Research on flight test method for minimum control speed during approach and landing (VMCL) dynamic test in civil aircraft

Abstract

This paper investigates the flight test method for the Minimum Control Speed during Approach and Landing (VMCL) dynamic test of a twin-engine narrow-body mainline airliner undergoing EASA type certification in accordance with CS- 25 requirements. The research identifies the core challenge as the significant energy state disruption caused by engine thrust transients during the test, which is exacerbated by the aircraft’s limited speed margin between VMCL and the Reference Stall Speed VSR. A detailed analysis of the airworthiness compliance methods reveals key operational differences between Acceptable Means of Compliance (AMC) used by European Union Aviation Safety Agency (EASA) and Advisory Circular (AC) which is currently followed by Civil Aviation Administration of China (CAAC), framing the specific constraints for the test. Through extensive simulator evaluation, two conventional test methods—the traditional Two-engine GA Trim Method and the Low-speed Trim Method—are shown to pose considerable risks, including speed loss with angle-of-attack overshoot or an insufficiently stringent demonstration at an elevated speed. To resolve these issues, this study proposes an innovative approach: Target Attitude Method. This method shifts the pilot’s control strategy from passively reacting to speed changes to actively guiding and stabilizing the aircraft to a predefined target pitch attitude corresponding to single-engine GA thrust at VMCL. Simulator data demonstrates that this approach enables a smooth transition of both attitude and airspeed, effectively mitigating the dynamic risks inherent in the conventional methods. The proposed method provides a safer, more controllable, and compliant test procedure, offering significant practical value for the airworthiness certification flight test of similar aircraft types with constrained speed margins.