Did a User Interface Kill 10 Navy Sailors?

I chose a provocative title for this post after reading the report on what caused the wreck of the USS John McCain in August of 2017. A summary of the accident is that the USS John McCain was in high-traffic waters when they believed they lost control of steering the ship. Despite attempts to slow or maneuver, it was hit by another large vessel. The bodies of 10 sailors were eventually recovered and five others suffered injury.

Today marks the final report on the accident released by the Navy. After reading it, it seems to me the report blames the crew. Here are some quotes from the offical Naval report:

  • Loss of situational awareness in response to mistakes in the operation of the JOHN S MCCAIN’s steering and propulsion system, while in the presence of a high density of maritime traffic
  • Failure to follow the International Nautical Rules of the Road, a system of rules to govern the maneuvering of vessels when risk of collision is present
  • Watchstanders operating the JOHN S MCCAIN’s steering and propulsion systems had insufficient proficiency and knowledge of the systems

And a rather devestating:

In the Navy, the responsibility of the Commanding Officer for his or her ship is absolute. Many of the decisions made that led to this incident were the result of poor judgment and decision making of the Commanding Officer. That said, no single person bears full responsibility for this incident. The crew was unprepared for the situation in which they found themselves through a lack of preparation, ineffective command and control and deficiencies in training and preparations for navigation.

Ouch.

Ars Technica called my attention to an important but not specifically called out reason for the accident: the poor feedback design of the control system. I think it is a problem that the report focused on “failures” of the people involved, not the design of the machines and systems they used. After my reading, I would summarize the reason for the accident as “The ship could be controlled from many locations. This control was transferred using a computer interface. That interface did not give sufficient information about its current state or feedback about what station controlled what functions of the ship. This made the crew think they had lost steering control when actually that control had just been moved to another location.” I based this on information from the report, including:

Steering was never physically lost. Rather, it had been shifted to a different control station and watchstanders failed to recognize this configuration. Complicating this, the steering control transfer to the Lee Helm caused the rudder to go amidships (centerline). Since the Helmsman had been steering 1-4 degrees of right rudder to maintain course before the transfer, the amidships rudder deviated the ship’s course to the left.

Even this section calls out the “failure to recognize this configuration.” If the system is designed well, one shouldn’t have to expend any cognitive or physical resources to know from where the ship is being controlled.

Overall I was surprised at the tone of this report regarding crew performance. Perhaps some is deserved, but without a hard look at the systems the crew use, I don’t have much faith we can avoid future accidents. Fitts and Jones were the start of the human factors field in 1947, when they insisted that the design of the cockpit created accident-prone situations. This went against the beliefs of the times, which was that “pilot error” was the main factor. This ushered in a new era, one where we try to improve the systems people must use as well as their training and decision making. The picture below is of the interface of the USS John S McCain, commissioned in 1994. I would be very interested to see how it appears in action.

US Navy (USN) Boatswain’s Mate Seaman (BMSN) Charles Holmes mans the helm aboard the USN Arleigh Burke Class Guided Missile Destroyer USS JOHN S. MCCAIN (DDG 56) as the ship gets underway for a Friends and Family Day cruise. The MCCAIN is getting underway for a Friends and Family Day cruise from its homeport at Commander Fleet Activities (CFA) Yokosuka Naval Base (NB), Japan (JPN). Source: Wikimedia Commons

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