Securaplane developing near-wireless flight-control system
Securaplane, a small company nestled in the Catalina Mountain foothills north of Tucson, Ariz., is taking large steps toward the emergence of near-wireless controls for airliners and corporate jets during the coming decade. You could call it “fly-by-wireless.”
Best known in the business aviation market for its on-aircraft security and surveillance systems, Securaplane is also a pioneer in airborne use of spread-spectrum radio-frequency (RF) emissions for wireless smoke and fire detection and suppression. Now, the 19-year-old company founded by its president, Dick Lukso, and former Learjet chief the late Bib Stillwell is proposing a range of other in-flight applications for the spread-spectrum wireless technology that for 40 years lay hidden under the cloak of military secrecy.
Securaplane is aiming two new wireless systems at near-term applications using the technology incorporated in the smoke/fire-detection and suppression system for aircraft cargo bays and inaccessible spaces. One is a cabin-alert system developed in the wake of 9/11 for discrete emergency communication from cabin crew of large passenger aircraft to the flight deck. The other is wireless control of LED cabin emergency egress and mood lighting.
Lukso predicts that while wireless technology on airliners and large business aircraft will at first serve non-flight-critical functions and backup systems, once the airframe OEMs and certifying authorities become familiar and comfortable with the technology it will find many applications.
“For example, it has the potential to provide links between the flight-control computer and the servos driving the flight control surfaces,” initially in a backup capacity. Eventually, he added, wireless could eliminate the need for wiring, cables and hydraulics between cockpit and control surfaces.
Securaplane’s president and technical director said wireless control of engines and other vital aircraft systems will offer the bonus of not only reducing wiring and weight but providing system status and diagnostic capabilities.
“If we can install a wireless sensor at the engine, for example, to record pressures, temperatures, quantities and so on for maintenance download, we’ll enable functions that are currently unavailable. Already the wireless smoke system’s diagnostics and memory capability can recreate an event in great detail. The sensor data goes to the central processor unit and is logged and downloaded.
“Wireless is coming sooner that many people think,” Lukso added, pointing out that a major airliner OEM has committed itself to drastically reducing the man-hours needed to build its next model. “Eliminating a lot of the wiring that goes into today’s aircraft is going to play a major role in achieving that goal.” He added that eliminating wiring will also favorably affect costs for operators. “Every wire on the airplane needs to be checked after major maintenance or modification to make sure it’s intact and correctly connected. There’s a big saving to be had in reducing that requirement.”
Hedy’s Big Idea
The spread-spectrum theory of RF propagation was postulated early in World War II and recognized in a U.S. patent granted to an unlikely recipient: glamorous Hungarian-born movie actress Hedy Lamarr. In 1942 the MGM star and her musician husband George Antheil were issued Patent No. 2,292,387, entitled “Secret Communications System,” which embodied Lamarr’s idea for a jamming-resistant means of guiding a torpedo by radio using multiple radio frequencies in a random pattern. After the couple donated their patent to the war effort, it remained classified until the mid-1980s, in the meantime becoming part of military secure-communications protocols. Spread-spectrum technology has been incorporated in systems ranging from the World War II Identification Friend or Foe (IFF) to Tacan (Tactical Air Navigation) and the military Joint Tactical Information System (JTIS).
The technique allows very-low-power RF emissions to transfer error-free information with selective addressing to and from multiple sensors on the same frequency in a noisy electronic environment. Its low output power in a narrow bandwidth between 922 and 925 MHz produces little or no interference with adjacent electronics while enabling high interference rejection.
Incorporated in the Securaplane wireless smoke-detection and fire-suppression system, spread-spectrum data exchange makes possible major reductions in aircraft wiring and weight. A code-modulation format enables multiple signals to be sent simultaneously on the same frequency through selective addressing and code-division multiplexing. In the RF signal-dispersion process, signals are of such low amplitude as to be virtually undetectable by normal receiving techniques, which perceive them merely as noise.
The smoke/fire system includes a series of independent solid-state smoke and heat sensors containing tiny built-in RF transceivers linked to a control-display unit in the cockpit. Each sensor is electronically coded by its mounting location in the cargo bay, much like a Mode S transponder installed in a specific aircraft.
Securaplane has equipped more than 1,000 airplanes, mostly airliners and freighters, with its wireless ST 3000 systems since retrofit smoke-detection/fire-suppression installations were federally mandated in 1997 following the ValuJet crash, which resulted from an in-flight cargo-bay fire. In the process, the 90-employee firm has become the leading supplier of such systems, not only for airline-retrofit programs but for large business aircraft, including many BBJs and Gulfstreams, and several VIP Boeing 777s and 757s.
