US Navy extends touchscreens due to accident risk


The US Navy again relies on mechanical levers and buttons to control its destroyers (missile destroyer, NATO classification DDG). The user interfaces with touch screens used since 2016 have proven to be a source of danger. The conversion of the fleet will take one and a half to two years, especially since the corresponding order must be tendered.

The reason for the rebuilding is an accident report from the US Department of Transportation Safety (NTSB) and feedback from those seafarers who control these warships. This reports the industry medium USNI News, On August 21, 2017 is the destroyer John S. McCain in the Malakka road with about three times as large tanker Alnic CM collided. Ten men of the crew of the McCain did not survive that.

The accident was investigated by the NTSB. He describes in his report a number of factors that have favored the accident, including lack of sleep of the bridge crew, poor workflow, insufficient training in the touchscreen system, its interface design and the lack of haptic feedback. The NTSB concludes that the design of the touchscreens controls the control and propulsion of the John S. McCain increased the likelihood of operator error and led to the collision, "it says in the official investigation report.

A control panel of John S. McCain

A control panel of John S. McCain

(Picture: NSTB report)

Currently, more than one station on the bridge can control the ship. Whoever has the control over what is displayed on the screens, but for the users, this is obviously not obvious. Unlike levers, there are no tactile feedbacks on touchscreens, so users can not sense whether the controller is responding to their inputs and whether the controls on the left and right propellers are working separately or are currently linked.

Detail from the GUI

This part of the touch screen interface is used to control port and starboard propellers. Only the small tick at the bottom indicates whether the setting of the two screws is currently linked, or each screw must be adjusted separately.

(Picture: NSTB report)

Shortly before the accident, the bridge crew had attempted to transfer propulsion control from one station to another. In fact, the controls were divided so that one station controlled the port screw, the other station the starboard screw. This led to confusion and the erroneous assumption of a failure of the controller. This was, inter alia, reacted with a command to reduce the propulsion. Although the control of the two screws was now reunited at one station, left and right controls were unrelated.

However, the operator did not notice this due to the lack of noticeable feedback. So he braked instead of two propellers only the port screw, which triggered an unwanted turn to port. This cut the McCain the originally parallel running tanker and was rammed by this. Ten men drowned in the invading seawater.

Two months before that was the destroyer USS Fitzgerald with the container ship MV ACX Crystal collided with seven marines lost their lives. After the two accidents, the US Navy questioned its sailors and also heard negative news about the touchscreens. Therefore, mechanical systems with noticeable feedback should be installed again.

Improvements will also be made to the receiver for data of the automatic identification system (AIS). This task is currently handled by a laptop. In the internal survey, sailors complained that the laptops were connected to the ship only with unreliable cables. In addition, these computers are placed behind other device and thus difficult to reach. "We will place the entire configuration differently," officer John Pope is quoted by USNI News, "It's easy to bring a laptop on board, but how to make sure it's being used correctly, correctly configured, and that Can a sailor rely on it? "

Steering Missile Destroyers are the most widely-used naval class of the US Navy since the end of the Cold War. Most of these ships are over 150 meters long, displacing around nine tons and have several hundred sailors crew. Currently, more than 60 missile destroyers are in service with the US Navy.


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