Le Dispositif de Déploiement Automatique : Une technologie spécifique au parachutisme, au service de la sécurité!
Estimated reading time: 14 minutes
One of the most frequently asked questions when discussing skydiving is: Can the parachute canopy open by itself? The answer is yes, absolutely! In fact, at Parachute Voltige, except for certain specific sports disciplines, what we call the Automatic Deployment Device (ADD, for those in the know) is mandatory on all equipment , including tandem equipment.
How exactly does an automatic parachute deployment system work?
Over time, the equipment used by skydivers to jump from an airplane at thousands of feet altitude has evolved considerably, much to everyone’s delight! Technology has helped improve safety aspects of skydiving. This is particularly true of the Automatic Deployment Device (ADD), also known as the Automatic Activation Device (AAD).
The latter is a small computer hidden in the equipment which will automatically deploy the reserve parachute (hence its name) if it detects that the parachutist is still moving at high speed, therefore in free fall , and at a lower altitude than expected.
This could occur if a jumper loses consciousness, if there is a malfunction with their main parachute, or if their altimeter is out of adjustment, for example.
That said, it is the responsibility of every sport skydiver or tandem instructor to check their equipment before donning it and to ensure that the automatic belay device (ABD) is fully operational. At Voltige, we perform this check at the start of each day, AND BEFORE EVERY JUMP!
A few technical points!
More specifically, how does it work ? Well, the device’s electronic module is accessible to the parachutist so they can turn it on, turn it off, or check that it’s functioning. This module usually looks like a small screen, just a few centimeters across, and is elongated. A button is located next to the screen for operation.
A cable, connected to this control module, runs inside the parachute’s backpack to the reserve canopy. At the end of the cable is another electronic module, concealing a small blade. Should a skydiver fail to open their main parachute at a certain altitude, the electronic module would trigger the blade, which would sever the loop holding the reserve parachute closed . It’s like a micro-guillotine or a cigar cutter, but with the closure loop as the victim!
How does the electronic module know at what altitude to trigger its guillotine?
First, when the skydiver activates their automatic parachute deployment (APD), it’s crucial to do so on the ground, at their intended landing location. The device then uses this reference point as ground zero . Once inside the aircraft, up to the exit altitude, the APD takes into account the change in atmospheric pressure . This is how it calculates the distance to the ground as it’s being created. Once outside the aircraft, while the skydiver is in freefall , the APD can detect if they are still falling at high speed, having exceeded the altitude at which they planned to deploy the main parachute . The APD will then automatically deploy the reserve parachute.
A little bit of Physics 101!
Let’s say the landing zone and the airport are located far apart , as is the case in some skydiving schools abroad. If the jumper activates their automatic beacon (ABD) at the airport’s altitude, and that altitude differs from the altitude at which they will land their parachute, this could disrupt the measurements the ABD uses to function correctly.
For example, if the airport is a few hundred feet higher than the landing zone and the jumper activates the device at the airport, it may trigger unnecessarily too early . The blade will activate a few hundred feet higher than intended because it will have taken into account the initial baseline measurement of the airport.
Conversely, if the airport is a few hundred feet lower than the landing zone, such an error could be fatal for the skydiver. The DDA (Deadline Assumption Device) wouldn’t consider the skydiver to be at the pre-programmed altitude and wouldn’t activate the automatic recovery system at the appropriate time. Rest assured: the Voltige landing zone and our takeoff runway are only a few meters apart and are therefore at the same altitude!
It’s important to remember that an Automatic Deployment Device (ADD) is an electronic device. No one is immune to malfunction. However, in 30 years, it has helped prevent more than 5,100 accidents [1] , making skydiving a safe sport! Keep in mind that in addition to the technical tools that science has provided for practicing this wonderful sport, it’s the extensive experience of the skydivers and tandem instructors that makes all the difference. We are more than happy to put over 20 years of invaluable experience at your service, to help you experience the most memorable moment of your life!
A text written by François Bertrand-Potvin
[1] Airtec Verwaltungs GmbH, CYPRES, https://www.cypres.aero/about/the-story-of-cypres-2021/#:~:text=saved%20more%20than%205%2C100%20lives
