Is anyone else tired of being lectured about “loss of control – inflight?” As is typical in aviation, every few years industry experts find a new threat to general aviation safety and then relentlessly remind us about it, through articles, videos, podcasts, and roundtable meetings. Previous winners have included runway incursions and datalink weather; right now it’s loss of control.
As tiresome as this current phase is, loss of control accidents are a real problem – they remain the leading cause of fatal accidents, even in turbine airplanes. Unfortunately, that broad term hides a lot of variation. An airliner that stalls at high altitude after a sensor failure is dramatically different from a Cessna that stalls during a low pass. One way to combat this vague language – and the urge to generalize – is to read specific accident reports. The details make the potential threat much more real, and the common threads suggest potential areas of focus.
Three fatal Cirrus accidents in late 2015 and early 2016 caught my attention, since all three involved low-level stalls. Two occurred with flight instructors on board and one with an experienced Cirrus pilot at the controls. Each one has lessons for us as we try to reduce loss of control accidents. The final reports are available now, so let’s consider each scenario and think about how you would react.
Accident one
A tragic result, but a familiar cause – loss of control.
In the first accident, a private pilot was receiving flight instruction in his SR22 on a good VFR day. After six touch-and-goes, the pilot requested a climb to 3,000 ft. in order to simulate an engine failure. That glide to the runway is when things went wrong, as the NTSB report explains:
The airplane then descended, and the airspeed gradually decreased from about 110 kts to about 87 kts. In the final three seconds, vertical, lateral, and longitudinal accelerations all increased to recorded peaks of 1.4 g, -0.2 g, and 0.4 g, respectively. During the last second of the recording, the airplane was at 646 ft when it entered a tight descending left turn of nearly 360 degrees. During this time, the roll values increased from 36 degrees to 45 degrees left, and the pitch values ranged from -0.5 degrees to 2.4 degrees.
Neither pilot was exactly a novice in the airplane: the pilot had over 500 hours in the Cirrus and the flight instructor was an expired Cirrus Standardized Instructor Pilot (CSIP) with over 3400 hours total time. The pilots had flown together on multiple occasions. And yet the result was tragedy, with the pilot killed and the flight instructor seriously injured. The airplane was destroyed.
Accident two
The second accident also involved an instructional flight, this time in an SR20. The pilot did not have a pilot certificate (the AME deferred issuing a medical certificate), but he had accumulated over 100 hours of flying time, including over 50 in the SR20. There were two passengers in the back seat, but the circumstances still suggest a training flight. After two touch-and-goes and two full stop landings, the airplane departed Navasota Airport (60R):
Shortly after taking off following the second full stop landing, while climbing through 550 ft mean sea level (msl) at an indicated airspeed of about 92 knots, the airplane entered a left bank and began to decelerate. The airplane began to descend, and the airspeed subsequently decreased below 75 knots before it began to increase.
What caused the airplane to bank left and slow down? We’ll probably never know, and the NTSB does not speculate. It’s possible there was engine trouble, although the NTSB found no evidence of preimpact failure. More likely is a momentary loss of situational awareness as the airplane turned crosswind, and a stall. The following math is a good reminder of how rapidly stall speed rises in a turn:
Calculations based on the airplane’s weight at the time of the accident indicated that, at 1g with flaps up, the aerodynamic stall speed would have been 75 to 78 knots calibrated airspeed. The stall speed in a 60° turn (2 g) would have been 105 to 109 knots. Therefore, it is likely that the combination of a steep left bank and low airspeed resulted in an accelerated aerodynamic stall.
Accident three
The final accident involved a husband and wife instead of a student and instructor, but the pilot was an experienced Cirrus owner with almost 2,000 hours in type. There is some discussion in the NTSB report about potential medication issues (including marijuana), but the fundamental mistake is sadly familiar. After takeoff on a cross country flight, the pilot reported engine trouble and attempted to return to the airport. The airplane entered a spin and crashed short of the runway. A typical story, right? In many ways it is, but there is an important factor: density altitude. As the report states,
The density altitude at the time of the accident was 7,446 ft mean sea level. The majority of the pilot’s flight experience was conducted at airports with a lower field elevation and he had flown to the accident airport on only two other occasions. It is likely that, after takeoff, the pilot misinterpreted the airplane’s reduced engine power and decreased climb performance, due to the high density altitude conditions, as an engine malfunction. During the turn back to the airport the pilot exceeded the airplane’s critical angle of attack and experienced an aerodynamic stall and spin.
