Going Ballistic

Airframe parachutes save lives

August 1, 2008

Most of us can name an airplane sitting on our ramp right now that incorporates a Ballistic Recovery Systems (BRS) airframe parachute. That’s a tribute to the success that BRS has had in bringing airframe parachutes into the general aviation consciousness—not to mention the host of aftermarket and OEM chute options for everything from ultralights to (someday soon) single-engine jets.

Founder Boris Popov had survived a 400-foot fall in a collapsed hang glider in 1975, and was frustrated by his lack of ability to do anything about the situation. He turned this frustration into the energy required to develop a whole-airframe parachute by founding BRS in 1980. BRS produced its first chute for the ultralight market in 1982.

It was a challenging problem to confront—to produce a system with a lightweight canopy and container capable of deploying the chute fast enough to make a low-altitude save, and strong enough to remain intact when deployed at higher speeds—as in a deployment from cruise speed, or even a dive.

Today, BRS assembles ballistic parachute systems for a wide variety of aircraft as aftermarket equipment on aircraft such as the Cessna 172 and 182, and as standard equipment on the Flight Design CT and all Cirrus Design’s models. Cessna will offer the system on its new 172s, 182s, and 206s as an option installed at its service centers. And Diamond Aircraft plans to offer a system on its D-Jet, likely the first very light jet to feature an airframe chute. BRS has shipped more than 28,000 systems to date.

A life saved

Pilot Patrick Dean experienced a probable control surface failure in his kit-built Slipsteam Genesis and deployed a Ballistic Recovery Systems whole-aircraft parachute on January 5, 2008, in Laurel, Maryland. His is the 208th documented life saved by a BRS emergency parachute system.

“The aircraft rolled over on its back and headed straight down,” said Dean. He deployed the BRS parachute just a few hundred feet above the ground. The aircraft landed in the trees, and witnesses helped Dean escape with a cut on his nose and minor bruises.

“The BRS system absolutely, positively saved my life,” Dean said. “There is nothing else that could have slowed me down enough to have kept me from hitting the ground at terminal velocity.”

Dean was flying his fabric and fiberglass two-seater he had built himself. The aircraft had been recently inspected by the FAA and was airworthy. During the construction process, his wife specifically asked him to add a BRS parachute. After the accident, she delivered a short, emotional message to BRS employees.

“Thank you very, very much for making these parachutes!” she said.

The system consists of three components: the parachute; the rocket used to deploy the chute; and the container in which it’s all packaged. In addition, there’s an activation assembly and the harness assembly attaching the chute to the airframe. Systems are categorized by the maximum weight and cruise speed of the aircraft for which they’re designed, or for a specific aircraft model for certain aftermarket systems. Containers include a framed soft pack, a canister, and the VLS (vertical launch system) for special applications. The soft-pack system is generally the lightest, and is available for the widest range of aircraft weights, from 600 to 3,100 pounds.

The chute is deployed when the pilot or passenger pulls a cockpit handle. A mechanical igniter lights a solid-fuel rocket that extracts the canopy, lines, and bridles from the container. From handle pull to full inflation takes about 5.5 seconds. The airplane descends under canopy at 15 to 28 feet per second—a survivable rate for the occupants, if not the airplane.

The reason BRS can produce chutes for so many airframes rests in its development of the slider, a ring that retards the full expansion of the canopy until several seconds after the chute is launched, and the descending airplane has slowed significantly. This reduces the chance of ripping the canopy in high-speed deployments.

Cirrus chutes

In 1993, BRS tested the Part 23 airplane waters with a chute designed for the Cessna 150 and 152. Although BRS sold only 11 of these chutes, BRS Chief Executive Officer and President Larry Williams said the successful tests proved the concept and led to a landmark deal with Cirrus Design.

Alan Klapmeier, co-founder and chief executive officer of Cirrus, survived a midair collision in the 1980s, and that event made such an impression that he vowed any airplane Cirrus brought to production would have an airframe parachute installed as a safety device. In the mid 1990s, as Cirrus developed its first single-engine piston production airplane, the SR20, it partnered with BRS to create the first airframe parachute recovery system as standard equipment on an FAA certificated airplane. The SR20 prototype flew in 1998, with customer deliveries beginning the next year.

Adapting the BRS system from the ultralight market to the heavier and faster Cirrus proved difficult. Paul Johnston, chief engineer for Cirrus, explains: “Taking the next step shouldn’t have been hard. If you double the weight, that’s twice the load on the chute; if you double the speed, that’s four times the load.” Therefore, an airplane like the SR20, which was roughly twice the weight and speed of aircraft for which the BRS chute was originally designed, put an eight-fold increase in load on the system. The SR20 has a maximum gross weight of 3,000 pounds (the SR22 weighs even more, at 3,400 pounds).

Similar challenges face BRS engineers as they develop what is internally called the “5500” designed for a 5,500-pound light jet—the D-Jet will be its initial installation. Frank Hoffman, vice president of engineering for BRS, says they decided early on to pursue a single-canopy system for the heavier aircraft. “With parachute clusters, you lose about 20-percent efficiency,” says Hoffman, also pointing to the greater complexity of a system with more risers and connections.

The larger chute offers its own hurdles because of its voluminous canopy. It takes a lot of space to pack the canopy—when a prototype chute is laid out in the largest building that BRS has to offer, it takes up the entire floor of the building. The chute will take longer to inflate as well.

Also, a different activation system is required for the light jets because the airframe is longer—a direct cable may not work. This leaves other options, such as electronic or hydraulic activation. Electronic activation has been problematic, says Hoffman, because it opens the system to the possibility that the rocket would fire when exposed to electromagnetic interference.

Saves

BRS tallied its first “save”—the first person whose life was saved by the use of a BRS parachute—in 1983. That number has grown to 213.

The process by which the systems are assembled is somewhat mesmerizing to watch when you consider the end product might save someone’s life. The components come into the hangar from various suppliers—the rockets composed of solid fuel, a casing, and a mechanical igniter; the parachutes composed of a canopy, risers, and a harness; and the shells containing the systems composed of heavy-duty fabric, or plastic, or metal.

Packing each chute for the system lends itself to a rhythm. First, the chutes are laid out on a long, narrow table, the lines stretched straight. A parachute rigger lays out the chute, smoothing the panels as they are stacked, to make sure the 60 panels (for an SR20 chute) lay in an orderly fashion. An in-process check by a quality control person ensures the process has been accomplished correctly.

Next, the chute is compressed in a small, rectangular container and baked in an alto-sham (low-temperature oven) for 24 hours at 175 degrees Fahrenheit. After 16 hours cooling in the container at room temperature, the chute is removed and assembled with the rest of the system. This process draws moisture out of the chute.

Taken separately, the components of the rocket are relatively benign. But together, they’ll send the chute through a panel in the airframe and in a trajectory away from the aircraft at enough speed to extract the chute without ripping it to shreds.

And some 213 aircraft owners are glad the BRS process works as effectively as it does.

Julie K. Boatman is a former technical editor for AOPA Pilot.