Turkish Airlines Flight 1951 from Istanbul crashed approximately 1.5 km short of Runway 18R while on an ILS approach. A faulty left radio altimeter suddenly indicated −8 feet, causing the autothrottle to enter "retard flare" mode and reduce engine thrust to idle. The flight crew, occupied with a high-workload approach from above the glide path, did not notice the airspeed decay until the stick shaker activated at 460 feet. The aircraft stalled and impacted the field, killing all three pilots and six passengers; 126 occupants survived. The Dutch Safety Board (DSB) identified an "automation surprise": the crew believed selecting the right autopilot and right flight control computer would isolate them from the left radio altimeter failure, but Boeing 737 documentation never disclosed that the autothrottle always received altitude data from the left radio altimeter regardless of autopilot selection.

Study Hook: The crew of TK1951 selected the right autopilot to isolate the failed left radio altimeter, but the autothrottle still used the left altimeter data. How did incomplete documentation about system architecture create a mode-awareness trap that killed nine people?

Visual Prompt: A Boeing 737-800 impact crater in a ploughed Dutch field near Schiphol Airport, with emergency vehicles and investigators in high-visibility gear, snow on the ground, and the airport runway lights visible in the distance.

Tags: [Turkish Airlines 1951, Boeing 737, automation surprise, radio altimeter, autothrottle, mode awareness, Dutch Safety Board, 2009]