Two aeroplanes collided in VMC. Obviously they didn't spot each other or else they wouldn't have collided. So something must have gone wrong, and "see and avoid" failed - whether it was bad airframe design creating a blind spot, sun in the eyes, not looking out, looking at the airport instead of "up final", concentrating on flying an ILS and looking at the instruments, another problem diverting crew's attention.....whatever
One thing that was mentioned was instrument approaches. An IAP in VMC does not absolve the commander of "see and avoid" any more than a VFR pilot joining the circuit. That goes for a 747 or a C150.
Perhaps it is time to enforce a) collision avoidance systems on ALL commercial aeroplanes and b) mandatory transponders on all aircraft?
Some will say this is a knee jerk reaction, but if we can't rely on See and Avoid then should something be done?