South Africa's civil aviation regulator grounded Comair's planes indefinitely on Sunday over unresolved safety issues, in a move that also affects low-cost airline Kulula and British Airways, leaving hundreds of passengers stranded.

A spokesperson for the South African Civil Aviation Authority (SACAA) said it had extended a 24-hour precautionary suspension of Comair's operator certificate indefinitely.

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

"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.

There would be considerable implications for the aviation sector and the country should the suspension be prolonged, he added.

CHARTERED FLIGHTS
Airports Company SA (ACSA), which runs the country's largest airports, said some of the stranded passengers were placed on chartered flights arranged by BA and Comair, specifically for commuters on the popular Johannesburg and Cape Town route.

"Priority is also given to those passengers who have onward international connecting flights," Terence Delomoney, ACSA's group executive operations manager said.

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 licence 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, prioritising vulnerable customers and those who most urgently needed to travel," Comair said, adding that customers would also be kept informed via text.