Deadly parallels
Part 1: The world now knows the name of the company “OceanGate” due to the recent tragedy of the submersible that imploded on its way to view the Titanic site. Five people lost their lives due to flaws in the submersible vessel, Titan, that they were traveling in. The Coast Guard announced the deaths from a “catastrophic implosion.”
Experts had cautioned that under intense pressure at extreme depths the Titan’s hull could implode, which would result in instant death for anyone aboard the vessel.
“I don’t think people can appreciate the amazing energy involved in the destructive process of an implosion,” Bob Ballard, a member of the team that found the Titanic wreck in 1985, told ABC News. “It just takes out and literally shreds everything.”
While OceanGate Expeditions, which owned and operated the craft, touted the Titan’s roomier cylinder-shaped cabin made of a carbon-fiber, industry experts say it was a departure from the sphere-shaped cabins made of titanium used by most submersibles.
The 23,000-pound vessel was made of “titanium and filament wound carbon fiber” and had been “proven to be a safe and comfortable vessel" that could "withstand the enormous pressures of the deep ocean,” OceanGate said on its website.
While carbon fiber has long been used within the aerospace industry, Kemper said it had not been proven to repeatedly withstand such deep-sea pressures.
The wreckage of the Titanic lies at a depth of about 13,000 feet. That is significantly deeper than the roughly 2,000 or 3,000 feet that a typical U.S. Navy submarine descends to.
At Titanic depths, the water pressure is nearly 400 times more than at the ocean’s surface, experts told NBC News. Some 6,000 pounds would have been pressing down on every square inch of Titan’s exterior.
“It’s a design that’s not been used in this way at this depth,” Kemper said, comparing a submersible to a balloon. “All it has to do is fail in one spot and game over.”
In contrast, U.S. Navy submarines are made with carbon steel, a “tried and true material” that is reliable and thoroughly understood, according to Captain David Marquet, a retired Navy submarine commander.
Carbon fiber, the former sub commander said, is a relatively new material, especially for building submarine hulls. He said multiple repeated dives, inspections, X-rays and ultrasounds are needed to fully understand how the material responds to stress and pressure over time.
The Titan was diving 10 times deeper than the Navy takes its submarines, which meant it was undergoing 10 times more pressure, Marquet said.
Arun Bansil, a Northeastern University physics professor, likened that “humongous” pressure to the force of “a whale biting on somebody.”
Though the Titan had a composite hull with inbuilt sensors that could withstand high pressures near the sea floor, any defect could result in a “near instantaneous implosion” in less than 40 milliseconds, said associate professor Eric Fusil, director of the Shipbuilding Hub at the University of Adelaide in Australia. “The passengers probably would have had no idea what happened,” Bansil said.
The Titan had made more than two dozen deep-sea dives, which put repeated stress on the hull, said Jasper Graham-Jones, an associate professor of mechanical and marine engineering at the University of Plymouth in the United Kingdom.
That stress could potentially cause delamination, a horizontal splitting of the carbon-fiber hull, he said.
A similar disaster occurred in 1963 when the USS Thresher, a nuclear-powered submarine, likely imploded when it exceeded “test depth” after a series of other failures. Killed were 129 sailors and civilians on a routine test dive off Cape Cod.
Part 2:
Just as there have been instances of nautical disasters due to the pressure of the ocean and weaknesses in the nautical vessels, there have been instances of aviation disasters that have been attributed to cabin structural failure or compromises in the integrity of the fuselage. Here are a few notable examples:
Aloha Airlines Flight 243 (1988): This incident involved a Boeing 737-200 aircraft. During the flight, a section of the aircraft's fuselage, including a significant portion of the roof, peeled away due to metal fatigue and corrosion. The failure resulted in rapid decompression, leading to the ejection of a flight attendant and the death of one passenger. The pilots managed to make an emergency landing, and subsequent investigations highlighted issues related to maintenance, aging aircraft inspections, and structural fatigue.
“We had never had airplanes flying for that many years, or that many flight cycles, in this sort of set of circumstances,” Jeff Marcus, chief of safety recommendations for the National Transportation Safety Board, tells The Independent. “And unfortunately, that’s the way, many times, that lessons are learned; that’s the reason why the NTSB exists, you do an investigation after something unfortunate occurs, and you learn from that.
At the time of the accident, according to the NTSB report, the plane “had accumulated 35,495 flight hours and 89,680 flight cycles (landings), the second highest number of cycles in the worldwide B-737 fleet.”
On its final flight, however, the plane suffered explosive decompression as a result of structural failures caused by “significant disbanding and fatigue damage.”
“As you go up in altitude, the air pressure outside reduces, so an airplane has systems that keep the air inside the airplane sort of the same pressure as it would be when you’re near the ground. When the skin blows out, then all of that air inside the airplane suddenly goes flying out, because it’ slow pressure out there, and that’s explosive decompression, because it happens very quickly,” Mr Marcus tells The Independent.
investigators determined, could likely have been avoided had more meticulous safety inspections and protocols been practiced. The accident led to more frequent and thorough checking of aircraft cracks and rivets after there was “obviously a failure of the maintenance program to catch these impending errors and repair them,” Mr Marcus tells The Independent.
