Forced Landings By Robert T. Smith, EAA 1685 194 South Cobb Dr., Mariett- , "•>. Key. So you must plan your approach to arrive at the High Key, flying in the same direction you will be on your final approach. When you arrive at High Key, you should have a specific minimum altitude. Thus, you must are your instructor's well-drilled forced landing procedplan your approach to the field to be at High Key point, ures are still fresh in your mind. But suppose you haven't and at High Key altitude. For a lightplane trainer, this had a dual ride in five years? How current are you on altitude is about 1,200 feet, as shown in our example. forced landing procedures? Remember, this is TERRAIN CLEARANCE ALTITUDE, If you're like me, it's been several years since you and NOT altitude above sea level. Be sure to check your had someone pull the throttle, and call "forced landing!" map for the terrain elevation BEFORE you arrive at High The other day I got to wondering what I would do. ModKey. I would suggest noting terrain elevations along ern engines aren't likely to quit running suddenly, but your flight path prior to take-off rather than waiting what about carburetor ice, empty fuel tanks? It CAN hapuntil the engine quits! pen—it DOES happen! From High Key we start a turn, right or left, with a Some months ago, I was instructing Air Force prishallow bank. What we want to do is turn 180 degrees mary students, and we used what I think is a fine idea to the Low Key position which is just opposite our infor forced landings. It was called simply the "Forced tended touchdown point, and at an altitude of about 900 Landing Pattern," and essentially it is a power-off 360 feet for thz typical trainer. You should be about as far degree, overhead approach. However, it has some variafrom the touchdown point as you'd be from the runway tions to enhance its usefulness over just a simple, poweron a normal traffic pattern downwind leg. You must vary off, 360 approach. But, before we go into this standard your bank to arrive over Low Key at the proper position Forced Landing Pattern, let us remember that engine failand altitude. From Low Key on, it's just a 180 degree ures can happen from altitudes of one foot to several side approach. thousand feet. Naturally, with minimum altitude, the Wind will naturally play an important part in this pilot has less choice of what to do, and when the engine pattern. If the wind is strong, your bank will be steeper quits on take-off, there simply is NOTHING to do but when turning into the wind. If you have a cross wind, land straight ahead, maneuvering just enough to avoid you'll know this because it will tend to blow you away obstacles. from, or toward the proper Low Key position. However, Let us discuss the Forced Landing Pattern for a typirather than trying to worry about what direction and cal two-seat light trainer, and then we'll discuss how you velocity the wind is, simply vary your bank as necessary can modify this pattern for the airplane you fly. to keep your pattern where it should be. You should The Forced Landing Pattern is a 360 degree, overrealize that a strong wind blowing straight "down the head approach as shown in Fig. 1. The idea is to maneuver runway" will tend to whisk you downwind at a great rate the airplane over the field, and directly above the touchwhile you're going from High to Low Key, but will be down spot on a heading into the wind. At a point where strongly against you from there in to the touchdown. the airplane is directly above, or slightly off to one side This will mean a shallow bank from High to Low Key, of the intended touchdown spot, the airplane is at High and a steeper bank from Low to Base Key, our next "check point" in this HIGH KEY Forced Landing Pattern. FLIGHT PATH Base Key is 90 degrees of turn away from Low Key with 90 degrees of turn left to line up on final approach. The Base Key altitude of 600 feet will hold good for most light ships, but should be higher for heavier, or faster ones. YOU MAY BE SLIGHTLY RIGHT OR LEFT OF From Base Key on we'll make TOUCHDOWN AT HIGH KEY minor, slight variations in our angle of bank in order to vary our ground track so that we will make the field START OF FINAL APPROACH without overshooting, or undershootWINGS LEVEL ing. If you're a LITTLE BIT HIGH, you can slip, if you're a LITTLE BIT LOW . . . well, you're a LITTLE BIT SHORT! This brings up the point, \ , which is always well taken, that your "intended" touchdown p o i n t should be about midway down the GROUND TRACK field. Then, a slight undershoot will still let you land ON the field, which is the desired final result.

