Another well known aircraft which is fitted with the JT3D (in TF33 form) is the Boeing B-52H Stratofortress. The 'H' model of the B-52 was the only production variant of the famous bomber to be fitted with turbofan engines, and the only model remaining in US Air Force service. It is expected to remain as a mainstay of the USAF heavy bomber fleet until at least 2040.