On November 24, a Turkish F-16 fighter jet shot down a Russian Su-24 bomber near the border of Turkey and Syria. In the immediate aftermath, officials from the two countries offered contradictory versions of what transpired: Russian president Vladimir Putin claimed that the plane was flying over Syrian territory when it was downed; Turkish president Recep Tayyip Erdogan countered that it was inside Turkey’s border and had been warned ten times to alter its course. Hours later, President Obama threw his support behind Erdogan. “Turkey,” he said, “has a right to defend its territory and its airspace.”

I asked Pierre Sprey, a longtime defense analyst and member of the team that developed the F-16, to examine what we know about the downing and determine what actually occurred that morning.

The Russians have claimed the November 24 downing of their bomber was a deliberate pre-planned ambush by the Turks. Is there any merit in that argument?

Looking at the detailed Russian timeline of what happened—as well as the much less detailed Turkish radar maps—I’d say the evidence looks pretty strong that the Turks were setting up an ambush. They certainly weren’t doing anything that would point to a routine air patrol along the border. Their actions in no way represented a routine, all day long type of patrol.

How can we tell that?

Well, let’s set up the situation and it’ll be a little easier to understand. The Russian pilots were assigned a target very close to the Turkish border, about ten miles in from the Mediterranean coast and about five miles south of an important border crossing at a little place called Yayladagi. That’s a border crossing that the Turks have used to slip jihadists into Syria, or to allow them to slip in. It’s also a place where there’s quite a bit of truck traffic, a fair amount of it probably oil tankers. It’s the only crossing for many, many miles around. This is a pretty sparsely populated, well forested and hilly area occupied by Turkmen—Turkish speaking Syrian tribesmen who are sympathetic to al-Nusra and the Islamic State, who harbor Chechen terrorists and who we know have been supported by the Turks.

The target area the Russians were interested in was about five miles south, along the road leading to this crossing. That was the target area that they assigned to these two Su-24s on the day of the shoot-down. The crews were assigned the mission at about 9:15 in the morning, Moscow time. They took off about a half hour later, headed for an area about thirty miles inland from the Mediterranean coast—in other words well east of this target area—to loiter until they got further instructions on hitting a target in the target area. At this point they’re just cruising and loitering at eighteen thousand, nineteen thousand feet, trying to conserve gas while they’re waiting to be assigned a specific target.

The flight to their holding area was very short, because they were flying out of a Russian base south of Latakia. It was like a ten-minute flight. They were only about thirty miles away or so. After they reached their loiter area—at roughly a quarter to ten—they were well in view of Turkish radar coverage because they were up high and not far from the border, roughly sixteen miles south.

They got assigned their target, which was the road south of this important border crossing, and executed a first strike, each of them attacking separate targets at about a quarter after ten. They then made a U-turn, so to speak, to follow a racetrack pattern back toward where they had been loitering to get ready for a second attack. They in fact executed the second attack about seven or eight minutes later. One of the two Su-24s hit its target right at about ten twenty-four and was almost immediately shot down as he was pulling off the target.

What about the Turkish air force, what were they doing meanwhile?

The Turks had launched two F-16s quite a bit earlier than the time we’re talking about, from Diyarbakir, a major base for the Turkish Air Force about two hundred and fifty miles away, to loiter just in from the Mediterranean over a mountainous area that was about twenty-five miles north of this border crossing. Interestingly, they arrived in that area to loiter just about the time that the Russian pilots were being assigned their targets, and the F-16s loitered over that mountainous area for about an hour and fifteen minutes.

Here’s the crucial thing. They were not loitering up at high altitude—say twenty to thirty thousand feet—to conserve fuel, which is where you would normally be loitering if you were simply doing a routine border patrol. They were loitering quite low, at about seven thousand five hundred to eight thousand feet, which, first of all, is below the coverage of the Syrian and Russian radars that were down around Latakia, and which is a very fuel-inefficient altitude to loiter. You suck up a lot of gas down at those low altitudes.

