Enhanced Flight Vision Systems Research Articles

The Use of Enhanced Flight Vision Systems (EFVS) for Low-visibility Takeoffs in Part 121 Operations

Twelve Part 121 operations commercial-carrier crews completed low-visibility takeoffs at Memphis International Airport using an Enhanced Flight Vision System (EFVS). A 2x2x2x3 factorial design with runway visual range (RVR; 500 and 700 feet), runway edge lighting (high intensity or medium intensity) and two levels of EFVS (either captain’s head-up display only or with additional first officer’s head-down repeater) was used along with supplemental sample points and several baseline trials representing current-authorization conditions. Tasks included normal takeoffs, EFVS failure (both continue and reject trials), and engine failure (reject). There were no significant main effects of display or infrastructure in the main design (500, 700 RVR), and pilot performances in the experimental trials with EFVS were not markedly different from the baseline (current authorization) trials. All crews were able to stop the aircraft successfully on the runway during rejected takeoffs. Pilots uniformly believed they could successfully complete takeoffs or reject them in lower visibilities with EFVS as compared with using the head-up display without EFVS, which was sup-ported by observed performance.

Assessing Dual-Sensor Enhanced Flight Vision Systems to Enable Equivalent Visual Operations

Synthetic vision and enhanced flight vision systems may enable a Next Generation Air Transportation System equivalent visual operations concept: that is, the ability to achieve safety and operational tempos of current-day visual flight rule operations, irrespective of the weather and visibility conditions. The operational feasibility and pilot workload of conducting straight-in instrument approaches in visibility as low as 300 ft by use of onboard dual-sensor imagery on head-up displays, without the need for or reliance on natural vision, were assessed in a motion-base simulation experiment. Twelve crews evaluated two methods of combining enhanced flight vision system imagery on pilot-flying and pilot-monitoring head-up displays, as well as the impact of adding synthetic vision to the sensor imagery, as they made approaches to runways with and without touchdown zone/centerline lights. These new methods were compared to two currently approved operations of head-up displays (with symbology only in 1800 ft visibility, and with forward-looking infrared imagery in 1000 ft visibility). The results indicated that all enhanced flight vision system concepts flown in extremely low visibilities had comparable approach, touchdown, and rollout performance without any workload penalty as compared to the two approved head-up display operational baselines. Adding synthetic vision imagery to an enhanced flight vision system provided situation awareness improvements but no discernible flight-path maintenance improvements or detriments.

OPPORTUNITIES OF ELECTRO-OPTIC VISUALIZATION PRACTICAL APPLICATIONS ON BOARD THE AIRCRAFT

The article covers the following issues: the development and practical application of airborne electro-optic systems in the civil aviation aircraft. They provide flight visual information for the pilot day and night in visual and instrument weather conditions. The legal documents establishing the requirements for the application of this type of electro-optic systems in aircraft are presented. The classification of airborne electro-optic systems, commonly named as electronic visualization systems is analyzed. The ways of implementing the recommendations in their construction are considered. There have been analyzed the possibilities of systems of different classes: enhanced vision systems (EVS), synthetic vision systems (SVS), combine vision systems (CVS) and on-board vision systems with advanced visualization features, Enhanced Flight Vision Systems (EFVS). It is determined that nowadays EVS systems are considered to be the potential application systems. In order to analyze the possibilities of practical application of such systems in the issues of flight safety at low altitude and landing, flight experiments of the system installed on a light helicopter were conducted. The research introduces the results of flight experiments on the practical work of television and infrared (IR) viewing channels of a promising typical system in simple and complex observation conditions. Based on the results of flight experiments, a conclusion can be made about the relevance of practical application of electronic visualization systems on board the aircraft to ensure flight safety. It is determined that the systems can be used in flight both for land observation tasks and ensuring a safe flight. When flying the helicopter at low altitude and landing procedures the pilot should use visual information from the rear hemisphere of the lower tail unit by electro-optical visualization system. It was elicited that in the infrared (IR) channel and the fast rotation of visualization system camera located there is a corresponding delay of vision direction and the actual direction of flight. The vision is blurred. In the mode of the infrared spectrum information there appears a filtering problem of interference caused by helicopter engine exhaust gases and snow in the sector of observation. It makes it more difficult to obtain the benefits of visualization systems vision in adverse weather conditions. The conclusions indicated that perspective visualization systems for IR channels require additional use of methods and algorithms to ensure high-definition vision.

Using Vision System Technologies for Offset Approaches in Low Visibility Operations

Flight deck-based vision systems, such as Synthetic Vision Systems (SVS) and Enhanced Flight Vision Systems (EFVS), have the potential to provide additional margins of safety for aircrew performance and enable the implementation of operational improvements for low visibility surface, arrival, and departure operations in the terminal environment with equivalent efficiency to visual operations. Twelve air transport-rated crews participated in a motion-base simulation experiment to evaluate the use of SVS/EFVS in Next Generation Air Transportation System low visibility approach and landing operations at Chicago O’Hare airport. Three monochromatic, collimated head-up display (HUD) concepts (conventional HUD, SVS HUD, and EFVS HUD) and three instrument approach types (straight-in, 3-degree offset, 15-degree offset) were experimentally varied to test the efficacy of the SVS/EFVS HUD concepts for offset approach operations. The findings suggest making offset approaches in low visibility conditions with an EFVS HUD or SVS HUD appear feasible. Regardless of offset approach angle or HUD concept being flown, all approaches had comparable ILS tracking during the instrument segment and were within the lateral confines of the runway with acceptable sink rates during the visual segment of the approach.