B-52 Stratofortress Service Life

The old joke that runs through the bomber fleet that when the B-1 and B-2 bombers are retired, the pilots will be flown home from the boneyard in the B-52 Stratofortress. With the recent proposals to re-engine the Boeing B-52 fleet, that may have some truth to it. This legendary aircraft has outlived nearly all of the aircraft designed to replace it.

Updated with modern technology, the B-52 will continue into the 21st century as an important element of US forces. There is a proposal under consideration to re-engine the remaining B-52H aircraft to extend the service life. B-52 re-engine plans, if implemented, call for the B-52 to be utilized through 2025. Current engineering analysis show the B-52's life span to extend beyond the year 2040. The limiting factor of the B-52's service life is the economic limit of the aircraft's upper wing surface, calculated to be approximately 32,500 to 37,500 flight hours. Based on the projected economic service life and forecast mishap rates, the Air Force will be unable to maintain the requirement of 62 aircraft by 2044, after 84 years in service

The May 1997 Report of the Quadrennial Defense Review (QDR), prescribed a total fleet of 187 bombers (95 B-1, 21 B-2, and 71 B-52). Since the QDR, two B-1s had been lost in peacetime accidents. However, the Report of the Panel to Review Long-Range Air Power (LRAP) concluded the existing bomber fleet cannot be sustained through the expected life of the air frames and that additional aircraft will eventually be required. To address this issue, the Air Force will add five additional B-52 attrition reserve aircraft, bringing the B-52 total from 71 to 76 for a total bomber force of 190. The B-52 fleet will remain the same with 44 combat-coded aircraft.

Since those studies, the Air Force has decided to retire 33 B-1s and 17 B-52Hs, reducing the current fleet of 208 bombers (93 B-1s, 21 B-2s, 94 B-52Hs) to 157. Of these bombers, only 96 will be combat coded, with the rest used for backup and other purposes. The B-52H and B-2 still retain a conventional and a nuclear mission, while the B-1 is roled for the conventional mission only.

The B-52H was designed as high altitude aircraft, but was adapted to low level tactical maneuvers in 1960's. A number of structural improvements were made during the 1960s and 1970s to equip it to fly the more demanding low- level mission and to address other structural issues.

The airframe life for the current fleet is estimated to be between 32,500 and 37,500 hours, depending on the usage history of the individual aircraft. The estimate is based upon scaling measurements from a full-scale test structure using assumed mission profiles along with historical and projected usage information. The upper wing surface is expected to be the life- limiting structural member. As of 1999 the average airframe had 14,700 flight hours. Boeing believes with high confidence that the average number of flight hours left is 17,800, at a minimum. The "oldest" B-52H is at about 21,000 hours and only experiences about 380 flight hours per year.

The Air Force outlined its plan for its bomber fleet in the fiscal year 2019 budget submission. Under this plan, the B-52, the oldest bomber in the fleet, will remain on duty for the next few decades, while the newest B-2 and B-1 bombers will be retired. The service based that decision on independent studies, and then multiple factors when it came to why we got to the selection of keeping the B-52. Those factors include maintenance and sustainment capabilities and the metrics that are associated with those, such as aircraft availability, downtime for maintenance, or downtime for supply, and the cost in terms of maintenance man-hours per flight hour. And the B-52 was the leading candidate for the keeping of the current fleet.

So as the Air Force looked forward into B-21 production and deliveries, a phase-out between the B-1s and the B-2s to associate keeping roughly 175 to 170-ish type bombers, between the B-21 and the B-52. The future of the Air Force is a combination of penetrating, non-penetrating, manned, unmanned, stand-off, penetrate, and drop from above. So the combination of the strategy of a B-52 with stand-off munitions and its capacity with a B-21 for the future gives the warfighting punch needed against China and Russia and the threats need to prepare for. The USAF decided to continue its operations until at least the 2050s.