Lessons
What can we learn from these three tragedies? First, they are a reminder that accidents don’t just happen on dark and stormy nights with inexperienced pilots. The weather was excellent in all three scenarios. The airplane appeared to be operating properly in all three (the NTSB used the familiar phrase, “examination of the airplane did not reveal any mechanical malfunctions or failures that would have prevented normal operation”). The pilots were qualified and experienced in all three accidents. None of these was an accident waiting to happen.
The effect of bank angle on stall speed is not well understood.
And yet the accidents did happen. One common thread is that each airplane appeared to stall during a turn. From the earliest days of flight training, we learn that an airplane stalls at a higher airspeed in a turn, but accelerated stalls are one of the least understood topics among GA pilots. Step one is to accept that turns are simply different than straight and level flight. Certainly, pilots should practice accelerated stalls during proficiency training, but even more important is a general awareness of the thinner margins during turns in the pattern. We must resist the urge to overbank or pull back in a turn. If 25 degrees of bank isn’t doing the job, consider intentionally overshooting and correcting in a more deliberate way. Likewise, if the airplane isn’t climbing well, wait until you’ve reached a safe altitude to turn, and then do it carefully.
Another key factor is performance. An SR20 with four adults on board isn’t automatically over maximum gross weight, but it will definitely be heavy and the stall speed will be higher. Likewise, an SR22 can safely take off from an airport at 7,500 ft. density altitude, but the pilot must be prepared for a longer ground roll and a slower climb. Such numbers should be part of a takeoff briefing, whether it’s verbal or in your head. Anytime the performance will deviate from your normal, it should be called out.
The third, and perhaps most important, lesson is to not panic, whether the emergency is practice or for real. One accident involved a simulated engine failure, one involved a pilot who thought he had an engine problem, and the other pilot might have at least had the suspicion of engine trouble. Regardless of the condition of the engine, the pilot must fly the airplane all the way to the ground. A simple training maneuver or minor abnormality need not turn into an accident if the pilot keeps the wing flying. When in doubt, push to unload the wing.
One final point to ponder: none of these airplanes were equipped with Garmin’s new Electronic Stability and Protection (ESP) system, which provides continuous protection against overbanking and stalling by using the autopilot servos. These systems are installed on newer Cirrus aircraft, and while it is hardly foolproof, it does offer an additional layer of protection. Might this have made a difference in these three accidents? Time will tell as more and more of these airplanes accumulate hours.
The best answer, of course, is not avionics but a well-trained pilot who stays away from the edges of the envelope.
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Understanding and use of an Angle of Attack Indicator could have prevented these accidents. It’s imperative that aircraft owners and pilots gain a deep understanding and use of an AoA.
Laurence. We have conversed online several times about your relentless assertions that AOA indicators (which you market and sell, I believe) will save us all from loss of control. And once again, I will say in response that while AOA indicators do provide useful information, therefore an added layer of safety, they are not the answer to LOC. Loss of control is not an avionics problem, and therefore will not be solved by another gadget on the glare shield. None of these accidents would have happened if the pilots had maintained a supportable pitch attitude with an unloaded wing. This type of accident is most likely the result of a pilot who has been trained to rely on instrumentation in lieu of the correct primary reference for aircraft control in VFR, the natural horizon. Adding a gadget won’t fix this issue. Better primary flight training will. By the way, Embry Riddle equipped all their training aircraft with AOA indicators. A few years later they removed all of them. That’s significant. Your endless assertion that AOA indicators are the answer to LOC is not. Understanding angle of attack is a very fundamental knowledge element, no pilot can be safe without it. But it is entirely possible to be perfectly safe without an AOA indicator when properly trained.
Amen
I’m an old time pilot – luv all the glass stuff and have a panel full of it – but I have to ditto everything CMCD stated above. We just don’t teach pilots the damn basics anymore. It’s sad all the way around.
Totally agree .
I suspect this 3rd accident was the pilot’s first flight into a high density altitude strip .Nothing much different on the landing , but after rotating at Vr , and noticing, as well as the much longer ground run, the surprisingly low pitch attitude necessary to keep Vx let alone Vy, and the low climb rate, he attributed it to an engine problem .
