The NTSB unanimously adopted on February 9 its determination that the probable cause of the crash on January 26, 2020, that killed all nine people aboard was the “pilot’s decision to continue flight under visual flight rules into instrument meteorological conditions,” leading to “spatial disorientation and loss of control.”
The board found that the absence of terrain awareness and warning technology on board the Sikorsky S–76B was not a factor because it would not have improved the likelihood of safely completing this flight. Zobayan lost control of the helicopter while attempting to climb above clouds, and crashed into a hillside in Calabasas, California, because he thought he was climbing when, in fact, the helicopter was descending rapidly.
Board members noted that this was a familiar scenario that has consistently claimed lives for decades despite efforts by government and industry to improve pilot training. Between 2010 and 2019, 184 fatal aircraft accidents, including 20 helicopter accidents, were caused by pilots becoming disoriented after inadvertent entry into instrument conditions.
“We are averaging one helicopter crash, VFR into instrument conditions, every six months for the last 10 years, so I guess the question I have to ask is, what part of ‘cloud’ … do pilots not understand?” said NTSB Vice Chairman Bruce Landsberg, expressing a frustration that appeared unanimous.
There is no way to replicate the disorienting effects of somatogravic illusions in simulators, board members and staff noted. Even full-motion simulators cannot realistically create the forces of acceleration during flight that act on the vestibular system and mislead pilots who lose visual references. Training in an aircraft with a view-limiting device also has limitations, including the ability to “peek” around the edges that can be difficult to resist, though it defeats the purpose of the exercise. This method also fails to realistically replicate how quickly visual references can disappear in real-world conditions.
Among the four new safety recommendations unanimously approved on February 9, the board called on the FAA to convene a multidisciplinary panel to evaluate emerging technologies such as virtual reality that could be incorporated into simulation training to better prepare pilots, including those who do not routinely fly on instruments, to ignore the misleading sensations that Zobayan must have experienced in the final moments of the flight.
The board found “inadequate review of and oversight of its safety management processes” by Island Express Helicopters Inc. was a contributing factor, along with “the pilot’s likely self-induced pressure” to complete the flight, and “plan continuation bias,” the tendency to err on the side of landing at the intended airport, particularly as the flight approaches its destination. Board members and investigators noted the yearlong investigation found no evidence that the company violated FAA regulations. Board members noted that the company, authorized to conduct charter flights exclusively in VFR conditions, had routinely canceled flights due to poor weather, including in the weeks leading up to the accident.
While the company, with a staff of 25 operating six helicopters, had not fully implemented a safety management system, they were not required to by FAR Part 135. Board members unanimously agreed that should change across the industry.
Investigators did not find evidence that the company pressured pilots to complete flights, though “the company didn’t really have a robust infrastructure to help out in case the pilot had to go to a plan B” such as diverting to another airport, said lead investigator Bill English. The board debated for several minutes use of the word “likely” in reference to self-induced pressure on the part of the pilot, but there was comparatively little discussion of the conduct of his employer, beyond noting that the flight risk assessment tool purchased from a vendor and used by all company pilots was not “robust,” and past safety audits found the company safety manager lacked formal training.
“There wouldn’t be any indication that Island Express was unsafe, or a problem operator,” English said during the board meeting in reference to the investigation docket spanning hundreds of pages.
The investigation produced radar and ADS-B analyses, transcribed interviews with company pilots and executives, eyewitness accounts, images taken from the ground (including video of the helicopter flying over a surveillance camera seconds before it disappeared into the clouds), and documents detailing maintenance records, and inspection of the wreckage of an aircraft determined to be in good working order at the time of the crash.
The investigation also confirmed Zobayan was not impaired by drugs, alcohol, or lack of sleep.
Similarly, while Island Express sued the FAA in August, alleging that air traffic controllers engaged in “numerous” negligent acts or omissions, including a request that Zobayan ident after he announced his intention to climb to avoid clouds, the NTSB took a different view. (The board’s determinations are not admissible as evidence in court proceedings.) Chairman Robert Sumwalt asked English during the meeting, “did any of the air traffic control actions, errors, or omissions contribute in any way to this horrible tragedy?”
English replied: “No, sir.”
Instead, the accident was the result of a series of decisions made by the pilot during the flight, decisions to continue toward Camarillo, California, amid deteriorating conditions, rather than land elsewhere (including an airport about 10 miles behind along the route of the ill-fated flight), or otherwise remain clear of clouds, as the company’s FAR Part 135 certificate required.
English summarized: “He didn’t follow his training.”
Loss of control
Zobayan was the chief pilot for Island Express, and had flown 8,577 hours, including 1,250 hours in Sikorsky S–76 helicopters. He held an instrument rating, though his instrument proficiency or currency could not be determined. His experience flying in actual instrument conditions was limited, investigators noted, with 68 of his 75 lifetime instrument flight hours in simulated instrument conditions. English said the pilot’s last documented instrument training was in May 2019.
