High energy approaches: student edition

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.

Solo crash
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.

Turning final
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.

27 Comments

  • “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.”

    So your Skyhawk stalls at 32-35 kias? Really?

    The pilot in the video that I watched attempted to steer his aircraft – on the ground – with full applications of AILERON.
    AND he drove into a perfectly good hangar, while carrying almost full power.
    He apparently needs more than a lecture about the proper use of rudders.

    • I find it funny that there is a pilot in this world that doesn’t know the stall speed of a Cessna 172. They are only the most ubiquitous training aircraft in the world. Been awhile since you’ve actually looked at a poh?

  • Well, from the moment he left the runway, he became a passenger, and by instinct, people can do all sorts of weird stuff, so, nothing to learn from that moment on. The key is avoiding the situation altogether. And about your question, “my Skyhawk”, at 2300 pounds 40o of flaps, the Cessna 172N has a stall speed of 36kts. Close enough for the “nearly” used in the article?

    • If your aircraft stalls at 36 knots, why would you come over the fence at 65-to-70?
      Altitude above you, and runway behind you…

  • Remember that when calculating VREF you should first convert VS0 from IAS to CAS, then convert back the result to IAS.

    Otherwise, sometimes you would get some strange numbers! Indeed, Pitot-static errors are greatest at high AOA, and so the somewhat big difference between IAS and CAS.

    Regards

    • Hey Diego, thank you for sharing your thoughts. In the everyday calculation of Vrefs in the airplanes I’ve flown, we use the flight management computer or at least a table to do that math, so the CAS/IAS factor is already built in. But your observation is precisely seen on the Cessna manuals for sure, where both values are presented in different sections, with differences up to 12 knots between them. Cheers.

    • Correct. For a C172R the Calculated Vso speed is 47, increased by 30% is 61, converted to indicated airspeed is 60, very close to the recommended 62KIAS.

  • What an interesting observation you brought up, Enderson. I used to be one of those student pilots who feared stalling the airplane during flare. Light airplanes are a lot more succeptible to speed variations and that is a good reason to carry extra speed on final when compared to the heavier airplanes.
    And you, Enderson, know that better than most people, having flown both the 152 and the Boeing 787.
    Great writting, as usual. Thank you!

    • “Light airplanes are a lot more succeptible to speed variations and that is a good reason to carry extra speed on final when compared to the heavier airplanes.”

      Totally the opposite of the truth. Read about the physics of wind shear.

    • Dear Gonçalo, you are totally aligned with the truth. Inertia plays a great roll, and the reason why Cessna manuals tell us to approach as fast as 70knots (C172N POH, 4-3) has certainly something to do with that. Besides, as you know, the traffic flow in an airport forces us some speed window, therefore, the last thing we need is someone approaching at a third of our own speed in front of us. Yesterday, the airport I was landing into had a restriction of 165kt until 5 miles out, and in Europe is very common to see 160kts until 4 miles out. If you are flying into this environment, choosing your speed solely based on your beliefs, is not among the options. Cheers! As much as I like the Dreamliner as an office, If I was an airplane, I’d be the Cessna 152.

  • Thanks for a great article, Mr. Rafael! I got both my private and instrument rating in 172’s and somehow it never occurred to me there was anything strange about the difference between approach speed and stall speed, although I studied the literature enough to know that a 30% margin over stall was considered adequate for most airplanes, even up to the heavy iron. Therefore, every approach in a 172 is what you’re calling a “high energy approach”, a new term to me, and if you try to just fly it onto the runway you’ll get a bounce. My primary instructor taught me to go around immediately if I bounced more than a few inches so I never got into trouble in that way. Both in the 172 and 182, flaring a lot and bleeding off speed before allowing the bird to touch down is the key to a good landing. In the 182 the deck angle required on touchdown is so different from that on approach that it’s hard to flare enough (also, the nose-heavy trim of the big-engine aircraft means you might need both hands on the yoke). To avoid this problem I usually didn’t deploy the last 10 degrees of flaps. Late in the production run Cessna actually eliminated the 40 degree flap position, although for different reasons.

    • Thank you, Steven! True, for even the lower inertia involved in a lighter airplane, we need this extra margin of speed, and during flare, with a lower speed, spending this extra seconds (when compared to a jet) is of no harm. And you are so right: once you bounce, the airplane is telling you it wants to fly. Regards!