Agree 100%. I would go in the opposite direction – no instruments. What do I mean? In basic training with students, I include practice in all of the maneuvers (including stalls and landings) with all of the instruments covered. Why? A far greater awareness of attitude and seat-of-the-pants feeling for the airplane. And any instrument can fail.
During the road to my private pilot’s license, we had a glider club on the field and I also went after my glider’s license at the same time (didn’t quite get it when the towplane got damaged).
Flying gliders is probably the best stick and rudder training you can get and helped tremendously. Not only is it really fun, but learning to slip, do coordinated turns and maintain airspeed helps you understand the flight controls. 5 hours in a glider would help every up and coming pilot.
Moving between powered and unpowered flight while learning each also made you pay more attention to both.
Actually, in this day and age, there is ZERO reason that a modern airplane should be able to be stalled, at all, period. The same with overspeed and other operational errors. Heck, Cirrus has (as do other Garmin-equipped planes) “envelope protection” in later planes.
Given that even a state of the art airliner or fighter jet can also stall, despite “stall protection”, I disagree when it comes to GA airplanes, if you want to keep cost to a reasonable (but still bottomless) fortune. But can we build some more safe guards like AOA indicators and training with that? Absolutely. But looking for a stall free guarantee by design is like looking fir a bullet proof vest (bullet resistant is the operative term); there is no such thing.
These three accidents have the same theme in common. They all involve attempts to continue to fly the airplane without enough energy to create the lift necessary to sustain flight. The lift needed to “fly” is a function mostly of angle of attack and airspeed squared. That means airspeed is the biggest component of the lift equation.
Attempting to climb a or maintain level flight without an adequate source of power means something has to be sacrificed (either airspeed or altitude). When airspeed is the chosen compromise, you only have so much to give up before there is not enough lift to sustain flight; the end result being loss of control.
You are not going to gain any more lift by pitching up (raising the AOA) without sufficient thrust. All that will happen is airspeed will decay; again with stall as the ultimate outcome.
Whether an angle of attack indicator would help in these cases is questionable. The real problem seems to be that pilots continue to think they can save or gain altitude by pitching up without sufficient thrust to be able to do so.
A normally balanced and properly loaded airplane will never stall on its own as it will merely pitch itself down to “keep flying”. Too many pilots seem to think they can violate the laws of physics by pitching up where there is insufficient energy to sustain lift when doing so.
An AOA indicator is merely another depiction of what is happening to the aircraft’s actual angle of attack; regardless of the airspeed. But the principal of “Pitch + Power = Performance” has been true for at least 100 years. Every pilot needs to understand what degree of pitch and power he/she needs for any performance operation desired.
As a CFI I often encounter too many pilots who fail to understand the role that power/thrust plays in these scenarios. In addition, once the airspeed decays to below best glide (the “area of reverse command”) there often is a poor understanding of the increased amount of thrust needed to manage that part of the envelope.
In summary, it is not just understanding angle of attack. The entire “pitch/power/performance” envelope needs to be properly understood and managed.
Agree 100% Brian. Pitch + power = performance is the way to fly. AoA is just the result of this. I’m not opposed to AoA sensors, but I don’t think they would prevent most of these accidents.
It’s not only angle of attack and airspeed at issue here, but the added detriment of a turn at low airspeed and AoA. Everyone needs to understand that the inboard wing of a turning aircraft will almost always stall before the outboard wing resulting in a dive to the inboard side and spin of the aircraft. At low altitude, this is almost never recoverable. Keep your turns shallow (not steep) at low airspeeds and low altitudes. Especially in slick wing aircraft like a Cirrus or Mooney.
Keep your turns coordiated* if at 1.3 stall your aircraft will not reach stalling speed in a 60 degree bank. Teaching to not make steep turns causes students and pilots to have a fear of banking which in turn causes them to make a skidding turn. This is what leads to the stall-spin. I teach to have them go around if that situation arises however I would much prefer a coordinated steep turn at 500ft than an uncoordinated shallow turn at 500ft.
“Everyone needs to understand that the inboard wing of a turning aircraft will almost always stall before the outboard wing resulting in a dive to the inboard side and spin of the aircraft. ”
That’s simply not true. The inboard wing of an airplane is actually at a lower angle of attack to the relative wind versus the raised wing. In an un-coordinated turn, the high wing will stall and roll the plane to the right. And another factor is wing planform. The angle of the leading edge, along with the taper, will change spanwise air flow along the wing and cause different stall characteristics.
