The UK’s aviation regulator has appointed a chairman to lead a review into the air-traffic system outage that hit the country on a national bank holiday, sending flights and passengers into disarray.

Jeff Halliwell, who has worked across the business and public sector, will be in charge of the panel, the Civil Aviation Authority announced in a statement on Friday as the independent review into NATS’ technical failure on Aug. 28 gets underway.

The air-traffic disruption was caused by an anomaly in a software system which misread two geographical checkpoints about 4,000 nautical miles apart when processing an airline’s flight plan, according to NATS’ preliminary report in September. The glitch caused the system to shut down, forcing air-traffic staff to input flight plans manually which limited the amount of air traffic that could be processed.

As a result, passengers were stranded, hundreds of flights were canceled and planes were left out of position. EasyJet Plc’s Johan Lundgren has criticized NATS for the disruption, while Ryanair Holdings Plc’s Chief Executive Officer Michael O’Leary has called on NATS CEO Martin Rolfe to resign.

“This event had a significant impact on many passengers, businesses and the aviation industry and it is clear lessons need to be learnt,” Halliwell said in the statement.

Halliwell was previously chair of Airport Coordination Ltd., which provides slot coordination to global airports. He also has a customer perspective given he was chair of Heathrow Consumer Challenge Board, an independent advisory body, and Transport Focus, a consumer watchdog for public transport.

The CAA’s review will look into various aspects of the incident, including the causes of the glitch, impact on consumers and costs incurred by the airlines. Halliwell, along with two panel members, will determine the findings and make any recommendations before a final report is submitted to the CAA and the Secretary of State for Transport. 

CAA Chairman Stephen Hillier said in September the review could take “months rather than weeks” and he wanted it to be thorough and timely.