AVE YOU ever wondered what you would do if the H engine suddenly quit? If you've just learned to fly, or just recently obtained your private ticket, chances

1

Fig. 1

Standard Forced Landing Pattern

(Continued on next page) SPORT AVIATION

13

FORCED LANDINGS . . . (Continued from preceding page)

You should be lined up, wings level, on the final approach at a MINIMUM—AN ABSOLUTE MINIMUM—altitude of 300 feet. If you've got a heavy or fast ship, you might make this 400 feet, or higher, but we used 300 feet in the jet-powered T-37, and it works out fine and dandy. Let's assume you have a ship whose altitude should be those given in our example Forced Landing Pattern. What happens if we pick a field right under us, and we have 6,000 feet? Nothing. Simply determine the wind direction, and start doing 360 degree turns over the field noting the altitude loss per turn. If you start at 6,000, and find yourself losing 1,000 feet per turn, you know that you'll arrive over High Key at 1,000 feet instead of the 1,200 you want. Therefore, during the descent from 6,000, you should adjust your 360 turn? to give you around 800 feet per minute for one turn, or make a wide 360 in which you lose 1,800 feet. Then, you'll find yourself at an altitude that will allow you to lose 1,000 feet per turn, and arrive at 1,200 feet at High Key. If you start at 5,000 feet (knowing you lose 1,000 feet per turn), and make one 360 real tight, you should arrive back over the field at 4,200, then you can go back to losing 1,000 feet per turn, and eventually you'll be at 1,200. Or, you could make a real wide turn, and lose 1,800 feet, arriving back over the field at 3,200 feet. Either way, you put yourself at an altitude that will enable you to lose the amount you will lose in a steady 360 turn so that you'll arrive over High Key with 1,200 feet. The important thing is to get this ironed out as early as possible. It might even be a good idea to take your ship up, and set up a normal power-off (engine at idle) glide, then establish a 20 degree banked turn, and note the altitude loss per 360 turn. Then, should a real forced landing come along, you'll know in advance how much altitude you lose in a 360 turn with 20 degrees of bank. You would also know that turning steeper would mean less altitude loss in a 360 while a shallower bank would mean more altitude loss in one 360 turn. Knowing this in advance would make your forced landing planning easier. What happens if you arrive at High Key with 200 feet of extra altitude? Obviously you can't make a 360 to lose that 200 feet, and just as obviously, if you follow the pattern to the letter you will be 200 feet high when you should be touching down. So, with 200 feet of extra

FLIGHT PATH

altitude at High Key, you merely fly a slightly wider pattern than that shown in the example. Or you swing a little wide from High to Low Key, and lose the 200 feet there. In a practical sense it is a good idea to know altitude LIMITS at the various Key positions, as it is difficult to hit the correct altitude right on the money. For a light airplane a figure of plus or minus 100 feet would be okay. If you are high, make a slightly wider pattern; if low, make a slightly tighter pattern, but in NO case should the "wings level" final approach altitude be compromised. This altitude is established for reasons of safety, and to give you a stabilized final approach which will better assure a safe touchdown. Your survival chances are greatly increased if you can make a normal final approach at normal speed, and make a normal touchdown. This will work even in extremely rough terrain, as the record clearly shows. Trying to make turns under SCO feet is cutting your survival chances to the bone. This entire Forced Landing Pattern is based on maintaining a normal glide throughout the pattern. Excellent comment on this subject is found in CAA Technical Manual 106 (The Pilot Instruction Manual). The pattern will work only as well as the normal glide is maintained. If you practice maintaining a certain glide air speed, you must remember to use that same air speed in an actual emergency. Allowing the air speed to vary introduces an error of unknown, and unpredictable magnitude, and completely ruins any other attempts to make the field. Aircraft control, and air speed control are the two prime factors if you are to have a successful forced landing. The final approach should be at your normal final approach speed, and if it is different from the speed you maintain prior to final, you should practice your Forced Landing Pattern using this speed, and changing it at the same point each time. We used 125 knots in the Forced Landing Pattern with the T-37, and changed it to 110 knots on the final. You might do the same thing in your ship. Consult your flight manual, and follow its suggestions. You can make very slight turns on the final to avoid obstacles, but keep the bank shallow, and maintain your speed. If you're landing on a field with trees, aim between two of them. You'll lose the wings, but that's better than losing your head! It will also slow you down, and better your chances for survival. Make the flare and touchdown normal. On soft ground hold it off as long as possible so your touchdown speed will be the slowest possible speed. NEVER try to "put it on" before the ship is ready HIGH KEY to land itself. Hold the wheel or stick well back as you touch, and bring it smoothly all the way back as you contact the ground. Don't let it go further forward until you are 1200 FT stopped. This will prevent your nose from digging in. Have your seat belt fastened firmly, and remember that a shoulder harness will greatly increase your chances of coming through with no injuries, or minor injuries. About the best support I can give to the shoul-

I

der harness is that it's found in ALL

military ships. Young Air Force pilots think "safety-belt-and-shouldorharness" is one word! They keep both

START N

300 FT — WINGS LEVEL!

14

SEPTEMBER 1963

GROUND TRACK

fastened all the time.

