In the search for the missing plane, we now learn that India sometimes shuts down some of its military radar.
Military systems, meanwhile, are often limited in their own coverage or just ignore aircraft they believe are on regular commercial flights. In some cases, they are simply switched off except during training and when a threat is expected.
That, one senior Indian official said, might explain why the Boeing 777 was not detected by installations on India's Andaman and Nicobar Islands, an archipelago which its planes were searching on Friday and Saturday, or elsewhere.
"We have many radar systems operating in this area, but nothing was picked up," Rear Admiral Sudhir Pillai, chief of staff of India's Andamans and Nicobar Command, told Reuters. "It's possible that the military radars were switched off as we operate on an 'as required' basis."
Separately, a defense source said that India did not keep its radar facilities operational at all times because of cost. Asked what the reason was, the source said: "Too expensive."
You can't tell me that somebody in the Pakistani Taliban isn't reading this, and isn't trying to figure out how to exploit it.