On Sunday, South Africa’s civil aviation regulator grounded Comair’s planes indefinitely, citing the airline’s failure to adequately address safety concerns, in a move that also affects passengers of low-cost airline Kulula and British Airways.

According to a SACAA spokesperson, the South African Civil Aviation Authority (SACAA) has indefinitely extended a 24-hour precautionary suspension of Comair’s operator certificate.

The suspension was supposed to end on Sunday, but Comair has not adequately addressed all necessary safety issues, according to the SACAA.

“This morning we communicated to them (Comair) that their air operator certificate is now indefinitely suspended until they close all of the findings,” SACAA spokesperson Phindiwe Gwebu told Reuters, effectively grounding the company’s fleet of Boeing aircraft.

Comair said it was unable to confirm when it would start flying again, after working through the night to provide documentation to SACAA following a review of certain policies, systems and procedures.

“This is a huge blow to our customers, employees and the flying public as it effectively takes 40% of the capacity out of the market,” Glenn Orsmond, Comair chief executive said in a statement.

“The implications for the aviation sector and the country are considerable should the suspension continue for any length of time,” he added.

Issuing the precautionary notice on Saturday, the regulator said in the past month Comair had experienced safety problems ranging from “engine failures, engine malfunction and landing gear malfunctions,” among others.

In its investigations, SACAA said it had discovered three so-called “level 1” findings “which pose an immediate risk” and must be addressed immediately.

Gwebu did not elaborate on what outstanding safety issues Comair, which flies local and regional routes from South Africa under the British Airways (BA) livery as part of a license agreement, needed to address before flying again. Besides flying BA planes, Comair also operates the Kulula brand.

A notice on Kulula’s website showed that Comair had been aiming to resume its schedule by 12 p.m. (1000 GMT) on Sunday, subject to SACAA’s approval.

“We will do everything we can to accommodate customers affected by the suspension on other flights, prioritizing vulnerable customers and those who most urgently needed to travel,” Comair said, adding that customers would also be kept informed via text.