Country of origin
1 950 kg
Bullpup, HE-FRAG or HE penetrator
680 kg (Bullpup), 1 450 kg (HE-FRAG), 540 kg (HE
Range of fire
1 200 km
TFR, INS and GPS
AGM-86B ALCM, the AGM-86C CALCM (Conventional Air Launch
Cruise Missile) is designed to discreetly destroy individual
high-value targets from a stand-off distance. It is almost
indistinguishable on its exterior from the ALCM, which is no
accident; every CALCM was converted from retired ALCMs, rather than
The USAF's interest in a conventionally-armed ALCM originated
in 1986, from combat experience gained during the air strikes on
Libya in Operation El Dorado Canyon. It was quite clear from the
results of that mission not only that an air-launched cruise missile
with a conventional warhead would be an extremely valuable addition
to the US Air Force (USAF) arsenal. Moreover, it was also becoming
increasingly obvious that the odds of a nuclear-tipped missile being
required in any foreseeable combat operation were slim at best,
while the US military would benefit from conventionally-armed
missiles in any potential conflict.
Work began later in 1986 to begin converting AGM-86Bs to
carry conventional warheads, and modify their guidance system for a
direct ramming attack on the target (the AGM-86B ALCM is designed to
fly *near* the target, and detonate in mid-air). The accuracy
required by this mission resulted in the addition of GPS into the
guidance system, and the conventional warhead for the modified
missile was significantly larger and heavier than the original W80
thermonuclear warhead; as a result, the fuel capacity had to be
significantly reduced to compensate, shortening the range of the
missile. Flight testing of the resulting AGM-86C CALCM was initiated
in 1987, though by then the conversions were already being made.
The CALCM was a secret program during the 1980s, to the
extent that they were euphemistically designated as XLRBs ("Extra
Long Range Bombs"). Aircrews jokingly referred to the missiles as
"Secret Squirrels", after the cartoon character of that name. It
wasn't until 1992 that the AGM-86C CALCM was finally declassified,
by which time they had already been used in combat during Operation
Ultimately, four different models of the CALCM were fielded;
the original AGM-86C Block 0 in 1986, AGM-86C Block I in 1996, the
AGM-86C Block IA in 2000, and the AGM-86D Block II in 2002. An
AGM-86E Block III has also been proposed in the early 2000s, but it
does not appear to have entered production.
The appearance, and propulsion are identical to that of the
AGM-86B ALCM; see the page on that missile for further details.
As with the ALCM, the only aircraft capable of carrying the
CALCM are the B-52G and
B-52H. A total of 20 may be carried, 8 on a rotating launch rack
in the internal bay, and 12 on external pylons.
Guidance for the CALCM is largely the same as that of the
ALCM, but with the addition of a GPS system to further enhance its
accuracy. Reputedly, the CALCM has a CEP (Circular Error Probable)
of 3 m, though this only means that half of a flight of missiles will
land within 3 m of one another (in other words, the guidance is very
precise, but not necessarily accurate). Similar guidance problems
encountered with the
BGM-109 Tomahawk almost certainly apply as
well, as the CALCM has the same guidance radar and computers.
Nonetheless, CALCMs have proven able to hit point targets in several
Three different types of warheads have been employed in the
CALCM. The AGM-86C Block 0 carried a 680 kg AFX-760 HE-FRAG warhead;
referred to as a "Bullpup" warhead, this is a directional shrapnel
munition that fires thousands of steel ball bearings downward in a
wide fan, essentially turning the CALCM into a giant flying claymore
mine. Bullpup warheads are extremely effective against "soft"
targets (radar sites, parked aircraft, fuel silos, and so on), but
much less so against "hard" targets (armored vehicles, hardened
aircraft shelters, bunkers, etc.). The AGM-86C Block I and Block IA
were re-armed with a more conventional 1 450 kg PBXN-111 HE-FRAG
warhead. Thanks to a more powerful polymer-based explosive in a much
larger quantity and a much wider fragmentation pattern, the PBXN-111
warhead is effective against a wider range of targets, including
some hard targets.
