How do Skydivers Know When to Open the Parachute?
Skydiving—it’s a real rush! Picture it: the clouds are zipping by as jumpers descend down the background of a bright blue sky, the wind rushing up against them as they fall. Some of them coming down in groups, students with instructors, tandem skydivers, and some solo jumpers. Each person flying their body, maintaining stability, taking in everything around them—the world below stretching on expansive and full. With all of this going on and so many things to focus on, you may wonder how do skydivers know when to open the parachute? How could they possibly keep track of it all? Here at Skydive California, we like to provide inside information for inquiring minds. If you would like some exclusive information on how skydivers know when to open the parachute, just keep reading.
Many sports have specialized equipment: baseball uses a bat and glove, soccer uses cleats and shin guards, rock climbing uses ropes, harnesses, and belay devices. Skydiving is no different. In order to know when to open the parachute, skydivers must be altitude aware, or in simpler terms, skydivers must be aware of how high up they are/ how far away they are from the ground. If you have watched any skydiving videos or seen skydiving on the television or in a movie, you may have noticed skydivers sporting something that looks a lot like a fancy watch. In skydiving, this ‘fancy watch’ is the piece of gear that is used to determine altitude, and it is called an altimeter. Altimeters function by using atmospheric/barometric pressure to determine altitude.
There are two primary types of altimeters used by skydivers: digital and analog.
Analog Visual Skydiving Altimeter
The analog visual altimeter looks very similar to a clock face and is marked from 0-12,000ft. The arrow on the altimeter points to the current altitude. Often, the face of the altimeter will be marked with yellow and red sections which mark the recommended deployment altitude and the emergency procedure decision altitude respectively.
Digital Visual Skydiving Altimeter
These neat little pieces of electronic innovation also operate using changes in barometric pressure. However, they indicate the current altitude with a digital number on a screen rather than with an arrow on a face. These tiny computers are often able to keep up with other things and may contain features that are able to record the speed reached on a skydive.
Audible Altimeters: Another Piece of Important Equipment for Skydivers
In addition to the visual altimeters, a skydiver may also utilize an audible altimeter to help them know when to open the parachute. The audible altimeter, also known as a Dytter, is a small computer that jumpers can slide into their helmets. Before a skydive, a jumper will program the Dytter to emit a warning tone at preset altitudes. In this way, even if the jumper has gotten a little carried away with the fun of it all, there’s a back-up to remind them that it is time to open the parachute.
When Do Skydivers Open Their Parachute?
It depends on what type of skydiver and license holder they are. Drop zones that are members of the United States Parachute Association adhere to certain basic safety recommendations. The United States Parachute Association provides minimum opening altitudes within the Skydiver Information Manual. These are the minimum altitudes above the ground that different levels of skydivers must open their parachutes. Keep in mind that these are minimums, and most drop zones set the altitudes that parachutes be deployed a bit higher.
- Tandem Skydivers must open parachutes by 4,500AGL (Though, most open around 5,000-5,500 to allow you to enjoy the view)
- Students and A License holders must open their parachutes by 3,000 feet AGL.
- B-License jumpers must open their parachutes by 2,500 feet AGL.
- C and D licensed skydivers must open parachutes by 2,500ft AGL (this is waiverable to 2,000ft AGL but no lower)
Skydiving is a sport that requires jumpers to be aware. After all, there is quite a lot going on. Thankfully, the jumpers at Skydive California are safety-focused and altitude aware. Now that you’ve learned how skydivers know when to open the parachute, why not come don a ‘fancy watch’ and give it a try yourself! You can leave it to the experts and let your tandem instructor open the parachute for you and go along for the ride! Live in Northern California? Then check out Skydive California for your first tandem skydive!
Why Do Skydivers Wear Helmets?
Helmets are required for student skydivers and worn almost universally by experienced skydivers.
The helmets worn by student skydivers are generally of open-faced style used at skate parks (often referred to by the “Protec” brand name). At many dropzones, there’s a pocket on one or both ears. The pocket configuration is designed to hold a radio, over which the student will be coached from the ground as s/he is landing. These helmets are impact-rated by the DOT and are meant to protect the student from injury if a bump occurs on the inside of the plane, on the teacher in freefall or upon landing. Pretty straightforward stuff, no?
Once that student graduates, the world of skydiving helmets gets a whole lot bigger. Experienced jumpers wear discipline-specific helmets that range from leather aviator-style chinstrap hats (called “frap hats”) to full-face helmets to–in rare cases–nothing at all. Helmet usage is not generally a requirement in the sport for licensed jumpers. (Individual dropzones, however, may set whatever gear pre requisites they wish to enforce for their communities.)
As opposed to, say, mountain bikers, snowboarders or the denizens in your local skatepark, skydivers aren’t just putting a lid on it for safety. In practice, skydivers wear helmets for a number of reasons:
The wind in freefall is a powerful thing. Lots of skydiving athletes wear helmets that aren’t impact-rated for one important reason: comfort. A helmet keeps your hair contained, helps you hold on to your expensive sunglasses and keeps the rush of the wind off your face (so you don’t have flappy cheeks on every single skydive). In fact, truth be told, “skydiving comfort helmets” are the most common helmet type in the sky.