A 30 degree banked turn isn’t a big deal as long as your airspeed is appropriate. That’s a combination of pitch and power, as everyone else is saying. That is why you absolutely, positively have to stay alert to your airspeed throughout the turn and why you have to remember that increasing your bank adds a load to the wing which in turn forces you to increase your angle of attack to support it. That therefore increases the stall speed for the aircraft.
This is why we train to fly a consistent pattern, period. Know your turn altitudes. Know your airspeeds for each leg. Establish a stabilized approach. Stay coordinated. And be ready and configured for a go-around the instant that anything doesn’t look right.
I don’t judge these unfortunate people for their mistakes. We ALL make them. These people lost their lives and we need to learn from that.
Sorry, should add that in a scenario like this the spin is probably going to be towards the low wing not because the low wing always stalls first, but the tendency to cross-control, skid, and recover can lead to a spin.
There are some PhD in Aeronautical Engineering folks who disagree with your claim about the inside wing. http://www.nar-associates.com/technical-flying/angle_of_attack/StallSpin_wide_screen.pdf
In a descending turn the lower wing is at a higher AoA than the outside(higher) wing . The opposite is true in a climbing turn . All those bank angle/load factor diagrams so beloved of pilot training books only apply to LEVEL-CONSTANT ALTITUDE turns . This should be made clear to students—and some CFIs.
I’d say they should look at the electric trim design. When your hand is oriented with the axis of the airplane it is very easy to trim left aileron when intending to trim nose up. When trying to trim nose down it’s easy to accidently trim right aileron. The side stick/yoke or yick as I call it is cool but feels slightly off in it’s orientation. Just a guess… Even after hundreds of hours in a sr20/22/22t it still doesn’t always feel natural. Full time CFI. I’ve never been close to having a dangerous situation resulting from this but I could see how when distracted and spatially disoriented it could add to the build-up of factors that lead to these situations.
I agree with Carson. It is not the bank angle that aggravates this issue; it is the coordination of what is happening during any bank angle. The steeper you bank, the more lift is diverted to the side meaning the airplane will want to sink lest more back pressure is added. That leads to a higher AOA and if you stall uncoordinated, a spin is the next result. But you cannot spin unless you first stall. The stall itself is always a pilot induced encounter which can be avoided with proper attention to coordinating the controls and understanding the proper use of pitch and power.
I also agree that the trim mechanism on a Cirrus is a weak spot in their design. It is far to easy to over trim a Cirrus as that electric trim is too sensitive and there is no manual trim wheel. Moreover, the small trim switch will also induce roll trim if pushed to the left or right of the center position. Most planes need no roll trim at all unless there is an extreme fuel imbalance. So why combine pitch and roll trim so close together in one small switch?
Flying with a side stick rather than a conventional yoke has some differences but overall I have never had any issue with the “feel” of the plane using the side stick. But one must remember that the side stick is very sensitive and only requires a small percentage of input, compared to a conventional yoke, to change the direction of the airplane.
John,
You made two excellent recommendations in your piece and I hope they get the attention they deserve.
First, to allow the airplane to overshoot the runway center line (when necessary) and then gradually recover the runway when the wings are leveled rather than attempt to hold the center line by increasing the bank.
Second, to unload the wing in a low-energy turn. Many readers, during their flying career, will need to make a very steep turn at very low airspeed and very close to the ground – often to avoid a mid-air collision on approach or departure.
One thing which nobody really mentioned here is that one common thing in all three is that it happened during take off. We all probably more concentrated and focused on the airspeed and overall airplane flying when preparing for landing. However take offs are relatively easy – full power and up you go. We are also usually paying more attention to the traffic avoidance, communicating with the ATC than to the airspeed. If anything goes wrong it seems to be much easier to get distracted and get the airplane really slow. Cessna does give you some fair warning long before the stall warning and the reaction should be push the nose over and unload the wing (harder to do when you are a couple of feet AGL). I think it’s important to brief your take off and really pay attention to the airspeed during take off (and be ready for different situations) the same way we usually do when we land.
Important point, Stan. Most stall training focuses on approach – the dreaded base-to-final turn. The accident record (and a recent AOPA report) show that go-arounds and takeoff are far more common. It’s a time to be alert for sure.
