She held up one finger—not to the crowd, to Neil: "Wait."
Eight seconds passed. Then she held up two fingers. Another eight seconds; two fingers again.
She opened her eyes. "Kill the right engine. Keep the left running."
Neil hesitated. That wasn't standard. You don't run a twin-engine jet on one side inside a hangar without safety clearance. Dr. Sutter gave the nod. Neil shut down the right engine; the left engine kept running.
And here's what changed: the idle smoothed out. Not perfectly, but noticeably. The stutter that had been cycling every eight seconds reduced to almost nothing.
"Now swap," Faith said. "Right engine only."
Neil restarted the right, killed the left. Same result: the right engine ran rough, but without the rhythmic stutter.
Faith turned to Dr. Sutter: "It's not the engines. It's what happens when both engines run together."
She asked Neil to pull up the fault logs on the diagnostic console—not the summary reports that every mechanic had been reading, but the raw data, millisecond-level timestamps. "Overlay them. Left and right. Same time axis."
Neil did it. The data appeared on the screen: two lines running side by side. And there it was: a tiny dip in fuel pressure on the left engine lasting 3/10 of a second, appearing exactly every 8 seconds. Every single dip lined up with a corresponding spike in the right engine's fuel flow.