The Southwest Airlines Pilots Association (SWAPA) does not expect that the  Boeing 737 Max aircraft will return to service with the carrier before February 2020.

The Southwest Airlines Pilots Association (SWAPA) does not expect that the Boeing 737 Max aircraft will return to service with the carrier before February 2020.

The Dallas-based airline has removed 737 Max 8s from its flight schedules through to 6 January. However SWAPA president Jon Weaks says in a letter to its members that "we are looking at probably a February timeframe to say the least", based on the pace Boeing is coordinating on modifications with the US Federal Aviation Administration (FAA).

Numerous steps must be completed for the FAA and other regulators to deem 737 Max aircraft safe to return to service in the wake of two fatal crashes. The pilot union has applied to be included in the FAA simulator testing of the modified 737 Max. Southwest will give its pilots 30 days for training to fly the modified 737 Max aircraft before the airline reintroduces them into its schedules, Weaks says.

"Our best estimate is late October for the simulator testing and early to mid-November for the certification flight or flights," Weaks adds, noting that these are "best case" scenarios.

The union's expectations for a drawn-out return to service are driven in part by reports from the US National Transportation Safety Board (NTSB) and the Joint Authorities Technical Review Panel (JATR) that criticised the FAA and Boeing for not adequately preparing pilots to fly Max jets.

The FAA and regulators in other nations have not set timelines on when to return 737 Max aircraft to service, but Weaks says the two reports while not officially linked with the return to service "obviously will have some input indirectly".

The FAA formed the JATR to analyse the agency's initial certification of the Max. It and the NTSB both reported that the FAA and Boeing made faulty assumptions about how pilots would respond to the Max's automated flight control software that investigators say is a key factor in the two fatal crashes.

The European Union Aviation Safety Agency has said it will not rely on the FAA return to service approval, and instead conduct its own review process that will include test flights conducted by its own pilots.

SWAPA on 7 October announced it filed a lawsuit against Boeing seeking damages for the 10,000 pilots represented by the union who have lost compensation since the grounding of Max aircraft. The lawsuit filed in the District Court of Dallas County, Texas, where Southwest is based, alleges that Boeing deliberately misled the airline and its pilots that 737 Max aircraft were airworthy and not significantly different from the previous generation 737NG aircraft.

Southwest had 34 737 Max 8s in service when regulators worldwide grounded the aircraft in March, which Cirium fleets data shows makes it the largest operator of the type. It also has 234 737 Max 8s and 28 Max 7s on order.