An additional reason I wanted to bring up the trim design is that when in the approach phase the aircraft is usually trimmed at that point and any ergonomic issues have already been overcome. I almost always have a slight aileron trim imbalance right after takeoff because the aileron trim indicators are not precise enough to ground trim perfectly. Hence on takeoff let’s say your hand is positioned in a way where nose down trim happens to actually give you left aileron trim. In order to readjust your hand you have to relax the back pressure but you’re in a takeoff rotation that requires a large amount of back pressure to the point where either you reach your other hand over to hold the stick or you accept a strong nose down pitch. I’ve had my hand in a position where I literally cannot trim nose up without readjusting my hand. I usually choose to just accept the high backpresser required until airspeed is adequate or AP is appropriate. If you are a Cirrus only pilot I don’t think this should be an issue but I often times will fly 4 or 5 different aircraft types in a day.
Bank angle alone isn’t the culprit in these types of LOC accidents. The diagram in the article shows the relationship between bank angle and load factor, assuming a level turn (an assumption emphasized in the calculated from NTSB). But it’s load factor, not bank angle per se, that drives the increase in stall speed. Your article hints at this important fact when you say “We must resist the urge to overbank or *pull back* in a turn” (emphasis added). That really is the key point. Regardless of pitch attitude, bank angle, airspeed, power setting, or other factors, it’s the action of the pilot that induces the stall. The pilot increases the angle of attack *and load factor* by pulling on the yoke or stick. Now, steep banks at low altitude are to be avoided for several reasons (e.g., they lead to high sink rates, may startle the pilot into making abrupt, incorrect control inputs, etc.). But again, it’s not the bank angle alone that causes the problem we’re discussing here.
Just wanted to correct my good friend Brian on the Region of Reverse Command. It’s slower than glide speed. It’s actually the speed just slower than best endurance. And that is the blue donut in an AoA.
Any slower and the AoA turns red indicating you are now in the region of reverse command and will require exponentially more power to counteract drag.
If you want a fourth example, the incident down at Houston Hobby in a SR22 is pretty much identical to these incidents. The pilot lost SA in the midst of trying to land at a busy commercial airport and it stalled in the middle of a sharp bank.
The common factor in all 3 accidents is an unstable aircraft close to the ground. Below a certain altitude, be it 500 feet or 1000 feet in high density altitudes, or in IMC, on departure or on final, it is crucial to fly the aircraft in a stable manner no matter what. Bent metal can be fixed, not so people.
Civilian flight training, as contrasted to military flight training, does not include aerobatics. Learning to control the aircraft in true three dimensions would go a long way toward teaching aircraft energy management.
I’ve never flown a Cirrus, so maybe my opinions here are suspect, but I have an idea that overemphasis on avionics and underemphasis on stick and rudder skills during both training and every day flying played a part in each of these 3 accidents.
I use an AOA indicator, and I’m often proselytizing about them, but in these 3 accidents, I don’t think it would have made much difference.
Experience by itself, measured in hours or certificates, makes little difference, if the pilots (including instructors) lack good stick and rudder skills—and those include significant situational awareness.
Great analysis, and useful commentary from savvy, caring pilots and CFIs. Flying is too often counterintuitive. A great example is learning that the critical angle of attack at which a wing stalls never changes, but the lowest speed at which an airplane begins flying does change. Once the CAI is reached, the plane always stalls, regardless of speed … or attitude. A 60 degree bank can double the load factor, increasing the stalling speed by 40%. Even a difference of a few hundred pounds of weight can increase stalling speed by five Knots or more. Add in increased density altitude to the list of factors that all pilots should consider. Knowing why they affect angle of attack is not mandatory. Knowing how they affect AOI is necessary. Being comfortable in the left seat can promote increased efficiency and vigilance or overconfidence and complacency. As the saying goes, always stay ahead of the plane. We should constantly review our plane’s limits when flying into or from an unfamiliar airport, especially at higher elevations. I’m a woodworker. To get the best outcome I always measure twice and cut once. The same applies to flying, even on a beautiful, clear day.
I could fly a DC-9 and a MD-80 like a 20,000 hr. Captain in the simulators at our airline (the sim techs were my buddies), but I’m a low time sunny cloudless day Cessna 150/172 dangerous novice. My question: I have not seen any reference to the Cirrus recovery chute in this discussion. Is this because in these cases the aircraft is too close to the ground for it to deploy effectively? Does anyone know what minimum deployment height is on the Cirrus?
