Motorglider Engine Failure
In one of my previous articles, Motorglider Endorsement, we discussed the three types of motor gliders and their basic designs. Let’s run through a quick review and discussion of some idiosyncrasies with motor gliders (MG), especially the takeoff and engine malfunction areas.
We will discuss the operational issues a pilot should know while flying the MG. This can be a lengthy discussion, but I will highlight some basics. Regarding the three types of MGs, take-off performance is the primary issue we must review in the MG GFM. This mainly affects the TMG and the HPSL. For your remembrance, TMG = Touring MG; HPSL = High-Performance Self-Launching MG. Ok, back to performance.
Before takeoff, it is IMPERATIVE that the PIC review this information. Flying out of the same launch site every day, at the same elevation, etc., tends to help create complacency, which can result in an incident or accident. As PIC, I'd like you to make every attempt to review your takeoff performance. This little review may help with an insurance claim or legal action. Always use the whole runway length, especially on grass, if available.
Back to the performance topic. Conclusion here; know your performance numbers, or even better, create a TOLD (take-off & landing distance) card and record the data in use, maybe 4-5 conditions. Make copies and leave them in the MG where you can do a quick glance for review. Each card will have one set of numbers for seal level, 1000 feet, 2000 feet, etc. Temperatures like, 15 degrees, 20 degrees, 25 degrees, etc. It would include Gross Weight as well. You want to know if this thing will fly!
You must also factor in Density Altitude. This is NOT considered in the performance charts during certification. The rule of thumb is what we refer to as the 3 H’s (hot, humid & high). Ensure that you, as PIC, have a complete and accurate understanding of the proper procedures to apply if an engine malfunction occurs. Ask yourself this question: What training did you receive (or did you) in your MG? I bet your instructor never discussed or demonstrated a partial power failure. Everyone gets those engine failures, but how about partial power? The probability of a partial power reduction is a greater chance than a complete engine failure.
During the takeoff run and after airborne, slightly turn downwind about 20-30 degrees, just like the tow plane does when towing a glider. This allows a safe return (called the button hook) if you have to return due to loss of power, etc. This allows the MG to complete one turn into the wind and be aligned with the departure area. If you decide to track straight out and have to make a 180, it may get very complicated, especially with the engine extended. You will have to make two turns; the last one will be the alignment turn, which will be very low.
Scenario: Imagine yourself at 400 feet on climb out at 50 Vy KIAS (blue line/way below Vg) in your Arcus/Twin Shark and suffer a power loss from 6500 RPM to 3700 or so. You still have power, right? Enough to sustain? For how long? Why did the engine rollback? ECU? However, through your training, you will never know how the HPSL/TMG will react with partial power unless you have received some instruction and hands-on demonstration. You decide to turn back to the take-off area, just as taught, but during that LEFT turn with 3700 RPM, the HPSL may want to tuck due to P-factor (based on propeller rotation/away for the positive prop side, there will usually be a tucking (nose tuck) tendency/into the propeller side (lift) there may be a pitching up or climbing tendency) and either the left or right turn. There are many things to consider. I recommend a good discussion with an experienced MG CFI and other pilots to get some feedback.
The 200-foot rope (glider) break versus the 200-foot MG engine failure is quite different. Most MG GFM will not give you a minimum altitude due to the various situations. Reduce angle attack immediately (within 1-2 seconds at most); remember that the engine creates drag and increases stall speed considerably, especially with a 45-degree bank turn added! Due to this drag component, the MG must have the angle attacked reduced substantially. Increase airspeed to at least Vg. Plan! I would never consider a 180-degree turn in a HPSL below 300 feet! It MUST be automatic for the pilot to react if you have to start thinking you may have a problem. Use the Tom Knauff method during takeoff: straight ahead, straight ahead, straight ahead; when you reach your decision altitude, then, you say out loud: turn right, left, etc.
