Let alone the parsimony that led the original 737 design (and so too its grandfathered descendants) to recycle the same horn sound for two different situations:

Let alone the parsimony that led the original 737 design (and so too its grandfathered descendants) to recycle the same horn sound for two different situations: incorrect takeoff configuration and cabin altitude. Boeing's reasoning was simple: one of them only gets heard on the ground, the other only at high altitude, so it won't be ambiguous. Except that many pilots will be familiar with the first case (e.g. skipped a checklist item before starting takeoff roll) and relatively few with the second case (pressurization failure). So on Helios 522 the increasingly incapacitated flight crew spent their final conscious minutes trying to debug the wrong scenario. https://en.wikipedia.org/wiki/Helios_Airways_Flight_522 https://en.wikipedia.org/wiki/Helios_Airways_Flight_522