The CEO of United Airlines penned a letter to employees outlining what he thinks the Federal Aviation Administration needs to do to fix all the delays plaguing Newark Liberty International Airport. The delays began last Monday when crews in the Philadelphia air traffic control facility that lines up flights into and out of Newark lost radar and communications with the planes for at least 30 seconds.

The Federal Aviation Administration said Wednesday that it plans to upgrade the technology used to get radar data to air traffic controllers directing planes to the troubled Newark, New Jersey, airport, and improve staffing to alleviate problems that have caused hundreds of flights to be canceled there.

United's CEO blamed the Newark flight cancellations on government equipment failures coupled with air traffic controllers walking off the job.