It is the nightmare scenario for every fighter pilot operating over Syria and Iraq today -- a crash-landing behind enemy lines.

At a training ground the size of central Paris in southwest France, a group of 15 pilots and navigators prepared this month for just that scenario.

Crews from Mirage fighter jets and attack helicopters are dropped in open country for an extreme 36-hour exercise in camouflage, survival, capture and interrogation.

In many of their minds is the fate of the Jordanian pilot who crash-landed in Syria in December last year, was then captured by the Islamic State group and later burned alive on film.

"I decided not to watch the video so that I don't have the images in my head," says Thomas, a young French navigator taking part in the exercise.

"The goal is to not be captured because, clearly, it won't be good," he deadpans.

Before being dropped off, there is time for some last-minute advice from one of the instructors, Alexandre: "Never find yourself alone. If one of you is injured, someone stays with him."

In their kit: a radio/GPS, flares, a first aid kit and a pistol, as well as water and food supplies and a section of parachute for shelter and warmth.

"Make sure the tourniquet is easy to reach in your clothing. Without that, it doesn't matter what you do, you will lose your teammate if there's a hemorrhage," insists the medical instructor.

- Sleepless night -

The first task is to find cover. Thomas and his teammate Gauthier, a Mirage 2000 pilot, smear their faces black and green and disappear into the woods.

With commandos on their trail, their task is to make a nondescript shelter and then try to make contact with friendly forces without being spotted by the commandos on their trail.

A sleepless night follows.

"The slightest noise put us on alert. Everything sounds suspect," says Thomas in the morning.

Their efforts are a failure -- within hours, one of the bad guys has them on their knees with bags over their heads.

The two men are thrown into a cage, dogs barking madly nearby to add to the chaos.

There follows an interrogation session designed to simulate as much as possible the stress of real captivity.

The details are kept secret, but their instructors have no doubt drawn on the lessons of real-life hostages to create extreme levels of anxiety and tension.

After several long hours, the exercise finishes with a simulated escape and helicopter rescue.

Thomas looks hugely relieved.

"It's good when the nightmare ends," he says. "And obviously, what we've been through is nothing compared to what could happen in reality."

Many of those on the training programme, which all French pilots must now undergo, also receive a talk from "Noug", a pilot with first-hand experience of going down behind enemy lines.

"Noug" -- his nickname -- crashlanded in a Taliban-held region of Afghanistan in 2011 and spent two extremely long hours waiting to be rescued by US forces.

"In one minute and 40 seconds, we were on the ground," Noug tells the trainees.

"I have to tell things the way they were -- you feel totally alone and you're dying of fright," he says.

He and his navigator had seen men in a nearby farm and were sure the Taliban had been notified of their presence.

A first flypast by two US helicopters failed to spot them, but they were eventually picked up when a fleet of A-10 aircraft and two Chinook helicopters came to their rescue.

"We have a tendency to think of ourselves as supermen for doing an exceptional job... but when you find yourself on the ground after a crash, you are terrified."