It is dark on a windy and chilly early Sunday morning in January. As an Air Force C-17 idles on the tarmac, about 35 people attend a pre-mission safety briefing within Yuma Proving Ground’s Air Delivery Building, a tall structure where parachutes are maintained and packed on a daily basis.
As usual, participants review the day’s extensive test schedule, but this morning is different. The testers appear nonchalant, but they know that in a few hours a distant range on the proving ground will host the first-ever test of the GigaFly, the world’s largest guided ram-air parachute. If the test succeeds, the parachutes could be deployed to combat zones overseas to quickly and precisely deliver heavy equipment to ground forces.
"We don’t know how smooth it will be," cautioned a test officer as he addressed the assembled personnel. There is reason to be cautious. The GigaFly’s maiden drop is carrying a 16-and-a-half-ton payload dropped from an altitude of 17,500 feet. A catastrophic failure of the 10,400 square foot parachute would send 33,000 pounds crashing to earth, soundly crushing anything in its path. Although an unlikely prospect, the extremely wide tips of the chute might not deploy properly, causing one or more panels of the chute’s five 200-pound sections to tear away. The on board flight software could cope with the loss of one or two panels, but no more.
After the safety briefing, the ground crew prepares to caravan by automobile to the drop zone. The mission payloads are driven on long flatbed trucks from the air delivery building and carefully loaded onto the C-17. In addition to the 33,000 pound weight tub the GigaFly will be carrying, a second system and payload are loaded into the massive aircraft: the MegaFly, a 9,000 square foot parachute that has been previously tested, and is attached to a M35 2-1/2 ton cargo truck. Both payloads are cushioned with a honeycomb-like material between the item and the steel palette that carries it.
Meanwhile, crew members at the test site are making final preparations for the drop. A large orange triangle is set up to mark the target area, photographers set up their equipment on a mesa overlooking the drop zone, and invited members of the media, including a film crew from the Discover channel, are escorted to the site. Among the observers is Brian Bagdonovich, airdrop technology team leader of the U.S. Army’s Natick Soldier Research, Development, and Engineering Center.
Since this is the first time the GigaFly has ever been deployed, the parachute’s engineers can only speculate how much to steer the parachute using their experience with smaller parachutes.
"It is a bit questionable how accurate the first landing will be," Bagdonovich remarked.
The C-17 flies toward the drop zone and makes a pass over the landing site before being given the go-ahead by mission controllers on the ground. A 15-foot extraction parachute is deployed, quickly followed by two 28-foot parachutes that pull the payload on a 120 foot line out of the aircraft. Dropping an extremely heavy load -- the maximum capacity of the GigaFly is equivalent to the weight limit a C-130’s cargo area is capable of carrying -- is not an easy task for the pilots, who must immediately correct their flight path and altitude when the plane bobs up following the exit of the payloads. The GigaFly is first out of the cargo hold, and within seconds, a small red, white, and blue parafoil blooms against the clear sky. "Sweet," Bagdonovich says approvingly as he watches through binoculars.
The massive payload falls to earth at approximately 20 feet per second, and takes over ten minutes to land. As part of its landing pattern, the GigaFly flys back and forth in a manner that may lead one to believe it is veering wildly off-course. This is a deliberate phase of the landing the engineers call energy management mode, which ends at a time selected by the onboard flight software. The massive payload lands with an audible thud a little over a mile away from the intended impact zone, a relatively minor discrepancy for the maiden flight on an expansive, vacant range. In order to simulate real-world use, the testers do not recover the GigaFly until the MegaFly has also been dropped. Ten minutes after the first landing, the C-17 returns to drop the MegaFly and its cargo truck passenger, which safely lands about 600 feet from the target.
Within minutes of the final landing, a parachute recovery team arrives on the drop zone to carefully untangle and pack the billowing sections of the parachutes, then tie them into bundles which are loaded onto large flat bed trucks. Various members of the test team look on, including program manager Bill Gargano of Airborne Systems North America, who had been in the ground control room.
"We’re very pleased with the test," Gargano said. "I’m happy with where we are and look forward to doing more."
"I’ve been coming to Yuma Proving Ground for eight years," added Justin Barber, a senior engineer for the same company. "There is no other facility like it in the world in terms of being able to do what we do. The number of drops conducted here is amazing."
Though the GigaFly is currently the world’s largest guided ram air parachute, it may not be for long. "I’d like to build a 90,000 pound parachute," Gargano said with an eager smile. "I think it is quite possible."