Power Failure Modern Aircraft Engines Almost Never Quit Almost Plane & Pilot Journal Budd Davisson The engine just quit where are we going to put it? The flattest spot may be the beach on the bend of the river. The shelf on the other side has possibilities, as does the flat spot low and to our right. Losing an engine on a single-engine airplane is one of the scariest possibilities in aviation. And for good reason. Next to scuba diving and skydiving, flying is just about the only voluntary endeavor where all the marbles depend on a mechanical apparatus to keep us alive. The good thing about a power failure, however, is that it doesn't necessarily mean immediate catastrophe. The outcome depends on a lot of factors. Number one among the factors that affect the severity of an engine failure is where and when that sudden silence happens. Number two is what we do in the seconds after the engine has decided to take a siesta. We only have minimal control over number one where and when it happens but we have unlimited control over what we do after it happens. The Factors: When, Where And Why "When" refers to the regime of flight we're in when the engine packs up. There's no good time to have an engine failure, but some times are better than others. The worst is on takeoff, the best, if there's such a thing, is on a cross-country flight (preferably 10,000 feet over Nebraska). The procedures for each are different. "Where" is our geographical location. The only control we have over the "where" is in the form of preparation and preventive measures. Other than monitoring and managing our systems correctly (fuel, etc.), we can't prevent an engine failure from happening. We can, however, do what we can to keep asking, "What if?" every few minutes. This is to orchestrate
our flight so, if "it" were to happen, we'd at least be in a better position to control the outcome. We limit exposure to those areas, where, if an engine were to quit, we'd be totally screwed. If, for instance, given a choice, don't fly directly over hostile terrain (deserts, mountains, swamps, etc.) that doesn't at least have some highways and/or occasional flat spots. If we make little deviations to stay within gliding distance of a road, it doesn't add much time at all to the trip. Also, if the unthinkable happens and we have to put it down off airport, being able to reach a road not only gives us a possible place to put the airplane, but having spectators means at least someone knows we're out there and may even come to help. If making an emergency landing, always try to have an audience. Stoppage Causes A lot of the time, the sudden silence is our own fault. We've run a tank dry or we're heavily leaned at altitude and bring it down to where we're simply starving the engine, and it has started to object. The first move in any stoppage, regardless of where or when it happens, is the same thing we were taught in the first few hours of flight training: nose down, establish a glide, mixture rich, boost on, switch tanks. That often brings the volume back online and only takes about three seconds. The vast majority of engine failures aren't abrupt, total stoppages, although those do happen. Usually, the engine will roughen up, start missing and generally give at least a little warning, but not always. This is why an occasional check of the oil pressure and temperature gauges should be part of our normal cockpit scan. Just as our own body's temperature and blood pressure are the first indications that it isn't happy, the same thing is true of an engine. Quite often, if we catch those needles just as they start in the wrong direction, we'll be so far ahead of serious problems that the result will be nothing more than a precautionary landing at a nearby airport. If zero oil pressure is the problem and we're at altitude in cruise condition, rising temperatures won't be far behind. But, the good news is that an engine will run for a period of time with little or no oil pressure, so we have a few minutes to deal with the situation. If it happens anywhere in the traffic pattern, there's almost always enough time to nurse it back to the runway. The problem, when this happens on a cross-country, is that in that condition, we have no idea how long the engine will run or what will happen (some will simply seize, some have caught fire, etc.). So when the oil pressure zeroes, the smart money finds a place to land as soon as possible, preferably on a runway. If the pressure is zero and temps are redlined, and a runway is some distance away, things are about to get very serious, very quickly. However, if the engine is still developing power, even a neophyte can land on a reasonably flat stretch of road or field. Given a choice between flying a few miles farther to reach a runway, which may increase the probability of a total engine failure, or making a controlled, off-airport landing, always take the controlled situation over the uncontrolled one. A controlled landing, with power, gives the pilot a multitude more
choices of landing places and makes the entire process much easier and safer. Plus, even if the landing destroys the airplane, a controlled landing in a reasonably unobstructed area is almost always survivable, and we're worried about the occupants, not the airplane. The Three Most Important Assets After An Engine Quits There are three factors that make emergency landings much more likely to have a happy outcome. The first and most important is a clear and functioning mind. The second is having a plan and a place to land already picked out, and the third is altitude. The first and second are imperative and totally under our control. The third, altitude, is a matter of happenstance on takeoff, but a self-governed factor, when on a cross-country. Clear And Functioning Mind. Don't let anyone kid you: The first time an engine quits, our brain automatically goes into denial mode for a few seconds. That didn't just happen, did it? If we haven't practiced engine failure procedures and maneuvers, our brain will momentarily be overwhelmed with adrenaline. And, if the event happens on takeoff, we don't have those seconds to spare. So, we need to prepare our brain through occasional practice and continual awareness of the possibility of an engine quitting at the worst possible time. A Pre-Existing Plan Is Literally a Lifesaver. Part of the aforementioned prac-tice includes developing a habit of knowing exactly where we're going to put the airplane should the engine quit at any given moment. This is critical because when an engine quits, much of our brain is going to simply cease to exist. It will be so overwhelmed we can't count on it to find the optimum landing spot while dealing with its own internal problems, getting the engine going again and calming screaming passengers. Our brain already has to have the engine failure procedures worked out and a field/street/whatever picked out on which to land, and this should be part of a never-ending thought pattern. Altitude: Another Lifesaver. On takeoff, should the engine quit, we have no choice but to work with the altitude we have at that moment. However, when in cruising mode, a few thousand extra feet means several more minutes and a much wider area in which to find the right place to put it down. A 172, for instance, has a glide ratio of approximately 9:1, so every thousand feet of altitude is 9,000 feet (1.7 miles with no wind) of horizontal distance it can cover. So, while it's fun to be buzzing along at 1,000 feet AGL enjoying the sights, the options of where to put it down in an emergency are severely limited: less than two miles as opposed to three times that at 3,000 feet. Altitude is a safety device.