Helmets look good. They’re available in all the colors of the rainbow, so they match your suit and your container. They provide a handy space to display your stickers–the local-pride ones; the brand-pride ones; the cheeky ones; the ones from the brewery you visited when you went to that boogie and you can’t quite remember what happened that night if you’re being honest but the pictures looked amazing.
Especially since the dawn of the GoPro, skydiving helmets have taken on another role: that of camera mount. While some skydivers debatably take it a little too far, most of us have a GoPro sticking Teletubby-style out the top of our heads or jutting from our chins. It’s part of it, really.
Note that camera usage is only allowed for licensed jumpers meeting the USPA recommended requirements such as having 200 jumps.
With all that said: You’ll rarely see a hard helmet on the head of a tandem student. Generally, students are either helmetless or frap-hatted, because there’s a chance that (if they really got a wind-up) they could knock their tandem instructor unconscious with a helmeted head. To be safe, the USPA teaches that tandem students should go without.
Ready to get your hair in the wind? Don’t be a stranger! Contact us today.
Why do skydivers use parachutes?
Skydivers need to use parachutes because those are the apparatuses that give human beings the ability to reduce their falling speed enough that they are able to land safely on the ground.
That’s the short version, so let’s look at the physics behind this answer from a scientific position.
Why Skydivers Need To Use Parachutes, According to Sir Isaac Newton
Skydiving & Falling Apples
Sir Isaac Newton  , well-known for his penchant for apples  , is better remembered for his formulation of the three Laws of Motion, the basic principles of modern physics.
The first law of motion describes inertia :
An object at rest stays at rest and an object in motion stays in motion with constant speed and in the same direction unless acted upon by an unbalanced force. 
Inertia is like momentum. The first law basically implies: if a thing isn’t moving, it will not start moving by itself. If a thing is moving, it will not stop or change direction unless some external force acts upon it.  A skydiver falling through the air cannot stop or slow down without the intervention of another force, which in this case would be the air resistance caused by a parachute.
The second law of motion addresses the cause and effect portion of falling. It states:
Acceleration of an object is dependent on the forces acting upon the object and the object’s mass. 
Keep in mind that acceleration exists whenever speed is changing, up or down. So it does not just mean going faster, it also refers to slowing down. In the case of skydiving, the second law of motion (F=m*a) or, Force = mass x acceleration, refers to the mass of the jumper plus their gear, as well as the forces it takes to speed them up (gravity) as well as the force that slows their descent (drag). We’ll get deeper into that a bit further down. * See illustrations below.
The third law of motion refers to a kind of natural symmetry, or the action/reaction effect.
Whenever one body exerts a force on a second body, the first body experiences a force that is equal in magnitude and opposite in direction to the force that it exerts. 
When you stub your toe on the corner of a door, both objects involved (your toe and the door) experience a force. That force translates into movement for the door, and pain for the toe. This applies during skydiving as air resistance acts on our body surface, creating the slowing down effect, or drag that we just mentioned .
Why Skydivers Reach Terminal Velocity
While the skydiver is in the airplane getting ready to jump, she is traveling horizontally through the air in tandem with the airplane. At this moment, gravity is being neutralized by the lift force caused by the air passing through the plane’s wings. This is true until she steps out of the aircraft and begins to accelerate on the vertical axis.
As the skydiver accelerates she gains momentum, and the air she passes through creates a resistance that pushes back up at her, increasing drag.
Eventually, the force of the resisting air balances out with the force of gravity, and the skydiver stops speeding up. Once she has reached this balance and is no longer accelerating, she has reached terminal velocity. Which is to say: drag is equal to weight, acceleration is zero, so velocity is constant.
Terminal velocity is a weird term because it sounds scary, but is really quite the opposite. When you are no longer accelerating, you feel almost like you’re floating. On a skydive, everything that happens to your body is according to its natural physical motion. It is nothing like a roller coaster or bungee jumping, because you are not suspended or attached to an object that drags you out of you body natural acceleration range. Skydiving is a magical feeling!
What happens when the parachute is deployed?
When the skydiver reaches “pull altitude” (the height at which she needs to deploy the parachute), she pulls a mini parachute called pilot chute from a special pocket in her parachute container, flinging it into the wind. The wind catches the pilot chute and the drag it creates initiates the parachute opening sequence. Once out of the container, the main canopy is inflated by the wind, causing the amount of air resistance to increase even more, and neutralizing the force of gravity at a much lower velocity .
Modern parachute canopy designs are made in a way that after inflated, the parachute becomes a wing. This creates lift as it glides thru the air, and also allows full controllability of the parachute’s heading direction as well as control over the glide, which is especially important for the landing.
So there you have it! Real facts for a valid question: why do skydivers use parachutes? You know, this article was almost much shorter. This was the first draft: “Because it saves their lives.”