JammedStab:
I’ll attempt to make my point one additional time. Of course you know that you are free to take what I say and check it’s validity, believe it, not believe it, or refuse to read any of my subsequent posts – or virtually any other course of action you choose.
It should be obvious to any pilot having a commercial or higher grade certificate that the amount of control provided by aerodynamic controls alone to maintain directional control during the takeoff is going to be dramatically insufficient initially and will become more sufficient as airspeed is increased. In fact, there is point at which such aerodynamic controls will become sufficient so as to be able to provide directional control without having to depend on the nose wheel control to assist in controlling direction. This airspeed, the minimum airspeed at which directional control can be maintained through aerodynamic controls ALONE (no longer needing nose wheel steering) while still on the ground, is called the minimum aerodynamic control airspeed on the ground. The accepted term for this is called the velocity - minimum control ground, or Vmcg.
Most airplanes with multiple engines do not provide forward thrust along a centerline (and we can discuss/argue what is and what is not actually “centerline” at a later point, if required) and, as such, logically, should a multi-engine airplane experience the loss of an engine during takeoff, the continued control of the direction in which the airplane is traveling toward the takeoff point will be affected. The directionality of an airplane during the initial application of power for takeoff is controlled by the pilot by controlling the position of the nosewheel, and is dependent on retaining sufficient weight on that nose wheel to prevent nose wheel “scuffing” and sufficient nose wheel movement - affected by either rudder pedal or "tiller" input. The force with which the nose wheel is held onto the runway surface can be supported by a forward control column position as soon as aerodynamic effect on the elevator(s) is achieved, and will assist in assuring that nose wheel will maintain sufficient contact with the runway surface to resist any tendency - through wind or thrust asymmetry – to deviate from the intended ground track during the takeoff roll. Should the airplane experience the loss of an engine very early in the takeoff, resulting in an asymmetrical thrust situation … and the pilot decides to reject the takeoff, that pilot can immediately correct any asymmetrical thrust problem by pulling all throttles to idle. Having virtually zero thrust on all engines prevents an asymmetrical thrust situation – and doing so would allow the pilot to continue to maintain directionality with nose wheel steering inputs. Obviously, there is a point during the takeoff acceleration where deciding to reject the takeoff may result in a runway “over-run” at the departure end. This is the reason that instructions are given to the pilots to designate a speed at which they should no longer attempt to reject the takeoff (where deciding to continue the takeoff is considered to be more safe than attempting to reject the takeoff ) and allowing the crew to then deal with the problem once safely airborne.
V1 may not be less than speed at the point the critical engine fails (Vcef) PLUS the speed gained during the time interval between the instant the critical engine is failed, and the instant at which the pilot recognizes and reacts to the engine failure, as indicated by the pilot's initiation of the first action (e.g., applying brakes, reducing thrust, deploying speed brakes) to stop the airplane during accelerate-stop tests. Also, Vcef may not be less than Vmcg, where Vmcg, is defined as the minimum control speed on the ground, with one engine inoperative (the critical engine on two engine airplanes), takeoff power on other engine(s), using aerodynamic controls only for directional control.
Also, according to the regulations, Vmcg, the minimum control speed on the ground, is the calibrated airspeed during the takeoff run at which, when the critical engine is suddenly made inoperative, it is possible to maintain control of the airplane using the rudder control alone (without the use of nosewheel steering), as limited by 150 pounds of force, and the lateral control to the extent of keeping the wings level to enable the takeoff to be safely continued using normal piloting skill. In the determination of Vmcg, assuming that the path of the airplane accelerating with all engines operating is along the centerline of the runway, its path from the point at which the critical engine is made inoperative to the point at which recovery to a direction parallel to the centerline is completed may not deviate more than 30 feet laterally from the centerline at any point. Vmcg must be established with (1) The airplane in each takeoff configuration or, at the option of the applicant, in the most critical takeoff configuration; (2) Maximum available takeoff power or thrust on the operating engines; (3) The most unfavorable center of gravity; (4) The airplane trimmed for takeoff; and (5) The most unfavorable weight in the range of takeoff weights.
There are also limitations on taking of and/or landing with crosswind conditions – providing limitations for the maximum crosswind limits. As I indicated in an earlier post, most manufacturers provide several, graduated maximum crosswind limits, based on the level of contamination of the runway surface, as described in terms of universally understood braking action (see my earlier post in this thread).