Virtual Parachute Training
Someone once quipped that a parachute is the only aircraft vehicle that gets built in flight. That means if something goes wrong, or if procedures are not followed correctly, the jumper is at the mercy of the deadly force of gravity.
There is tremendous potential for serious injury or death during a jump. The problem, though, is training. Live training jumps are logistically difficult, time-consuming, and very expensive.
That’s not just the case with operational jumpers. It is a particularly thorny issue vis-à-vis flight crew. Most flight crew will never need to parachute out of their aircraft, since planes becoming disabled in mid-air is a relatively infrequent phenomenon. Why go through all the time and expense of training flight crew (via live jumps) to parachute, if in all likelihood they’ll never have to do it? But if it ever do have to bail out and they’re not trained to jump, the consequences could be devastating.
That dilemma had been dogging the U.S. military for decades. But in the early 1990s, a partial remedy was found: a parachute simulator.
Called the Virtual Reality Parachute Flight Simulator or ParaSim, the user wears a harness connected to risers (i.e., straps that normally connect to a canopy, except in this case there is no canopy), and puts on a head-mounted display/virtual reality goggles, which has a head-tracking system that senses where the user is looking. A sensor indicates when the user pulls the ripcord. There also are sensors on the risers.
The ParaSim depicts all phases of a jump, from leaving the aircraft to the parachute landing. Users can choose from various kinds of canopies, degrees of altitude, wind conditions, light conditions, and other factors. Different kinds of parachute malfunctions can be replicated. The simulator also has the capability to replicate landing zones based on actual terrain anywhere in the world. And there is a networking capability, so the user can practice jumping with other users.
The device appears to be the only product of its kind on the market.
Jeff Hogue, Principal Specialist at Systems Technology, Inc. (Hawthorne Calif.), invented and developed the product. He approached the Army after building it for the smoke jumpers of the U.S. Forest Service and Bureau of Land Management. Smoke jumpers are those who parachute into remote wilderness areas in order to fight forest fires. In the 1980s they acquired high-performance parachutes, including what’s known as ram-air parachutes, which are capable of faster speed and better maneuverability. Their benefits notwithstanding, these parachutes leave little room for error regarding safety issues.
“I went up to Missoula, Mont. and took a look at (the smoke jumpers’) flying problem and training issues, and came up with a concept for them, which they said really helped with their training problems and with relatively low cost,” recounted Hogue.
He added, “These people are not jumping for fun like they do in sports. They’re jumping to be inserted somewhere, and you only do parachuting in instances of last resort because it’s regarded as so hazardous.”
Of course, that applies to military jumpers as well. And the military indeed has become a big user of the ParaSim—to train operational jumpers in addition to flight crews. Currently there are hundreds of such simulators in various locations throughout the military.
One such location is Andrews Air Force Base, Md., where the Air National Guard provides parachute training for its pilots in the event they ever have to eject. Their ParaSim consists of a large metal frame with risers extending downward. There are two computer monitors next to the frame. One is the user interface, which allows the user or trainer to input variables (such as the user’s weight, wind speed, fog, rain, etc.), and the other monitor displays the view that the user sees while wearing the virtual reality goggles.
The trainee straps on a parachute harness, hooks him- or herself onto the risers, and puts on the head-mounted display. The drill then begins, where the user can look up to see the virtual canopy, and down to see the virtual landing site. (To be sure, the trainee sees a square screen, as opposed to an all-encompassing visual display.) While in flight the user practices basic procedures, such as steering the descent by pulling on the risers.
“Starting from an altitude of about 3,000 feet, you get enough time to practice all your post bail-out procedures,” said Chief Master Sergeant John Mansfield, 121st Fighter Squadron (Andrews AFB), Life Support Superintendent. “Using the risers you can steer the parachute, and can actually see the effect of that with the simulator. There’s a downwind indicator, because once you get to about 250 feet, you want to turn yourself into the wind. And then you get ready for your PLF or parachute landing fall.
“Afterward,” Mansfield continued, “we review it to see how close you actually got to the marker that indicates where you should land. And after you’re finished, this system basically grades you and tells you how well you performed.”
HAZARDS OF JUMPING
The incidence of injury in military parachuting is 6 per 1,000 descents, according to a study carried out in 2003.
A tremendous number of things can go wrong during a jump. While exiting the aircraft the jumper can collide with the exit doorframe, with the aircraft itself, or with other jumpers. Jumpers can get tangled up with the risers. The large groups of jumpers characteristic of military jumps increases the chances of mid-air collisions.
Mike Russell, Safety Director at U.S. Special Operations Command (MacDill Air Force Base, Fla.), said there are two basic categories of malfunctions. “One is a total malfunction, where you don’t get anything out of your pack at all” after pulling the ripcord. “The other is a variety of partial malfunctions: you can have a line-over, where a line loops over the canopy, and you can have a situation where the slider hangs up so the canopy doesn’t open fully. Or one of the brake lines can become unstowed, break, or get hung up in one way or another during the opening process, so the canopy wants to fly in a spiral instead of straight. And you can have ‘blown’, or torn, panels in the canopy, itself.”
