Friday, April 12, 2013

Hijacking With Android

Nope! not gonna happen. Well, not without a lot of other technology.

CNN as they are wont to do, posted a sensational article about some dude using an Android phone app to take over an airplane. That is all it is, sensational. There are some bits that could be true, but lets look at things from a more technical point of view.

Hugo Teso used a simulator to 'demonstrate' this 'hack'. It wasn't on a real airplane. The hardware he chose was not flight certified, so most of his claims are completely dubious.

First, lets get some terminology right. Hackers are getting a bad rap by this Hugo. Malicious people are crackers or criminals. Hackers are are people who repurpose technology. Think of a car customizer, someone who takes perfectly good cars and makes them better or different, they might be considered a hacker. In the pre-computer days, hackers were the folks who could do amazing things with very little. They were the folks you went to, to get things done. Places like Hack A Day is an example of a group of these folks, or the Maker movement.

An Android cellphone only work in frequencies maybe at the low end 700MHz, and if you include Bluetooth and WiFi there are radios that talk in the 2.5GHz or 5GHz frequencies. There are actually several radios covering the various modes, including Voice and the various data modes, like 3 and 4G, HSPA+, LTE, etc. They are all between about 700MHz up to about 5GHz.

ACARS is a ground to air digital messaging system. Think of it like instant messaging ( IM) from the airline operations center to the airplane. ACARs allows the airtraffic Controller Pilot Data Link Commands (CPDLC). The ACARS radios are in the 110-130Mhz frequencies. The Cell phone can't talk on frequencies that low. He would need a radio that will talk on those frequencies to talk to the ACARs device to inject some CPDLC commands. The CPDLC commands are like "turn right heading 230", the pilot must acknowledge or reject that 'command' before the aircraft will react.

ADS-B is a technology that allows the airplanes to tell each other where they are using GPS location, and a transceiver that are in the participating aircraft. The ADS-B signals are either on Universal Access Transceiver (UAT) on 976MHZ or on 1090Mhz mode-s transponder frequencies. Since UATs are US only, the dude might have gotten his cellphone to talk on the 1090Mhz frequency (although that is highly unlikely, but I don't know what brand phone he had or what radios the european version of that phone contains, it may be possible). Most of the radios in the phones aren't that programmable, and the FCC pretty much gives the 1090MHz frequency and surrounding frequencies to aircraft and not cell phones.

The Flight Management System (FMS or FMC) are the 'brains' of the aircraft. It manages the auto pilot, connects to the ACARs radio, and the initertial reference system (IRS) some of the other navigation systems. The FMS talks to the airplane. The FMS doesn't talk WiFi, so you can't just use the WiFi on the airplane to talk to the FMS or any of the displays in the cockpit (unless they have an iPad or other tablet, but those aren't connected to the airplane anyway). The FMS usually talks something like ARINC-429 and has a giant plug on it with each device having a separate wire.

FMSs can be reprogrammed, but not over the air (at least that I know of, there may be some new brand or version that can be, but if that were allowed, I am pretty sure it wouldn't allow being reprogrammed while controlling the airplane). They are finicky, and the ones in version X of the 737 can't be programmed the same way as version Y of another 737. If you want to know if Airbus and Boeing share anything, it is unlikely any of those FMSs would even share one line of code.

There is no one technology that can get this guys app to hijack a plane. You aren't going to find terrorists lining up at the T-Mobile stores to buy Android phones and downloading the app so they can take over the airplanes. Actually some might, it might be good for the stores selling phones, but folks are gonna be disappointed, and return the phones, and go buy and iPhone to be like all the cool kids until Apple comes out with that app.

We can all relax, sit back and enjoy the ride. Airplanes won't be hijacked by cell phone.

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