Even with a complete power loss (engine failure), what is the minimum altitude for your 180-degree turn to start? For example, the Arcus GFM states if the engine fails and remains extended, your L/D is approximately 13;1 with a 450 FPM decent started! Not good! Most of the HPSL GFM will require the pilot to retract the engine (even with the prop turning), which helps reduce some drag. With the prop still turning creates more drag, ideally, the prop should be stopped! Again, a thorough review of your GFM is needed. These steps/procedures should be applied by memory!
Most GFMs refer to landing with the engine extended (they do not differentiate between running or static engines) as an emergency-type landing. If you land with the engine extended (not running), ensure you touchdown smoothly, and beware of control buffet or inference with the rudder and elevator. Use airbrakes at a minimum and carefully!
We need to mention the Sustainer. This discussion would also apply to the sustainer, except regarding takeoffs. DO NOT! End of discussion.
What is the Engine reliability for the TMG/HPSL/Sustainers? Actually, it is very good if you comply with the GFM. The TMG should be very simple since it is often flown like an airplane. The HPSL/Sustainers are entirely different and require additional input from the pilot. Please review your GFM again. You see I refer to the GFM very often, because; it’s your bible of flying your make & model! Again, Review!
How many people do you know have an HPSL/Sustainer who has ended up landing in an off-field landing? During a cross-country flight, you should have all switches and values already set for engine start. Then, all you do is select one or two switches and bingo, the engine is extended and starts; you will be saved by the “Iron Thermal!” Then we found out a couple of things: the HPSL/Sustainer fuel was empty or inadequate, the fuel value was in the close position, and the engine had not been started in 6 months (contaminated fuel). Yes, I have seen and heard all of these, plus others.
In conclusion, it is best to keep in the books (GFM) and ensure that your engine is working and has proper maintenance. If you own a high-performance self-launch, when your flight review comes up, I recommend taking it in your own HPSL with an experienced CFI. If that is not available, have a thorough discussion with your CFI on some of these topics. My last word: Run your engines at least monthly. They will work when needed. Fly Safe and often!
Shawn Knickerbocker has been flying gliders since the mid-sixties. Is a retired FAA DPE who held designations in Airplanes, Helicopters and Gliders for all rating, including the elusive CFI initial, plus numerous type ratings, he has over 62 FAA authorities as a DPE/SAE/SMFT. He also possesses a TCCA (Canada) License with ATP Ratings for airplanes, all classes (SMELS), plus numerous type ratings and Aerobatic Instructor (ABI) in Gliders for Canada. He was the SME for the FAA in rewriting the Airplane Handbook, Helicopter Handbook and the Glider Handbook and PTS in 2000. He was instrumental in developing the CAP Glider Program for Florida back in the mid 90’s to include the “wing runner & tow pilot manual” and has developed many other training programs for the military and US Government Aviation Agencies. He is the current Program Manager for the SSA Cross-Country Instructor Pilot Program. Shawn been flying 58 years, a FAA Master Pilot with over 25,000 hrs. Shawn lives at Seminole Lake Glider port. Email; [email protected]. C- 904.382.9614
Banner photo by Petr Kolmann
Shawn Knickerbocker has been flying gliders since the mid-sixties. Is a retired FAA DPE who held designations in Airplanes, Helicopters and Gliders for all rating, including the elusive CFI initial, plus numerous type ratings, he has over 62 FAA authorities as a DPE/SAE/SMFT. He also possesses a TCCA (Canada) License with ATP Ratings for airplanes, all classes (SMELS), plus numerous type ratings and Aerobatic Instructor (ABI) in Gliders for Canada. He was the SME for the FAA in rewriting the Airplane Handbook, Helicopter Handbook and the Glider Handbook and PTS in 2000. He was instrumental in developing the CAP Glider Program for Florida back in the mid 90’s to include the “wing runner & tow pilot manual” and has developed many other training programs for the military and US Government Aviation Agencies. He is the current Program Manager for the SSA Cross-Country Instructor Pilot Program. Shawn been flying 58 years, a FAA Master Pilot with over 25,000 hrs. Shawn lives at Seminole Lake Glider port. Email; [email protected]. C- 904.382.9614