The US Federal Aviation Administration (FAA) has downgraded Mexico's safety rating from Category 1 to Category 2, following an audit that revealed non-compliance with minimum ICAO safety standards.

The regulator did not publicly name the shortcomings but said that it conducted the audit of the Mexican Federal Agency for Civil Aviation (Agencia Federal de Aviacion Civil - AFAC) between October 2020 and February 2021 and found several infractions.

The downgrade means US-flagged carriers are no longer allowed to add new routes to Mexico or code-share on flights operated by Mexican carriers, although they can maintain existing in-house flights to the country. The FAA has also vowed to increase its scrutiny of Mexican carriers serving the US.

"The FAA is fully committed to helping the Mexican aviation authority improve its safety oversight system to a level that meets ICAO standards. To achieve this, the FAA is ready to provide expertise and resources in support of AFAC's ongoing efforts to resolve the issues identified in the International Aviation Safety Assessment (IASA) process," the FAA said.

According to the ch-aviation capacities module, the US-Mexico market sees 403,785 scheduled seats on sale for the week starting on May 31, 2021, spread across 2,566 scheduled passenger flights operated by 13 carriers. The largest airlines by capacity in the market are American Airlines (19.9% market share), United Airlines (17.9%), Volaris (13.5%), and Delta Air Lines (11.1%).

Delta Air Lines, which has a codeshare partnership with its Skyteam partner Aeroméxico, said it did not expect the downgrade to have any significant impact on its operations.

"For customers who have booked a flight with Delta that is operated by Aeroméxico, Delta may reissue their reservation onto the corresponding Aeroméxico-operated flight," the airline said. Aeroméxico itself also dismissed the adverse impact of the downgrade.

Delta owns a 51% stake in Aeroméxico, although it does not have majority voting rights.

In turn, Mexico's largest low-cost carrier, Volaris, said that while the decision would curb its growth plans in the United States, it will continue its partnership with Frontier Airlines.

"Volaris will be unable to add new aircraft to its FAA operations specifications. However, Volaris' fleet may continue to grow, as the FAA action does not limit Volaris from incorporating any additional aircraft into its Mexican Air Operator's Certificate, nor does it preclude Volaris from deploying such aircraft to Mexican and Central American markets. Additionally, our codeshare partner Frontier will remove its code from flights operated by Volaris, although customers will still have the option to purchase flights from Volaris and Frontier through the companies' websites," the LCC said.

Delta and Volaris both stressed that the downgrade concerned AFAC's safety practices and did not reflect on the safety standards of any one carrier.

The current list of FAA Category 2 countries comprises Bangladesh, Curacao, Ghana, Malaysia, Mexico, all supervisees of the Eastern Caribbean Civil Aviation Authority (Antigua & Barbuda, Dominica, Grenada, St. Lucia, St. Vincent & the Grenadines, and St. Kitts & Nevis), Pakistan, Thailand, and Venezuela.