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Joint Direct Attack Munition

The Joint Direct Attack Munition is a guidance tail kit that converts existing unguided free-fall bombs into accurate, adverse weather "smart" munitions. With the addition of a new tail section that contains an inertial navigational system and a global positioning system guidance control unit, JDAM improves the accuracy of unguided, general purpose bombs in any weather condition. JDAM is a joint U.S. Air Force and Department of Navy program.


In active service


Original contractor: McDonnell Douglas
Manufacturer: Boeing


Late 1991 - AWPGM (Adverse Weather Precision Guided Munition) program started by the U.S. Air Force and U.S. Navy (later renamed to JDAM (Joint Direct Attack Munition))
1993 - The U.S. Air Force successfully demonstrated a GPS-aided inertial (GPS/INS) guidance package
April 1994 - Development contracts given to McDonnell Douglas and Martin Marietta
October 1995 - McDonnell Douglas selected as prime contractor for further development of JDAM
1996 - Testing began
April 1997 - First Low-Rate Initial Production (LRIP) contract awarded
December 1998 - Initial Operational Capability (on the B-52H Stratofortress)


The GBU-31/B is the JDAM version carrying a 2000-pound warhead. The following types of warhead may be used with these tailkits: the standard Mk 84, the BLU-109/B penetrator warhead, the BLU-117A/B, and the BLU-119/B Crash PAD (Prompt Agent defeat) weapon.


Length (GBU-31(V)1/B): 3.879 meters 12.73 feet
Length (GBU-31(V)2/B): 3.879 meters 12.73 feet
Length (GBU-31(V)3/B): 3.774 meters 12.38 feet
Length (GBU-31(V)4/B): 3.774 meters 12.38 feet
Diameter (GBU-31(V)2/B): 46 centimeters 18.11 inches
Diameter (GBU-31(V)4/B): 37 centimeters 14.57 inches
Finspan: 64.3 centimeters 25.31 inches
Launch weight (GBU-31(V)1/B): 923,51 kilograms 2 036 pounds
Launch weight (GBU-31(V)2/B): 945.74 kilograms 2 085 pounds
Launch weight (GBU-31(V)3/B): 959.35 kilograms 2 115 pounds
Launch weight (GBU-31(V)4/B): 980,67 kilograms 2 162 pounds
Warhead weight: 907,18 kilograms 2 000 pounds
Range: 24,14 kilometers 15 miles
Ceiling: 13 700+ meters 45 000+ feet
Guidance system: GPS/Inertial
Warhead (GBU-31(V)1/B): Mk 84
Warhead (GBU-31(V)2/B): Mk 84 or BLU-117A/B
Warhead (GBU-31(V)3/B): BLU-109/B
Warhead (GBU-31(V)4/B): BLU-109A/B


The designation GBU-32/B was allocated to the 1000-pound class JDAM bombs. The following types of warhead may be used with these tailkits: the standard Mk 83 and the BLU-110/B for the U.S. Navy, which is externally identical to the MK 83, but uses the PBXN-109 thermally insensitive explosive.