The biggest problem that is faced by Malaysia and families of crews and travellers on the missing MH370 plane is knowing the whereabouts of the plane. The problem? The transponder might have been switched off! That is the main factor that hampered effort of several countries who chipped in to help with the search and rescue. How I felt knowing that transponders and ELTs could be manually turned off? Flabbergasted!
I blame air plane manufacturers for allowing captains/pilots to have the access to turn off transponders at their discretion (if not whims; read about manual override of transponder and ELT). If the rationale was to allow plane to go invisible for safety reason (esp. during time of war), how frequent is that an advantage in normal times? See what it has caused us in MH370 case (if indeed the plane was hijacked). That is a big negligence in the manufacturers’ part for providing a loop-hole for hijackers to steal.