Some good options here: looks like a green meadow low at our one o'clock and a narrow one at three o'clock. When we do backcountry flying, we do so knowing our engine-out options will be limited. Total Failure At Altitude: Plan The Landing, Don't Let It Just Happen While on the way to Grandma's house, rather than just staring out the windows and watching the GPS count down the distance, we should be playing a game that, after a short time, becomes an unconscious habit. The name of the game is, "What If," and the goal is to always have a field/road or airport picked out on our path that will become our focus if, at that particular moment, we find we're flying a glider. Our eyes casually examine the landscape ahead and around us without much effort, locating those places that are emergency-friendly so, in effect, we fly from one landing spot to the other, except we don't change our flight path. We're just picking out places, so that's one less decision we have to make with our adrenalineaddled brain. As soon as we're hit with the reality that we're actually going to have to land, we have two immediate tasks that have to happen simultaneously: The mechanics of the airplane have to be attended to while, at the same time, we're setting up an approach to our predetermined landing spot (already having that spot in mind saves valuable time). The mechanics of getting the engine going again are pretty basic, as we pointed out earlier, and they either work or they don't. There aren't a lot of nuances involved. Assuming some sort of internal catastrophic mechanical failure hasn't happened (broken crankshaft, etc.), the reasons it's not running are pretty limited. Either it's not getting gas (tank is dry, valve is in wrong position, too lean), it's not getting air (icing, get the carb heat on) or no spark is flowing to the plugs (mags don't usually both quit, but it's worth changing the position of the mag
switch, left to right and back, just to be sure). If there's sufficient altitude to justify the time, go ahead and crank the engine. It's worth the effort, but only if you have lots of altitude to burn off first. At all times, the first rule is to fly the airplane, so if you don't have lots of altitude, concentrate on flying the airplane. One piece of knowledge we should have on every airplane we fly is how much altitude it loses in a 90-degree gliding turn. We find this out by just setting up glides and measuring the altitude lost in turns. That's important because when we're looking down at a field or road we hope to land on, and we have a bunch of altitude to lose, we can arrange our descending approach to it in a very logical manner. Just figure out how many 90-degree turns we need to make to burn off excess altitude and put ourselves on downwind to the field opposite the point we want to touch down. At first, once we have the field/road in mind, we don't want to think about the touchdown point on the ground, we want to think about where we have to be to place us in a normal position on downwind: Even though it's an emergency, we want to make the approach as "normal" as possible, because that's how our visual references and muscle memory are set up. This assumes, of course, we make periodic power-off landings part of our normal approach procedures. Not all of our landings need be power off, but do enough that we know exactly where the airplane is going, if it has no power. As we make the approach, we visualize our touchdown point, which is just a little ways down the field, and come in a little high so we know for a fact that we're going to make it. We then fine-tune the glide slope with a slip. If we aim for the edge of the field and we're wrong, we'll be short. It would be tragic to find a good field and then crash 20 feet short. Avoid dropping flaps until we're sure we have it made and delay putting the gear out as long as practical: better to land gear up in a good field, than gear down short of the pretend runway. Don't add drag until we know we can afford it. Failure On Takeoff: It's All About The Energy Available An airplane in flight has two very distinct types of energy: potential energy that's a func-tion of its height, and kinetic energy that's the result of its speed. So, simply put, the higher and faster an airplane is, the larger its energy footprint (the farther its energy will carry it from its current location). This gives the pilot more options in terms of making turns after an engine quits. Immediately after the airplane leaves the ground and it has very little altitude, its energy is minimal and entirely dependent on the speed. So, its energy will only carry it to points on the ground that are pretty much straight ahead. However, as it gets higher, its potential energy continues to build and will, at first, let it reach points left or right a few degrees, but the angle and distance available increases as the speed and altitude increase. Eventually, it will get high enough and fast enough that it has enough energy (height and speed) to turn completely around. However, one of the reasons instructors beat it into students' heads to land pretty much straight ahead in a takeoff emergency is because most aircraft don't reach an altitude
that will let them make a 180-degree turn until they're too far off the end of the runway to safely make it back to the runway. A few hot-rod aerobatic specials can do it, but almost no others can. "Normal" airplanes can, however, reach an altitude on upwind fairly quickly that will let their pilots turn left or right to find good fields or roads. How far left or right is dependent on the altitude. This is another area where every pilot should know how much altitude their airplane loses in a gliding turn. Without that seemingly innocuous piece of information, a pilot making a 90-degree turn without power is simply guessing and may be painting himself into a corner. It All Boils Down To Practice And Planning We should all know every viable landing spot within a few miles of our home airport because that's where we spend much of our time so our exposure is greatest. Once they're known and we know how much altitude it takes to reach each of them, we have the semblance of a plan in place. Then, although we can't make practice approaches to someone's backyard, we can pick out a point on the runway and make a game out of trying to touch down on it while cutting the power on downwind. The more practice approaches we do, the better we'll be prepared to handle the awful silence that envelopes us, when the engine quits, whether we're at our home airport or not. With a little practice, we'll be able to think better and can put our emergency plans into action. He who doesn't practice engine outs is on a test flight into the unknown when it actually happens. Don't be that person.