Testing Near Airspeed Limits During Safe Separation Flight Test

Although all flight tests possess their own inherent risks, safe store separation tests, especially those targeting release conditions at or near maximum sanctioned clearance limits, add more hazards to an already bloated list of obstacles. Since the success of most modern flight test programs is measured in terms of cost, schedule, and performance, an unsuccessful test flight can add tens of thousands of dollars and months to an already beleaguered program. With ever-increasing flight hour costs and dwindling budgets, reducing or eliminating unnecessary or unsuccessful sorties is essential. The trick, then, is to fly to achieve desired test conditions, yet not exceed aircraft limitations and cause the tester to return to base prematurely or, worse, not return at all.

With the requirement to test near the aircraft airspeed limits, occasional clearance limit violations are expected. However, during the weapons separation Follow on Test and Evaluation (FOT&E) phase of the F/A-18 E and F model Super Hornet, of the 55 attempts at test endpoint conditions targeting 600 knots calibrated airspeed (KCAS), 1.20 indicated Mach number (IMN), and 0.5 g normal acceleration, 11 resulted in airspeed limit exceedances. These failures accounted for 20% of the total number of attempts. Aircraft clearance limits are imposed by many engineering disciplines. Thorough knowledge of these aircraft limits and their genesis is vital for effective risk assessment, decision making, and avoidance.

This thesis examines modern weapons separation test techniques for the F/A-18 E/F Super Hornet, the obstacles faced with regard to testing near airspeed limits, the planning and flight techniques required to overcome them, results, and lessons learned for test planners and pilots alike.