Reserve Throw Study

Dr. Matt Wilkes generated the most careful study of reserve deployment behaviour I’ve ever seen. Andre Bandarra interviews him in this video, asking many of the questions that frequently arise when pilots talk about this stuff. It’s 30 minutes long and absolutely packed with data, observations, and recommendations. This video probably settles a few campfire bets.

Some of the observations were eye-opening to me, and challenged my assumptions. For example, I’ve been teaching pilots to wind up the throw across the body before throwing the reserve (to give it a hard throw). In the tested cases, this is an unnatural technique. At worst, the wind-up caused a couple of pilots to tangle in their reserve lines or reserve bridle. The study observed that a single, up & backward deployment movement was applied by 70% of pilots regardless of reserve location, and that when the reserve didn’t slide out of its container easily (such as with some underseat reserves), the pilot changed their grip on the reserve handle so that they could pull up & backward harder. Throwing hard is helpful in cases where the pilot is in slow autorotation or otherwise moving through the air slowly. Nevertheless, In the heat of the moment we’re all going to do what feels natural and right, so I’m going to teach to that.

Another fascinating observation made by the study: When the strop between the reserve handle and the deployment bag was too long, the pilot had a hard time extracting the reserve from the container. Additionally, the pilot’s throw became weaker due to the lagging connection between the pilot’s arm and the reserve’s mass. In the study, pilots with shorter arms had difficulty extracting the reserve due to the strop being too long. Contrast this with the scenario in which the length of your reserve strop is shorter than the length you need to pop the pins free of the reserve pin loops, locking your reserve in its container. It’s clear that strop length is an important factor in reserve deployment success.

With just under 1000 hours of flying to date I’ve seen over 30 reserve deployments in the wild, but I have yet to see own. In 2015 I almost threw after 3 cascading oscillations, but I hesitated and instead opted for full-stall-reset, for reasons. I was lucky I had the altitude to waffle in indecision for so long, and the recent practice in full-stalls. One of the recommendations near the end of the video is for pilots to seek out practice in reserve-throw decision-making, throw their reserve in a maneuvers clinic, and remove inhibitions that may prevent the pilot from making that throw decision.

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