Originally Posted by
PEI_3721
zzuf, yes missing, misinterpreting - most probable.
The quest was for a practical answer - if rolling 'g' is not limited by the AFM, then do crew have to be concerned by a combined pull / roll during an upset recovery.
My conclusion is no, and that in some circumstances the control input is difficult.
Furthermore, with the surprise in such situations then the likelihood of the crew recalling an obscure limit, if it exists, is remote.
§ 25.303 Factor of safety.
Unless otherwise specified, a factor of safety of 1.5 must be applied to the prescribed limit load which are considered external loads on the structure. When a loading condition is prescribed in terms of ultimate loads, a factor of safety need not be applied unless otherwise specified.
§ 25.349 Rolling conditions.
The airplane must be designed for loads resulting from the rolling conditions specified in
paragraphs (a) and
(b) of this section. Unbalanced aerodynamic moments about the center of gravity must be reacted in a rational or conservative manner, considering the principal masses furnishing the reacting inertia forces.
(a) Maneuvering. The following conditions, speeds, and aileron deflections (except as the deflections may be limited by pilot effort) must be considered in combination with an airplane load factor of zero and of two-thirds of the positive maneuvering factor used in design. In determining the required aileron deflections, the torsional flexibility of the wing must be considered in accordance with § 25.301(b):
(1) Conditions corresponding to steady rolling velocities must be investigated. In addition, conditions corresponding to maximum angular acceleration must be investigated for airplanes with engines or other weight concentrations outboard of the fuselage. For the angular acceleration conditions, zero rolling velocity may be assumed in the absence of a rational time history investigation of the maneuver.
(2) At VA, a sudden deflection of the aileron to the stop is assumed.
(3) At VC, the aileron deflection must be that required to produce a rate of roll not less than that obtained in paragraph (a)(2) of this section.
(4) At VD, the aileron deflection must be that required to produce a rate of roll not less than one-third of that in paragraph (a)(2) of this section.
(b)
Unsymmetrical gusts. The airplane is assumed to be subjected to unsymmetrical vertical gusts in level flight. The resulting limit loads must be determined from either the wing maximum airload derived directly from
§ 25.341(a), or the wing maximum airload derived indirectly from the vertical load factor calculated from
§ 25.341(a). It must be assumed that 100 percent of the wing air load acts on one side of the airplane and 80 percent of the wing air load acts on the other side.
'
V-speeds defined in 14 CFR part 1
VA design maneuvering speed
VB design speed for maximum gust intensity
VC design cruising speed
VD design diving speed
VDF/MDF demonstrated flight diving speed
VEF speed at which the critical engine is assumed to fail during takeoff
VF design flap speed
VFC/MFC maximum speed for stability characteristics
VFE maximum flap extended speed
VFTO final takeoff speed
VH maximum speed in level flight with maximum continuous power
VLE maximum landing gear extended speed
VLO maximum landing gear operating speed
VLOF lift-off speed
VMC minimum control airspeed with the critical engine inoperative
VMO/MMO maximum operating limit speed
VMU minimum unstick speed
VNE never-exceed speed
VNO maximum structural cruising speed
VR rotation speed
VREF reference landing speed
VS stalling speed or minimum steady flight speed at which the airplane is controllable
VS0 stalling speed or minimum steady flight speed in the landing configuration
VS1 stalling speed or minimum steady flight speed obtained in a specific configuration
VSR reference stall speed
VSR0 reference stall speed in the landing configuration
VSR1 reference stall speed in a specific configuration
VSW speed at which onset of natural or artificial stall warning occurs
VTOSS takeoff safety speed for Category A aircraft
VX speed for best angle of climb
VY speed for best rate of climb
maximum speed in the takeoff at which the pilot must take the first action (e.g., apply brakes, reduce thrust, deploy speed brakes)
to stop the airplane within the accelerate-stop distance. V1 also
V1 minimum speed in the takeoff, following a failure of the critical engine at VEF, at which the pilot can continue the takeoff and achieve the required height above the takeoff surface within the takeoff distance.
V2 takeoff safety speed
V2min minimum takeoff safety speed
The highest load case does not occur in the rolling g manoeuvre, the greatest loads occur if a limit control input is reversed with a suitable lag to the aircraft response, particularly in the rudder control, and to a lesser extent for ailerons, and elevator. A rapid reversal of ailerons will achieve a high torsion and associated bending load, and that is not covered as a criteria in certification. The rudder is the most problematic control inn that regard, as shown by AA587, For Airbus electrojets the controls are relatively good at achieving a linear response which is nice. For older Boinkies, the speed brake has a marked effect on roll response, and you can move from good to badness by putting in the control and then pulling the brake. The Max added FBW for parts of the spoilers, which is good. The Airbus authority is derived from a lookup table of commanded rate and a deflection command, this being subject to the position of the T.E. flap. If that gets out of sorts, the plane is most entertaining, refer HDA323 and the USAir GA at NY with a jammed T.E. flap.
One event on a XXXX brand had the rocket scientists achieving a 150KCAS overspeed and at about that time, the aircraft data showed a clear case of aileron reversal, but not for long... shortly thereafter the wings fell off and it all ended in tears. Sad.
When you invert a Part 25 aircraft, it is imperative to get the aircraft blue side up, its far prettier that way, as long as you are inverted, alpha stability will be driving your pointy end ever more downward, at around 10 degrees a second, give or take. Your plane just don't got the elevator authority to do the upside down canopy to canopy bird pinkies that Maverick and Goose did, your stab trim is agin ya, and the elevator AND authority is just not going to get good marks on an Aresti score card. The dart is trimmed normally around 1g, which will be around 2.3-2.5 AOA on most planes, and that means upside down, unfettered by human intervention you are going to be pitching to about 2g hence the world getting big in the window promptly. Roll rate other than the bus, is going to be a function of AOA, and at least the plain is helping in that case, the AOA it is trying to achieve is what you had shiny side up, so unless you are pulling ailerons will be effective. Applying rudder is "heroic" and unless that is all that is left, not all that helpful. Once you are over on your back, you will see a lot of the planet, and the recovery will be raucous. The overspeed isn't what hurts, it's the g. Your roll rate you can see in your sim, it is not bad but it isn't a Pitts, Acro, A4 or MIR3, and it aint no T38/F5. Rolling upright takes a finite time and your nose will be dropping until the lift vector is skyward. For your UPRT cases, the sims aren't bad, well, most nowadays aren't, but they are also not perfect in the way outside the envelope case. Low speed is pretty good, and if approved under ICAOs UPRT simulator QTG requirements they are pretty good, but only to a point. A B767 or 737 etc is a dart, and given enough direction it will behave like all darts. The FAFO point on that is using the wrong controls for yaw and roll, and getting slow. These planes are really really good, but we seem to get them out of sorts if we try hard enough. In overspeed, once you are past MMO +0.06 or thereabouts, congratulations, you are a test pilot, and if you survive, feel free to share your data with the OEMs. (there are various aircraft that data hads been gained beyond those speeds, but mostly they came from the FDR, or by really good AAI followup, such as the Air Chine B747SP 6-flags ride on the way to SFO way back when. Getting thrust off ASAP is critical, more or less no matter what the cause, as you are going to get steep, really fast, do the math.
Fly safe, and treat your planes with kindness, as others have flown it before you... and hopefully others will afterwards.
IMHO, E&OE... boring is good.