The Washington Post, Al Jazeera, and others have been reporting in the last twenty-four hours on the uptick of regime aerial bombings in the city of Aleppo. What seems to be catching everyone’s attention (rather than the large casualty numbers) is the type of weapon being deployed by the Syrian Air Force: the barrel bomb.
The barrel bomb is a fairly straightforward weapon. Cram as much high-explosive as possible into a steel drum, attach and light a simple fuse, and kick it out the back door of a HIG helicopter. Most Syrian barrel bombs contain large steel fragments, such as cut rebar or large industrial bearings, that act as high-velocity shrapnel on impact.
If you really want to get into the weeds on barrel bombs, I highly recommend Richard M. Lloyd’s guest post on Brown Moses Blog.
The Syrian military has used barrel bombs in the past, but recent tactical developments by opposition fighters have forced changes that have resulted in a much higher rate of destruction for these do-it-yourself munitions. The deployment of MANPADS (Man-Portable Air Defense Systems) by opposition ground forces has forced Syrian helicopters to fly higher and has reduced the accuracy and success rates of barrel bombs. The first, crude versions of the barrel bomb only had a rate of success (meaning a ground-level explosion) of about 25%.
(An interesting aside: experts are now calculating bomb impact success rates based on how probable the bomb is to impact not only grass or concrete, but also “rubble.” We’ve reached a point in the war now that rubble is so widespread across Aleppo and other cities that it must be accounted for in munitions targeting and success rates.)
However, necessity has been the mother of innovation for barrel bombers. The Syrian Air Force has developed a new family of barrel bombs that are bigger (around 2,000 pounds of high-explosive), more accurate (feature stabilizing fins welded to the sides), and more reliable (utilize impact detonators). Even at higher altitudes, these new barrel bombs are estimated to have a success rate of close to 40%.
What is still unclear is why this particular (and relatively inaccurate and unsophisticated weapon) is being used instead of conventional unguided high-explosive munitions. The danger is that Syrian barrel bomb construction and deployment will improve and become even more deadly. Video and photographic evidence shows that the government may be converting HIG-8 helicopter auxiliary fuel tanks into bombs, which could mean bombs capable of carrying up to 3,000 pounds of TNT.
Another danger to keep an eye out for could be increasing deployment of barrel bomb versions of Fuel-Air Explosives (FAEs), also known as “vacuum bombs.” These bombs have the ability to generate explosions greater than 15 ton TNT equivalent weights. The Syrian Air Force has employed this type of explosive in the past.