One retired US Army Black Hawk pilot on deployment described an IIMC flight over flat terrain in a degraded visual environment (DVE). A dust storm, like a “blizzard without wind … came down like snow”, when he realized a complete loss of contrast, feeling like he would never reach his destination, notably when the ‘blind spot’ was the dust cloud above his Black Hawk. “The crew chief was watching, but didn’t see a dust cloud coming, nor did I see it because it was on top of me,” he said.

“Without the quick assessment by the flight crew, who pointed the infrared searchlight straight down, I would have flown straight into the desert floor,” he added. “Staying ahead of the cloud is critical.”

IIMC in DVE is an equal-opportunity event. IIMC does not discriminate. The loss of depth perception and visual reference while experiencing spatial disorientation (SD) affects all pilots in all industries.

The critical decision to safely mitigate IIMC-DVE conditions depends on a matrix of multiple variables, both internal and external, which can exponentially develop into one of the most challenging conflicts for pilots to reconcile.

The question is: what kind of equipment and avionics assist the pilot’s decision-making ability in IIMC-DVE situations when visibility is massively restricted?

AirMed&Rescue spoke to industry leaders who shared their experiences and knowledge about safely managing an IIMC: Robinson Helicopter Company, with its core focus on sound decisions and risk management; military-to-civilian (M2C) pilots with experiential insights into DVEs during deployments, and whose civilian careers led them to FlightSafety International as flight instructors; and Sikorsky Innovations, which brings options through its MATRIX autonomy system integrated in the multi-mission, optionally piloted Black Hawk. But we begin with Oklahoma-based flight training company AT Systems, which focuses on aeronautical decision-making (ADM) as the most effective answer to training for IIMC in DVE, based on the research report by the US Helicopter Safety Team (USHST).

Aeronautical decision-making: training the brain

When thinking about the brain’s ability to instantly process a number of data streams, internal and external, to ‘land and live’, multiple factors must be assessed, categorized, compartmentalized and strategized while effectively navigating technology, communications, innovative systems, and devices to mitigate an IIMC in DVE – typically in less than one minute.

Safely dealing with IIMC in a DVE doesn’t culminate in one solution.

“Every DVE is different and every pilot is different,” said Tyson Phillips, President of AT Systems and an Oklahoma National Guard Black Hawk pilot. “While we train recovery techniques, our flight training system focuses on ADM, which we believe is the most effective answer to training for IIMC in DVE.”

The crew chief was watching, but didn’t see a dust cloud coming

The AT Systems flight training system includes simulation training, while Phillips and his team of military-trained rotor pilots also offer in-aircraft simulation, a training system and the academics for SD “to put the pilots into visual conditions conducive to SD, while the aircraft provides the movement for the vestibular system”.

“Simulator training has always lacked the vestibular illusions, and the in-aircraft training, without a visibility-limiting system, has lacked the visual illusions,” he said.

A 2020 USHST working group research paper, Spatial Disorientation Induced by a Degraded Visual Environment: Training and Decision-Making Solutions, prepared “to provide industry training that can reduce the risk of fatal helicopter accidents”, addressed the impact of visual and vestibular illusions with respect to critical decision-making during an IIMC (see box at end).

The USHST report further states: “During flight in low-visibility conditions, the pilot can experience visual illusions such as a false horizon. During this time, the vestibular system can be stimulated, creating illusions such as the leans.”

“Our training system allows us to expose the pilot specifically to low-visibility conditions in a controlled and safe environment,” Phillips said. He explained that the training uses an organic attitude and heading reference system (AHRS) from Levil Aviation, which provides critical information for automation, as well as the safety controls that allow the system to go clear if preset limits are exceeded.

In a survey conducted by USHST, Phillips said that over half of the 750 responses from all types of pilots said they had experienced SD but in actuality had developed an illusion. “Illusions lead to SD but not all illusions are SD,” he said.