480 feet when in straight and level flight below max chute deployment. 980ft when in a spin.
Orville:
The chute needs room to deploy. On takeoff climbing in an upward trajectory, the minimum altitude to pull the chute is 500-600 feet depending on your vintage of Cirrus. When descending you realistically need to be at 1000 feet or higher to expect the chute to fully deploy and slow you down. In a one turn spin, certifications tests showed the plane would lose 900 feet. So if you are out of control you need more room between you and the ground than these cases had at hand to deploy. This also assumes you would deploy immediately. While figuring out what is going on you are losing many feet per second.
I believe that an aid is available. In the military aircraft I have been in, the verbal annunciation systems over-ride task saturation to a degree. When Bionic Betty starts telling you that “attitude” is bad or “airspeed” is deficient or “power” is insufficient, you instinctively remediate the problem areas. I believe that the advances in sensors (g loads, airspeed, bank angles, etc), power of processing (computing) and attention stimulation’s (aural, visual) are available that can be an invaluable resource for pilots. Technology does not solve deficiencies in training but with well trained personnel, the gentle warnings can save lives.
With low time in helicopters (licensed PPL), none in fixed wing and an armchair quarterback, I looked up stall speeds for Cessna 172 and Cirrus SR20. A difference of about 25 knots, higher for Cirrus. I imagined Cirrus as a step up in performance from a Cessna and generally regard piloting a Cirrus requiring a bit more experience along with expanding the flight envelope/experience level. It’s grim, reading about Cirrus issues and I couldn’t understand why some fall out of the sky until reading this story. While I do understand most LOC issues, my guess is Cirrus’ require higher speeds overall to stay above stall speeds. I can see why complacency occurs and gaining experience requires a positive approach whenever situations change. While a student in helis, I searched the NTSB databases to learn why high time and low time pilots make the same mistakes, possibly from complacency due to repetition and presuming a slight change won’t make a difference. Unfortunately, time in aircraft and hours don’t explain overlooking basic airmanship. It was many hours later just to learn how to use electric trim to overcome stick forces in non hydraulic cyclic control systems. My guess is similar trim is needed for fixed wing for take off speed, cruise, and landing as speed changes aerodynamic forces in wheel, stick or cyclic controls. I have a better understanding now how one can get into trouble in a Cirrus even though I haven’t flown fixed wing. It’s always good to read and learn from the mistakes of others to have some perspective on how each of us flies when in PIC mode.
Contrary to what a lot of people seem to think it’s not the bank angle that increases the stall speed, it’s the increase in G caused by trying to maintain height during the turn. If you descend as you turn there may be no increase in G at all and therefore no increase in stall speed. In the event of EFATO so long as you are sure you have sufficient height you should bank quite steeply as you descend back to the runway. Done correctly this won’t result in increased stall speed and will give you the best chance of making it safely back to the runway.
Allan, i’m Not sure you are wholly accurate. I think the bank angle does increase the stall speed however I think your action of increasing speed by descending in the turn merely stays ahead of the increase of bank angle. If your speed were not to increase, the increasing stall speed – as a result of g induced loading – would eventually cause the loss of control. I can’t immediately back up my thoughts with facts but I think i’m correct.
Hi Dave. The stalling AofA (approx 17°) doesn’t change with speed. So long as you don’t pull back while banking (to maintain height) you can avoid reaching that critical AofA irrespective of the speed you are doing. That’s why aerobatic pilots can do maneuvers like a “stall” turn (hammerhead) where the aircraft never actually stalls even though its airspeed may be almost zero. Noel Kruse explains it much better than me – http://www.flybetter.com.au
In these 3 accident reports and the responses, the AOA is a popular gadget, but what about the forgotten SWH? In every case I am left wondering if the Stall Warning Horn was screaming for help and went unnoticed. With today’s noise attenuating headsets, add a little music in the audio panel, radio chatter, conversations in the cabin, and any other distractions, is it possible the stall warning gave the pilot a heads up in plenty of time to correct the situation?
Let’s ask a basic question that almost nobody ever addresses. Why doesn’t a bird stall? Because the bird literally feels non-laminar flow of the relative wind eddies rubbing its feathers the wrong way!
