Ukraine got the keys to the F-16. Now come the lessons.

It could take less than half the time — just four to six months — to train Ukrainian fighter pilots to fly American F-16 fighter jets, as the Biden administration allowed it.

That assessment, from an internal document by the US Air Force and a former NATO commander, can only cover a few pilots at a time, and only applies to those who have up-to-date flying experience on Ukraine’s fleet of jets from the Soviet era. But it means Ukraine could have one of the last remaining advanced weapons it says it needs to deter Russia faster than originally thought.

For more than a year, the United States has been hesitant to give Ukraine the fighter jets the Biden administration feared could be used to attack Russian territory. The administration changed its stance last week, saying it supported training.

But while President Biden made it clear he would allow the jets to be sent to Ukraine, he would not predict when they would be delivered. He called it “highly unlikely” that they would be part of the counter-offensive Ukraine is expected to launch in the coming weeks. US officials said the planes would help Ukraine defend itself against Russia in the long run.

Training Ukrainian pilots is a necessary first step for the country to get a jet that can outsmart most other fighter jets while also carrying nearly any bomb or missile in the U.S. Air Force’s arsenal.

On Tuesday, Poland said it was ready to train Ukrainian pilots. It will join a coalition set up by Britain and the Netherlands to supply F-16s to Kiev, but Poland may have a better comparative experience: its armed forces have switched to the F-16 from Soviet jets, and the Poles may find it easier to communicate with their fellow Slavic speakers across the border.

Here’s a look at how the workout might go.

How long does the training take?

The Air Force internal reviewdated March 22, concluded that at least some Ukrainian pilots could be trained to fly the F-16 within four to five months.

The review, which was first reported by Yahoo Newsand verified Monday by an Air Force spokesman, was based on a 12-day evaluation of two Ukrainian Air Force officers who underwent flight simulations over the winter at Morris Air National Guard Base in Tucson, Ariz.

The report found that the two pilots still needed certain technical skills, including understanding the instruments of the Western cockpit and learning how to fly comfortably in American standard formation with other aircraft.

According to one projection, including time for specialized English language classes, there would be about four pilots in each class, with between 12 and 14 pilots completing training in a 12-month period. The assessment was shared with seven NATO states, including Poland, which have flown F-16s. It was also given to Bulgaria and Great Britain.

But it didn’t specify whether the pilots would graduate as “combat ready” — a term that Philip M. Breedlove, a retired U.S. Air Force general who is a former NATO commander and F-16 trainer, said was a necessary basis for determining how long the training would take.

If the pilots had recently and regularly flown over Ukraine, they most likely needed four to six months of training, Gen. Breedlove said. President Volodymyr Zelensky of Ukraine on Sunday said he would bring forward some of his most experienced pilots “to shorten the training process”.

What should Ukraine’s pilots learn?

General Breedlove, who has flown F-16s for about 60 percent of his military career, including combat missions in Kosovo, said there are two major differences between that fighter jet and the Soviet-era planes that make up most of Ukraine’s fleet.

“The biggest change they’re going to see is the cockpit,” he said, referring to how pilots use the sensors, control panels and weapons systems. Most older Soviet jets, he said, need pilots “to reach and turn and change and flip switches — and all these things that take your concentration away from fighting the other plane, or just dropping the bomb.”

The electrical impulses that are part of the F-16’s more advanced technology allow for easier control of the flight systems, meaning the way the cockpit is configured is different.

The other difference is the “hands-on throttle and stick” or “HOTAS” technology, a system that includes a so-called dogfight override switch that allows F-16 pilots to switch from bombing targets on the ground to air-to-air combat. . dogfights without taking their hands off the controls. Switching from one activity to another on a Soviet-era MiG-29, which Ukrainian pilots are currently flying, requires “quite strenuous changes in the cockpit,” General Breedlove said.

On an F-16, “never take your eyes off the fight,” General Breedlove said. “It’s something that’s much more intuitive and much, much, much easier to navigate under stress.”

When and where are they trained?

Last week, even before Mr Biden agreed to participate, the leaders of Britain and the Netherlands were announced an international coalition to provide Ukraine with F-16s and training to fly them. Britain’s Prime Minister Rishi Sunak then said the training would take place start this summer; On Monday, the Dutch Minister of Foreign Affairs, Wopke Hoekstra, predicted it would start “really soon”.

Outside of Poland, it’s not yet clear where else the pilots will be trained, and US and European officials said on Monday many of those details had yet to be worked out. Belgium, Denmark, the Netherlands and Norway have all indicated their willingness to help – either by training Ukrainian pilots or by transferring their F-16s to Kiev.

It is likely that US pilots will be part of the training effort for Ukraine, especially given that the United States is helping to train other countries that buy the F-16 from Maryland-based manufacturer Lockheed Martin. The United States has stationed F-16s at two airbases in Europe: Spangdahlem in Germany and Aviano in Italy, General Breedlove said.

He said that “some of the most experienced F-16 pilots in the world are now in the NATO Air Force” as the US Air Force largely transitions to a more advanced fighter jet, the F-35.

General Breedlove said the West should not underestimate how quickly Ukrainian pilots were able to master the F-16 given how they performed on other weapons systems.

“They have exceeded our expectations every time,” he said.