Joint Direct Attack Munition

Joint Direct Attack Munition

The Joint Direct Attack Munition (JDAM) is a guidance kit that converts existing unguided gravity bombs, or "dumb bombs", into all-weather "smart" munitions. JDAM equipped bombs are guided to their target by an integrated inertial guidance system coupled with a Global Positioning System (GPS) receiver for enhanced accuracy, giving them a published range of up to convert|15|nmi|km from the release point. The program's approach was in contrast to earlier laser-guided bomb and imaging infrared technology, both of which can be hindered by adverse ground conditions; however, laser designators are now being fitted to some JDAMS as well, because of their suitability for attacking certain types of targets. The JDAM is a joint United States Air Force and United States Navy program.


The JDAM is not a weapon; rather it is a "bolt-on" upgrade for unguided gravity bombs, installed during build up of the munition by Naval Ordnancemen or Air Force Munition Systems Specialists. JDAM-equipped bombs range in size from convert|500|lb|kg to convert|2000|lb|kg, by nominal bomb weight.cite web|url=|title=JDAM continues to be warfighter's weapon of choice|accessdate=2007-07-27] A JDAM kit consists of a tail section with aerodynamic control surfaces, a strake kit, and a combined inertial guidance system and GPS guidance control unit. When installed on a bomb, the JDAM kit is given a GBU (Guided Bomb Unit) nomenclature, superseding the Mark 80 or BLU (Bomb, Live Unit) nomenclature of the bomb to which it is attached. Thus, the gravity bomb on which the kit is installed becomes the warhead for a precision guidance system.

History and development

The bombing campaign in the initial phase of Desert Storm highlighted a shortfall in air-to-surface weapon capability in the US Air Force. Limited visibility of the ground caused by smoke, fog, dust, and cloud cover limited the employment of precision guided munitions, and also degraded the accuracy of unguided weapon delivery from medium and high altitudes. Research, development, testing and evaluation (RDT&E) of an "adverse weather precision guided munition" began in 1992. The first JDAM kits were delivered in 1997, with operational testing conducted in 1998 and 1999. During testing, over 450 JDAMs were dropped achieving a system reliability in excess of 95% with a published accuracy under convert|10|m|ft Circular Error Probable (CEP).citation| title =JDAM: The Kosovo Experience and DPAS|publisher=The Boeing Company, Charles H. Davis| date=19 April 2000| url=| accessdate=2007-09-01] In addition to controlled parameter drops, the testing and evaluation of the JDAM also included "operationally representative tests" consisting of drops through clouds, rain and snow with no decrease in accuracy from clear weather tests.In addition, there have been tests involving multiple weapon drops with each weapon being individually targeted.cite press release| title= U.S. Air Force B-2 Bomber Drops 80 JDAMS in Historic Test| publisher= The Boeing Company| date= 17 September 2003| url=| accessdate=2007-09-02]

JDAM and the B-2 Spirit stealth bomber made their combat debuts during Operation Allied Force. The B-2s, flying 30-hour, nonstop, round-trip flights from Whiteman Air Force Base, Missouri, delivered more than 650 JDAMs during Allied Force. An article published in a military acquisition journal in 2002 cites that " [d] uring Operation Allied Force ... B-2s launched 651 JDAMs with 96% reliability and hit 87% of intended targets..."Mark 83, beginning development in late 1999. As a result of lessons learned during Operation Enduring Freedom and Operation Iraqi Freedom, the Navy and Air Force are both pursuing enhancements to the kits such as improved GPS accuracy as well as a precision seeker for terminal guidance for use against moving targets.

JDAM bombs are inexpensive compared to alternatives such as cruise missiles. The original cost estimate was $40,000 each for the tail kits, but after competitive bidding, contracts were signed with McDonnell Douglas (later taken over by Boeing) for delivery at $18,000 each. Unit costs have since increased to $21,000 in 2004 and are expected to reach $31,000 by 2011. [ [ DEPARTMENT OF THE NAVY FISCAL YEAR (FY) 2006/FY 2007 BUDGET ESTIMATES] ] For comparison, the newest Tomahawk cruise missile, dubbed the Tactical Tomahawk, costs nearly $730,000 apiece. [ [ "The JDAM Revolution"] article by Peter Grier in "Air Force Online", the journal of the Air Force Association, September, 2006] [cite web|url=|title="BGM-109 Tomahawk: Variants"|accessdate=2007-07-27]

