and flew with that crew and plane for the duration.
There were exceptions, of course. Some air crew might be asked to fill in a vacancy with another crew. If their aircraft was not available, an air crew might be assigned to fly a different aircraft for a mission. The first 16 air crews were the original crews and generally flew together for the duration. Many were able to complete 35 missions before the end of the war. When replacement crews arrived, the policy was for them to fly with an experienced Aircraft Commander for 5 missions, while their Aircraft Commander served as Pilot with the experienced crew. After the first 5 missions, the air crews resumed flying together with their original Aircraft Commander. However, especially later in the war, replacement crews were split up to serve as individual replacements on more experienced crews.
The air crew of a B-29 generally included eleven people. Each occupation had a different MOS (“military operating specialty”), and required special training. The Airplane Commander, Pilot, Navigator and Bombardier were generally officers. The Flight Engineer, Radio Operator, and the Gunners were generally enlisted men. The Radarman was initially an enlisted man but was later an officer. The following is a list of the crew members, with the MOS indicated in square brackets.
Airplane Commander 
Pilot (or Co-Pilot) 
Flight Engineer 
Radioman (or Radio Operator) 
Radarman (or Radar Observer) 
Central Fire Control (or CFC Gunner) 
Right Gunner 
Left Gunner 
Tail Gunner 
6th Bomb Group
The photo shows standard uniforms for a typical B-29 crew in the Pacific. This is how many crew members dressed when flying missions (without the medals, of course). Crew did not typically wear flight jackets or fleece-lined boots that the bomber crews in Europe wore. In some cases, the men wore flight suits. While on a mission, they also generally wore yellow life preservers.