Skydive Mag is a free, international, online skydiving magazine with daily updates of news, event coverage, educational articles, safety information, videos and more

Jump Run for Wingsuits

Exiting the Twin Otter — by Next Level Flight
Exiting the Twin Otter — by Next Level Flight

By Matt Gerdes and the Next Level Flight team

Ah, the pilot. The boss. The captain. With no exaggeration, our life is in their hands. Sometimes, our pilot is a young’un building time, day-dreaming of future flight attendant conquests. Sometimes, our pilot is a salty relic in snakeskin boots and a leather jacket, whose aviator-shielded eyes you’ve never seen. Sometimes they’re sweet and accommodating, sometimes they just want you the heck out of their aircraft. Regardless, one thing is a fact: statistically speaking, it is very unlikely that your aircraft pilot is also a wingsuit pilot. That is to say, he’s a REAL pilot, and you’re just a yahoo with a foolish hobby.

For that reason, we need to communicate better with real pilots.

The pilot. The boss. With no exaggeration, our life is in their hands.

For that reason, we need to communicate better with real pilots.

Wingsuits are very different from the rest of the skydivers on a load. It is only recently that serious conversations about structured safety progression have been taking place, and it’s only recently that all of the factors of wingsuit exits have begun to be understood.

he’s a REAL pilot, and you’re just a yahoo with a foolish hobby

This article does not cover the techniques that wingsuit pilots themselves should employ to exit safely – that is First Flight Course material and will be covered in more depth in a future article. Right now, we’d like to focus on improving communication between wingsuit jumpers, DZ S&TAs, and Chief Pilots around the world. It’s important, and we believe the future of wingsuit flying depends on it.

The following points are, we think, the most important aircraft factors that affect wingsuit exit safety. They were developed over several years of cooperation between professional wingsuit pilots, commercial pilots and flight instructors, and DZOs, all of whom have extensive knowledge of common jump aircraft: The 182, Twin-Otter, Caravan, Porter, PAC, etc.

In multi-engine aircraft such as the Twin Otter (pictured), cutting the left side (or door side) engine is very helpful for wingsuits — by keith forsyth
In multi-engine aircraft such as the Twin Otter (pictured), cutting the left side (or door side) engine is very helpful for wingsuits — by keith forsyth

The Cut

It is our belief that too much focus has been put on Indicated Airspeed, and not enough has been put on Power, or Torque. When a wingsuit pilot exits the plane, they feel wind. An airplane pilot thinks airspeed. What is lacking from both assessments is the effect of the prop-blast and deck angle on exiting jumpers.

The Power Cut, in our opinion, is equally or even more important than Indicated Airspeed. In single engine aircraft such as Caravans, PACs, or even 182s, the prop-blast is a huge factor in wingsuit exits because it is responsible for a large part of the relative wind, and it is also independent of Indicated Airspeed, meaning that the pilot and jumper may see a desirable airspeed on the dial, but the wingsuit jumper may still jump out into undesirable relative wind.

the prop-blast is a huge factor in wingsuit exits because it is responsible for a large part of the relative wind

In twin engine aircraft such as the Twin Otter or King Air, the cut to the left side engine is critical. The Twin Otter might be the most forgiving of all common jump planes, but tail strikes are still possible, and likely, when factors align. It has been said that the Twin Otter’s engines are distal enough from the door to not affect jumpers, but this is not entirely accurate.

Recommended Procedure: Cut the engine or left side engine to 0-10lbs torque. In the Twin Otter, for instance, the left side engine can be flown idle. In most Caravans, the power setting should read approximately 3-4lbs torque on the dial. In many aircraft, the plane will be descending at a moderate rate (the Twin Otter could still be climbing). The pilot maintains a minimum safe airspeed for controllability, with the engine power cut.

A descent during the wingsuit segment of the jump run is ok – it is far more important to reduce prop-blast, and airspeed.

Airspeed

Most jump aircraft, even a King Air, can be slowed to below 90 KIAS. On any aircraft, if the engine or left side engine is cut, and flaps are applied (if applicable), the proper airspeed will come naturally. Sub-75 KIAS is ideal, and is crucial on some low-tail aircraft such as a PAC. Indicated airspeed will vary with jump run altitude, and pilot comfort, but the power cut should be applied to all aircraft whenever wingsuits are exiting.

In single engine aircraft such as the Caravan (pictured), cutting the power during the wingsuit segment of jump run is very important — by andy farrington
In single engine aircraft such as the Caravan (pictured), cutting the power during the wingsuit segment of jump run is very important — by andy farrington

Aircraft AoA, and Deck Angle

One problem with focusing too much on indicated airspeed is the Aircraft AoA and how it affects the position of the tail. For instance, in a Caravan, if the pilot is focused on maintaining a low airspeed and maintaining altitude (i.e., not descending), then he/she will need to keep the power on. Remember, the cockpit airspeed instruments do not indicate prop-blast. If the pilot is focused on maintaining altitude and also a low indicated airspeed, with the power on, the net result is that the prop-blast is severe and the tail is low!

the net result is that the prop-blast is severe and the tail is low!

