Freefall Data Systems is studying how skydivers judge altitude errors. You will read about one planned skydive and judge 34 short events that occur during it. It takes about 8 minutes.

Taking part is voluntary; you can skip any question or stop at any time. The survey is anonymous: we do not collect names, emails, USPA numbers or IP addresses. Results are reported only in aggregate. There are no foreseeable risks and there is no direct benefit to you.

You must be 18 or older and a skydiver (any experience level). Questions: casey@freefalldatasystems.com.

By clicking Continue, you agree to take part.

A response has already been sent from this browser. If that was you, please don’t take the survey again; if you are someone else, go ahead.

A B-licensed jumper makes a 4-way belly jump from a Cessna 182 at 13,000 ft (120 mph fall rate, 1.0 wing loading). The four are the whole load.

The plan: break off at 5,000 ft and pull at 3,500 ft. Under canopy, the jumper's decision altitude is 2,000 ft; they plan to enter the landing pattern at 1,000 ft, turn base at 600 ft, and turn final at 300 ft. The other three jumpers land using the same pattern in the same general location, and nobody else is in the air.

You will see one event at a time from jumps with exactly this plan. For each, decide whether it is an acceptable deviation from it.

Your answers help build a measured picture of how skydivers judge altitude errors. Results will appear in the Research section once the full run is complete.