PK-275 was a scheduled flight from Mumbai to Karachi on 29 December 2008. Earlier, same aircraft had arrived from Karachi to Mumbai as flight PK-274. The departure of flight PK-275 from Mumbai was uneventful till it levelled off at FL-360 and had flown for about 170 NMs out of Mumbai.- While passing ground position, the Captain of the aircraft realized that the aircraft is heading in opposite direction towards Mumbai. He announced the error and turned the aircraft on correct course. He also apologized on his error. Indian Radar controller asked Captain to despatch his de-brief as soon as he lands, before flights on next day. Captain's de-brief was faxed to Station Manager PIA Mumbai and the matter was resolved. PIA continued scheduled flights to Mumbai as planned. (Appendix 'B').