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The Front Office | Descents

By Chas Hines

The Front Office | August 2019
Friday, July 19, 2019

After the last of the jumpers leave an airplane, the pilot tries to get back on the ground as safely, legally and quickly as possible to land and pick up another load. So … what is the experience like?

Well, first, as the last group exits the aircraft, the pilot makes a radio call to ATC (air traffic control) and reports, “Jumpers away, descending,” or something to that effect, and he’ll also transmit a call on the local airport traffic frequency to advise nearby aircraft that jumpers are in the air. If they have a company frequency, they’ll also let manifest know that the aircraft is descending so manifest can update the next load’s call time. Seems pretty routine and mundane, right?

The kicker is that all this happens simultaneously while the pilot reduces the power for descent, raises flaps, adjusts the rpm on the one or more propellers (typically to maximum) and lowers the nose to lose altitude. The door that was open for your jump still is … unless your pilot was lucky enough to have someone close it or there is a closing mechanism on the airplane. On some aircraft (such as the Cessna 182 or 206) the pilot reaches over and closes the door while performing the tasks above.

The idea is to get the airplane back on the ground and minimize the cost of the descent, since it is not generating revenue until it picks people back up again. The airplane costs $2.50 to $15 per minute or more to operate, so every precious minute saved helps.

During the descent, the pilot aggressively looks for other aircraft that might be in the way and also guides the plane safely away from the path of any jumpers. In order to fly the airplane into a safe position to enter the traffic pattern, the pilot needs to know the runway direction the airfield is using. (If the pilot is lucky, this will be the same direction all day long). To be a good neighbor and not cause problems with other people using the airport, the pilot tries to work the jump plane into the traffic flow as courteously as possible without wasting time. This can be challenging at some airports where there are flight schools, helicopters, transient aircraft, other DZs (God forbid) and so on.

On weekends at some DZs, it is routine to have four or five airplanes in line for the traffic pattern, as well as airplanes landing and taking off. Add to that the complexity of managing an engine or two, talking on the radio, configuring the aircraft with flaps and landing gear, etc. It can be stressful, but overall being a jump pilot is a total blast, and the descent is a big part of that. For that couple of minutes, it’s just you and the airplane. It’s surreal. It’s Zen. I’m drooling just writing about it.

Each airplane has its own variations for the pilot to consider when configuring for jump runs, descents, landings and so on, and there are large differences between turbines and piston-powered aircraft. With a turbine engine, a minimal amount of wear occurs during descents with the engine(s) at idle … they actually kind of work better, because the cool air rapidly lowers the temperature of the hottest sections of the engine, and there really aren’t any tight-fitting components that suffer from this. On the other hand, if a pilot were to climb to altitude in a piston aircraft like the Cessna 182 and just chop the power and descend at high speed, a huge rush of cold air would flow around the cylinders, which would shrink slightly faster than the pistons and rings moving inside. As you can imagine, this process—called shock cooling—is enormously destructive.

With piston aircraft, pilots have to plan the descent early. On turbocharged piston aircraft, they have to do so minutes early, before the door even opens on jump run. The goal is to slowly reduce the power and control the engine rpm (via the prop-speed control) to retain as much precious heat as possible during the ride down while meticulously adding speed. The more heat the pilot can retain during descent, the better off the engine will generally be. Ask any aircraft owner whose engines have been shock cooled (which will be almost any plane owner who has been around for a while), and they can explain how expensive it is to replace the components that a pilot who was too hasty on the descent destroyed.

With turbine aircraft it is possible to land the airplane far before the skydivers land; with piston aircraft, it is often an indicator that the pilot is abusing the equipment. So, the nice thing about turbine aircraft is you don’t think twice about engine heat on the ride down … just chop and drop. Pretty sweet, eh?

So, the pilot makes a bunch of radio calls, configures the aircraft to descend, enters the crowded traffic pattern, lands the airplane and taxis to either refuel or pick up another load. This happens anywhere from zero to 30 or more times in a day. The punishment for not being on top of it all for even one load? I’m sure you can imagine. Add in the complexity of busy airspace and additional clearances, weather, formation loads and airplane limitations (like its max speed with door open on descent), and you have a uniquely complicated job. As always, I hope this inspires you to buy your pilot a beer at the end of the jumping day.

Chas Hines | C-41147
FAA Certified Flight Instructor and Airline Transport Pilot

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