JDAM

Joint Direct Attack Munitions (JDAMs) are an all-weather smart munition meant to improve ground striking capabilities during bad weather conditions (e.g. smoke, dust, fog, clouds which are causing difficulties for the LGB seekers to keep the laser lock). JDAM are guided with a GPS-aided inertial navigation system and first seen combat during Operation Allied Force in 1999. Those are the perfect weapons against static targets like bridges, factories or bunkers.

Learning objectives

1. Know how to align JDAM and when they're fully aligned
2. Set up the different settings in the SMS page : Arming Delay (AD) and Impact Azimuth (IMP AZ) (other settings are not implemented in game yet)
3. Know the different modes of the JDAM (PRE - VIS)
4. Know the flight envelope (offset of no more than 60° from the target bearing)
5. Know the basic symbology of the HUD DLZ, LAR2 scale and the speed limitations (DLZ will be blanked when aircraft speeds are less than 0.5 Mach or greater than 1.5 Mach)
6. Know how to drop JDAM on target steerpoint coordinates
7. Know how to drop JDAM on a target designated with the TGP
8. Know the differences between JDAM and LJDAM and their SMS settings (Laser receiver control)
9. Be familiar with the 1.6 seconds pickle delay (Depress and hold until the FPM flashes > 1.6 seconds for single, or 3.2 seconds for ripple ! you must hold it until weapon release, otherwise you'll get a HUNG weapon)

Common JDAM Types

Joint Direct Attack Munition or JDAM is a guidance kit fitted to Mk-82/84 dumb bombs to give them all weather attack capability.

GBU-31

1/B

-Warhead: 945lb BLU-117 (HE)

-Weight: 2085lbs

-Range: ~15nm

-Guidance: INS/GPS

3/B

-Warhead: 530lb BLU-109 Penetrator (HE)

-Weight: 2162lbs

-Range: ~15nm

-Guidance: GPS/INS

GBU-38

-Warhead: 192lb BlU-111/B (HE)

-Weight: 558lb

-Range: ~15nm

-Guidance: GPS/INS

GBU-54

-Warhead: 192lb BLU-111/B (HE)

-Weight: 558lb

-Range: ~15nm

-Guidance: GPS/INS or Laser Guidance

SMS Page (GBU31, 38, and 54)

1. The number of Weapons, status of weapon (INT- Initializing, A08 - Alignment transfer, RDY - Ready)
   • Remember it can take up to 3 minutes for your bombs to align so make sure to power them on with enough time before your attack.
2. Power ON/OFF
3. Ripple quantity
   • Note that with this if you set RP to 4 and have 4 bombs each bomb will go to the same target unless they are programed in the DED for a specific target. This is a great way to ripple all of your bombs off in one pass for a lofting attack in Israel.
4. Arming Delay (0-99sec), how long until the warhead of the weapon is armed after release.
5. IMP ANG = impact angle (set to 65 in the DED) | IMP AZ = Impact Azimuth or Heading (set to 195 in the DED) | Impact Velocity = velocity at which the bomb will impact (set to 500fps in the DED)
6. Target ID = Steerpoint number and target name
7. Active weapon station
   • The gbu-54 will have similar option but has one additional sub page in the sms which is toggled to via osb9 to control whether or not the INS/GPS or Laser guidance kit will be used.

DED Page (GBU 31,38, and 54)

In the DED you can program your JDAM’s to hit specific targets. This functionality is very similar to the SPICE bombs in the Israeli theater. To access the JDAM control page you first press seq (in Israeli F-16’s only) then 0 followed by another 0.

1. Weapon name for JDAM (BC)
2. Impact angle - can be used to adjust the angle at which the bomb impacts the ground
3. Impact Azimuth - Used to adjust the heading from which the bomb will hit its target (000 -360) *note that 0 means that it will impact from the heading the bomb is released from.
4. Impact Velocity
5. Ripple Count - Adjusts how many bombs hit each target
6. Target STPT (not weapon targets but normal steerpoints!!!)
7. SP = Steerpoint
8. Current targets page, counts up from 00 so if you have 8 gbu-38’s you will move up to another page as there is a max of 4 programmable targets per page. You can go to the next page by placing the asterisk on this field and press M-SEL on the ICP. (ISRAELI F-16I ONLY!)

