AI.II.P.K6
KnowledgeThe relationship between minimum control speed (VMC) and stall speed and the effect of density altitude on that relationship.
From the FAA library
- Chapter 6: Flight Controls › Flight Control Systems › Primary Flight Controls
Flight Control Systems Flight Controls Aircraft flight control systems consist of primary and secondary systems. The ailerons, elevator (or stabilator), and rudder constitute the primary control system and are required to control an aircraft safely during flight. Wing flaps, leading ... edge devices, spoilers, and trim systems constitute the secondary control system and improve the performance characteristics of the airplane or relieve the pilot of excessive control forces. Primary Flight Controls Aircraft control systems are carefully designed to provide adequate responsiveness…
- Chapter 13: Transition to Multiengine Airplanes › Engine Inoperative Flight Principles › ⦁ All propeller controls in the recommended takeoff position throughout VMC determination
determination of VMC in certification is solely concerned with the minimum speed for directional control under a very specific set of circumstances, and not the optimum airplane attitude or configuration for climb performance. During dynamic VMC determination in aircraft certification ... cuts of the critical engine using the mixture control are performed by flight test pilots while gradually reducing the speed with each attempt. VMC is the minimum speed at which directional control could be maintained within 20° of the original…
- Glossary › Numbers and Symbols
Stalling speed or the minimum steady flight speed in the landing configuration. In small airplanes, this is the power-off stall speed at the maximum landing weight in the landing configuration (gear and flaps down). The lower limit ... white arc. VS1. Stalling speed or the minimum steady flight speed obtained in a specified configuration. For most airplanes, this is the power-off stall speed at the maximum takeoff weight in the clean configuration (gear up, if retractable…
- Chapter 13: Transition to Multiengine Airplanes › Engine Inoperative Flight Principles › VMC Demo Stall Avoidance
airplane to the entry airspeed. Note that noise within the flight deck may mask the sound of the stall warning horn. While the VMC demonstration shows the earliest onset of a loss of directional control when performed in accordance with ... foregoing procedures, avoid a stalled condition. Avoid stalls with asymmetrical thrust, such that the VMC demonstration does not degrade into a single-engine stall. A VMC demonstration that is allowed to degrade into a single-engine stall with high asymmetrical…
- Chapter 4: Principles of Flight › Pressure › Density Altitude
Density Altitude SDP is a theoretical pressure altitude, but aircraft operate in a nonstandard atmosphere and the term density altitude is used for correlating aerodynamic performance in the nonstandard atmosphere. Density altitude is the vertical distance above sea level ... standard atmosphere at which a given density is to be found. The density of air has significant effects on the aircraft’s performance because as air becomes less dense, it reduces: • Power because the engine takes in less air • Thrust…
- Chapter 13: Transition to Multiengine Airplanes › Engine Inoperative Flight Principles › Derivation of VMC
They also describe the conditions used to determine the manufacturer's published speed. Historically, in aircraft certification, dynamic VMC has been determined under the following conditions outlined in historical 14 CFR part 23, section 23.149: ⦁ Maximum available takeoff power initially ... each engine (section 23.149(b)(1)). VMC increases as power is increased on the operating engine. With normally aspirated engines, VMC is highest at takeoff power and sea level, and decreases with altitude. With turbocharged engines, takeoff power, and therefore…