Air swirls in the wake of aircraft are a result of the lift generated at the wings; as invisible wake vortices, they can persist along the flight path for quite some time. In flight tests last year, DLR is testing a wake vortex warning system with the research aircraft ATRA and Falcon.
The Airbus A320-232 'D-ATRA', has been in service for the German Aerospace Centre (DLR) since late 2008. and is the largest member of its fleet. The Advanced Technology Research Aircraft (ATRA) is a flexible modern flight research platform that is setting new benchmarks for airborne test vehicles in European aeronautics research.
Modifications
Basic FTI
The basic Flight Test Instrumentation (FTI) system is used for recording aircraft data that relate to experiments and transferring them to the user's experimental systems.
The basic FTI is being further developed and ATRA’s range of applications are being expanded over the course of the utilisation phase. Many future improvements and modifications to the test vehicle will be strongly tied to specific scientific experiments, in which case they will only be temporary. Requirements in terms of modularity, expandability, simplicity, reliability and durability will be met by adopting widespread standards in selecting components and structures.
Missions – key areas of research
ATRA is used in the following areas:
Testing of aeroelastic measurement methods
Studies of interior acoustics
Airflow noise measurements
Aerodynamic measurements on the wings and the empennage with the aim of saving fuel
Testing of the latest measurement techniques such as Image Pattern Correlation Technique (IPCT), an optical method of measuring the flexing of wings
Detection of wake vortices and the study of algorithms for avoidance. These are air turbulence that results from the lift generated by the wings
Engine measurements
Research into alternative fuels
Testing of state-of-the-art navigation and communication technologies for aircraft
Improvement of the latest pilot assistance systems and testing of the modern display technologies
Research into low-noise approach and departure procedures
Studies on pilot workload and work distribution
Wake vortex research with ATRA
Vortices occur behind aircraft as a result of the lift generated by the wings. These invisible wake vortices may remain present along the flightpath for a considerable time. Because of this, strict safety distances are specified for commercial aircraft – not just in cruise flight, but particularly near the ground, during take-offs and landings. These determine the take-off and landing intervals at large airports and may lead to bottlenecks in capacity during peak traffic times. This results in holding patterns and delays, which are undesirable for passengers and airlines alike.
To prevent aircraft from flying into wake turbulence, DLR is developing a system for tactical, aircraft-based wake vortex warnings and avoidance during all phases of flight. This is the Airborne Wake Encounter Avoidance and Advisory System (WEAA). Wake vortex behaviour and possible conflicts are calculated based on weather and flight data. Warnings and course deviations are recommended to pilots in the cockpit for this purpose. Initial flight tests with the ATRA and the DLR's Falcon 20E-5 research aircraft have already been successful and demonstrate the viability of the concept.
High-lift research with ATRA for efficient take-off and landing phases
Air transport is facing an array of challenges. Increasing worldwide air traffic means that increased aerodynamic performance during the take-off and landing phases is becoming more important, along with the need to reduce aircraft noise. DLR is addressing these challenges as part of various German and European research projects.
The design and development of complex high-lift systems, which have a considerable impact on take-off and landing characteristics and on aircraft noise emissions, are among DLR’s key areas of research. DLR is conducting research into these issues in cooperation with the High-Lift Systems division of Airbus in Bremen.
