Spurred by the mid-air collision between a Saudi Arabian Boeing 747-100 and a Kazakh Ilyushin Il-76 in November 1996 near New Delhi, India, the US Federal Aviation Administration is investigating the feasibility of employing used transponders to reduce the risk of collision. The shelved transponders were those replaced by traffic-alert and collision avoidance systems (TCAS), with integral mode-S transponders when the USA decided to make TCAS compulsory.


Source: Flight International