That tells you right away, if they hung out there for seventy-five minutes, they must’ve been tanked on the way in to that mission, because they were quite far from their home base—two hundred and fifty miles—so they must’ve topped up on fuel to have enough to even last for an hour and a quarter at this inefficient low altitude. The Turkish Air Force does have a number of American tankers that they own, so they certainly could’ve and almost beyond a shadow of a doubt did tank these F-16s before this whole engagement.

They’re hanging out at low altitude over this mountainous area north of the border, and it’s now about 10:15. The Russian fighters, the Su-24s, are just finishing their racetrack pattern after their first strike and are about to re-attack from this holding position well east of the target. At that point, the two F-16s break out of their loiter patterns to fly in a straight line south, quite certainly under Turkish ground control because they clearly are not hunting for the Su-24s and following a curved path, they’re heading straight for an intercept point that apparently ground control has  provided them—a point that’s very close to the target that the Su-24s have just bombed. That’s clearly the point they’re coming back to bomb again.

The F-16s arrive quite nicely and precisely timed to a missile-shooting position very near the border and three to four miles from the second Su-24—who has just finished bombing his second target—at about 10:24. One of the F-16s  locks onto him, launches a missile—an infrared missile according to the  Russians—and  immediately dives down to get back under the Syrian radar coverage.  The F-16 makes a hard diving right turn and is back down under eight thousand feet in no time at all and heading north away from the scene of the engagement. In that turn he actually is penetrating Syrian airspace before he heads north to go home to Diyarbakir, probably at that point out of fuel and hooking up with a tanker again in order to make it home.

Would he have been in Syrian airspace when they fired the missile?

Not necessarily. It’s hard to tell at this point. All this action is pretty close to the border, and there’s no reason to believe either the Turks or the Russians about distances of half a mile or a mile north or south of the border, but there’s no question that the Turkish F-16 penetrated Syrian airspace in executing his diving turn to get out of the area. He was heading due south to attack the east-west track of the Su-24 that had just finished bombing the target. That Su-24 augured in almost immediately, about a mile and a half south of the border.

The bone of contention here is not the target area. The target area is roughly four or five miles south of that famous border crossing we were just talking about. The bone of contention is a narrow finger of Turkish land about five miles long, sticking straight down into Syria, about a mile and a half at its widest at the northern end and tapering down to a half mile at the southern tip. That finger is a good six miles east of the target area. So when heading west on their way to attack their targets, the Su-24s necessarily had to pass very close to the southern tip of the finger. In other words, the whole controversy about whether this shoot-down was legitimate or not is whether the Su-24s on the way to the target happened to cross that finger for a few seconds.

Remember again the setup. You’ve got a target that’s like ten miles in from the Mediterranean to the east. Another six miles or so east of there is this finger of land. It’s well east of the target area. The loiter area that the Su-24s were coming from is another sixteen miles to the east of that. They’re flying from their loiter area, which is well south of the border. They’re flying past the finger, maybe they crossed it, maybe they were just below it, and heading for the target.

But if the Russians were in Turkish airspace, as the Turks claim, wouldn’t it be reasonable for the Turks to intercept them?

There’s a little detail that’s very telling. The alleged border-crossing took place on the first bombing run from the loiter area to the target, and according to the Turks the Russians were roughly half a mile north of the tip of the finger and so they were in Turkish airspace for about seventeen seconds—a tiny, short, brief time—on their way to hitting the first target. The Russians, of course, say they were south of the finger by about a mile. God knows who’s right. I’m sure if we had access to the radar records we could tell very promptly who’s lying and who’s not, but nobody is going to give us access to the exact radar plot.

Here’s the very interesting thing. This border-violating incursion was on the first run to the target at around 10:15. On the second run to the target the Russian planes were clearly further to the south. This is according to the plots and maps released in the Russian briefing, which are very, very detailed with exact time marks every minute. The seventeen-second crossing of the border alleged by the Turks happened at about 10:15, but the Turks waited. They didn’t come in and attack the airplane that had crossed the border at that point. They simply sat and waited until the plane flew a long re-attack pattern and came back on a second run seven or eight minutes later, and that’s when they attacked and shot him down.

