High energy approaches: student edition

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Recently, a video of a Cessna 172 crash into a hangar after landing in Canada went viral. The student pilot got out of it with minor injuries, but the fact that he was just another one saved by Cessna’s generous engineers underscores a critical point in training that might have been overlooked. Once again, just as in any safety case, the saints are not important; the miracle is what really matters. It is a systemic issue across the industry, and it has to be mitigated, like any threat.

The difference, though, is that this threat is an essential characteristic of any airplane. Even autoland systems are limited to certain crosswind components because automation too has its boundaries. So human pilots must compensate for these limits—we can’t afford to not address this subject emphatically from the beginning.

That centerline is there for a reason.

We have talked before here in Air Facts about crosswind landings, so I will not bother getting into it deeply again. Everybody knows what to do, and in the Cessna 172—or any similar model–a sideslip must be accomplished before touchdown for several reasons. The main point on this Canada case, or in another solo flight that veered left of the runway last year and also went viral, is that both students likely failed in using the rudder pedals.

Just because tricycle gear airplanes are much simpler to land does not mean they are inherently centerline stable. So, even light wind components–and I say this from my own scary experience during a takeoff with my wife and mother onboard many years ago–can push the airplane onto the runway edges quite decisively. It is the pilot’s responsibility to keep it on the centerline, and this must be addressed from the first hour of training. It is not just the wind, but P-factor, torque, etc. So yes, a rudder (at least a right one) must always be applied.

Nevertheless, since no further investigation will probably reveal much more, we will take the videos to do a kind of debriefing on ourselves. The pilots involved learned it already the hard way, so let’s not waste their lesson and generosity. Yes, I am not that critical of cameras on solo flights, although I think it is wise to save them for after the private pilot checkride at least.

Both crashes started the same way: a high energy approach. We’ve been talking about this in the airlines for years and we train on them in the simulator quite often. Yet once again, it looks like general aviation is not being as cautious. The balked landing training we make every six months on a widebody Level D is exactly that: a deliberate (for training purpose, obviously), high energy approach that smashes the airplane into the ground in a way that tends to make it bounce. So the trainee must assume the controls once it happens and save the day–usually by getting power in and initiating a go around.

In general, the idea is to create resilience by the mechanics of the maneuver. Once you do it many times, you won’t have to think much if it happens to you in real life; you will recognize it quickly and react accordingly. This is the way we address time critical failures or maneuvers, since “thinking” is a luxury we won’t have in these situations once they develop.

What we can think of, though, is how to avoid them altogether. A high energy approach will not start during the few seconds of the flare, but possibly even in the top of descent, half an hour earlier. And even in a small single engine piston in the traffic pattern, the pilot will have more than a couple minutes to realize and fix its energy state before landing.

I won’t get too technical, but let’s think of typical approach speeds in a Cessna 172 and compare them with any airliner. I’ve said this before, maybe not here–although you’ve heard it from other authors here at Air Facts—but the way you land a light GA aircraft is fundamentally different from the way you land an airliner or jets in general. And the key is the amount of energy and how to bleed if off during the flare.

A bounced landing almost always starts from a high energy approach.

Just to start with, airliners have what we call Vref, which is a weight-based speed. Since they vary greatly with the weight–in the Dreamliner alone, we are talking about over 40 tons during normal operations–they must be calculated for every landing. Every 4,000 pounds or so will make a knot of difference in the landing speed, and on top of that, we put a five knot buffer, which is called Vapp.

So during final approach, in full landing configuration, you are going to be on Vapp and transition during the flare to ideally touchdown on Vref and power in idle. These five knots–and no more or less–should be bled during the final seconds of the flight, below 50 ft, by seeking the correct attitude. If that is not set, you might find yourself with too much energy and a bounce. If you bleed too much, you can easily have a tail strike, just to start the package of a bad day in the office.

But the fundamental difference from a GA aircraft approach speed is not the weight itself: generally speaking, a jet Vref is based on 1.3 times the stall speed. So, at the moment you touch down, you are 30% above the stall speed. And that excess third is the key for a smooth and safe ride. It is not too much, but not too little either.

When it comes to a Cessna 172 it is another world. You are approaching at 65-70 knots for a normal landing. Yet your stall speed is much lower, less than 50 knots even at maximum weight. So you have far more than the stall speed during approach. Do not get fooled: you are already in a high energy state and you are doing the right thing. The key is to keep it that way, on the target speed, until you start the flare.

Once again, the Skyhawk is very easy to fly, and that’s why over 40,000 have been built, making it the most popular civilian aircraft ever. Nevertheless, it is not autonomous—it needs an acting pilot in command to fly and land properly. Once you cross the threshold, start bringing the power back and the nose up accordingly. Remember, you may have half of your speed to bleed before you touch down. On top of that, you definitely don’t want to touch down flat, and in order to get the main gear on the ground first, you need to be slow enough.

A common fear students have is to stall during the flare, and to convince them they are very far from it during the approach, the slow flight dirty maneuver is a great tool. Once they get the concept, it’s a matter of practicing. Getting to the ground with the right amount of energy–which in the Skyhawk is touching down near the stall speed after approaching at nearly twice that–is the start of a nice and safe ground roll.

And of course, do not forget the rudder pedals. Ever.

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