http://edition.cnn.com/videos/world/2015/03/26/newday-germanwings-crash-plane-lock-explainer.cnn

How do cockpit lock controls work?

Source: CNN

Added on 1319 GMT (2119 HKT) March 26, 2015

Aviation experts David Soucie and Justin Green explain how the locking mechanism worked for the the cockpit of Germanwings Flight 9525.

Germanwings co-pilot Andreas Lubitz (14)