I've spun and/or departed a lot of different airplanes but spins in an EZ-like canard are not high on my list of things to do.
Given that it was flight test it's hard to predict what they were doing and what the inputs should have been but the article indicates that you've got to ignore some fairly unambiguous cues to get to the point where it lets go. I also don't know what (if any) changes have been made in the last 20 years up to the AC-130J that might affect those characteristics.
I haven't seen the actual report, but from someone who has, apparently the 3.19g is the design limit that was exceeded. The accident airplane apparently reached over 7gs, so that may explain it better.
I'm having a little trouble resolving 7g, 100kt overspeed, and 5000 ft altitude loss.
There's a whole lot more to the picture than any of us have at the moment.
Not unrelated but since stalls keep coming up I'll point out that the public sources say this was a departure out of a steady-heading sideslip for a flying qualities test. That type of test typically isn't done close to balanced-flight stall AOA, although stranger things have happened. Departure boundaries are usually defined by a combination of AOA, sideslip, and rates, not just what many people thing of as 'stall AOA'. Again, we don't know what we don't know and won't know it until more is known.
It's not likely that an increase in power *available* induced a departure out of a level flight SHSS - if the departure happened as has been reported here. More likely that aerodynamic and mass properties changes as a result of that power increase or other J changes had an adverse effect that required the subject testing. The actual cause of the departure may be more complex or even simpler than that, however.
100kt overspeed with the flaps down may be the diving factor in that is all I can think.
That would fall under "aerodynamic changes"; however, the article reads as though it's primarily a high AOA (where high is relative to the C-130) issue and resulted in the addition of a stick shaker, etc. In that, given enough control power (i.e. rudder authority), one can depart *any* airplane at *any* AOA when combined with large sideslip angles, what confidence do we have that they were anywhere near stall or any regime where airflow characteristics were significantly adverse? If the maneuver was as described (i.e. level flight steady-heading sideslip), the uprated engines were putting out the exact same thrust the derated engines would put out under the same conditions. Do we know the flight conditions (AOA, sideslip, and speed) and do we know that the new props significantly affect handing at those conditions? No.
You must have interpreted his question and intended your response in a much different way than I took them.
[emphasis added]
)
What. If it was as described in the articles linked here and elsewhere it's a stability and control/handling qualities flight test technique for evaluating directional control power, directional stability, and dihedral effect. Sounds like they found a boundary.Was the slip for an aiming technique or what?
