This week, the US Transportation Security Administration (TSA) announced new security measures on flights coming into the United States. One of these measures is that uncharged cell phones and other electronic devices will not be permitted on planes.

The new rule allows TSA officers to ask travelers to power up their devices during the security checkpoint. Powerless devices will not be allowed on board the airplane and the owner could undergo additional screening. There is no official list of the overseas airports this applies to, but it’s been reported that Heathrow Airport in London is one of them.

While this new measure may seem silly to some, reports have suggested that it’s in response to information about terrorists in Syria and Yemen that have developed bombs that could pass through the previous screening processes. According to Rafi Ron, former director of security at Tel Aviv’s Ben-Gurion International Airport, checking to see if a phone turns on is a quick, easy and low-tech way to ensure the phone’s battery has not been tampered with.

Regardless of the reasons, it’s important to be aware of this new measure before you travel. So if you’re taking a trip abroad this summer, make sure your phone is charged before your return. As long as your phone can power up, you should have no problem making it home, except for maybe a slightly slower security line.