  • Hi Enderson, thanks for the article and the landing insights. I’ve never flown a jet but have done about 2500 hours of instruction in the last three years in a Cirrus SR22. I’ve noticed that many of my flight review students tend to land flat, on all three wheels – a great technique for a tail-dragger, not so good in a Cirrus. They have forgotten from their training that an airplane bounces on landing not from the springiness of the gear, but because at the moment the wheels touch the runway, the wings are still producing lift equal to the weight of the airplane, but now some of the weight is transferred to the runway. The excess lift causes the airplane to take off again, possibly even out of ground effect, exacerbated by the pilot pulling back on the stick, or the nose wheel striking first. If the pilot doesn’t immediately apply full throttle and go around, he could be setting up a disaster. I show all my students a great YouTube video called “Runway Safety @ CNO” (https://www.youtube.com/watch?v=cO2r5ko7XIo). The FAA put this out to develop airport awareness, but there was a short clip near the end (3:10) which accidentally captured a near crash. I teach my students to “kiss the runway.” On flare, try to hold the wheels about one foot off the runway until you hear the stall warning. That will guarantee a landing on the mains pretty near stall speed, preventing the plane from bouncing up and avoiding that irritating nose-wheel shimmy common in Cirruses that land too fast. As to being afraid to stall on flare, isn’t that what we’re supposed to do? FAA Airplane Flying Handbook: “The round out and touchdown are normally made with the engine idling and the airplane at minimum controllable airspeed so that the airplane touches down on the main gear at approximately stalling speed.”

    • What a great video! Many airport designs are a threat themselves. And yes, that porpoise lasted forever! I’m glad the pilot eventually executed a go around. And about you last comment, afraid of stalling before they are low enough, I meant, like over the threshold, for example, or short of the runway. Thank you for sharing your thoughts and the nice video!

  • I’ve shared this excellent training video with my 200 customers and first off, there is so much to learn from this accident. I was told it was a supervised solo ( if true) the accident will be charged to his instructor. Point one; CFI’s never solo anyone unless you are sure you can turn your back and walk away. The student has to have the skills of a PIC even on his first solo, why? Because that is exactly what he is! The CFI here may have some sole searching to do. If you break this down, there is learning from before landing and right up to the point of impact! Never think or teach you are ever a passenger. If you are PIC then you are PIC until the plane comes to a stop.

    • Sure, Jerry. It is a big responsibility from both parties to recognize the student is ready. Nevertheless, we will always be learning in this business, and to assume he or she is ready for anything at all is a bit optimistic – or we wouldn’t see extremely experienced pilots killing themselves late on their career. I totally agree with you on the PIC thing, but human factors come into play, and depending on how lost you get, you may react unconsciously, like we saw clearly on the “steering wheel” move. That’s why my approach to the subject was to avoid the risk of losing the control during landing as much as possible from the energy management perspective. Cheers and thank you for the insights!

  • My older brother with 18000 flight hours was my CFI as I got my private ticket. Primary aircraft was a Cherokee 140. He had me checking out a C172 when I made a near perfect first landing. The 172 just felt solid as we descended to the runway and flaired, lightly chirping the tires. My brother said I bet you can’t do that again as we powered up for another go around. Second landing was a near duplicate. Luck both times! Another pass around the pattern he pulled power at 3/4 downwind and said, now put it on the runway. Wasn’t pretty as I plopped the 172 on, but it was acceptable. He always preached manage the speed and make the plane do what you want it to do! We nearly always did full power off approaches from downwind to touchdown, only carrying extra speed and proper flap setting by planning accordingly, when confronted with adverse winds. Feel the plane he’d say! Only once early on did I hit nose wheel first while flying the Cherokee, and that was followed by a raised voice of “what the hell was that!” I had carried a bit of extra speed, flared, and ballooned. Instead of using some power and patiently waiting for the plane to lightly descend I had moved the control slightly forward to arrest the rise. The Cherokee promptly lost lift and you know the result. What I learned from these events was to always manage and fly the aircraft, continue to take control, yet not over control. My brother provided me a great gift of his oversight and experience to provide me with a cherished pastime. Leukemia took him back in 2014, and I miss him terribly.

