Human-Computer interaction
The user experience of a system or a program is something that everyday users might take for granted, depending on their needs. Today's mainstream applications and devices usually feature carefully thought out designs to make the interaction between man and machine as seamless as possible (with a few exceptions). However, in some applications, HCI can quickly turn into a life-or-death matter.
When it goes wrong
In aviation, a lot can happen during a brief period of confusion. Air Inter flight ITF148, an Airbus A320, was on approach to Strasbourg Airport when the pilots forgot to switch the autopilot mode from Vertical Speed Mode to Flight Angle Path mode for landing. The pilots then intended to set the aircraft's autopilot to a normal 3.3-degree descent angle and input the number "33" to the system. However, in the Vertical Speed Mode, this 33 translated to a descent of 3300 feet (or around 1000 meters) per minute. This happened in the mountains at night, and there were low, fairly dense clouds, so the pilots had no visual cue of how fast they were descending. Shortly after that, the aircraft crashed into the mountains, and no survivors were found. In response, Airbus changed the way their system displays descent speed, which is now displayed as a four-digit number instead of just two to prevent confusion.
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| ITF148. Wikipedia |
There have been other similar incidents over the years, most of which were met with aerospace companies improving their designs to what they are today. Hopefully, by now, they've gotten it right, or at least right enough.
When it goes right
Generally, good HCI is achieved when the user, its needs, capabilities and limits are considered in the system's design. Staying on the topic of aviation, the General Dynamics F-16 fighter jet is completely fly-by-wire (meaning that the pilot input is given to a computer, which then controls the aircraft based on how it interprets the input). This feature allowed the designers to incorporate something called the Automatic Ground Collision Avoidance System, which, as the name suggests, avoids colliding with the ground. This is especially important in fighter jets, where the pilots could potentially pass out mid-maneuver due to extreme G-forces. To date, it has reportedly saved 10 pilots and 9 aircraft in total.
The USAF released footage of this system in action a few years ago:
Conclusion
HCI can potentially make or break a bad situation, especially in crucial applications such as aviation. The human aspect of a system is a very important thing to consider.
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