The NTSB report found that “the probable cause of this accident was the failure of the Aloha Airlines management to supervise properly its maintenance force” and “the failure of the FAA to evaluate properly the Aloha Airlines maintenance program and to assess the airline’s inspection and quality control deficiencies,” among other factors.
But this week, paraphrasing a late NTSB colleague, Mr Marcus says: “In essence, this was not something we could have reasonably foreseen.
“It was unfair to say the FAA ignored issues with the maintenance department; it was unfair to say that Boeing had not done adequate engineering,” he says. “It was a case of: This was just something we didn’t know before.”
Hazel Courteney, president of the International Federation of Airworthiness, says that the factors behind the Aloha Airlines accident were “not as if someone was just flagrantly not doing their job; everyone was trying to do their job.”
The advice from Boeing, she tells The Independent, “was not really calibrated around aircraft that worked that hard, so Aloha probably should have made a tighter program up — [but] they went with the kind of default program ... but the program wasn’t quite good enough for what the aircraft was being asked to do, and the training wasn’t quite enough for people to really spot what they should have spotted, and the culture was encouraging people to have the aircraft ready. So it’s all those kinds of subtle things.”
The April 1988 incident, she says, “sparked significant change, really.”
“It’s sparked a lot of attention to aging aircraft and how we manage them,” she says. “I think it gave everyone a shake, and made everyone think, you know, we really do need to look at what we’re doing and whether it really does meet the standard.”
Part 3:
The regulation and safety oversight of aviation and nautical vessels, including experimental submarines, involve distinct frameworks due to the different operating environments and characteristics of these industries. Here are some similarities and differences between how U.S. aviation is regulated and kept safe compared to nautical vessels:
Similarities:
Regulatory Bodies: Both aviation and maritime industries have regulatory bodies responsible for establishing and enforcing safety standards. In the United States, the Federal Aviation Administration (FAA) oversees aviation safety, while the United States Coast Guard (USCG) and the Maritime Administration (MARAD) have responsibilities for maritime safety.
Safety Standards: Both aviation and maritime sectors have established safety standards and regulations to ensure the safe operation of their respective vessels. These standards cover areas such as equipment requirements, operating procedures, crew qualifications, emergency response protocols, and maintenance practices.
Inspections and Audits: Both aviation and maritime industries conduct inspections and audits to monitor compliance with safety regulations. Regular inspections, including scheduled and unscheduled checks, are performed to verify the condition and safety of vessels, equipment, and operational practices.
Accident Investigation: Both aviation and maritime accidents undergo thorough investigations to determine the causes and contributing factors. The National Transportation Safety Board (NTSB) investigates aviation accidents in the United States, while the USCG investigates maritime accidents, including those involving nautical vessels.
Differences:
Operating Environment: Aviation operates primarily in the air, while maritime operations encompass water bodies. The different environments pose unique challenges and risks, necessitating different safety considerations. For example, aviation focuses on aspects such as airspace management, navigation aids, and weather monitoring, while maritime operations require attention to waterway navigation, marine charts, and collision avoidance.
Certification and Licensing: In aviation, aircraft and personnel, including pilots and mechanics, undergo a certification process. Aircraft must meet specific airworthiness standards, and pilots and mechanics require licenses or certifications based on their qualifications. In contrast, nautical vessels, including experimental submarines, do not have the same certification requirements for the vessel itself or for crew members.
Operational Limitations: Aircraft operate within defined airspace with established rules and procedures. They follow air traffic control instructions and operate in accordance with defined flight plans. Nautical vessels, including experimental submarines, have more flexibility in terms of their operating areas and routes, but they still need to adhere to navigation rules and regulations specific to water bodies.
Safety Culture and Reporting: The aviation industry has a well-established safety culture that emphasizes the reporting and analysis of safety incidents and near-misses. This culture promotes open communication, learning from mistakes, and implementing safety improvements. In comparison, the maritime industry is still evolving in terms of safety culture, and reporting systems for incidents and near-misses are not as standardized or widely adopted.
Conclusion:
There have been tragedies over the years, both aviation and nautical, involving lack of maintenance and a lack of testing and regulations. Thankfully, these incidents have been rare.
Nautical vessels such as experimental submarines are not as closely regulated as aircraft are. Had the Titan submersible been constructed with appropriate materials to withstand the pressure of the ocean, could its implosion have been prevented? Experts have stated that the carbon fiber used had not been studied thoroughly to determine how the material responds to stress and pressure over time. The Titan had made more than two dozen deep-sea dives, which put repeated stress on the hull. If the Aloha Airlines fuselage in 1988 had been properly inspected, could that incident have been averted? This incident sparked change for aviation safety. Could Titan change the nautical industry the way that Aloha Airlines Flight 243 changed safety for aviation? Should regulations for experimental submarines become more strict?
Want more information? Learn more or request a detailed analytical report on the data in this article by visiting Consulting by Cota or listen to episode 29 of The CoaTcasT as I discuss this topic. Listen for free on Spotify, anchor, or apple podcast on the cotacast homepage.
