EXCERPTS FROM: Martin Doms Air Inter Flight 148 Posted on January 24, 2011. by Martin Doms...

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EXCERPTS FROM: Martin Doms Air Inter Flight 148 Posted on January 24, 2011. by Martin Doms On January 20, 1992, Air Inter Flight 148 crashed into the Vosges Mountains while approaching Strasbourg Airport in Strasbourg, France. 87 of the 96 crew and passengers on board were killed. Many factors came together to cause Air Inter Flight 148 to hit a mountain. However one of the primary causes should be of concern to anyone developing a User Interface. The Airbus A320 had the most advanced cockpit in the world. H FPA -3.3 VIS -33 THE LAS ARDE 045 02109 -28 240 AS-LR 71.3 600 APPA KDS SEAR $4.14 260 STAT BEATS 29363 S33 01392 The majority of the gauges and instruments in front of the pilots in this machine are digital. When the captain of the aircraft was approaching the runway through thick clouds, he thought he had set a descent angle of a mild 3.3 degrees for a gentle descent above the Vosges Mountains. However, unbeknownst to him the plane was descending at a rate of 3,300 feet per minute, much faster than the descent would have been at 3.3'. The aircraft struck a mountain top and exploded. Air accident investigators noticed the similarities between those two numbers - the pilot's intended descent rate (3.3') and the actual descent rate (3,300 fpm). 02 As it turns out, the airbus A320 used a single display for two different descent modes - Vertical Speed (VS) Mode and Flight Path Angle (FPA) mode. The display showed FPA as two digits separated by a decimal point, and VS as just two digits (and both had a minus sign when their values were negatives). To the right is an image of the display showing an FPA of -2.8'. This simple design error led the pilot to believe he was in one mode while he was in another. It was not the only factor in the accident, but the crash almost certainly would not have happened had the aircraft's user interface been more clear. EXCERPTS FROM: Martin Doms Air Inter Flight 148 Posted on January 24, 2011. by Martin Doms On January 20, 1992, Air Inter Flight 148 crashed into the Vosges Mountains while approaching Strasbourg Airport in Strasbourg, France. 87 of the 96 crew and passengers on board were killed. Many factors came together to cause Air Inter Flight 148 to hit a mountain. However one of the primary causes should be of concern to anyone developing a User Interface. The Airbus A320 had the most advanced cockpit in the world. H FPA -3.3 VIS -33 THE LAS ARDE 045 02109 -28 240 AS-LR 71.3 600 APPA KDS SEAR $4.14 260 STAT BEATS 29363 S33 01392 The majority of the gauges and instruments in front of the pilots in this machine are digital. When the captain of the aircraft was approaching the runway through thick clouds, he thought he had set a descent angle of a mild 3.3 degrees for a gentle descent above the Vosges Mountains. However, unbeknownst to him the plane was descending at a rate of 3,300 feet per minute, much faster than the descent would have been at 3.3'. The aircraft struck a mountain top and exploded. Air accident investigators noticed the similarities between those two numbers - the pilot's intended descent rate (3.3') and the actual descent rate (3,300 fpm). 02 As it turns out, the airbus A320 used a single display for two different descent modes - Vertical Speed (VS) Mode and Flight Path Angle (FPA) mode. The display showed FPA as two digits separated by a decimal point, and VS as just two digits (and both had a minus sign when their values were negatives). To the right is an image of the display showing an FPA of -2.8'. This simple design error led the pilot to believe he was in one mode while he was in another. It was not the only factor in the accident, but the crash almost certainly would not have happened had the aircraft's user interface been more clear.