Security News > 2021 > April > US aviation regulator warns of mid-air collision risk if Garmin TCAS boxes are not updated
American aviation regulators have ordered private jet operators to install software updates for Garmin collision avoidance units after multiple reports of false alarms - raising the risk of a mid-air crash.
The affected Garmin products, its GTS 8000 series, generated seven false Traffic Collision Avoidance System warnings, said the US Federal Aviation Administration in a formal Airworthiness Directive published [PDF] earlier this month.
Alex Lomas, aviation security lead at British infosec consultancy Pen Test Partners told The Register: "TCAS works with dedicated transponders that interrogate both the 'ownship' and 'intruder' to calculate a closing rate and generate alerts accordingly. In this case it seems that this calculation has failed safe in one regard, which is that alerts are generated when an intruder is too far away, but the knock on effect is that instructions to the pilot could then increase the risk of collision with a third aircraft."
Typically TCAS is fitted to jet airliners and commercial aircraft.
The agency explained that with unmodified Garmin GTS 8000s, a TCAS event "Involving three or more airplanes can result in mid-air collision," saying that a three-way collision warning raised the risk "That the TCAS, in resolving the false RA with the initial airplane, will create an actual loss of separation with a third airplane."
"This condition, if not addressed, could result in an RA being generated when no risk of loss of separation or risk of collision exists between the airplanes involved, which can lead to a mid-air collision with a third airplane," it concluded.