Air traffic controllers are being warned that layoffs are coming as Nav Canada pursues a "full restructuring" in response to a revenue slump caused by the COVID-19 pandemic, CBC News has learned.CBC News has obtained a confidential memo sent internally to air traffic controllers on Thursday. In it, Ben Girard, Nav Canada's vice-president and chief of operations, told staff that the company has seen a $518 million drop in revenue compared to its budget.He said he's been pushing the federal government for help, but — unlike some other countries — Canada has not released an industry-specific bailout package yet."We anticipate that until air traffic returns to higher levels, which will not occur until the end of this fiscal year, we will continue to operate in a daily cash negative position and this will be made worse as funding from the [Canadian Emergency Wage Subsidy] program is ratcheted back," Girard wrote. Girard did not say in the memo how many air traffic controllers will lose their jobs or which locations will be affected. The memo said it's looking to reduce the number of "IFR controllers." These controllers are higher on the pay scale and work at area control centres in Gander, N.L., Moncton, N.B., Montreal, Winnipeg, Toronto, Edmonton and Vancouver.The workers are responsible for controlling large amounts of airspace between airports using radar. Their job is to make sure planes keep proper distance from one another."I know this is very difficult news to hear. It is also very difficult news to deliver," Girard wrote. "This is a decision that has been made at my level based on what needs to be done to ensure Nav Canada's financial sustainability."Nav Canada manages millions of kilometres of airspace over Canada and used to provide air navigation services for more than three million flights a year. It's funded through service fees paid by air carriers.The Canadian Air Traffic Control Association said it is very concerned with the memo. "It is the opinion of this union that safety is not being taken into consideration in making sound decisions," president Doug Best and executive vice-president Scott Loder wrote in a letter to members."Safety is the number one priority for Nav Canada and it has somehow taken a backseat to cost containment as the number one and only priority."'We're facing years of a downturn in air traffic'In November, Canadian air traffic was down 54 per cent compared with the same time period in 2019, according to the memo."Over the summer and fall months, the outlook for the aviation industry has deteriorated significantly and it has become increasingly clear that we're facing years of a downturn in air traffic that is much larger and broader in scope than we all initially believed, and will be much deeper and longer than any downturn in the history of the industry," Girard wrote.Nav Canada says it is conducting studies of air traffic control towers in Whitehorse, Regina, Fort McMurray in Alberta, Prince George in B.C., and Sault Ste. Marie and Windsor in Ontario that "will result in workforce adjustments." The company is also looking into closing a control tower in St. Jean, Que.Government 'pressed' for help The company has been focused on securing liquidity and tapped into the Canada Emergency Wage Subsidy (CEWS) to pay up to 75 per cent of employees' wages, he wrote. Girard added that these payments are being reduced and will run through December, but Nav Canada isn't sure if it can continue receiving that wage support."While an extension for the CEWS program through June 2021 was recently announced, NAV CANADA's eligibility is uncertain," he wrote. Girard said the federal government has so far failed to come up with a bailout package for the airline sector, despite "significant lobbying."Last month, the Globe and Mail reported that the federal cabinet is working on a package for the airline sector that would include low-interest loans. Since Sept. 22, Girard wrote, the company has cut more than 700 managers and employees — 14 per cent of its workforce. It also let go of 159 students earlier in the pandemic, he added, and in November cut even more, "leaving just a few in the system." Along with the cuts, seven air traffic control towers are being considered for a downgraded level of service, and another 25 sites that are already Flight Service Stations — which provide only advisory services — could face more cuts.Nav Canada's board of directors has cut its fees by 20 per cent, and executives and managers have dropped their salaries by up to 10 per cent, Girard wrote.These cost reductions, as well as access to government support through the wage subsidy program, have saved the company $200 million since March 1, he added. "However, that number still pales in comparison to the $518 million reduction in revenues as compared to budget," Girard wrote."Despite these cost-containment efforts, we find ourselves in a situation where we expect our revenues to continue falling far short of our costs for several years, and we continue to require further cost-containment measures and indeed, a full restructuring of our business."In an environment where 30 per cent of costs are associated with 'things' and 70 per cent of costs are associated with 'people,' when all possible cuts with 'things' have been done, any further cuts will directly affect people." Girard added that he hopes the company can bring back some of the laid-off staff once the pandemic passes.The Canadian Air Traffic Control Association said it will continue to challenge Nav Canada. The union hopes there will be "enough interest" in departure incentives for older controllers to offer them a package to retire. "The views of Nav Canada at this point are violating the vision, mission and overarching objectives of this company," Best and Loder said in their letter to members.