You are in cruise flight in your single engine helicopter, patient and crew on board. It's 3 am, so dark that your goggles sparkle. You are over a wooded area, destination in sight, and your worst nightmare happens.
Your turbine's steady whine changes pitch. A momentary sagging... Your heart trips and thumps in your chest. "Don't do this!" A surge, and then sound, rotor RPM, and instrument indications all fall off. You push down on the collective, enter autorotation, and training kicks in.
You are in a new AIRBUS product. It is a single-engine helicopter with E.L.A. (Emergency Landing Assist) AIRBUS has taken it's experience with an all-electric airplane, able to take off, fly, and land with nothing but battery power, and migrated knowledge and technology into it's light single engine helicopter line. Your helicopter is a hybrid.
Your finger finds the E.L.A. button on the collective, lifts the guard, and activates the system. Instantly, a surge of electrical energy from the lightweight and powerful batteries flows to the starter-generator-emergency power system. You set your airspeed at 65 knots and stop your descent!
You know you can't hover, for this takes too much power. More than the E.L.A. system can provide. But you can maintain flight at the minimum-power airspeed for between five and ten minutes. You have time to breath, and think, and plan. If you pull up on the collective too much, rotor RPM will droop. You balance power available with power required, and your VSI indicates level flight.
You tell the crew, "call the comcenter and tell them we have lost engine power, We are flying on the Ella." You switch off the selector to that radio. You call ATC and declare an emergency. You check your instruments. The engine has well and truly failed, but you are able to leave enough power applied to maintain flight.
You scan the L.E.D. indicators for the E.L.A. system. All lit. You look for a place to land. "Over there! to the right! A large field!"
"Okay guys, I have a field in sight. We are going to do an assisted-auto into it. The wind is off the nose, get ready to land."
You reduce power for landing. As the rotor system enters the autorotative state, power is no longer pulled from the E.L.A. system, and it begins to flow the other way - regenerative autorotation. You will use this power to assist your flare, deceleration, and touchdown.
And you will walk away from an undamaged aircraft.
Imagine. And watch this...
(Note: AIRBUS does not yet have a helicopter with an emergency-landing-assist system available. But here's hoping they make one soon. We have the technology now. We already use a starter-generator on a helicopter. It should be possible to create a starter-generator-landing assist system. We may not be able to hover on battery power, but we should be able to produce enough thrust to maintain low speed flight for several minutes after losing engine power, allowing us to reach a suitable area for autorotation.)