Delta Air Lines is still struggling to get back on track five days after the global IT outage, prompting Transportation Secretary Pete Buttigieg to take action.
Hundreds more flights were delayed or canceled Tuesday after grounding more than 1,200 a day earlier.
The Department of Transportation will open an investigation.
The airline’s struggles could continue for the rest of the week.
Delta customers have been advised to contact the DOT to determine whether the airline is providing adequate customer assistance.
The DOT said it has already received a ‘high volume of consumer complaints’ about Delta since Friday.
“We want to hear from passengers who believe that Delta has not complied with USDOT-enforced passenger protection requirements,” the Transportation Department said.
Delta is cooperating with the investigation.
“We remain entirely focused on restoring our operation,” Delta said.
“Delta teams are working tirelessly to care for and make it right for customers impacted by delays and cancellations.”
Most airlines are up and running will full flight operations.
However, Delta’s is being hampered with problems with its crew tracking system.
The airline said it will likely continue for a few more days.
Delta effectively doesn’t know where its flight crew are.
Some have said they have been sleeping at the airline as the system cannot book them layover hotels.
The prolonged meltdown has cost Delta about $163 million as of the end of Monday, according to an aviation analyst.
