Southwest Airlines (WN, Dallas Love Field) will need up to five months to resume B737-8 operations once the type is re-certified by the Federal Aviation Administration (FAA), Chief Operating Officer Mike Van de Ven said during a quarterly investors call.

He said that Southwest estimates it will need between 30 and 40 days from the date of recertification to update its training procedures and manuals, as well as to re-train pilots. A further two to four months will be needed to resume the type's full-scale operations.

The LCC managed to take delivery of thirty-four B737 MAX 8s before the type's grounding in March this year. According to the original delivery schedule, a further 41 units would have been delivered by the end of 2019, including B737-7s. The airline has thirty MAX 7s and 119 MAX 8s on firm order from Boeing.

"That gives us 75 aircraft of backlog to ingest into the fleet when the grounding is lifted. We believe that we can manage that at a rate of about 5 to 10 airplanes per week which if you do the math implies to two to four months before all of our 2019 and prior MAX aircraft are back into operational service," Van de Ven said.

Southwest Airlines has removed the B737 MAX 8 from its schedule through February 8, 2020. It currently expects the type's recertification to take place in mid-December.

Due to the halt in deliveries of the B737 MAX, Southwest expects its fleet to shrink by 68 aircraft at the end of 2019 compared to its initial forecast at the beginning of the year. The LCC admitted that the groundings' negative impact on revenues has grown each quarter as the gap between expected and actual fleet size widens. So far, the LCC has amassed USD435 million in lost operating income due to the grounding.

Southwest also revealed that Boeing formally proposed to adjust the delivery schedule for the B737 MAX 8s. The manufacturer now plans to deliver seven more aircraft of the type to Southwest by the end of the year with the remaining 34 deliveries originally planned for 2019 slipping to 2020.

"For 2020, based on Boeing's targeted return to service timeline, we expect to be back on our aircraft delivery schedule around mid-2020. This would result in seventy-two MAX deliveries in 2020 and we currently expect to retire 20 to 25 of our B737-700 aircraft next year, resulting in a total fleet of approximately 800 aircraft by year-end 2020," Chief Financial Officer Tammy Romo said.

According to the ch-aviation fleets module, Southwest Airlines currently operates 511 B737-700s and 201 B737-800s.

Chief Executive Officer Gary Kelly also said that while the airline had evaluated adding other aircraft types in the past, it was "not entertaining this question today".