The first B-1B was delivered to the Air Force at Dyess Air Force Base, Texas, in June 1985, with initial operational capability on Oct. 1, 1986. The final B-1B was delivered May 2, 1988.   

The swing-wing design and turbofan engines not only provide greater range and high speed at low levels but they also enhance the bomber's survivability. Wing sweep at the full-forward position allows a short takeoff roll and a fast base-escape profile for airfields under attack. Once airborne, the wings are positioned for maximum cruise distance or high-speed penetration.   

The aircraft's AN/ALQ 161A defensive avionics is a comprehensive electronic counter-measures package that detects and counters enemy radar threats. It also has the capability to detect and counter missiles attacking from the rear. It defends the aircraft by applying the appropriate counter-measures, such as electronic jamming or dispensing expendable chaff and flares. .   
  

General Characteristics  

Primary Function: Long-range, multi-role, heavy bomber  
Builder: Rockwell International, North American Aircraft  
Operations Air Frame and Integration: Offensive avionics, Boeing Military Airplane; defensive avionics, AIL Division  
Power plant: Four General Electric F-101-GE-102 turbofan engine with afterburner  
Thrust: 30,000-plus pounds with afterburner, per engine  
Length: 146 feet (44.5 meters)  
Wingspan: 137 feet (41.8 meters) extended forward, 79 feet (24.1 meters) swept aft  
Height: 34 feet (10.4 meters)  
Weight: Empty, approximately 190,000 pounds (86,183 kilograms)  
Maximum Takeoff Weight: 477,000 pounds ((216,634 kilograms)  
Speed: 900-plus mph (Mach 1.2 at sea level)  
Range: Intercontinental, unrefueled  
Ceiling: More than 30,000 feet (9,144 meters)  
Crew: Four (aircraft commander, pilot, offensive systems officer and defensive systems officer)  
Armament: Up to 84 Mark 82 conventional 500-pound bombs and 30 CBU-87/89/97. Also can be reconfigured to carry a wide range of nuclear weapons  
Date Deployed: June 1985  
Unit Cost: $200-plus million per aircraft  
Inventory: Active force, 51 primary mission aircraft inventory (PMAI), 72 (actual), 2 (test); ANG, 18 PAA (20 actual); Reserve , 0