Real-time weather information is a key enabler of the US vision for next-generation air traffic management. While the long-term goal is to negate the effect of weather on system capacity, there are technologies available that could improve safety and save money in the near term – if transitioned to operational use.

NASA is nearing the end of two research projects that could improve the detection and reporting of turbulence and reduce both the cost of injuries to cabin crew and passengers and of diverting around weather. Both technologies are being evaluated in revenue service, but there are no firm plans for further development or deployment.

Injuries and inefficiencies caused by turbulence cost US airlines more than $100 million a year, says atmospheric hazard detection and mitigation specialist AeroTech Research (ATR). Supported by NASA Langley, ATR has developed software to automate the in-flight reporting of encounters with turbulence and to predict the hazard posed by turbulence detected by the aircraft’s weather radar.

Turbulence encounters are “grossly under-reported”, and those pilot reports (pireps) that are made are “late, subjective and not distributed to dispatchers and controllers”, says Paul Robinson, president of Newport News, Virginia-based ATR. The firm’s Turbulence Auto-Pirep System (TAPS) software automatically generates a turbulence report datalink message when g load, measured by existing on-board sensors, exceeds a threshold.

TAPS is being evaluated in service on 71 Boeing 737-800s and 52 767-300/400s flown by Delta Air Lines. Turbulence reports are sent via ACARS datalink to Arinc, and distributed in near real-time via the service provider’s web-based dispatcher’s display. Ultimately, the data would be uplinked automatically to other aircraft. Proof-of-concept air-to-air transmissions of TAPS reports are also planned.

Between 10 June 2004 and 19 May this year, TAPS reports were generated on more than 15,500 Delta flights – 75 of them severe and more than 620 moderate. “This is a factor of hundreds, or thousands, more than the pireps,” says Robinson.

The companion project involves the in-service evaluation of enhanced turbulence mode (E-Turb) radar in a Delta 737-800. Current weather radars can detect turbulence, but cannot predict its severity as they do not factor in aircraft size or flight configuration. Turbulence above a fixed threshold is simply displayed in magenta.

E-Turb is a hazard prediction algorithm that calculates the g loading on the aircraft that will result from the measured turbulence. The system produces a two-level hazard advisory display: speckled magenta for loads requiring seat belts on; and solid magenta for severe turbulence to be avoided if possible.

ATR’s software was certificated for the Rockwell Collins WXR-2100 radar in Delta’s 737-800, and 3,000h in-service use will have been accumulated by September. “Tests show a strong correlation between predicted and measured loads,” says Robinson.

Combined, TAPS and E-Turb provide an integrated turbulence hazard-awareness tool that could allow aircraft to penetrate weather with no risk, says Robinson, saving time and fuel by avoiding or minimising detours. Preliminary analyses suggest the software-only upgrades could pay for themselves quickly, he says.

Both evaluations are to end in September, unless NASA extends the projects, says Robinson. Meanwhile, a TAPS ground-station product will be ready by year-end, with initial cockpit displays – likely for electronic flight bags – expected by early 2007, he says. E-Turb could be in new radars by the end of 2006, with retrofits for the 4,000 predictive-windshear radars flying available in one to two years.


Source: Flight International