While we’ve seen the civilian and military rotor industry come to better understand the need to integrate visual and vestibular illusions for effective and comprehensive SD training programs, there is still a gap in rotor training for pilots to recognize the conditions conducive to SD and the recovery process, said Phillips. “We owe all pilots, regardless of where they were trained or what industry they are in now, a safe and effective training tool that will enable pilots to make better decisions sooner,” he added.

Sikorsky Innovations: a ‘critical flight safety enabler’

It’s been 101 years since Igor Sikorsky founded the company that still bears his name. Today, Sikorsky, a Lockheed Martin company, continues to play a leading role as a large helicopter manufacturer for commercial and military operators worldwide.

Less well known is Sikorsky’s role as an emerging leader in autonomous flight. Since 2013, the company’s rapid prototyping group, Sikorsky Innovations, has focused on flight autonomy as a key technology pillar. Composed of researchers, designers and engineers, the innovations team has made significant strides to reduce pilot workload and prevent accidents.

“We know there’s an increasing need for autonomy systems in rotor- and fixed-wing aircraft to overcome the challenges of DVEs and controlled flight into terrain, in combat and during training,” said Igor Cherepinsky, Sikorsky Innovations’ Director. “Drastically reducing accidents and incidents while enabling pilots to effectively mitigate complex operations prompted the development of our MATRIX autonomy system.” MATRIX combines software and hardware components for autonomous flight in obstacle-rich environments, creating a safer flying experience overall for military and commercial customers. “Linked to sensors, such as light detection and ranging (lidar), and infrared (IR)/visible spectrum cameras, the MATRIX system can give helicopters a significant safety margin,” he said.

Options for safety: optionally piloted Black Hawk

Sikorsky Innovations’ MATRIX autonomy system also enables optionally piloted flight, a scenario where rotor- and fixed-wing aircraft can be operated with or without humans onboard, depending on the mission.

“This means operators can literally flip a switch on the cockpit dash directing the aircraft how to fly, with the choice of an uncrewed aircraft, or with a single pilot, or as a sophisticated autopilot for two-pilot operations,” Cherepinsky said.

Seeing the potential of the MATRIX system for safer flight in the US military, the Defense Advanced Research Projects Agency (DARPA) placed Sikorsky under contract as part of its Aircrew Labor In-Cockpit Automation System (ALIAS) program, explained Cherepinsky. In early 2022, DARPA and Sikorsky Innovations demonstrated ALIAS to the US Army at Fort Campbell, Kentucky. “The demonstration took the form of an optionally piloted Black Hawk without humans during a 30-minute flight,” he said. “The aircraft flew a programmed circuit, while avoiding ‘pop-up’ obstacles autonomously and doing so successfully.”

Without the infrared light, I would have flown straight into the desert floor

Interest peaked as the Army requested a second demonstration later that year, this time with no safety pilots onboard. At the Yuma Proving Ground, Arizona, Sikorsky’s optionally piloted Black Hawk flew uninhabited with the MATRIX autonomy system. Demonstrated were a troop resupply mission with a cabin filled with boxes of blood plasma while flying at just 200ft above ground, an evacuation mission of a manikin in a contested environment, and a long-distance resupply mission while slinging an external load. All flights were performed without a ground controller controlling the aircraft, explained Cherepinksy.

On the fixed-wing side, Sikorsky has flown the MATRIX system aboard a large commercial transport aircraft to demonstrate single-pilot and compromised single-pilot operation.

“These diverse missions show how the MATRIX autonomy system can be scaled to fly a variety of aircraft sizes and types,” said Cherepinsky, who added that transport aircraft integrated with the MATRIX system could become Federal Aviation Administration (FAA) certified.

