Boeing Co. (BA.N) won its first deal for 737 Max jets since a March grounding that followed the second deadly crash in five months.

IAG SA, the owner of British Airways, signed a letter of intent for 200 of the planes, Boeing said in a statement Tuesday. The mix of 737-8 and 737-10 planes would be delivered between 2023 and 2027 assuming the deal is formalized.

The agreement with one of the world’s leading carriers hands Boeing a big boost as it struggles to get the Max back in the air amid a grounding that recently entered its fourth month. The Max crashes in October and March were caused when a software system received erroneous readings from a sensor, repeatedly forcing the nose of the planes down until pilots lost control.

“We have every confidence in Boeing and expect that the aircraft will make a successful return to service in the coming months having received approval from the regulators,’’ IAG Chief Financial Officer Enrique Dupuy de Lome said in the statement.