September 1,2008:
Parachuting supplies to troops is
becoming more popular in Afghanistan. This is more expensive, but gives the
growing number of Taliban placing roadside bombs, far fewer targets. So far
this year, over 4,400 tons of supplies have been air dropped by U.S. Air Force
C-130s and C-17s. That's more than was dropped in all of 2007. In the last four
years, 8,500 tons have been dropped, with 98.5 percent of the drops being
successful. Accuracy is important in Afghanistan, with all the hills, gullies
and forests. Air dropped supplies have landed, on average, with 185 meters of
the aim point.
Where high
accuracy is required, the air force has developed JPADS (Joint Precision
Airdrop System) and ICDS (Improved Container Delivery System). Both of these
are systems whereby pallets of supplies are equipped with GPS, and mechanical
controls, to guide the direction of the descending parachute for pinpoint
landings. After the pallet is pushed out of the aircraft, but before the
parachute is deployed, the pallets first release a parafoil (a parachute that
can be controlled in such a way that the user can gain altitude and travel over
long distances), and the pallet descends at about 44 meters a second (from an
altitude of about 6,000 meters, safely away from any ground fire), guided
towards the landing point. When a few hundred meters over the programmed drop
zone, the parafoil is released and the parachute deploys, bringing the pallet
(with up to five tons of supplies) down within a hundred meters of the
programmed landing point. A single C-17 can deliver up to 40 pallets this way,
to many different landing zones. JPADS has release point information
(calculated using current weather conditions) sent to the C-17, along with GPS
landing coordinates for the pallets. This GPS data is transmitted to each
pallet via a wi-fi type system.
The new system was developed from earlier precision
para-drop systems. All rely on GPS to give accurate landing information, and
easily manipulated parafoils to provide the maneuverability. The aircrews find
it fascinating to push a bunch of pallets out, then watch as they form into
"flocks" and head off for their various drop zones. For the troops on
the ground, it's a convenient way to get supplies, no matter where they are out
in the boondocks.
Before the
development of GPS guided air drops, a large percentage of air dropped supplies
were lost, either by falling into enemy hands, or into things that destroyed
them (especially water). With the new delivery systems, it's possible to do
night drops, which is preferred when you don't want to alert nearby enemy
troops. Often, you can accurately drop pallets without the GPS systems, if you
have a large flat drop zone, daylight, and calm winds. But if conditions are
difficult, you now have GPS guided drops.