(Continued Next Month)

PART TWO

Forced Landings By Robert T. Smith, EAA 1685 194 South Cobb Dr., Marietta, Ga.

HE EXAMPLE Forced Landing Pattern shows altitudes

for a typical 65 hp trainer. Heavier and faster ships T will have higher, wider patterns. You can determine the

altitudes for your ship the same way I did for the 65 hp trainer. Go to an airport with little or no traffic, and fly straight and level down the landing runway at an altitude you judge to be correct for your ship for High Key. As you approach the runway close the throttle, and allow the ship to coast to glide speed so that you arrive at High Key position with the proper glide speed, and directly over touchdown. Have carburetor heat on at least a full minute before closing the throttle, and periodically clear the engine during the approach. Watch for other traffic, and get advance permission from the tower if you're at a controlled airport. Try to fly the pattern at a constant amount of bank. I can tell you right now you won't be using more than about 20 degrees of bank if you make your track over the ground correct. As you fly the pattern note your altitude at Low Key, Base Key, and as you turn, final, if you're approaching 300 feet, put the juice back on and go around. Next time try a higher High Key altitude. The important thing, once you learn the proper High Key altitude, is to do it the same way every time. Then, should you be faced with an actual emergency, you will fly the pattern automatically. I would suggest that you write your Key altitudes on a card, and put this on your instrument panel. Then every time you fly, you'll be reminded of these altitudes, and before long they will become habit. Now that you have the Forced Landing Pattern down pat, and can fly it blindfolded, what happens if you have less altitude than High Key altitude? Does this make this pattern worthless? Not hardly—NOW is when knowing the basic pattern is most valuable. If you are faced with a dead engine at an altitude lower than your High Key altitude, you must try to make the next lower Key position, which, in this case, is Low Key. If you are at High Key altitude when the engine quits, you know you can make the field under you, or one to either side, or directly ahead. Fig. 2 shows how you would make a field directly off to one side. Just make sure you will be the proper distance from the field at Low Key position. Wind and terrain will enter into your decision, and your choice of a field. But, keep in mind, when you are at an altitude less than High Key altitude, you must make the next lowest Key position—both as to altitude and distance from the field. Then pick a field that is within range. If you have been practicing your Forced Landing Pattern you will have an excellent idea of how far away a field can be, and still be within gliding range. If you haven't been practicing the Forced Landing Pattern, you can only hazard a rough guess. If you are at Low Key altitude when the engine quits, you can make Base Key on an adjacent field. If the field you choose is directly ahead of you, and you have Low Key altitude, chances are you don't have sufficient altitude to mess around with making a Base Key

as such. Glide straight ahead until you are approaching

the point where you should be on final, wings level, at 300 feet. When you realize this point is coming up, start a series of "S" turns to lose any extra altitude so that you will be at the correct altitude and distance from the field for interception of your normal final approach. You will know when you are close to this point if you have been practicing the Forced Landing Pattern. If you haven't practiced, the best you can do is a rough guess. If you have Base Key altitude when the engine goes silent, you can make one 90 degree turn, and NO MORE! So any field to your side is within easy range, and straight ahead can be made "no sweat." If you have 300 feet when the mill goes on strike, STRAIGHT AHEAD ONLY! The important thing, regardless of your altitude, is to know your next lowest Key altitude, and MAKE IT GOOD. Keep the glide normal, and make a normal flare and touchdown. Engine failure at a very low altitude will demand your utmost in piloting skill and judgment. If you have practiced a Forced Landing Pattern until you're proficient in it, the real thing will be a piece of cake. And practice it to the right and left. On the real thing you may have to turn either way, so be proficient either way. What about retractable gear? Leave it down? This is a very touchy subject. If you have engine failure within gliding range of an established airport you might be able to make a successful, gear down landing. I would take this stand on the matter — if you have a ship with retractable gear, I'd practice Forced Landing Patterns both gear up and gear down. Drag is higher with the garbage out, so you will need higher Key altitudes. If you do this, be sure to post gear up and gear down Key altitudes on your instrument panel. When you would maki a gear down forced landing is largely a matter of your own choice and judgment, but so that I don't mislead you, let me state that trying it gear down on a field that is ANYTHING other than an established airport might easily prove fatal. Play it safe and leave it up. If you do have engine failure and an airport is handy, glide with the gear up to your High Key position, and when you arrive there, if you have enough altitude to make it gear down, put the gear down, and fly your gear down Key altitudes. Keep in mind that you may be faced with having to lower the gear with the emergency system if the engine is dead. Save your battery juice for radio calls if you have electric gear, and if you can get a positive gear down indication with the emergency system. If you have hydraulic gear, use the hand pump. If the gear is electrically controlled, and uses an electric hydraulic pump motor, pull the pump motor circuit breaker, and lower the gear with the hand pump, then reset the circuit breaker — if it controls the green "gear down" lights. Allow sufficient time before High Key to get the gear down, and save some juice for the flaps if you have them. They should be used on final, at the start of final, (Continued on bottom of next page) SPORT AVIATION

