Enhanced Flight Vision Systems (EFVS) were certified for the first time in the early 2000s and from that moment they have been steadily expanding across both commercial and business aviation. What is the level of adoption of EFVS in industry? What are the benefits, enablers and inhibitors of EFVS, the human factors consideration that guide EFVS development, and the peculiarities of retrofitting? Read on to find out.
According to Dror Yahav, chief executive officer at Universal Avionics, over the years, EFVS has been adopted and made standard on many forward fit aircraft. “It has also been adopted by FedEx on most of its widebody aircraft. Elbit Systems and Universal Avionics alone have delivered over 3,000 Enhanced Vision System sensors since the early beginnings in 2001,” he said. “In retrofit, Universal Avionics’ ClearVision system is currently being certified on the King Air B200 and on the Boeing 737NG. Similar ClearVision systems from Universal Avionics are in advanced development for the rotorcraft market.” See sidebar page 24.
Indeed, EFVS is available on some commercial aircraft models. According to Grant Blythe, director of product marketing for Avionics at Collins Aerospace, until 2017, regulations did not allow airlines (Part 121 carriers) to conduct EFVS operations, limiting the market for these systems on commercial aircraft. “Since those regulations were updated, airlines have shown strong interest in this technology and we have been working quickly to bring these systems to market for commercial operators,” he said. “Collins Aerospace EFVS is available now for the Boeing 737 and will enter service on Airbus A320/A321 in 2025. We are looking forward to announcing additional aircraft soon.” See sidebar page 22.
For now, Airbus is developing EFVS on the A320 and the A350 families, said Maurice Garnier, avionics systems manager at Airbus. “This will include the A350 Freighter and the Airbus Corporate Jet Family. This EFVS capability may be deployed on other Airbus aircraft,” he said.
For what concerns business jet operators, EFVS operations have been allowed for much longer time, according to Blythe. “Subsequently, EFVS is widely available on mid-size and larger business jets. In fact, EFVS is often included as standard equipment on these higher end corporate jets.”
EFVS Benefits, Enablers and Inhibitors
According to Yahav, among the benefits of EFVS there is increased safety at night and during adverse weather conditions. “The ClearVision system is certified all the way to touchdown and rollout in reported visibility as low as 1,000’, making operating in almost any conditions possible. For Part 135 and Part 121 operators, the system also enables dispatch if the EFVS visibility is higher than 1,000’ at the arrival airport, increasing dispatch reliability,” he said. “This means the use of EFVS decreases delays and cancelled flights due to low visibility conditions. Coupled with a Head Wearable Display (HWD), the system allows safer flying in crowded airspaces by enabling pilots to operate Head-up during high workloads.”
Indeed, a valuable combination of operational and safety benefits is provided by EFVS, according to Blythe. “Providing a night-vision-like capability, EFVS is particularly valuable in identifying runway incursions by wildlife or other aircraft, avoiding wrong-surface operations, or identifying terrain,” he said. “Operationally, EFVS can provide a very advanced all-weather operations capability at low cost for both airports and operators. For example, EFVS approaches can be performed today in visibility as low as 1000 feet RVR (Runway Visual Range) even at airports with limited ground infrastructure. This means better on-time performance resulting in happier passengers, lower operating costs, and reduced carbon emissions.”
The main benefit provided by EFVS is situational awareness, said Garnier. “It provides the capability to see during the night and through different kinds of weather and low visibility conditions. Based on new regulations regarding all weather operations (AWO), EFVS will also bring operational benefits. The flight crew will be allowed to perform the flight toward the destination airport and attempt the approach in low visibility conditions using the EFVS in lieu of visual reference for the final part of the approach.”
Currently, advanced infrared and visible-light sensors are at the core of EFVS systems, according to Blythe. “These sensors can detect energy at very low levels and in spectrums outside the range of the human eye providing this enhanced visibility,” he said. “Of course, these sensors are still limited by physics. Today they are certified to provide a 33% visual improvement to natural visibility or ‘visual advantage’. With additional optimizations and possible integration of future technologies like millimetre-wave radar, Collins plans to further improve the effectiveness of these systems in the future.”
Garnier points out that since it is via the Head-Up-Display (HUD) that the EFVS delivers the information to the pilots, the main enabler is the HUD. “The HUD option already proposed by Airbus is based on a digital HUD with a video input capability. EFVS function will be fully integrated into Airbus operations and avionics architectures with dedicated controls, failure management and maintenance messages,” he said.
Human Factors Considerations
The goal of developing EFVS systems is to help pilots make better decisions and operate aircraft more precisely by presenting them with the best information available, according to Blythe. “Further, it is important we allow pilots to look through the EFVS system rather than simply look at it. Subsequently, we spend a great deal of effort removing any extra information from the display,” he said. “At higher altitudes before the EFVS can detect the approach and runway lighting pilots are looking for, our EFVS systems are tuned to not display static or blank fog only presenting pilots with useful information and detail.”
It is important that training be anticipated by customer operators, as trajectory and energy symbology is very important to fly with EFVS, observes Garnier. “The first step to this symbology is the ‘harmonized’ primary flight display (hPFD) that is available on all current Airbus Family aircraft. Pilots who are familiar with the hPFD symbology will be best able to take advantage of the EFVS,” he said. “There is no clear inhibitor identified but we consider that the main challenge will be ensuring the full integration of this new product in Airbus aircraft and avionics systems.”
According to Yahav, the human factors related to the management of symbology and information in the system to ensure a balance of important information are important to the EFVS design and development. “Cockpits are incredibly busy spaces, so ensuring that the information provided to the flight crew is relevant, helpful, and efficient is incredibly essential to maximizing performance and minimizing pilot fatigue,” he said.
With regard to EFVS, Airbus follows Human Factors considerations and precautions that are similar to the ones that already apply for any avionics development in Airbus Design Office. “Pilots and human factors experts are involved in the design that is continuously challenged through evaluations on simulators,” said Garnier.
Advantages and Disadvantages of EFVS Retrofitting
Various EFVS retrofit solutions are available directly from the OEMs, observes Yahav. “Universal Avionics, having made its name in the retrofit space, offers its ClearVision system for retrofit applications,” he said. “The ClearVision system is designed as in ideal forward fit or retrofit fit solution by leveraging Head Wearable Display (HWD) technology. This technology is considerably less intrusive to install as a retrofit solution than traditional HUDs and therefore minimizes aircraft downtime. Once installed, the system affords the same operational credits as a forward fit installation.”
EFVS will be proposed for retrofit, and some system provisions will be proposed before EFVS certification in order to ease such retrofits, said Garnier. “The same EFVS product will be available for line-fit as for retrofit. EFVS retrofit will allow customers to update their in-service aircraft to the same level as their new delivered aircraft with EFVS function. They will both benefit from the same state-of-the-art EFVS system.”
Collins Aerospace offers EFVS solutions for both retrofit and linefit applications, affirms Blythe. “Retrofit EFVS gives our customers the flexibility to adopt new technologies like EFVS on the best timeline for their operations. It also allows them flexibility to update aircraft when they might acquire or lease used aircraft without EFVS,” he said. “Retrofit installations sometimes have additional challenges in completing wiring and mechanical work and need to account for the opportunity cost of aircraft downtime but we offer turnkey retrofit packages and on-site installation support to make these installations simple and straightforward for our customers.”
Some aircraft downtime is be entailed by retrofit embodiment / working party access to the aircraft, depending on the configuration. “The closer that an aircraft is to the full EFVS configuration then the shorter that downtime. We recommend customers who are interested in EFVS to implement the HUD option on their aircraft and EFVS full provisions as soon as they are available,” concluded Garnier.