Overview
- The Aviation Geek Club, drawing on Paul Crickmore’s new book, reports a wartime emergency limit raised the SR-71’s inlet temperature cap to 450°C from 427°C for bomb-damage assessment flights over Libya.
- The higher cap let pilots approach or exceed Mach 3.4, aligning with crew accounts of faster dashes on those missions.
- Near those speeds, unstable air at the inlet could reach the engine and cause a flameout, highlighting the narrow safety margin at the top of the envelope.
- The Blackbird’s hard-to-ignite JP-7 fuel relied on triethylborane for starts and afterburner light-offs, stored in small nitrogen-inerted tanks that maintainers handled under strict procedures due to its hazards.
- At roughly 80,000 feet the crew saw a near-black sky with many more visible stars, a view that aided the jet’s astro-inertial navigation system.