Folks,
Yes, it is an old argument.
A comment first about helicopters. The great thing about helicopters is that they enjoy direct thrust control: the cyclic points the thrust vector and the collective controls its magnitude. The relevance: attitude is the primary airspeed control and power is the primary rate of climb/descent control. For all intents and purposes, this primary allocation of control does not change. Forward speed is relatively slow so most corrections are small and there is time to get things sorted out.
I use the word primary because there is always secondary cross-coupling in that a change in one control generally creates a need for a secondary correction in the other control.
In aeroplanes, the primary control for airspeed is attitude and that for rate of climb/descent is thrust for most of the time when manoeuvring (power is just a proxy for thrust). The only time that we reverse the primary allocation of controls in most common aeroplanes (ie less control power and not so flash thrust values) is when
the flight path is constrained and airspeed is less critical: ie, we are either maintaining level flight or flying to a specific point on the ground.
I would never die in a ditch over the level flight case and most Naval aviators will argue that the primary allocation of controls does not change - however, they are usually given highly responsive (pitch and thrust) machinery that allows them to maintain speeds to within a couple of knots while flying down the ball to their wet postage stamp landing point.
In the most discussed case of flight path constraint, final approach to landing, the argument goes as follows. I fly to my final entry gate for either a visual straight-in or an ILS using attitude for airspeed and thrust for rate of descent. When I get there, I effectively change the plot by fixing the flight path angle and planned point of impact with attitude and I let thrust become the variable to control the speed. The interaction between controls means that a change in one will effect the other, however the precision of attitude control over that of setting thrust suggests that attitude be used to control the most critical variable.
The other (important but not controlling) issue that comes into play is that of Flight Directors. They are demanders of rates of change and do so by demanding pitch or roll attitudes. In particular, in ILS mode, they can demand only pitch changes for glidepath control. Most heavy metal instructors have little tolerance for poor F/D discipline and will expect that the flightpath is maintained by following the pitch demands.
My experience is that folks flying down final in fast machinery trying to control their flight path with power while using attitude for airspeed have the most trouble and get overloaded very quickly.
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Stay Alive,
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