National Transportation Safety Board: fatal consequences of IIMC

IIMC leading to spatial disorientation continues to be a leading cause of fatal rotor- and fixed-wing accidents around the world. In the USA, from 2014–23, the National Transportation Safety Board (NTSB) investigated 163 civil aviation rotor accidents attributed to IIMC, which was cited as “an event somewhere in the sequence of events leading up to the accident”. Of the 163 accidents, 119 were fatal.

Robinson Helicopter: sound decisions and risk management 

Founded by Frank Robinson in 1983, “the Robinson Helicopter Safety Course has been offering the comprehensive training specifically prioritizing public safety through education multiple times a year, and continues to evolve regularly, addressing new safety challenges faced by pilots,” said David Smith, President and CEO of Robinson Helicopter.

Although much has changed since the original safety course, including the capabilities of our helicopters and threats to safety, Smith said, “the company’s “core principle remains constant: building a foundation of sound decision-making and risk management” with the knowledge that “safe navigation in DVE conditions relies heavily on pilot judgment”. By recognizing these risks and making informed choices, pilots can prioritize avoiding situations that require recovery from unexpected visibility loss, he said. “Many DVE scenarios are preventable by applying proper planning and techniques crucial for ensuring safe outcomes,” said Smith.

Flight simulator training: safely mitigating IIMC

FlightSafety International (FSI) provides customers with current and comprehensive S-70 and S-70i training designed to increase pilot proficiency and enhance safety in routine and unexpected operating environments, while ensuring access to the latest technical information and service bulletins.

“As flight simulation training instructors, it is our job to make sure our customers are aware of the challenges associated with flying DVE conditions and are adequately prepared for safe operations,” said FSI S-76D and S-70A/M Flight Instructor Bruce Hoffmann, who also worked with FSI S92 Flight Instructor Jess McGee at the Sikorsky Aircraft facility to produce the comprehensive proprietary flight simulation training program courseware in 2014. “Our Sikorsky simulators exhibit the most innovative technology in the simulator training industry, notably in the incredible ‘Mike’ model that is used to train as a separate aircraft with a couple of flight directors,” said Hoffmann. While mitigating an IIMC, he said, “you have to trust your instruments”.

Safe navigation in DVE conditions relies heavily on pilot judgment

In 2017, FSI received the new Sikorsky S-76D Graphical Flight-Deck Simulator (GFS), a key component of the MATRIX (unrelated to the Sikorsky MATRIX autonomy system), FSI’s Integrated Learning System, and in 2019, FSI began offering FAA-approved instrument flight rules (IFR) training in the Sikorsky S-76 Level D qualified simulator at its Learning Center in West Palm Beach, Florida, where Hoffmann and McGee both train military, government agency, and commercial pilots. Both instructors bring the dual M2C perspective from their military careers as retired US Army UH-60 Black Hawk pilots.

It was Hoffmann who recalled the DVE flight over flat terrain when he realized a complete loss of contrast, feeling like he would never reach his destination, notably when the ‘blind spot’ was the dust cloud above his Black Hawk. “The crew chief was watching, but didn’t see a dust cloud coming, nor did I see it because it was on top of me,” he said. With a quick assessment by the flight crew, Hoffmann said the crew pointed the infrared searchlight straight down. “Without the infrared light, I would have flown straight into the desert floor,” he said. “Staying ahead of the cloud is critical.” You have to land at a forward speed while monitoring your instruments, added Hoffmann. “The Black Hawk has hover modes that pick up the altitude and heading, but if you move around, the instruments can’t detect, which means there is no time to react,” he said. Questioning your ‘hover power’ is also critical. “You have to pull that power in, then commit to the approach without varying from that point,” explained Hoffmann.

It’s about trust: trusting instruments, training and aircraft

As an FSI S-76B Flight Instructor, McGee said, he’s seen “an increase in IIMC training over the past 10 years”.

“I will say that IIMC can be prevented during the planning stage of flying,” he said. As a retired US Army Black Hawk pilot, McGee said, when he flew into a dust cloud while serving in Baghdad, he “trusted the aircraft”.