The basic CBU-87 is designed to be dropped from an aircraft at any altitude and any air speed. It is a free-falling bomb and relies on the aircraft to aim it before it drops; once dropped it needs no further instruction, as opposed to guided munitions or smart bombs. The bomb can be dropped by a variety of modern-day aircraft. It is 7 feet 7 inches (2.31 meters) long, has a diameter of 16 inches (41 centimeters), and weighs roughly 950 pounds (430 kg). The price is US$14,000 per bomb^{[citation needed]}.

Each CBU-87 consists of an SUU-65B canister, a fuze with 12 time delay options and 202 submunitions (or bomblets) designated BLU-97/B Combined Effects Bomb. Each bomblet is a yellow cylinder with a length of 20 centimeters and a diameter of 6 centimeters. The BLU-97/B bomblets are designed to be used against armour, personnel and softskin targets and consist of a shaped charge, a scored steel fragmentation case and a zirconium ring for incendiaryeffects. The CBU-87 can also be equipped with an optional FZU-39/B proximity sensor with 10 altitude selections.

When dropped from an aircraft, the bomb starts spinning. There are 6 speeds that can adjust the bomb's rate of spin. After it drops to a certain altitude, the canister breaks open and the submunitions are released. Each bomblet has a ring of tabs at the tail end, these orient the bomblet and deploy an inflatable decelerator to decrease the falling speed of the bomblet. When the submunitions hit the ground, they will cover a large area and the CBU-87 can be adjusted so it can cover a smaller or wider area. Depending on the rate of spin and the altitude at which the canister opens, it can cover an area between 20x20 meters (low release altitude and a slow rate of spin) to 120x240 meters (high release altitude and a high rate of spin).

Manufacturers and the Department of Defense have claimed that the failure rate for each bomb is about 5%.^[2] This would mean that of the 202 bomblets dropped, about 10 will not explode on impact. Landmine Action has claimed the failure rate of the BLU-97/Bs used in the Kosovo campaign was higher, between 7 and 8 percent.^[3]

The JDAM was meant to improve upon laser-guided bomb and imaging infrared technology, which can be hindered by bad ground and weather conditions. Laser seekers are now being fitted to some JDAMs.^[2]

From 1998 to November 2016, Boeing completed over 300,000 JDAM guidance kits, and is now building them at a rate of over 130 kits per day.^[3]

Design[edit]

The BLU-109/B has a steel casing about 1 inch (25.4 mm) thick, filled with 530 lb (240 kg) of Tritonal. It has a delayed-action tail-fuze. The BLU-109 entered service in 1985. It is also used as the warhead of some marks of the GBU-15 electro-optically guided bomb, the GBU-27 Paveway III laser-guided bomb, and the AGM-130 rocket-boosted weapon. This weapon can penetrate 4–6 feet of reinforced concrete,^[2] which is greater than the 3 foot capability of the Small Diameter Bomb.^[3] The BLU-109 is not likely to be retired anytime soon, due to the much larger blast capable from its warhead.^{[citation needed]}

Raytheon production of the Paveway II is centered in Arizona, Texas, and New Mexico. Lockheed Martin production is centered in Pennsylvania.

Laser-guided bombs are often labeled as "smart bombs", despite requiring external input in the form of laser designation of the intended target. According to Raytheon's fact sheet for the Paveway 2, 99 deliveries of guided munitions will yield a circular error probable (CEP) of only 3.6 feet (1.1 m), compared to a CEP of 310 feet (94 m) for 99 unguided bombs dropped under similar conditions.

On 14 February 1991, an air-to-air kill was scored by a GBU-10 when an F-15E Strike Eagle of the 335th Tactical Fighter Squadron hit an Iraqi Air Force Mil Mi-24 Hind. 30 seconds after firing, the F-15E crew thought the bomb had missed and was about to fire an AIM-9 Sidewinder air-to-air missile when the helicopter suddenly exploded.^[1]

Both Lockheed Martin and Raytheon have developed GPS-guided versions of the GBU-10.^[2] Lockheed Martin calls its version the DMLGB (Dual-Mode LGB) GPS/INS, and the U.S. Navy issued Lockheed Martin a contract in 2005 for further development of the weapon system. The GPS/INS-equipped version of the GBU-10 produced by Raytheon is the GBU-50/B, also informally also known as the EGBU-10 (GPS/INS-enabled LGBs are frequently referred to as Enhanced GBUs or EGBUs). So far, Raytheon-built Paveway II EGBUs have only been produced for export, and have been used in combat by the British Royal Air Force over Afghanistan and Iraq.