Investigators confirmed that Zobayan had obtained a weather briefing prior to the flight, and that he had also completed a risk assessment form required by Island Express that scored the risks involved in this particular flight, including weather, within limits that did not require further evaluation or consultation. A marine layer of clouds covered most of the flight route with an overcast ceiling, though it was at least 1,000 feet agl for much of the route.
None of the information available to Zobayan prior to takeoff from John Wayne/Orange County Airport in Santa Ana, California, at 9:07 a.m., would have indicated that the weather was too poor to complete the flight.
“There’s nothing there that should have said no-go,” English said during the board meeting. “The conditions we see, even up until the accident site, were at no point below the (VFR) minimum for a helicopter. It was the in-flight decisions where the breakdown occurred.”
It is common practice for helicopters to follow highways, and Zobayan was following U.S. Route 101 toward Camarillo after an “uneventful” transit through controlled airspace. Zobayan requested and received updated weather at Van Nuys Airport, just north of the route of flight and 11 nautical miles from the crash site, learning that visibility (2.5 miles) was somewhat less than forecast. While the helicopter had maintained at least 500 feet agl during the prior phases of the flight, Zobayan began to descend as he followed the highway west toward Camarillo, the terrain rising to meet the clouds. He descended as low as 350 feet above the highway.
“It would be reasonable to assume that he had a sense this isn’t working,” said Landsberg. English concurred: “I think that’s consistent with the data that we have, including his call to ATC.”
It was here, in the final three minutes of flight, that Zobayan began to deviate from what he was trained to do in this situation. He did not slow down, maintaining 140 knots less than 500 feet above the highway. He did not turn around and head for Van Nuys, about 10 miles east. He did not find a safe spot below to land the helicopter.
At 9:44 a.m., roughly two minutes before the crash, Zobayan told air traffic control that he was initiating a climb to get the helicopter “above the [cloud] layers” ahead. Radar and ADS-B data show the helicopter immediately began climbing at about 1,500 feet per minute, and also began a gradual left turn, following the highway below.
Investigators were unable to determine precisely when Zobayan lost sight of the ground, but the helicopter reached a maximum altitude of 2,370 feet, very close to the reported cloud tops in the area, before it began descending rapidly toward the terrain, banked and turning left as it climbed, and continuing the left turn as it began to descend. ATC asked Zobayan to “say intentions” seconds before impact, and Zobayan reported he was climbing to 4,000 feet, when, in fact, he was descending at about 4,000 feet per minute. An eyewitness saw the helicopter emerge from the clouds in a left-banked descent 1 or 2 seconds before impact.
The vestibular system, located in the inner ear, allows a person to sense balance and spatial orientation, though it has a vulnerability that all pilots are familiarized with during their training, particularly during instrument training: It can be very misleading when visual cues disappear.
“Like all accelerometers, the vestibular system cannot distinguish between load factors due to motion versus load factors due to gravity,” the NTSB notes in the Performance Study conducted during the investigation. “Simply put, on its own, the inner ear cannot differentiate between accelerations and tilt. Additional sensory inputs, such as visual cues, are needed to correctly perceive attitude and acceleration.”
Instrument-rated pilots are trained to disregard all sensations of motion and instead rely exclusively on instruments when visual references are lost to discern the aircraft’s attitude, but “the path of the helicopter is not consistent with committing to the instruments,” English said.
Zobayan also had an autopilot available, but he did not engage it.
The NTSB issued four new recommendations as a result of this investigation, two of them closely related and directed at the FAA: That the agency require Part 135 helicopter operators to use “appropriate simulation devices” during initial and recurrent pilot training to provide scenario-based training on the decision making, skills, and procedures to recognize and respond to changing weather conditions. The board’s second new recommendation urged the FAA to “convene a multidisciplinary panel of aircraft performance, human factors, and aircraft operations specialists to evaluate spatial disorientation simulation technologies to determine which applications are most effective for training pilots to recognize the onset of spatial disorientation and successfully mitigate it.”
The board also recommended that Island Express participate in the FAA Safety Management System Voluntary Program, install flight data recording devices, and establish a flight data monitoring program capable of identifying deviations from established procedures and other potential safety issues.
The NTSB reiterated previous recommendations as well, some dating back years, including one that the FAA require all Part 135 operators to establish a structured flight data monitoring program, and mandate implementation of a safety management system (which is currently voluntary).
The board also reiterated previous recommendation that the FAA require aircraft operated under Part 135 be equipped with crash-resistant voice and flight data recorders.
The board did not reiterate a recommendation made in 2006 that terrain awareness and warning systems be required for Part 135 helicopter operations. Sumwalt, in a media conference following the meeting, took pains to clearly state that such systems would not have prevented this accident. Zobayan was aware of the terrain, and thought he was climbing toward clear air when he was actually in a deadly descent. Investigators concluded (and the board concurred) that the pilot’s longtime relationship with his celebrity passenger “likely” contributed to his decision to press on toward Camarillo Airport, just under 20 nm from the crash site, rather than slowing down or turning around before entering instrument conditions.
“I think this illustrates that even good pilots can end up in bad situations,” Sumwalt said.