"We'll have to take our chances. We need to minimize that window of AAM vulnerability."
"I agree." Androv gestured for him to sit, then glanced up at the screens. "We have two and a half minutes. I've set Petra for full auto. All you have to do is just talk her through the key intervals of the sequence."
Vance settled in and examined the huge flight helmet looming above him, making him look like an alien insect from science fiction. Now the cabin had taken on an eerie quiet, with nothing but silent screens flashing data. He'd never talked to an airplane before, and the thought gave him some disquiet.
Two minutes.
"What do I do first?"
"You probably should start by attaching that nozzle there on the legs of your G-suit to the pressure hose on the console. When the G-forces go above eight, tubules in the legs automatically inflate using bleed air from the engines. It's going to squeeze hell out of your lower extremities. If you begin to gray-out, try to grunt as hard as you can. The M-l maneuver, I think you Americans call it. If your vision begins to go entirely, just try and talk Petra through."
"What else?"
"Once you start pushing through the hypersonic barrier, keep an eye on screens B-5 and B-6, which report engine strut temperature and stress loads. Those are the most important data for the scramjet mode. But first check the C-2 screen. Core rpm has to be zeroed out before the scramjet geometry modification, since the compressors need to be completely shut down. If it's not, then instruct Petra to abort the sequence. It could cause a flameout."
"And that's when I switch over to liquid hydrogen?"
"Exactly. Petra will set the new engine geometry, then sample compression and temperature and tell you the precise moment. But the actual switch-over is manual. I insisted on it." He pointed. "It's those blue toggles right behind the throttle quadrant. Just flip them forward."