Operational use

Guidance is facilitated through a tail control system and a GPS-aided inertial navigation system (INS). The navigation system is initialized by transfer alignment from the aircraft that provides position and velocity vectors from the aircraft systems. Once released from the aircraft, the JDAM autonomously navigates to the designated target coordinates. Target coordinates can be loaded into the aircraft before takeoff, manually altered by the aircrew in flight prior to weapon release, or entered by a datalink from onboard targeting equipment, such as the LITENING II or "Sniper" targeting pods. In its most accurate mode, the JDAM system will provide a minimum weapon accuracy CEP of 13 meters or less when a GPS signal is available, though Boeing and the Air Forces report less than 10 meters CEP in testing. If the GPS signal is jammed or lost, the JDAM can still achieve a 30 meter CEP or less for free flight times up to 100 seconds.cite web|url=|title=USAF Factsheet: JOINT DIRECT ATTACK MUNITIONS|accessdate=2007-07-27]

JDAM can be dropped from very-low to very-high altitudes in a dive, toss-and-loft, or in straight-and-level flight, with an on-axis or off-axis delivery. In contrast, previous precision guidance kits, such as the laser guided Paveway, required the pilot to fly a much tighter envelope to ensure that the weapon would track to the target upon release. Furthermore, JDAM enables a single aircraft to drop multiple weapons targeted against single or multiple targets on a single pass. The JDAM system permits variable fuzing, from air-burst through contact- and penetration-fuzing. Fuzing must be set prior to takeoff, as the aircrew have no way to adjust this in flight.

Despite their precision, JDAM employment does not come without risk. On December 5 2001, a JDAM dropped by a B-52 in Afghanistan nearly killed Hamid Karzai, while he was leading anti-Taliban forces near Sayd Alim Kalay alongside a US Army Special Forces (SOF) team. A large force of Taliban soldiers had engaged the combined force of Karzai's men and their American SOF counterparts, nearly overwhelming them. The SOF commander requested Close Air Support (CAS) to strike the Taliban positions in an effort to stop their advance. A JDAM was subsequently dropped, but instead of striking the Taliban positions, it struck the Afghan/American position. An investigation of the incident determined that the terminal attack controller attached to the Special Forces team had changed the battery in the GPS receiver at some point during the battle, thereby causing the device to return to "default" and "display its own coordinates." Not realizing that this had occurred, the TACP relayed his own coordinates to the delivery aircraft.cite web|url=||title=Killing Your Own: The Problem of Friendly Fire During the Afghan Campaign |accessdate=2007-07-27] [ [] Why-Because analysis (p. 9).]


U.S. military experience during Operation Enduring Freedom and Operation Iraqi Freedom highlighted the need for additional capability in one package, resulting in ongoing program upgrades to place a precision terminal guidance seeker in the JDAM kit. [cite web|url=|title=Dual Mode Guided Bomb|accessdate=2007-07-27] The Laser JDAM (LJDAM), as this upgrade is known, adds a laser seeker to the nose of a JDAM equipped bomb, giving the ability to engage moving targets to the JDAM. The Laser Seeker is called Precision Laser Guidance Set (PLGS) by Boeing and consists of the Laser Seeker itself, now known as DSU-38/B and a wire harness fixed under the Bomb body to connect the DSU-38/b with the tailkit. During FY2004, Boeing and the U.S. Air Force began testing of the laser guidance capability for JDAM, with these tests demonstrating that the system is capable of targeting and destroying moving targets. [cite web|url=|title=Boeing Scores Direct Hit in Laser JDAM Moving Target Test|accessdate=2007-07-27] This dual guidance system retains the ability to operate on GPS/INS alone, if laser guidance is unavailable, with the same accuracy of the earlier JDAM.

On 11 June 2007, Boeing announced that it had been awarded a $28 million contract by the U.S. Air Force to deliver 600 laser seekers (400 to the Air Force and 200 to the Navy) by June 2009.cite press release|title =Boeing Awarded Laser JDAM Contract|publisher=The Boeing Company|date=11 June 2007|url=|accessdate=2007-09-02] According to the Boeing Corporation, in tests at Nellis Air Force Base, Nevada, Air Force F-16 Fighting Falcons and F-15E Strike Eagles dropped twelve (12) convert|500|lb|kg LJDAMs that successfully struck high-speed moving targets. Using onboard targeting equipment, the launch aircraft self-designated, and self-guided their bombs to impact on the targets. In addition to the LJDAM kits, Boeing is also testing under a Navy development contract, an anti-jamming system for the JDAM, with development expected to be completed during 2007, with deliveries to commence in 2008.cite press release|title =Boeing Completes JDAM Anti-Jamming Developmental Flight Test Program|publisher=The Boeing Company|date=18 June 2007|url=|accessdate=2007-09-02] The system is known as the Integrated GPS Anti-Jam System (IGAS).Boeing announced on September 15, 2008, that it had conducted demonstration flights with the LJDAM loaded aboard a B-52H. [ [ Boeing Press Release, September 15, 2008] ]