In this scenario, the tail is even lower than normal, and although the pilot could be seeing 65 KIAS on the instrument, the wingsuit jumper feels a relative wind that is more like 90 knots thanks to the prop-blast. This is caused by the pilot not being a wingsuit jumper, and the wingsuit jumper not being a pilot.

Pilots must understand that a “Level Deck Angle” is key. Wingsuit jumpers must understand that the relative wind is not just airspeed.

High or Low Tail

Low tail aircraft are the bane of wingsuit pilots everywhere. The most notorious are the King Air, PAC 750, and Porter. Let’s assess these common planes:

King Air: If the pilot cuts the left side engine, uses flaps, and allows the plane to descend gradually, the exits are actually very tolerable. If the wingsuit jumper does not jump “up” when exiting, and maintains a proper wings-closed body configuration, tail strikes are unlikely. If only we could do something about that tiny door.

PAC 750: This plane is a breeze to fly slowly. With flaps on, the power cut, and the plane descending slightly, it feels more like a helicopter exit than a plane. Wingsuit jumpers are more likely to smash their helmet cameras on the flaps of the main wing itself than on the tail (warning, the main wing really is close to the front of the door, and if you lean into a relative wind that is less than you’re expecting, hitting the wing is a real possibility).

Porter (PC6): A low ceiling and a step kind of get in the way, but this plane can be flown at extraordinarily slow airspeeds. With the power cut and flaps on, there is little chance of hitting the tail if the wingsuit pilot exercises proper technique: wings closed, chest low, knees bent.

wingsuit exits - thoughts for pilots and wingsuiters

Multi or Single Engine

Either way, cut the engine that affects the jumpers. In most multi-engine jump aircraft, the right side (non-exit-side) has no effect on jumpers. In a Twin Otter, for instance, the right engine torque can be at 40 lbs with the left side down to 0 lbs, and the plane is just as easy to fly as it is to jump out of.

Mixed Jump Runs

Wingsuits shouldn’t “need” any special considerations on jump run. The only common rule is that they should get out last – with almost zero exceptions – after everyone else. High-Pullers, CRW-dogs, everyone, gets out before wingsuits. Wingsuits can get out and fly a pattern back to the DZ whether they exit at 0nm from the spot, or >2nm from the spot. Since wingsuits get out last, it does not affect other jumpers on the load if the pilot reduces power and begins to descend slightly after the last slick jumper exits the plane. It is up to the pilot to observe the groups exiting, and up to the wingsuits to communicate with the pilot about when the last slick jumpers are out. At that time, if the pilot has not already, the power can be cut. It needs to be, anyway, for descent, so this should not be an inconvenience for the pilot.

Special Patterns

If the wingsuit jumpers want something special, and the pilot, chief pilot, and DZO are all very accommodating and generous people, wingsuits might get a special adjustment to jump run such as an offset or a turn, or their own pass. Since wingsuits exit last, this shouldn’t be too dramatic – it’s just a little extra time. If this is requested or required, the pilot can keep normal power on after the last slick jumpers exit, and cut the power once the “green light” is back on for the wingsuit’s special spot.

The Aircraft’s Descent, and Wingsuit Flight Patterns

One thing that should always been communicated between wingsuits and aircraft pilots is where the plane descends and where wingsuits fly. Today’s wingsuits are capable of 3:1 glide ratios and horizontal speeds of over 160mph. This means that the interaction between wingsuits and jump planes is possible even >2nm from the spot. The aircraft should consider a distant and circuitous descent route, in a pre-determined location, keeping in mind that if there are student or inexperienced wingsuits on the load, there is a chance that the planned wingsuit flight pattern may not be strictly adhered to. In that case, or in less than optimal visibility, or when the DZ’s resident “loose unit” is on the load, the aircraft pilot should assume that there is the possibility of wingsuit traffic where there maybe shouldn’t be. And wingsuit pilots should keep an eye out for unexpected airplane traffic as well – it’s up to all of us to “give way” in the sky.

In Summary

Wingsuit jumpers and aircraft pilots should communicate (at an appropriate time, and without distracting the pilot from his tasks). Wingsuit pilots are ultimately responsible for their exits, since the exit itself is usually optional. Aircraft pilots are responsible for giving wingsuit pilots the best chance of success. By working together, and looking out for each other, we can minimize the risks of tail strikes and collisions.

The video below expands on this theme…

Special thanks to Dave Kaiser (chief pilot at Kapowsin Airsports), Lance Aikins (CFI), Geoff Farrington (commercial pilot, DZO), and Andy Farrington (commercial pilot and wingsuit pilot extraordinaire).

advertisement

advertisement