The FAA has proposed a $3.685 million civil penalty against NavWorx of Rowlett, Texas, for allegedly producing and selling automatic dependent surveillance-broadcast (ADS-B) units containing a GPS chip that did not meet the agency’s requirements, and misrepresenting the products to customers.

That fine may be hard to collect since NavWorx says it has ceased operations.

In March 2015, the FAA notified the aviation industry it had tightened System Integrity Level standards for GPS chips used in ADS-B units. That equipment becomes mandatory as of Jan. 1, 2020, for all aircraft entering controlled airspace. Rather than replace the lesser chips, however, the FAA alleges that NavWorx altered the units’ internal software to transmit a code that indicated they met the higher standard. The agency also alleges the company then refused to comply with its directive to modify the software to transmit an accurate code — and that it inaccurately advertised that the equipment met the FAA’s tighter standards.

In November 2016, the FAA issued an emergency order suspending NavWorx’s authority to manufacture the components after the company repeatedly refused to allow the agency to inspect its records and manufacturing operations. Once the company did allow the inspections, the agency reinstated the manufacturing authorization.

The FAA is working with customers to ensure the safety of the affected products, it said. In June, it issued a final airworthiness directive requiring owners to remove or disable the units or modify them by linking them with a GPS unit containing the proper chip. “NavWorx has been in communication with the FAA about the case,” the agency said.

On its website, NavWorx said that its ADS600-b Gen 2.0 product uses a GPS module from a third-party vendor. The vendor represented its module as meeting the FAA requirements, although the FAA has determined that it does not, the company said. “We are unable to sell the ADS600-B or provide AD updates, for either certified or experimental aircraft,” the company’s website said. “Therefore, we are not currently conducting any business and have ceased operations. We will provide updates if they become available.”