During a recent visit to Securaplane headquarters, AIN heard Lukso explain the wireless system’s appeal to airlines and corporate operators alike. “It saved nearly a mile of wiring in each of the 737-300s operated by Southwest Airlines, the launch customer for our system, compared with a wired smoke/fire system. More important, our wireless system averaged 250 man-hours to install versus 750 to 1,000 for a wired system, and in one instance a Southwest 737 [installation] took only 125 hours.” He added that Securaplane’s experience in developing and certifying the wireless spread-spectrum smoke/fire system promises to pay big dividends with new applications of the technology that the company is preparing to introduce.
“It wasn’t cheap to get the smoke and fire system certified, but the time and money is proving to be well spent,” Lukso said. He noted that software certification to DO-178B, level-C standards took six months, and that 16 million software test cases were run on the spread-spectrum commercial off-the-shelf (COTS) software and hardware. “The FAA required us to do on-aircraft EMI [electromagnetic interference] tests on the ground and in actual flight conditions for the entire 737 series and the 727-200, as well as MD-80s, DC-9s and DC-8s. We proved our system would not affect navigation or flight control,” he added.
Securaplane created the wireless cabin-alert and monitor system in November 1991 for an anticipated STC program for Delta Air Lines’ MD-80s. It consists of a series of small, battery-powered cabin-alert transmitters, each registered to an individual aircraft, an alert receiver unit located above the cabin ceiling and a cabin display unit in the flight deck. The transmitters can either be mounted at strategic locations within the cabin or carried by attendants. Pressing a transmitter’s “alert” button three times within three seconds will activate an alarm in the cockpit. The alert receiver unit serves to assess and relay cabin-alert transmitter signals, while the cabin-display unit will monitor the health of the transmitters’ lithium batteries in addition to alerting the pilots.
To date, Lukso said, air-transportation security priorities and resources have been directed more toward reinforcing doors between cabins and cockpits than in providing less obvious and more survivable crew-alerting capabilities.
Securaplane is pursuing the lighting-control application jointly with lighting-system provider Luminator Aircraft Products of Plano, Texas, which in turn is teamed with French avionics manufacturer Thales. The immediate goal is to gain a position on a pending major new passenger jet program for LED interior lighting and potentially for exterior position, navigation and logo illumination LED lighting. Securaplane has been working with Luminator to incorporate wireless control into the variable-color cabin mood lighting the Texas firm is providing to Qantas as part of the Australian carrier’s extensive enhancements inside its 747-300s and -400s. The colors projected by the indirect-lighting system can be programmed to change with time of day to present tones that researchers have found to be most pleasing to passengers.
Luminator and Honeywell are among those offering LED external aircraft lighting to replace incandescent bulbs. Lukso said that once Securaplane and its partner meet the “extreme documentation demands” of certifying wireless-controlled LED emergency egress and exterior lighting, the savings to operators through longer life, lower-powered light sources and wiring elimination will be significant. Brian Stark, Luminator application engineer, added that operators will save at least as much with wireless control of interior lighting and passenger amenities such as attendant paging and entertainment selection because each seat will be independent of aircraft wires. “That way, when they reconfigure their seating, operators won’t have to tear up the cabin to move and reconnect all the wiring.”
Securaplane currently has three primary market segments: the wireless RF-controlled product line; aircraft electronic security systems and airborne video camera systems; and a line of aircraft electrical power products, including main ship batteries, emergency batteries, battery chargers and inverters. Lukso’s son Mark, the company’s vice president of sales, described Securaplane as “an opportunity niche” company. “We identify needs, markets we can serve better than they are being served, by providing new technology or innovations in existing products.” His father added that Securaplane has succeeded in selected product fields by learning that “it’s not what we know to do; it’s what we know not to do.”
Back to the Drawing Board for Whiskers
In May 2001, Securaplane said it was nearing certification of its wing collision avoidance system (WCAS or "whiskers"), a planned $28,000 low-power radar that, during taxiing, would be capable of detecting objects in its field of view larger than two inches in diameter. Technical problems, which had prevented earlier certification, appear to be persisting because when asked what is happening with whiskers, the company said, "Not a lot." Apparently, Securaplane got pretty far along in the development program before realizing that the technology wasn’t as precise as it needed to be. The company is currently exploring new technologies, but has nothing to report and no timetable. As an alternative, Securaplane suggests installing exterior cameras pointed at the wingtips.