ths@lanl-a.UUCP (10/01/84)
This morning I gave my student a simulated engine failure at 350' AGL over the departure end of rwy 20 at Santa Fe (field elevation 6344' MSL). I had previouly requested that she attempt to turn back when I called the engine failure, so she was briefed and ready (so was the tower). IAS was 65 knots (approx best angle) in a C-172, about 200 lbs below gross with OAT at 42 degrees. When I reduced power to zero, she looked out the left side, determined that since she was slightly right of the center line, a left was most appropriate. She then executed a 35 to 45 degree banked turn while putting in full flaps. I suggested that perhaps full flaps might bring her to the ground before she completed the turn, so she immediatly backed-off to 20 degrees. I have to admit to being very suprised at the outcome. We not only were able to complete a 180 but also had enough altitude left to maneuver back to the center line of the runway. We touched down about 1500 feet down the runway. The key to the maneuver seems to be: 1) Start the turn ASAP, 2) keep the airspeed reasonably low to reduce the radius of turn and to keep the rate of turn high. The flaps seemed to do this almost automatically. 3) Use at least 35 if not 45 degrees of bank angle. I recall going thru this exercise with another student in his C-182 a few years back but I don't have the numbers we came up with. The conclusion about airspeed and bank angle were the same. As far as "teaching" the maneuver I am still somewhat divided. Performing in a C-152, C-172 or even a C-182 is quite a bit different than in a higher wing loading a/c like a Bonanza or Lance. I think the student is better-off being taught the method BUT carefully advised that an unexpected power failure within 500' AGL might best be handled by the "whatever you can see out the front windscreen is where you should set it down". The odds for survival are almost 100% using that axiam. Turning back to the runway will probably result in a stall/spin perhaps 25% of the time. Even if sufficient altitude would have allowed completion of the maneuver. I am also a firm believer in nothing greater than a medium bank turn under "normal" conditions in the pattern.
cfiaime@ihnp4.UUCP (Jeff Williams) (10/04/84)
I used to teach the turn back after 500 feet maneuver, at altitude, and quit when several students spun the airplane. The 25% stall/spin rate that was mentioned on the net is probably quite accurate. Just because you may fly a twin, don't think that this discussion does not apply. It does. For an example, I was taking a 135 ride in a Grumman Cougar (GA-7, not an F9F-8) in Lincoln, Nebraska. The examiner pulled the critical engine (naturally) on me after liftoff, and while the gear was in transit. Even at Vyse (single engine best rate of climb), the poor airplane could not climb on a 95 degree day. I told the examiner that I would land straight ahead in a field by the airport. The examiner suggested that under the circumstances, he would do the same thing, but even closer to the airport than I was going to "land." It is a sobering thought for the multi-engine drivers in the crowd. Several weeks later, same runway, same airplane, different examiner, and 20 degrees cooler, the airplane was easily able to climb on one engine. (This was on my multi instructor ride.) It goes to prove that you need to look at the performance charts and do some preplanning before you fly. This discussion brings up some other pet peeves about pattern flying. 1. You should fly downwind close enough to make the airport if you lose the engine. 2. You should fly the pattern in accordance with the recommendations of AIM Part 1, and Advisory Circular AC 90-48B. (The AC is available free from the Feds.) 3. Strange maneuvers in the pattern should be avoided if at all possible. (I have seen people do aerobatics in the pattern, make low altitude turns into traffic while in the pattern, ignore traffic in the pattern, and get killed in a mid-air collision in the pattern.) 4. Long final approaches should be avoided. 5. I teach a maximum of 30 degree bank in the pattern. If you use much less than 20 degrees, however, your pattern gets quite wide. If anyone wants the information on ordering the free Advisory Circulars, send me mail. Jeff Williams AT&T Bell Laboratories, Naperville, Ill. ihnp4!cfiaime
bl@hplabsb.UUCP (Bruce T. Lowerre) (10/11/84)
Here is another report on the "experiment." While with my student in a C152, we set up 500 AGL (2100 MSL) over a "runway" (a road on top of a hill) and initiated a climb out. When we reached 2600 MSL (500 feet above the "runway") we pulled the power, established 60 knots, and initiated a right 180 at about 30 degrees of bank. We lost 200 feet doing the 180 and another 200 feet maneuvering back to the "center line." We passed over the departure end of the "runway" at 2200MSL; we could have made it back. My conclusion? If I lose it a 500 AGL I'm going to land straight ahead. Ironically, while better climb performance and greater headwind will help you make it back to the runway, it will also contribute to your death when you overshoot the downwind landing! There are too many variables and too little time to cope with them. Bruce Lowerre, CFI