For the landing, uneven terrain, high winds, and obstacles such as trees add to the hazards. Descending at a typical vertical speed of about 13 mph, the landing force is about equivalent to jumping off a 9 to 12 foot wall.
Night time jumps add to the danger, as do jumpers weighted down with equipment. “Injury risk increased with a greater number of soldiers exiting the aircraft, winds from the rear of the aircraft, simultaneous exits from doors on opposite sides of the aircraft, smaller parachute canopies, higher ambient temperatures, and airborne refresher courses (vs. introductory courses),” stated the study mentioned above, titled “Factors for Injuries During Military Parachuting” by Joseph J. Knapik, Stephen C. Craig, Keith G. Hauret and Bruce H. Jones, published in the journal Aviation, Space, and Environmental Medicine.
By increasing the jumper’s horizontal velocity (in addition to the vertical velocity), wind increases the overall landing velocity. “What kills in the parachute is the total velocity vector. It’s not just vertically, it’s also forward,” observed Hogue. And wind also can blow jumpers away from their designated landing zone to areas with rough terrain or obstacles.
High-performance parachutes such as ram-air, which are more steerable, which are capable of being deployed at high altitudes (30,000 feet), and which enable faster vertical and horizontal velocities, are becoming more common in the military. While they enable greater maneuverability, they also are associated with increased risk of injury.
When you start working with highperformance canopies the margin of error, once you’re under the canopy, becomes very small,” explained Russell. “So relatively minor mistakes can have catastrophic results, particularly with landings. If you make a mistake, you can hit the ground very hard or at a high rate of speed. And you may have other folks flying around at relatively high rates of speed, so the potential for canopy collisions, or entanglements increases. Also, inexperienced jumpers have a tendency to get target fixation on the landing area and may end up crowding each other and forcing someone into a bad situation at low altitude.”
Bigger parachutes are becoming more common as well, as military jumpers carry larger cargos, or carry out tandem jumps in order to bring in mission specialists who are not jump qualified. Such factors introduce additional training challenges.
For non-operational jumpers, such as flight crew, parachuting can be sensory overwhelming. “What happens when you get overwhelmed in a novel situation is, quite often you panic,” averred Hogue. “Panic kills. So the one thing that they teach you is that you don’t want to panic. You’ve got to be in control. Well if you can provide somebody with the visual experience that replicates the kind of environment that they need to be operating in, and you can get people beyond that, that’s basically what the ParaSim does.”
SIMULATING TO SURVIVE
ParaSim users can program digital terrain data of actual locations. 3-D objects can be generated, with multiple levels of detail, using OpenFlight format, a leading format for visual images in the flight simulation industry. And though the user feels no actual wind while in the simulator, wind elements can be programmed into the computer so that the virtual reality display acts as if there is wind.
“You’ve got to figure out, one, is my parachute OK and if not, what to do about it? Two, where is the safe place to land on the ground? And three, what’s the strategy to follow to get to that safe place?” pointed out Hogue. “Or maybe I pick another safe place. The simulator gives users the ability to practice in that environment and interact with skilled instructors who can tell them what techniques to use to get to that correct location on the ground.”
At high-altitude jumps, such as at 30,000 feet, without oxygen the parachutist could black out. So the simulator can replicate a black-out if the oxygen is not deployed.
He continued, “You do this a few times and users will know what to expect and what their reactions are going to be. You learn to do things safely, so when you go out there the stuff makes visual sense. You’ve provided ‘positive transfer of training.’”
The ParaSim enables the ability to play the sequence of events back for after-action review. “Did the jumper look up to make sure his parachute deployed properly? If he tries to correct the parachute, does he look up again to make sure the parachute is correct? Did he check to see if somebody else is on a collision course with him? Did he land on the ground safely?” Hogue says it’s amazing how many things people don’t pay attention to when their life is at stake. But such events can be played back and pointed out to the trainee.
ParaSim training is mandatory for Special Forces, according to Garry Dixon, the project officer with U.S. Army Special Forces Command (Ft. Bragg, N.C.). “We took lessons learned from the Forest Service. There’s at least one (ParaSim) in every Special Forces group now. It’s part of the POI (program of instruction) that the soldier has to have before he can jump the SF-10A personnel parachute, which is the new replacement for the MC-1C personnel parachute.”
Of the simulator, Dixon said that, of course, the user knows he or she is not in the air. “But other than that, you can really learn good canopy control and how to land safely on target.”
Added Russell, “We first looked at the parachute simulator in the spring of 2003, and thought it was a pretty good system. Like any simulator, it has its limitations. It’s not a substitute for the real thing. It’s probably most beneficial in learning to recognize emergency situations, reinforcing critical procedures and practicing high-risk operations under the safety umbrella of a training environment.”
The pilots of the 121st Fighter Squadron at Andrews AFB take refresher training in the ParaSim once a year. “A large portion of their day is gone,” said Chief Mansfield. “But it’s worth it. We train like we fight. The pilots go up feeling more comfortable now. And sometimes they tell me, ‘Thank you for everything you did for me.’ But with the parachute trainer, the only thing we really did was just put some key thoughts into their head to say, “Listen, because this is what you have to do in order to survive a situation.” ♦