The US Department of Defense has upgraded GBU-12 production versions to include GPS guidance modes. Lockheed Martin is the sole source for US Navy purchases of this version. Raytheon sells upgraded GBU-12s to the US Government and other nations. Laser-guided bombs are often labeled "smart bombs" because they are able to follow a non-ballistic trajectory when laser designation of the intended target is undertaken. According to Raytheon's fact sheet for the Paveway 2, 99 deliveries of guided munitions will yield a circular error probable (CEP) of only 3.6 feet (1.1 metres), versus a CEP of 310 feet (94.49 metres) for 99 unguided bombs dropped under similar conditions.

The GBU-16 Paveway II is an American Paveway-series laser-guided bomb, based on the Mk 83 general-purpose bomb, but with laser seeker and wings for guidance. It was introduced into service around 1976. It is used by USAF, US Navy, US Marine Corps, and various NATO air forces. It uses a 1,000 pound general purpose warhead. The bomb in the GBU-16 Paveway II is a 1,000 pound Mk 83 bomb.

Paveway II laser-guided bombs use what is known as "bang bang" guidance. This means the bomb's fins deflect fully, rather than proportionally when it is attempting to guide to the laser spot. For example, if it sees the laser spot and determines that it should make a change it deflects its fins until it has over-corrected and then it deflects back the opposite direction, creating a sinusoidal type of flight path. This type of guidance may be less efficient at times, however is more cost effective and allows the use of simpler electronics in the guidance system.

• Mk. 84 – 910 kilograms (2,000 lb) General Purpose
• BLU-109 – 910 kilograms (2,000 lb) Penetrator
• BLU-116 – Advanced Unitary Penetrator
• CPE-800 – Used in the BPG-2000, a similar, indigenous Spanish weapon

Compared to the GBU-10 family, or the Paveway II family, the GBU-24 glides farther as a result of more efficient guidance technology. The Paveway III guidance kit is more expensive, however, making the GBU-24 suitable against well-defended, high-value targets. It was introduced into service c. 1983. This weapon is in service with the USAF, US Navy, US Marine Corps, and various NATO air forces.

The bomb requires a spot of pulse-coded laser energy to home on; this can be supplied by the delivery aircraft, another aircraft (Buddy Lasing), or by a Ground Laser Designator. After release from the delivery aircraft, the thermal battery for the Guidance Computer Group fires to supply power; the arming wire for the fuze is withdrawn; the wings are released; and depending on the configuration, either the turbine generator or the safety switch (to power the fuze) is activated.

Once this has happened, the seeker guides the bomb toward the designated impact point. If the laser illumination is lost, the bomb stops guiding and follows a roughly ballisticpath, although interference from the guidance kit can lead to the weapon wandering off course. While the GBU-24 is guided, it is not a powered weapon—i.e., it has no propulsion. Its range, therefore, depends on aircraft speed, altitude, wind speed, etc. The GBU-24 is precise enough to be able to fly down ventilation shafts into hardened targets, although accuracy is usually dependent on the ability to point the laser correctly rather than the bomb's ability to hit the impact point. The GBU-24 is cleared on aircraft such as the F-15E, F-16A MLU, F-16C Block 40/42, F-16C Block 50/52 CCIP, F-16C+ Block 30 SCU8, F/A-18, Panavia Tornado, Eurofighter Typhoon, Mirage 2000, Rafale, F-14 Tomcat (prior to the Tomcat's retirement from US Navy service), F-111C AUP and the Predator C UAVs.^[1]

Twenty-three GBU-24s were dropped by the US Navy during the 2003 invasion of Iraq.^[2]

Combat history[edit]

The GBU-27 was used in Operation Desert Storm. It was the weapon used in the February 13, 1991 attack on the Amiriyah shelter, which resulted in the deaths of more than 400 Iraqi civilians. It was also used in a series of strikes on the Muthanna State Enterprise site during February 1991.^[3]

During the 2003 invasion of Iraq, the US Air Force dropped 98 EGBU-27s on Iraqi targets.^[4]

The first foreign sale of the GBU-27 was the acquisition by Israel of 500 units equipped with BLU-109 penetrating warheads, authorized in September 2004. (Raas and Long 2006) Delivery of such precision guided weaponry was accelerated at the request of Israel in July 2006, though the exact munition were not specified. Israeli Defense Forces officials state that other precision-guided munitionshave been used to attack Hezbollah facilities in the 2006 Israel-Lebanon conflict.^[5] However, the bunker busting technology in the GBU-27 could be directed, according to Israeli military sources, at Iran or possibly Syria.^[6]

As of 2011 the UK's RAF have also ordered the GBU-27 for use in Libya.^[7]