49

The Bryan "Special" F

OR SEVERAL years, the Bryan II readable airplane was the most popular aircraft at our annual Fly-Ins. Inquiries have been made about the present status of this airplane, and Leland D. Bryan (EAA 1220), 597 S. Kinner Rd., Highland R. 2, Mich., informs us that it has just been set aside, with the first Bryan "Special," for the Bryan HI presently under construction. The Bryan III will be a delta wing configuration with a pusher propeller, and Leland expects to begin the construction very shortly. It will also be readable, but will feature a separate tail group. In case anybody should wonder what the first Bryan looked like, it too was a readable aircraft, registered as N-5787N, and featured the same type of basic fuselage pod. Since it also used a pusher mounted engine, twin booms extended the fuselage to the tail. However, contrary to the Bryan II, the booms were above the engine, with a single boom running from the tail to the bottom of the fuselage pod, forming an inverted triangular cross-

FORCED LANDINGS . . . (Continued from preceding page)

or slightly later if you need them to correct for errors in judgment. But don't try to mess with the flaps, or anything else during the final stages of the approach — concentrate on controlling the aircraft, and making a good approach, flare, and touchdown. This may make the difference between a successful and an unsuccessful forced landing! On the subject of using the gear for a forced landing, be guided by the rule that it's "gear up" except at an established airport WITH plenty of altitude to make your gear down Key altitudes. If you haven't practiced with the gear down, FORGET IT — make it gear up. The big advantage the Forced Landing Pattern has is that it is something you can practice right to actual touchdown — thus proving the worth of the maneuver. Remember, first you must determine your Key altitudes, then you must practice. Once you get the pattern down pat, keep proficient by doing one or two per month. If you're a little dubious about what you can do by yourself, explain the thing to an instructor, and ask him to go along for your first couple of practice patterns. It isn't a bad idea to have an instructor along anyway as he can see errors you're making that you might never discover. And, remember, in this maneuver you CAN'T be sloppy! Your life may some day depend on properly executing the maneuver! This Forced Landing Pattern has proven itself invaluable to the military services. They have recovered 50

OCTOBER 1963

section. It is a high-wing, single-place design, with a single tail, and using a tricycle landing gear for both road stability and visibility. The wing panels detach from the c?nter section of the constant chord wing, but are then switched to the opposite sides of the ship, where their own struts form part of the mounting rig and guard. Headlights are attached at the point where the struts attach to the fuselage in the road version. The details of the powerplant ars not available, but the fuselage pod is of welded steel tubing and fabric covered. It was built at the time when the uss of factory built components was still permitted, and possible use of these components may have been made. The wheels are off a Taylorcraft, and the tail appears to follow the same lines as a Schweizer sailplane. A

many airplanes and pilots that might otherwise have been lost, through the use of a Forced Landing Pattern. They can even use a Forced Landing Pattern for the big, heavy (and hot) Century series fighters. What better proof of the value of such a pattern? Some time ago I flew one or two of these Forced Landing Patterns every day. I demonstrated it to students, and critiqued them in their flying of it. Before long, I began to believe in it to such an extent that I could tell right from High Key what kind of a Forced Landing Pattern we'd have! I actually believed in this pattern to the extent that I had the confidence to try it even in a jet trainer that is pretty hot by personal aircraft standards. The pattern WILL work, and knowing it, and practicing it, takes the guesswork out of forced landings. When you try it, make it a Key pattern — keep your Key points in mind not just for the Forcsd Landing Pattern, but also for yourself — gear down at High Key if at an established airport, otherwise up. Safety belt and shoulder harness, all electrical equipment off at Low Key. Base Key means a preliminary judgment for flaps — will you need them? Wings level on final means make it normal all the way — normal glide and normal flare, and use flaps if necessary, or if you've got it made. Put them down early. Knowing and practicing this Forced Landing Pattern may be a small price to pay for the insuranc? it will give you if the situation ever comes up for real. Try it, and see for yourself! A