Deadstick Technique for RV Pilots

07 Oct 2005 Deadstick Technique for RV Pilots

This excellent article is from Ross Farnham of Simple Digital Systems. The original article is here: http://www.sdsefi.com/air44.htm

Deadstick Technique for RV Pilots

This article deals with some of the lessons learned from my forced landing on Jan. 22/05 and will hopefully be of use to other RV pilots. Comments from other RV pilots with similar experiences or input is welcome.

Observations

1. The descent rate, glide ratio and apparent glide angle are different with no power as opposed to simulated idle power. The glide ratio is dependent on weight and propeller drag. Our calculated glide ratio with the engine out at gross weight is only around 6.75-7.5 to 1. It is logical to assume that propeller drag may be higher with 3 blade as opposed to two blade props. On controllable pitch props, the glide may be extended by going to full coarse if loss of oil pressure or electrics does not prevent this. Going to WOT if you remember may also extend the glide.

2. Testing on our aircraft shows that best glide airspeed is somewhere around 80-85 knots. Your aircraft may be different. It is worth testing at idle power to find out. Check your VSI at different airspeeds and calculate the glide ratio. Velocity divided by descent rate = glide ratio. VSI in ft./min., airspeed in miles per hour needs to be converted to ft./min. by multiplying by 88. For example, 80 mph X 88= 7040 feet per minute. If your VSI reads 1000 fpm, 7040 divided by 1000= 7.04. For working in knots, multiply your airspeed by 1.15.

3. With the small aspect ratio on the typical RV, induced drag in turns at low airspeed is relatively high. In other words, turns with no engine power will require that you lower the nose to maintain airspeed. This increases the descent rate appreciably. I would therefore recommend that you don’t make any major turns at low altitude. If you must turn to avoid obstacles, keep your bank angles to less than 30 degrees, USE THAT RUDDER for heading changes and watch the ASI like a hawk. NEVER let the ASI drop below 80 knots/ 85 mph.

4. If you have plenty of altitude, you MAY have time to switch to 121.5 and transmit a Mayday after checking fuel, swiches and engine controls. You MAY NOT have time. You may not have electrical power for the radios as in our case. FLY THE AIRCRAFT FIRST! Things can happen fast in a real engine out situation. Inattention to flying by switching radios and other distractions can use up precious decision making time. Calling Mayday is less important than surviving the forced landing. Watch that ASI.

5. In my incident, I thought I had plenty of altitude 2-3 miles out to make the runway. It was very deceiving and I ended up WELL short. Plan to arrive MUCH higher than you think. You can always side slip or use full flaps (if you have electrics or manual flaps) to lose altitude when you are very close to the field. You can’t gain back what you have already lost. Unless you are at least 3000 feet AGL, I would not recommend a standard forced landing pattern as I think with the RV glide characteristics, it is very likely that you will use up all your altitude in the turns and end up too short. Pick the best area and aim for it. You cannot see the obstacles or even judge the terrain very well from 2-3000 feet up anyway. Watch that ASI and keep saying in your head- don’t stall, don’t stall!

6. The pitch attitude during the glide may not look too bad at 500 or 1000 feet above the ground but as you get down to 100-200 feet, it will look downright scary. Absolutely resist the temptation to pull back on the stick when this hits you. It will be a very powerful urge at low altitude to arrest the descent rate. You MUST maintain 80-85 all the way down to the flare. If you pull back at 100 feet, speed will fall off, descent rate will increase and you will either stall and be killed or hit even harder as you will not have enough energy to complete a flare. Another way of looking at this is that 1000 fpm is 16.6 feet per second. That is a hard hit if you can’t flare. At 60 knots, the descent rate may be as high as 20+ feet per second. Fly the aircraft right down to 20-25 feet at 80-85 before starting the flare. Elevator authority will be reduced with no power so the flare will take longer to execute and speed will bleed off faster with no residual idle thrust from the prop. Get the aircraft into ground effect and let the speed bleed off until you touch down.

We all hope that we never experience an engine failure but it can happen to anyone. Practice your procedures and get to know how your aircraft handles at idle power. If possible, practice approaches at idle power from a ways out on your normal runway. Without adjusting power except for safety, see if you can touch down where you anticipated. Practice side slipping to lose altiude on some of your approaches. Knowing how the aircraft feels and responds may save your life sometime. If you always land with partial or full flaps, do some landings clean as an RV flys quite differently. Don’t become complacent about your ability to force land your aircraft as it WILL be different from any training scenerio when you really do lose all power.

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