Between the fuel-guzzling low altitude of the holding pattern of the F-16s, which miraculously coincided with the flight times of the Russian airplanes, and the fact that they didn’t even chase the airplane immediately upon its alleged border incursion, all that smells very much like a pretty pre-planned operation. The Turks allowed the Russian plane to hit a target and make a long seven or eight minute re-attack pass and then came in from their hidden low altitude position. They came up a little higher to gain a good firing altitude, came whistling south, hit the Su-24, dove under the radar coverage at the same time that they entered Syrian airspace and headed north out of radar coverage to head back to Diyarbakir.

Such an ambush wouldn’t have been hard to pull off, because the Russians, in their detailed account of this, state very clearly that they had coordinated with NATO, with the Americans, announcing this attack well in advance, and had followed the protocol of listening on the NATO-agreed frequency for any warnings or alerts from NATO or from the Turks. There was plenty of time for the Americans to inform the Turks that this mission was taking place. They might’ve even been informed by the Russians the day before it was going to take place. All the prerequisites for a setup were there.

The Turks made a big deal about the ten warnings they said they issued to the Russian planes. What do we make of that?

Again, that’s one of those things where it’s hard to tell and hard to know which side to believe. The Russians in their briefing, in their detailed briefing, are very clear and very adamant that the F-16s themselves, the attacking F-16s never transmitted any warning. Nor are the Turks or the Americans claiming that the F-16s warned the Russian fighters. But of course the international protocols for defending against incursions of your airspace require the attacking fighters themselves to inform the target—visually or by radio—whether it’s an airliner or a fighter or whatever, that they are now violating airspace and need to turn away.

The Turks do say they transmitted their warnings from a ground-control station. They also claim they transmitted those radio calls on both the civilian international emergency “guard” UHF-band frequency and on the military VHF-band frequency previously agreed to by NATO and the Russians. The Americans were quick to confirm that their monitoring equipment picked up the Turkish ground-station radio warning calls, but they’ve been careful not to say what frequency they heard. Now it so happens that Su-24s have no radios onboard for receiving UHF-frequency signals, a fact which is well known to American, NATO, and Turkish intelligence. 

There’s a lot of outs to this that could be the fault of either side. It’s quite likely true that the Turks radioed warnings, but those warnings may have been deliberately transmitted only on the international civilian frequency so that the Su-24s would never hear them. Or it may be that the Su-24’s military frequency radios were on the fritz, which is easy to believe given the well-known unreliability of Russian electronics. 

I do believe that the F-16s never issued any warnings, because it would be astonishing if they did. Here they went to all the trouble of tanking up and flying at a very low altitude, stretching their fuel endurance just to stay out of radar coverage of the Russians and the Syrians, and then why would they suddenly announce that they were there by warning the fighters when they had so obviously set up a situation where they were hiding? The ground-control station in Turkey probably did issue warnings, but they may have been warnings that were intended not to be received.

Would the United States have had radar coverage from its Airborne Warning and Control System or from their facilities at Incirlik? Would they be able to watch what was going on?

It’s very likely that they had a good track on that area, probably just as good as the Turks had. The Turks of course have a fairly extensive border network of radars, and the Russians and the Syrians have well mapped those radars and know exactly where the coverage is, which is why the Russians can be so precise as to say that the Su-24s entered Turkish radar coverage at 9:52, because they know pretty exactly where that radar coverage is.

The Americans could very possibly have access to those radar results. I have no idea whether they had an AWACS in the air at the time, but if they did it would’ve been easy to cover that area, too. For sure the Americans had complete radio monitoring coverage of the area, certainly heard all the radio transmission involved.

Now the Russians say that they activated air defense missiles, the famous S-400 I guess, to make sure this doesn’t happen again. Does that indeed preclude the Turks interfering with the Russians carrying out strikes in that area?

The answer is no, but it’s a hell of a threat. The longest range version of the S-400 is good for two hundred and fifty miles. The Russians are installing it at their base just south of Latakia, within fifty miles of the border. So conceivably they could shoot two hundred miles into Turkey. They may or may not be able to prevent a hidden Turkish fighter from firing at another Russian attack in the border area, but they certainly have the possibility of catching him or his friends on the way home.  This is a real sword poised over the heads of the Turks now that the Russians have the capability to shoot deep into Turkey and can do so any time they want.