That’s exactly what pilots need…indications of relative wind from the side and from too high an angle of attack, and it should be by a combination of training, sight, and feel. If you could literally feel the relative wind spilling across your “feathers” as the critical angle of attack becomes more critical, and if you could feel sideways movement through the air, you could appropriately compensate!
The biggest challenge for pilots is low altitude encounters with accidental spins because PERCEPTION is that the nose is LOWER than it really is.
Once upon a brave, overly bold time, (there are few old, consistently bold pilots) I actually tried to fail my engine after takeoff, not kill myself, and turn around and land in a Cessna 152. I was screaming at myself to put the nose down with the second, higher pitch of the stall warning horn already on as I made the turn. It seemed way too low, but was NOT.
Of course, the radius of turn, the altitude of the practice engine failure, and distance back to the runway were indeed impossible. That is why a lot of glider tugs turn a few degrees downwind from a straight out departure immediately after liftoff. The turn back to the runway will be into the wind and the radius of turn shortened. After about 700 feet of altitude gain at low density altitudes is minimum with a sidestep downwind.
The problem is that aerobatics have been eliminated from basic flying training. Persons who have learned to fly in simple designs like the typical C150/172 and PA 28 aircraft have never seriously encountered the concept of an increasing stall speed with higher “g” wing loading. Put this together with a higher than typical basic stall speed in a Cirrus means that they are not really aware of the increasing stall speed/manouvre problem . The majority of modern flying instructors who trained on Cessna and Pipers are ill equipped to pass on this information and may not realize that they are not really teaching their students to handle the type in an emergency situation. In essence there is nothing wrong with the aircraft but there is a failure in the training system to handle the type.
I guess as a retired USMC single seat pilot I need to stop reading about these accidents involving landing pattern stalls. A digital AOA indicator in the military replaces the airspeed indicator once the gear and flaps go down, no matter the conditions you fly the optimum AOA. I would concur a non- digital AOA indicator is not good enough, shows no trend, you can go from green to amber to red too quickly. I am now past flying but if I did I would insist on a digital indicator, anyway safe flying to all.
I think most high performance a/c like the Cirrus and some others should come equipped with AOA indicators I believe that would help.
Interestingly, my former Marine pilot CFI always drilled into me one of your thoughts: When in doubt, push to unload the wing.
For some reason no one teaches how to fly without the possibility of stall.
The only way an aircraft will pitch to the critical angle-of-attack is for the pilot to pull and hold the control aft. Pilots cause all stall.
Once more, lets look at the 2014 Mar/Apr FAA Safety-Bulletin page 13. There you will see how to control an aircraft while understanding what is going on psychologically when manually inputting a control.
There have been several Lear Jet crashes recently, both during VFR and base to final turns. KPWK and KTEB.
It can be difficult during high stress situations, such as a rough running engine on takeoff, caught in a downdraft, or low and close to your runway during a circle to land with a stiff x/wind and an overshoot to final, to “push” the nose down. Or go around if the pattern isn’t going to work.
The stall warning horn on the C-152 saved me twice, 30 years ago. Once on takeoff with a sudden rough running engine, the horn blared right away as I tried to “turn back” to the runway, and I pushed the nose down. I kept flying and was resolved to an off airport landing. The plane is still around. The other time was a practice go around with a student. 200 feet up we encountered a strong down draft and as I tried to prevent “not climbing,” the stall horn reminded me to lower the nose. Again, I forced myself to accept flying the plane, even though I believed we would end up on a roof. TV antennas were going by the window as the airspeed slowly began to increase, as we were still descending. Finally we began to climb and slowly gained altitude.
I bring up these stories not to brag, but to illustrate how difficult and counter intuitive it can be to push the nose down knowing that you WILL be sacrificing altitude to maintain airspeed. Those incidents stayed with me ever since.
In fact, recently a student told me he “kept hearing my voice to lower the nose, keep flying “ as his C-172 lost power shortly after takeoff.
He didn’t get hurt.
I don’t instruct anymore, so I’m not sure if these basic flying rules are being hammered into students today. Which is why I began with the LearJet crashes.
I’ve flown everything from gliders to MD-88s, not just most of the general aviation available fleet…
Airlines and operators of high performance aircraft have learned the hard way that training for emergencies IN AIRCAFT results in costly accidents. That’s why, aside from price, airlines and corporate operators do transition and recurrent training in simulators. If pilots get it wrong in a simulator they can always have a cup of coffee, a discussion about the maneuver and a do-over. As long as emergency training is done in aircraft,
aircraft will, from time to time, KEEP CRASHING.
