John Barnes - Directive 51

The A-10s wouldn’t have been as fast as the Dreamliner at high altitude in a straight-line chase, but the airliner was flying low and slow and zigzagging among the ridges, and they’d be able to dive on it. One of the Warthogs might well be first to the kill.

If Bad Dreamliner somehow dodged through the closing arc of A-10s, there were other chances. CVN 76 Ronald Reagan , just off North Island, had already catapulted two Super Hornets, which could overtake the 787 in a stern chase before it reached LA. Three Marine F-35s that had been returning to North Island had enough fuel to divert to intercept as well, and a flight of Utah ANG F-22s would be able to intercept just south of Long Beach, if Air Force Two somehow got that far.

Someone was going to shoot down that plane. She hoped Samuelson wasn’t still alive.

“They’ve got an interception vector for an A-10,” one of the DoD people announced. “First shot in about four minutes. Less than a minute after that we’ll have a window for an F-18 to put an AMRAAM on his tail. If he’s headed for somewhere around LA—and it looks like he is—we get at least five good tries to bring him down, plus three long shots.”

Kim Samuelson was talking with President Pendano, their arms around each other as if they were already at the funeral.

Cam spoke beside her. “Do you have Jim Browder on the line, Heather? Urgent question for him.”

“I’ve got him standing by on secure IM.” She typed, Phn me, encrypt #.

Her phone rang; she docked it in her terminal, set it for Record, Transcribe, and Speakerphone, and said, “Jim. Mr. Nguyen-Peters of Homeland Security has a question for you. Cam, Jim is fully briefed per your instructions.”

“Good. Dr. Browder, the vice president yelled ‘barrels on the plane’ three times. We’re about to shoot it down over uninhabited desert, almost nothing human downwind for hundreds of miles. Is there anything that they could have put on it that will cause massive problems if we just blow the plane up? Anything that will be made worse if it burns?”

“Probably not in uninhabited desert,” Browder said. “Planes burn hot. Fire should kill any weaponized germs or toxins we know about. Most nerve gases are destroyed by flame and heat, except maybe Novichok-5, which hasn’t been seen since the 1990s and it’s possible the formula is lost. Depending on which ex-Soviet scientist was telling you which self-serving mixture of lies and truth, that stuff might or might not have been heat resistant, but its chemical cousins are not. So I don’t think you have to worry about anything chemical or biological.”

“Nuclear? Radiological?”

“Nukes require very complex moving parts to work exactly right very, very fast. They’re the last thing in the world that you could set off by just whacking them or burning them. So if it was gas, germs, or nukes, they were planning to pull the trigger or open the nozzle before crashing the plane, and shooting it down in the desert should take care of it.”

“That leaves radiological.”

“Yeah. If the drums contained flammable radiological material, of course, that doesn’t stop being radioactive when it burns, and burning it might spread it around more. Either something like tritinated hydrocarbons or something like radiosodium might be kept in barrels. But I don’t think it’s likely; the physics is all wrong.”

“Wrong how?”

“The flight time is too long,” Browder explained. “The shorter the half-life, the stronger the radiation. If they used something with a short-enough half-life to be quickly, immediately deadly, that’s going to be a half-life of hours rather than weeks or years. They’ve been on that plane for close to fifteen hours with it, and short-half-life radioactives are too energetic for any shielding less than tons of lead to deal with. They’d all be dead of radiation poisoning.

“That rules out things like sodium-24, which I thought of at first because it’s the classic radiological weapon—real strong radioactivity and chemically super active, so it would burn its way right into the body and would catch fire easily and be hard to put out. That’s why they store sodium in barrels, immersed in oil so it doesn’t spontaneously combust from the air around it. But the reason sodium-24 has been talked about as a fallout enhancer is because you make it by putting ordinary sodium in a strong neutron flux, like around a hydrogen bomb or in a nuclear reactor. Even if they made it in a reactor the day before they seized Air Force Two, and loaded it right on, it would be mostly gone now—and would have killed them in the early hours of the flight.

“The other family of radiological weapons is long-half-life stuff that isn’t very strong radioactively, and it could be on that plane—say tritinated methanol, methanol with superheavy hydrogen substituted for the ordinary hydrogen. If that burned it would put radioactive water into the air—but because it’s comparatively feeble, it’s purely a scare weapon, years or more likely decades before people would get sick from it, and you’d treat inhalation with lots of water and diuretics, it could be flushed out fast before it hurt most people. And on top of that, a long half-life means a small cross section of neutron absorption—”

Cam held his hands up in self-defense. “Whoa. I only got through one year of college physics.”

Browder closed in for the kill. “The cross-section for neutron absorption is closely related to how easy it is to make something radioactive. The weak stuff, that would last a long time and wouldn’t kill them while they flew here, is much more difficult and expensive to make than the strong stuff, which wouldn’t last all the way here and would already have killed them. So, the only things they could deliver on a flight that long are pretty mild and expensive and difficult to make. If it was any of the really bad kill-you-right-now stuff, it would already have killed them. If they are using the weak stuff, it’s mostly just a scare tactic, not something you really have to worry about; you need a good PR campaign, is all.”

Heather rolled her eyes; leave it to the science guy to think that all you had to do was explain things calmly and rationally, and everything would be fine.

Browder added, “But in case there’s something I didn’t think of, definitely warn the pilots not to fly through any plume of smoke after the crash, and if you can bring it down without blowing it all over, that might be extra safe. You probably don’t want the hero who saved us all to die of radiation poisoning next week.”

Cameron nodded infinitesimally. “Excellent. We’ll do that. Thank you, Dr. Browder, that’s what I needed.”

“Talk to you again soon, Jim.” Heather undocked her phone. When Cameron finished relaying Browder’s advice, she asked, “Wasn’t that really more of a question for someone at the Department of Energy? I mean, they’re the ones that build atom bombs and have all the physicists.”

“I wish,” Cameron said. “But there was no time—I’d’ve had to ask twenty of them and each one would have told me about one small detail. Your guy Browder used to be a science reporter, so he—”

“Fullback Fourteen will be on the target in thirty seconds,” Marshall said. “Going to feed from the Pentagon’s war room.”

The big screen wavered a moment and then they were looking southward across the mountainous desert through the cameras on the A-10. A tiny white bird shape just showed in a corner of the screen. The room was so quiet that they could hear the static in the link.

Greg Redmond didn’t have spare time or attention to be surprised when he heard, “Fullback Fourteen, you’ve got first shot.” His hands and feet mechanically did the necessary tasks as he listened. “Begin your attack immediately on sight. We have confirmed there are no civilian or military airliners anywhere in the vicinity. Investigative personnel have requested you bring it down with gunfire to preserve more evidence. Make one pass with the cannon, and if it’s still flying afterward, send both Sidewinders after it.”