    • Dear Mike, I’m sorry for your loss. It looks like you are taking his lessons forward, and that’s the best way of keeping his memory alive. I’m sure he would be proud. I also felt the difference when I first landed the Cherokee after flying the Cessna for a couple hundred hours. This naturally “pitch up” attitude of the many GA singles make it easy to misjudge the correct pull during flare. Practice is the key. Regards! Thank you for sharing!

  • Hmm, I didn’t really see anything in this article of any help. Well, I did see several incorrect things.
    – Carry extra speed for safety? This is the main cause for many accidents. It’s the first step toward a porpoise.
    – 65-70??? 60-65 is the actual book numbers and much safer.
    – Always go-around. Sounds good. But, a skillful pilot will simply do piloty stuff and fix the landing.
    – About half of the instructors I’ve came across teach incorrect things. The students have no way of knowing this. Just like any jet, you fly a C172 the same. Vref 60 + 5 until the last 100ft.

    I train at the windiest airport in the country, at 5000msl. I always use Rod Machado’s teaching method of the low pass at 5-7ft similar to slow flight. The fastest way for a student to gain SKILLS. I then name the 1200ft stripe and have them touch down on it.

    The cause of CFI’s teaching wrong is their own instructors, back at PPL. It’s called “Primacy”. It’s also rampant at “Pilot Mills”. The 20yr old teaches the 18yr old who then becomes a 20yr old CFI. None are actually experienced pilots and most don’t actually analyzed the teaching. Some of the worst CFI’s I’ve come across come from ATP and the ilk. But, I’ve also seen plenty of 60-80yr olds teaching weird stuff.

    So sorry for the diatribe. I’m way critical of CFI’s. If a pilot does something goofy, I figure it was usually their CFI.

    • Hi, Matt, I’m glad you are so beyond this article. I agree with you that many mistakes we make are result of being thought incorrectly. Although the article used the Skyhawk as an example, it was not meant to be type specific. The extra speed was on approach, not on touchdown. The 60-65 is for no engine landings, flaps up is 60-70 for normal operation (55-65, flaps 40). Fix the landing… well, not sure if an unstable approach should be “fixed” during touchdown. A bit late for that. Don’t be sorry, we are all here to learn, right? I liked the word “diatribe”, never heard it before. Thank you! I sure learned something!

  • Extra airspeed is the wrong answer and is the cause of the vast majority of runway departures (off the side and past the end).

    ALL airplanes should be at 1.3Vs.

    There is a difference between Vapp and Vref. Vapp is 1.3Vs1 in the approach configuration (typically less than full flaps). Vref is 1.3Vso (full landing flaps). Flying faster than this results in longer landing distances. So does bleeding off airspeed over the runway … although if the runway is very long, it saves wear and tear on the airplane.

    The pilot should read the AFM/POH. Newer ones will tell the reader how the performance numbers were flown. If not, read the regulations; they will tell one how the airplane has to be flow to meet the book values. All pilot should be able to meet or exceed book performance. That’s how they are written.

  • Couple of thoughts: 1.3 Vs provides a margin above stall, but it also places the aircraft very close to the bottom of the power curve. This is important to ensure speed stability and to stay on the front side of the curve. Once you get into the margin you are on the back side of the curve and your corrections become much more problematic.

    Also, bear in mind the huge differences in power-off drag between a jet and a propeller airplane. I can fly the 737 several thousand feet down the runway at idle power with too early a flare. It simply does not slow down…unless we use flaps 40. A propeller driven airplane creates quite a lot of drag at idle power, and can thus kill the speed more efficiently. Indeed, in a turboprop with incorrectly rigged flight idle blade angles, the effect of idling the power in the flare can be rather like popping a drag chute.

    Speaking of which, someone mentioned Cessna’s change years ago from flaps 40 to flaps 30. This, too could be significant. As with the 737, the final 10 degrees of flaps in a 172 is total drag and a lot of it. If limited to flaps 30, one’s ability to get rid of excess airspeed may not be quite as useful as it was using flaps 40. Ergo, better speed control is essential.

    • Perfect points, Steve! Not just the inertia, but the drag makes the whole difference in the way these two kinds of airplane manage speed during the final portion of the flight. Thank you for your insights!

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