Happy to see this discussion continue. I thought it would have died out by now. There have been a lot of excellent discussions and comments here and we all know that the issue of loss of control continues which I am sure is frustrating to all here.
In response to Arnie, the airline world uses simulators because they duplicate nearly precisely all of the realism and aspects of flying the actual aircraft. You can, therefore, practice all emergencies in the sim and have them be totally realistic. The same is not true of the GA piston world. Although simulators are becoming better at duplicating the real aircraft, they are still not quite the same and there are far too few of the “good ones” available nationwide. I happen to think “Fly This Sim” is one of the best products out there as the program can be configured to a wide variety of airplanes and the fidelity is pretty good. But the limitations of “computer” yokes and rudder pedals still makes these sims less than totally realistic. But we are slowly getting there and that is part of a solution to some training issues.
The bigger problem I believe is the way we, as CFIs, train students. We are good at teaching “go arounds” when a landing is going to require near acrobatics to salvage it. But we rarely teach that any unstabilized situation in any phase of flight requires the same response. Once your airplane is out of the proper stabilized parameters for any portion of a flight, that pilot has lost command of the airplane. Loss of command precedes loss of control. If you are 2 miles from the airport and still 2000 feet above the traffic pattern, you need the equivalent of a go around to make that work properly. Trying to salvage being outside the “normal envelope” is a bad idea unless you have tons of experience allowing that to work. But it is a bad example to teach a primary or relatively inexperienced pilot that model. It is just asking for trouble. Part of staying “ahead of the airplane” is flying all phases of flight in a stabilized manner. We are good at showing that on landings but not so in other phases of flight.
The idea that the presence of an AOA indicator alone will save these flights is a far too simplistic answer to the problem. Loss of control is all about a lot more than not knowing the AOA. It is more about allowing yourself to get “unstabilized” and outside the normal envelope of doing things. Every airplane phase of flight and maneuver has a specific pitch and power setting that will yield a predictable performance. The “pitch” part is AOA but there is still the “power” part to think about too. Many LOC accidents have the wrong power setting for the task attempted. Putting it all together involves knowing you have lost command and correcting early or starting over to deal with it.
Brian
Old saying; at the first sign of something wrong, unload the wing and then wind your watch
Push-Roll-Power-Stabilize: These three actions will work on most any airplane near entry into a stall and/or spin. Notice I did not say if actually in a spin. If the impending stall is due to a nose high attitude above the horizon and with a likely loss of airspeed, modify this to: Push-Power-Roll-Stabilize. But always use the POH instructions for your aircraft to fully recover from a spin (and it is not always Power-Aileron-Rudder-Elevator for some aircraft, especially high performance multi-engine t-tails). I had the privilege of recovering Extra 300s with some professionals, nose up, down sideways, and inverted. It’s something else to see the plane stall nose down and inverted, and the proper response is to push the stick away from the horizon and even temporarily lose airspeed, but it works. But sure enough, once in that spin, only P-A-R-E-R (with opposite rudder of recovery to negate going into a spin in the other direction) would get me out, not Push-Roll-Power-Stabilize.
In regard to Orville’s question about chute deployment. Recently, a pilot experienced engine trouble at about 600 ft agl and pulled his chute. It stalled the plane in the Chute did not deploy fully by the time it hit the ground the pilot. The pilot had a lot of field area to land around the airport.
You stated that the calculated stall speed of the Cirrus in the second accident was 75-78 knots at 1 G. Book value is published at 65 KIAS, so I wonder that the difference between KIAS and KCAS should be so much. I think you calculated 78 KCAS as the stall speed at 2 Gs, mislabeled it as 1 G, and then recalculated the 2 G stall speed again, getting the 4 G stall speed.
Also, the SR-20 POH (and same for the SR-22) states, “If, at the stall, the controls are misapplied and abused accelerated inputs are made to the elevator, rudder and/or ailerons, an abrupt wing drop may be felt and a spiral or spin may be entered. In some cases it may be difficult to determine if the aircraft has entered a spiral or the beginning of a spin.”
There’s more to CIrrus than just stall / spin. Lots more, and the digital flight data doesn’t necessarily tell the whole story.