HUD (GBU 31, 38, 39, and 54)

1. Steering Line = This line will be displayed in CCRP mode, it is the fall line that provides steering guidance to line up with the target to drop your bombs. Placing your flight path marker on the line will line you up the target. This line will also provide the launch cue with a flashing circle when you have reached the appropriate range for lofting. The Hud will also produce a fall line that will tell you when to release your bombs, although with guided munitions you have a window of time where you can release your bombs regardless of the fall line.
2. Time Until Next Cue = This line will provide the time till the next cue on the HUD. A cue could be the flashing circle indicating the time to pop up for a lofting attack. Or it could provide the time until you can release your weapons.
3. Rmin = This vertical line represents the minimum range at which you can release your guided weapons. When the range marker falls below this point your weapons can not be released.
4. DLZ -DynamicLaunchZone, this is the set of ranges from Rmax to Rmin from which you can release your weapons and still hit the target. This zone will automatically adjust its size to fit the current altitude, angle off (from the target), and speed of your jet. For the SDB it will say JIZ when you have met the parameters for the SDB to drop (also you need to be above 300kts to drop a sdb).
5. Range Marker

Deployment

Set up

1. Set up your target's marker points for the targets (I usually use steers 15-25)
2. Load up the bombs
   1. If using 31/38’s set up the bombs on the DED, at a minimum
3. Takeoff and approach the target
4. Power on the bombs at least 3 minutes before you want to use them
5. If using SDB’s or GBU 54’s set up the bombs in SMS page
6. Approach the target and release the bombs once you're in parameters.
7. Come off the target and RTB.

CCRP

A CCRP attack is the simplest and safest attack option for the JDAM. CCRP, or Constantly Computed Release Point, is a wings level release from high altitude. A normal CCRP attack with any guided munition will generally be between 19,000 and 26,000 ft as lower would put your bomb laden jet in range of SHORAD's and any higher you would either be stalling out or have to be in afterburner constantly which would burn an insane amount of fuel. A general attack would see you:

1. In BMS you can set a steerpoint on a target in the 2D map, this will allow you to access this steerpoint later while flying to target; we often use steerpoints 15-25 for targets.
2. Load up a GBU-31/38/5/39
3. Set up the AD, Impact angle and Azimuth
4. Turn on the bombs
5. Approach a preset target steerpoint
6. Fly around 100-200 feet agl while keeping your speed above 450kts to 500kts, as you approach the target you will get a flashing circle on your HUD as the first cue. 2 seconds after this cue you will want to pull up to your preset lofting angle (20-30 degrees) and press and hold the pickle button once the range marker hits the DLZ .
7. Dropping the ordinance when all the release parameters are meet.

Benefits

• Stay above AAA and Manpad ranges
• Can have a wingman in A/A scanning for air threats
• Standoff range
• Saves fuel

Risks

• Pop-up SAM’s are more dangerous as you will be high and slow
• Visible target to enemy defense network

LOFT

Lofting is a common attack profile we use at UOAF, a lofting attack is quite simple once you know what to do. A loft is where you fly very low and very fast and at a certain range from the target (calculated for you by your jet) you would pop up to a preset angle. This puts the bomb on a parabolic trajectory like an artillery shell and like an artillery shell it can be launched from behind a hill and for dumb bombs it can give increased range, due to the fins on JDAM's this may not always be the case (the exception to this rule are glide bombs which can not be lofted as they can not achieve very high speeds due to their wings). A common attack would look like:

1. In BMS you can set a steerpoint on a target in the 2D map, this will allow you to access this steerpoint later while flying to target; we often use steerpoints 15-25 for targets.
2. Load up a GBU-31/38
3. Set up the AD, Impact angle and Azimuth
4. Turn on the bombs
5. Approach a preset target steerpoint in CCRP mode.
6. Fly a level approach at 100 to 250 feet while keeping your speed around 450 to 500 kts. When you get close to the target you will get the first cue which is a set of 2 flashing circles on the HUD. 2 Seconds after this cue you will pull up to your preset climb angle set in the SMS and press pickle once the range marker hits the DLZ or you see the time to release on the bottom right of the HUD when it reads 1-2 seconds.
7. Pull of the target with a hard slice while dropping chaff and flares.

Benefit

• Low altitude you can remain hidden from enemy radar
• Fast ingress/Fast Egress
• Minimal exposure to defenses around the target area
• Easier to defend against larger SAM systems

Risks

• Manpads, Manpads, Manpads, and more MANPADS!!!
• Pop-Up air threats my go undetected by you until they're behind you and killing you
• “Remember the ground has a PK of 1!”
• Less range than the High altitude CCRP attack

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