Sen. Martin Heinrich (D-N.M.) sent a letter to Defense Secretary Ashton Carter on Thursday expressing concern over the Pentagon's plans to dramatically increase drone flights over the next four years amid a drone pilot shortfall.
"There is indeed a need for broadened surveillance and intelligence collection, but I remain very concerned that the anticipated growth is unsustainable without corresponding growth in recruitment, training, and retention," he wrote in a Sept. 1 letter.
Heinrich is a member of the Senate Armed Services Committee and represents Holloman Air Force Base and Cannon Air Force Base in New Mexico, which he said are the nation's premier drone pilot training locations.
Last month, the Pentagon confirmed a Wall Street Journal report that it was planning to increase by 50 percent the number of daily drone flights to cover hotspots including Ukraine, Iraq, Syria, the South China Sea and North Africa.
Heinrich in his letter also urged the Pentagon to complete a report on how it will rectify drone pilot shortfalls.
The senator included language in the 2016 defense policy bill requiring the Air Force to submit a report on drone pilot manning policies and actions the Air Force will take to rectify personnel shortfalls, such as recruitment and retention bonuses, incentive pay, using enlisted personnel, and considerations for promotion.
He also noted in his letter that the Air Force was losing drone pilots faster than it could train new ones, and the force is already stretched thin.
While the service plans to increase its daily combat air patrols from 55 to 60 in 2016, it already faces a shortfall of 400 pilots out of the 1,200 required to carry out those patrols.
"The increased demand has resulted in lower crew ratios working longer hours and longer assignments," he said.
"Our nation's operational units and formal training units must have adequate personnel and resources if they are expected to meet military commanders' requirements."