Joint Direct Attack Munition
Guided Bomb Unit 31 (GBU-31)
The Joint Direct Attack Munition (JDAM) GBU-31 is a tail kit developed to meet both USAF and U.S. Navy requirements.
On 15 February 2001, F-14s from VF-11, VF-143, and VX-9 took part in a live-fire exercise and delivered 2,000-pound JDAMs to the NAWS China Lake ranges. This was the first time fleet F-14 squadrons trained with the new weapon. The exercise was an outstanding success, and fleet aircrews scored direct hits on their targets, proving the capabilities of the GPS-guided JDAM.
On the evening of 11 March 2002, an F-14 dropped the first-ever combat JDAM during a mission against terrorist targets in Afghanistan. One F-14 crew commented: "We may be mature, but the claws are still sharp!"
Both the F-14B Upgrade and F-14D had the capability to carry the 2,000-pound version of the JDAM.
The F-14B(U) is capable of carrying both the GBU-31(V)4 with the 2,000-pound BLU-109 hard-target penetrator warhead and the GBU-31(V)2 with the 2,000-pound BLU-117 general-purpose warhead.
The JDAM in the Tomcat can be employed against targets of opportunity, with coordinates programmed in flight, or in a pre-planned capacity, where target coordinates and weapon terminal parameters are loaded via the AN/ASQ-215 Mission Data Loader prior to takeoff. Weapons intended for pre-planned delivery can be reprogrammed in flight.
The weapon automatically begins its initialization process during captive carry when power is applied by the Tomcat. The weapon aligns its INS with the F-14B(U)'s systems. Targeting data is downloaded to the weapon via the UPDATE function on the PTID JMSN page. Once downloaded from the F-14B(U), the weapon is ready for employment. When the Tomcat reaches the release point within the Launch Acceptability Region (LAR), the weapon is released. Weapon maneuverability and range are enhanced by fixed aerodynamic surfaces (mid-body strakes) attached to the bomb body.
Once released, the bomb's INS/GPS takes over and guides the bomb to its target regardless of weather conditions. Guidance is accomplished through the tight coupling of an accurate Global Positioning System (GPS) with a three-axis Inertial Navigation System (INS).
The weapon system allows launch from very low to very high altitude and can be employed in a dive, toss, loft, or straight-and-level delivery, with either an on-axis or off-axis attack. Aircraft guidance via LAR and Launch Point is provided for straight and level deliveries only. JDAM also allows multiple target engagements in a single pass. It provides the user with a variety of targeting schemes, including pre-planned targeting and in-flight retargeting.
Guided Bomb Unit 38 (GBU-38)
The Tomcat's JDAM capability continued to evolve during its final years in service. By the opening of Operation Iraqi Freedom in 2003, the F-14D had received GBU-31 JDAM capability through the D04 operational software load. The software was designed to support both the 2,000-pound GBU-31 and the 500-pound GBU-38, although only the GBU-31 had completed the required integration and was employed operationally during the opening stages of the war.
While the software already supported the GBU-38, the weapon itself had not yet completed the flight-clearance program required for release from the Tomcat.
For the 2005–2006 deployment, the F-14D received the D05 operational software, which added the 500-pound GBU-38 JDAM to the Tomcat's approved weapons inventory. This provided crews with a lighter GPS-guided weapon that complemented the existing GBU-31 and was better suited to many close air support missions where the larger 2,000-pound weapon was unnecessary.
The F-14B Upgrade was retired before the GBU-38 completed its flight-clearance program and therefore never received operational clearance to employ the weapon. Had the F-14B Upgrade remained in service through 2005–2006, it would have received the same capability, as the underlying JDAM software architecture already supported both the GBU-31 and GBU-38.