The AGM-86D is armed with an AUP-3M 540 kg HE
penetrator warhead. The design of the AUP-3M emphasizes blast force
rather than fragmentation, and its hardened casing allows a diving
AGM-86D to drive it deep underground before exploding, even through
layers of solid material such as metal, stone, or concrete. This
gives the AGM-86D the ability to destroy hardened underground
facilities (though not at great depths, as the CALCM is only a
subsonic weapon), and virtually any individual surface target.
However, as mentioned above, the CALCM is significantly
heavier than the ALCM, and has a smaller fuel capacity as a
consequence of the much larger volume occupied by the conventional
warhead. Thus the decreased fuel load and increased workload on the
engine had roughly cut the range in half, to 1 200 km, though this is
still an exceptionally long range for an air-launched,
The first combat use of the CALCM was during the "Round
Robin" missions supporting Operation Desert Storm in 1991, flown by
seven B-52s carrying 39 missiles. These were at the time the longest
and farthest combat missions ever flown, covering more than 22 000
km over some 35 hours of continuous flight, supported by many
aerial refuellings. Flying to a series of designated launch points,
these seven aircraft launched 35 missiles into Iraq, destroying a
number of high-value targets, and catching the Iraqi military
off-guard. Another 13 CALCMs were launched in 1996, in support of
Operation Desert Strike, in a joint USAF-Navy mission that also
BGM-109 Tomahawk missiles launched from ships and
submarines; however, several CALCMs went off-course, and some that
successfully hit their targets caused no damage, due to the hardened
structures of the facilities hit. The CALCM was used in combat again
only 3 years later, in Operation Desert Fox, during which 90 (more
than in all previous operations combined) were launched into Iraq.
More than 100 AGM-86C CALCMs and BGM-109 Tomahawk missiles were
launched against targets in Kosovo in 1999, in support of Operation
Allied Force, though the exact numbers of each are uncertain.
More CALCMs were launched in combat during the 2003 Invasion
of Iraq than in any other conflict to date --- a total of 153. The
most dramatic moment in the CALCM's career came on the night of
March 21st 2003, three B-52s fired the first shots of Operation
Iraqi Freedom, when they launched more than 100 CALCMs in a matter
of minutes, in what was possibly the most devastating air strike in
history. More importantly, this attack also validated the argument
made for the original ALCM in the 1970s; that a single, small flight
of B-52s could almost simultaneously launch more than 100 cruise
missiles deep into enemy territory, without ever coming within range
of their defenses.
By 2013, a total of 622 ALCMs had been converted into CALCMs,
though almost a third of these have been expended in combat. Each
conversion cost approximately $150 000, in addition to the unit cost
of an AGM-86B ALCM. It is possible that more ALCMs will be converted
into CALCMs in the immediate future, but this is becoming
increasingly unlikely due to the weapon's age, and the
unavailability of a successor to either weapon. Both the ALCM and
CALCM are to be replaced by a new cruise missile under the LRSO
program, but even the design of this weapon has not yet been
finalized, and the future of the program is still uncertain.
The USAF remains the sole operator if the AGM-86C/D CALCM,
and due to the weapon's origins as a delivery system for nuclear
warheads, it is very unlikely to proliferate.
CALCM Block 0: First production model, equipped with a 1st
generation GPS, and a 680 kg AFX-760 HE-FRAG warhead. 105 were
AGM-86C CALCM Block I: Upgraded Block 0 missile with a 2nd
generation GPS, and a 1 450 kg PBXN-111 HE-FRAG warhead. 200 were
AGM-86C CALCM Block IA: Upgraded Block I missile with a 3rd
generation GPS, improved electronic counter measures, and new diving
attack profile. 163 were converted.
AGM-86D CALCM Block II: Has further improved electronic
counter measures and attack profile, and a new AUP-3M 540 kg HE
penetrator warhead. It can destroy hardened underground facilities ,
though not at great depths. A total of 130 were planned, with an option for up
to 195, but only 50 conversions were made.
AGM-86E CALCM-ER Block III: Loner-range version of the
AGM-86D, developed for the USAF's ERCM (Extended Range Cruise
Missile) program. None have been built, and the program appears to
be in limbo.
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