Spanair accident at Madrid

[clearedtocross]

WOW logic

Thank you, SPA83, for this extraordinary piece of information. It shows that:

1. the air ground mode relies entirely on the left and right nose wheel switches. The two switches are not combined into a redundant logic (Left OR right), they control different sets of logic.
2. The line from the left switch and the switch itself must have been operational to to get the FDR record "air mode" (R2-212).
3. The R2-5 may have got stuck to fail to actuate the take off warning and to set the air data heating off. It may also have become disconnected.
4. There is no cb in this said line, so R2-5 may not have been disengaged by a quick intervention when the RAT heating had to be switched off. Whatever the mechanics did to get the RAT heater of, theres nothing in this circuit that would switch off R2-5.