为什么有时候不同航空公司的不同航班却同时起飞于同一机场和同时降落于同一机场?

为什么有时候不同航空公司的不同航班却同时起飞于同一机场和同时降落于同一机场?
why could there be different flights from different airlines but take off at a same airport in a same time and also land at a same time in a same airport?why and why the time is exactly the same?
such as the follows:
Scheduled Time Airline Flight From Status
15:25 Singapore Alines SQ5325 Kuala Lumpur Landed at 15:25
15:25 SILKAIR MI335 Kuala Lumpur Landed at 15:25
15:25 Malaysia Air MH9153 Kuala Lumpur Landed at 15:25