Friday, June 23, 2023

The Titan and the Comet

 The sad news came yesterday that the tourist submersible, Titan, apparently suffered a catastrophic breach of its pressure vessel and imploded. The crew and passengers on board the sub were likely dead shortly after contact was lost on June 18.

While the cause of the accident is not yet known, an obvious point of focus is the safety concerns raised by a whistleblower five years ago. Back in 2018, David Lochridge, the former Director of Marine Operations at the sub operator OceanGate, sued the company after allegedly being fired for bringing up safety issues. For the record, Lochridge was not an engineer.

Titan submersible (Photo credit:

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As described by Law and Crime, among Lochridge’s complaints was a concern that the Titan was using a viewport that was only certified to 1,300 meters (4,265 feet). This was a problem because the Titanic wreck is at a depth of 12,400 feet (3,780 meters). In scientific terms, this is what is referred to as “not even close.”

When I heard this, it reminded me of the story of the world’s first passenger jetliner. Even though submersibles and airplanes operate under vastly different conditions, they have some similarities. One of these is that they are subjected to the stresses of immense pressure charges. In an airplane, the high pressure is on the inside as the craft flies at high altitudes with very low air pressure outside.

For submarines, it’s the opposite. The weight of the column of water atop the vessel is very high. Scientific American notes that the water pressure at the Titanic site is 375 atmospheres. At that depth, the water pressure per square inch (PSI) generates more force than the bite of a crocodile or great white shark.

But back to the airplane. The De Havilland Comet entered service in 1952 as the world’s first jet airliner. The airplane was popular and relatively safe for its time with only a few pilot-induced mishaps in its first year.

A BOAC de Havilland Comet jet airliner, en route to Johannesburg from London, breaks its journey at Entebbe Airport, Uganda. 1952 (public domain/Wikimedia)

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But then, exactly one year after it entered service, a British Overseas Airways Corporation (BOAC) Comet broke up in a thunderstorm over India killing all aboard. The cause of the crash was determined to be an in-flight breakup due to the extreme forces encountered in the thunderstorm.

Then, in 1954, a series of more mysterious accidents began to occur. On January 10, another Comet operated by BOAC crashed into the Mediterranean with no survivors or witnesses. A South African Airways Comet broke up in flight, again over the Mediterranean, on April 8. After this crash, the entire fleet was grounded and the Comet was subjected to an intense investigation to determine the cause of the crashes.

A test Comet was placed in a large water tank where it was subjected to repeated pressurization and depressurization cycles. Ultimately, the cause was determined to be metal fatigue. Stress cracks developed after far fewer cycles than the designers had estimated. The South African Airways plane had broken up after only 900 pressurized flights. This is a very short life span for an airliner.

What made me think of the Comet was that when I first heard the story, I heard the urban myth version that held that the Comet’s in-flight breakups were due to an explosive decompression that resulted from cracks that developed at the corner of the cabin windows. This turns out not to be true, as I only learned when researching this article, but the rectangular windows on the early Comets were replaced by oval windows on later models. (If you’d like more details on the De Havilland Comet and the accident investigations, Admiral Cloudberg has an excellent in-depth discussion that was the basis of much of my synopsis.)

At any rate, the Comet still bears lessons for the Titan investigation. When a piece of machinery is subjected to repeated cycles of pressurization and depressurization, the immense stress placed on the metal and other components can cause sudden and catastrophic failures.

The windows of the Comet might not have been the culprit of the jetliner crashes, but in my admittedly limited knowledge of the Titan, the window that was rated to less than half of the pressure to which Ocean Gate intended to take the craft is a prime suspect.

Like the metal skin of the Comet, the Titan’s window wouldn’t necessarily have failed on its first or even second dive, but every dive beyond the rated depth would have increased the chances of catastrophic failure. And when a window blows out at 12,000 feet below the surface, it is just as catastrophic as an airliner losing its wings at 40,000 above the ground.

When operating at the limits of human technology, safety and redundancy are of paramount importance. The more that I’ve learned about Ocean Gate and the Titan, the more I’ve been appalled at the lack of concern for safety.

The De Havilland design team considered the effects of metal fatigue, but they still grossly miscalculated its effects on the Comet. On the other hand, the Titan team seems to have had a very cavalier attitude towards the dangers that the sub faced.

In 2022, CEO Stockton Rush told CBS News, “At some point, safety just is pure waste. I mean, if you just want to be safe, don't get out of bed. Don't get in your car. Don't do anything.”

This is not the attitude that I’d want from the guy building a machine to take me 12,000 feet underwater. Some risk is necessary, but Rush’s attitude makes me think less that his risks were carefully calculated and more that he carelessly disregarded basic safety protocols in building his craft.

I wouldn’t want to trust my life to a $50 video game controller and I definitely wouldn’t want to go to 12,000 feet sitting next to a window that was only rated to 4,500 feet. If the allegations are true, they paint a picture of flagrant disregard for safety.

When we operate in extremely dangerous environments, extreme caution and attention to safety are needed to prevent needless accidents. If the reports about Ocean Gate are accurate, an accident was probably inevitable at some point. You can only tempt fate so many times before your luck runs out.

The worst part of the tragedy is that Rush knew (or should have known) the danger of the risks that he was taking. That is not true for the passengers who trusted Rush to carry them safely to the bottom of the sea and back.

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