According to NTSB data, in the first decade of this century, over 40 percent of fixed-wing general aviation fatal accidents occurred because pilots lost control of their airplanes.
I find statistics like these mystifying. Why do people fumble the recovery from loss-of-control situations so often? After giving more than 2,500 hours of instruction, I haven’t noticed any particular trouble with it in training.
Perhaps that’s the problem: circumstances conspire to prevent accurate simulation of the scenario we’re trying to model. I’ve long harbored such suspicions, but could never really put my finger on exactly why. But in this month’s AOPA Pilot, Bruce Landsberg posits a theory that helps connect the dots:
Recovery from spiral dives, as presented in training, seems simple. Distract the trainee; place the aircraft into an incipient dive; have the trainee recover by immediately reducing power, rolling wings level, and returning to a level pitch attitude.
Unfortunately, this does not replicate reality. The trainee is primed to look for an unusual attitude, so distraction is absent. The recovery is started quickly for safety reasons, before the speed becomes a factor, so it’s a “baby” spiral — not its nasty big brother.
It’s difficult to induce vertigo under these circumstances, and true vertigo is a big distraction. In a well-developed spiral, the aircraft will quickly accelerate to well above trim airspeed.
As soon as the aircraft is rolled to level — assuming the pilot gets that far into recovery — it will seek trim speed. If cruise (and trim) airspeed is 150 knots and the pilot manages to get wings level at around 210 knots (and the maneuvering speed is 130 knots), there will be a pitch up as the aircraft seeks to regain trim speed. The pilot must push forward — firmly — to unload the aircraft structure.
Being so far above maneuvering speed, and possibly above redline, it’s not surprising that many inflight breakups follow a spiral. In some cases a trainee is told that since the aircraft is going down, they need to pull up. In a fully developed spiral, that’s exactly the wrong guidance! It’s going to be wings level and a push — if the aircraft continues to climb for a bit, getting away from Mother Earth is a great solution.
You’d think after 7,500 hours I’d have figured this out. But then, I’ve never been 50 or 60 knots beyond redline in a normal category airplane while trimmed for cruise.
As Bruce notes, the spiral dives we simulate in training are not like the ones encountered in real life. They can’t be, because we avoid exceeding Vne at all costs. It profits nobody if we cause an accident while providing the very training necessary to prevent one. Instructors are very much like doctors in that regard: “first, do no harm”.
So what’s the solution? Simulators? Unfortunately, even the most sophisticated Level D boxes — which cost millions (if not tens of millions) of dollars — can’t duplicate the loading a post-Vne spiral dive would generate. It seems to me that if the situation can’t be accurately modeled, we’re in no better of a position than with the baby-spirals we currently use in actual aircraft.
Regardless of where they’re held, these training events already lack the genuine surprise inherent in any real-world upset. When the instructor briefs a spiral dive recovery prior to the flight, you can bet your bottom dollar one might be in the offing.
Most pilots have never even been in a real spiral dive. These things are extremely dangerous. When I teach spins, I make a point of discussing and demonstrating the difference between spins and spiral dives. The primary difference, of course, is that spins are a stalled condition where excessive angle of attack and high drag keep airspeed low and stable. A spiral dive is an unstalled condition. Airflow over the wing is smooth, drag is low, and as a result the airspeed builds rapidly. Even to aerobatic airplanes, the spiral dive can be a fatally destructive event and I’ve seen people attempt a spin but not reach the critical AOA. The resulting flight path looks like a spin but is not.
Speaking of aerobatic airplanes, the latest trend is to utilize them for upset recovery training. This is a good thing, but spirals are a unique case. Aerobatic aircraft are better able to simulate the forces and sensations involved with a high-speed spiral dive, but the airframes aren’t like the ones we fly in instrument conditions. If you put 6g on an aerobatic aircraft, it won’t complain. The normal category ship, on the other hand, would be well beyond even the 50% safety factor of its 3.8g limit. The acro mount will also, among other things, feature larger and more responsive control surfaces, higher pitch and roll rates, lighter stick forces, and far less stability.
We can talk about a spiral dive all day long, but until you’ve seen one, I’m not sure the odds of recovery in a surprise situation are all that great, especially if vertigo is thrown into the mix.
If someone asked me how to best prepare for a scenario of that ilk, I’d recommend not even trying to simulate it with full fidelity. Instead, I’d suggest 10-12 hours of basic aerobatic training. Familiarity and experience in all-attitude flying goes a long way toward keeping panic at bay, bringing a sense of been-there-done-that to the unexpected. The load factors will be familiar. Higher than normal control pressures and/or deflections required for recovery will be as well. And most of all, staving off tunnel vision may allow the wayward pilot to recognize the increasing airspeed and figure out what’s happening before it’s too late.
It’s not a perfect answer, but at the moment it might be the best we’ve got.