On July 24th, 2008 Germany signed a contract with Boeing to become the first international customer of LJDAM. Deliveries for the German Luftwaffe will begin in mid-2009. The order also includes the option for further kits in 2009. [ [] , - Germany becomes the first international customer of LDJAM]


JDAM is currently compatible with:
*AV-8B Harrier II
*A-10C "Warthog"
*B-1B Lancer
*B-2A Spirit
*B-52H Stratofortress
*F-117 Nighthawk
*F-14A/B/D Tomcat
*F-15E Strike Eagle
*F-16C/D Fighting Falcon
*F/A-18C/D Hornet
*F/A-18E/F Super Hornet
*F-22 Raptor
*F-35 Lightning II
*Panavia Tornado

Follow-on integration efforts are currently underway or planned to evaluate compatibility with:

*S-3 Viking
*MQ-9 Reaper
*Eurofighter Typhoon


The U.S. Government has approved the JDAM for export sale under the Arms Export Control Act, though in limited numbers to only a few countries. Outstanding requests for purchase are under review.

Export customers

*flag|Australia [cite web|url=| Boeing JDAM Wins Australian Competition|accessdate=2007-07-27]
*flag|Germany (first international customer of LJDAM)
*flag|Israel [cite web|url=|title=First International JDAM Sale: Boeing to Integrate Weapon on Israeli Aircraft|accessdate=2007-07-27]
*flag|Italy [cite web|url=|title=global|accessdate=2007-07-27]
*flag|Netherlands [cite web|url=|title=Dutch secretary of defense details plan for purchase of JDAM's|accessdate=2007-07-27]
*flag|Norway [cite web|url=|title=Norway Signs Contract for Boeing JDAM|accessdate=2007-07-27]
*flag|PakistanFact|date=May 2008
*flag|Saudi Arabia [cite web|url=|title=Gates says Washington to sell smart bombs to Saudi Arabia|accessdate=2007-07-27]
*flag|South Korea

Export requests

*flag|Finland [cite web|url=|title=FMS: Third Phase of Finnish F/A-18 MLU|accessdate=2007-07-27]
*flag|Greece [cite web|url=|title=FMS: Greece - F-16C/D Munitions|accessdate=2007-07-27]

General characteristics

* Primary function: Guided air-to-surface weapon
* Contractor: Boeing
* Length: (JDAM and warhead) GBU-31 (v) 1/B: convert|152.7|in|mm; GBU-31 (v) 3/B: convert|148.6|in|mm; GBU-32 (v) 1/B: convert|119.5|in|mm
* Launch weight: (JDAM and warhead) GBU-31 (v) 1/B: convert|2036|lb|kg; GBU-31 (v) 3/B: convert|2115|lb|kg; GBU-32 (v) 1/B: 1,013 lb convert|1013|lb|kg
* Wingspan: GBU-31: convert|25|in|mm; GBU-32: convert|19.6|in|mm
* Range: Up to convert|15|nmi|km
* Ceiling: convert|45000|ft|m
* Guidance system: GPS/INS
* Unit cost: Approximately $21,000 per tailkit (FY 01 dollars)
* Date deployed: 1999
* Inventory: The tailkit is in full-rate production. Projected inventory is approximately 240,000 total, 158,000 for the US Air Force and 82,000 for the US Navy. (As of October 2005)


* 2,000 lb (900 kg) nominal weight
** GBU-31(V)1/B (USAF) Mk-84
** GBU-31(V)2/B (USN/USMC) Mk-84
** GBU-31(V)3/B (USAF) BLU-109
** GBU-31(V)4/B (USN/USMC) BLU-109
* 1,000 lb (450 kg) nominal weight
** GBU-32(V)1/B (USAF) Mk-83
** GBU-32(V)2/B (USN/USMC) Mk-83
** GBU-35(V)1/B (USN/USMC) BLU-110
* 500 lb (225 kg) nominal weight
** GBU-38/B (USAF) Mk-82,(USN/USMC)Mk-82 and BLU-111
** GBU-54/B LaserJDAM (MK-82)

ee also

* GBU-39 Small Diameter Bomb



* JDAM Press releases:

External links

* [ Boeing (McDonnell Douglas) JDAM - Designation Systems]
* [ Product Update: JDAM]
* [ Precision Strike Weapons]
* [ Diamond Back Range Extension Kit]
* [ How Smart Bombs Work]
* [ DAMASK Overview]
* [ Safeguarding GPS] April 14, 2003 Scientific American
* [ Joint Direct Attack Munition (JDAM)]
* [ Boeing JDAM gallery]
*YouTube|7eFqdmV5aqk|Video of a JDAM explosion
* [ JDAM Matures (Australian Aviation)]

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