Published in AEROSPACE Tech Review
Written by Jeff Guzzetti
From the early days of aviation over a century ago, advances in aerospace technology have depended mostly on tests conducted under actual flight conditions. The wireless transmission and reception of flight test data — known as telemetry — first became widespread in the 1950s and has allowed near-real-time access to engineering data required to reduce risks and costs while incrementally advancing technology.
Telemetry is critical for the aviation industry to deliver new products. It’s a key asset to aerospace research, testing and FAA certification. Higher speeds, altitudes and performance requirements, combined with increasingly complex and integrated systems, have added to the need for instantaneous test data.
Airplanes, helicopters, missiles, commercial space vehicles, unmanned aircraft systems, and electronic vertical takeoff and landing aircraft are all born as “test articles” and must be pushed to their limits in flight tests to succeed. For example, “flutter” tests are performed to stress the wings and control surfaces to the point where aerodynamic, elastic and inertia forces can produce potentially violent oscillations that, once begun, are difficult to control. Likewise, flight envelope-expansion testing, such as stall, spin, and dive tests, requires that aircraft be flown to the limits of their airspeed and load factor design capabilities. All of these tests are inherently dangerous to the pilot and persons on the ground. Even routine tests can involve significant safety risks.
Telemetry allows controllers on the ground to monitor the second-by-second performance of a test article. Controllers can warn a TA pilot to abort maneuvers that threaten a structural failure, out-of-control flight, or other system emergency. And real-time data captured can be analyzed to resolve potential problems that could make or break a new aerospace design, or even aid in reconstructing the cause of a crash.