Checks are to be carried out on a second Boeing aircraft model following the blowout of an unused door on one of its planes earlier this month.

The US Federal Aviation Administration grounded more than 170 of the 737 Max 9 fleet after a cabin panel broke away thousands of feet above the ground.

On Sunday, the agency said airlines should also inspect older 737-900ER models, which use the same door design.

The FAA described the move as an “added layer of safety”.

It said there had been no reported issues with the 737-900ER, but that it uses the same style of panel to “plug” an unused door as the plane involved in the terrifying 5 January incident.