Search results
- Loss of tail rotor effectiveness (LTE), also known as unanticipated yaw, is a distinctive dynamic phenomenon that affects single-rotor helicopters and frequently leads to loss of control resulting in accidents and casualties. In the United States, about 5–10 helicopter crashes occur every year due to LTE.
www.nature.com/articles/s41598-022-06647-0Data-driven analysis and new findings on the loss of tail ...
People also ask
Is loss of tail rotor effectiveness a risk factor for helicopter accidents?
What causes a tail rotor to yaw?
What happens if a rotor helicopter crashes while yawing?
Did a yaw rotor fail?
What happens if a helicopter rotor fails?
Is unanticipated right yaw a complete loss of tail rotor thrust?
LTE can occur in all single-engine, tail rotor-equipped helicopters at airspeeds lower than 30 knots and, if uncorrected, can cause the pilot to lose helicopter control, potentially resulting in serious injuries or death.
- Abstract
- 1. INTRODUCTION
- 4. EXPLAINING UNANTICIPATED YAW BY THE PEDAL CURVE
- 4.3. Tail rotor is felt ineffective
- 4.5. Unanticipated yaw when performance is limited
- 6. CRUSHING MYTHS
- 6.4. It is safer to fly with left wind when performance is limited
- 7. CONCLUSION
- 8. ACKNOWLEDGEMENTS
The helicopter community has been plagued during the latest forty years by accidents due to unanticipated yaw, also called Loss of Tail rotor Effectiveness (LTE). How the problem was identified and what answers were given are first reconstructed from period documents and Airbus experience. A part of the mystery still remained and especially no clea...
From time to time a single rotor helicopter operating at low speed starts spinning against the will of the pilot, who does not succeed to stop the rotation. It crashes while still yawing and this usually results in significant material damages and, too often, in fatalities or injuries. The following investigation shows that no failure was existing ...
A simple case is considered in this chapter, where the helicopter is making a hover spot turn in steady wind. It makes things easier to understand while being a real accident case. It can also enlighten more complex events. The pedal curve is perfectly suited to this simple case and allows understanding how unanticipated yaw occurs and in what cond...
Recovering from the unanticipated yaw at least requires coming back to the pedal curve. As the point where unanticipated yaw starts is the maximum of that curve, the trim position may only shift downwards when the heading changes. Two different recovery maneuvers have been plotted in Figure 11, one in blue and a second — less abrupt — in yellow. ...
This is the most critical case but represents only a limited number of the accidents in the database. Most of them occur in low altitude condition, where performance is not an issue. When operating close to the performance limit, applying a significant left pedal step, possibly to the stop, increases significantly the tail rotor power. If the engin...
The pedal curve provides new understanding of unanticipated yaw phenomenon and may be used to kill some believes that can be found in pilots forums.
Some pilots advocate for choosing left wind conditions during approach, when performance is limited. It reduces the need for tail rotor pitch and therefore asks for a lower tail rotor power, making more power available on the main rotor. From pure performance view, it obviously brings a slight improvement. It shall however also be considered from t...
Unanticipated yaw is a lasting problem that was not clearly understood. Whether the tail rotor was able to recover was questioned. The Loss of Tail Rotor Effectiveness wording but also the recommended recovery maneuver and the belief in endless spinning to the right with full left pedal are examples of the doubts raised about the tail rotor behavio...
The author would thank all the pilots sharing their experience in forums or blogs, providing different views of a problem. He also thanks the aeronautical investigation boards that have developed easily accessible databases, making possible the analysis presented in chapter 3.
Sep 28, 2015 · Yes, it is possible to make an emergency landing in a helicopter should a tail rotor failure occur. The procedure is that same as that of a engine failure and it's called an autorotative landing. Essentially a powerless helicopter becomes an autogyro (gyrocopter) in flight and can be flown as such.
May 30, 2024 · LTE results in an uncontrollable yawing motion, which can lead to a loss of helicopter control and a possible LoC-I accident. It is induced by wind, not by a technical failure or maintenance error.
Tail rotor drive system failures include driveshaft failures, tail rotor gearbox failures, or a complete loss of the tail rotor itself. In any of these cases, the loss of antitorque normally results in an immediate yawing of the helicopter’s nose.
Feb 16, 2022 · Loss of tail rotor effectiveness (LTE) is an unstable dynamic phenomenon that affects single-rotor helicopters and frequently leads to accidents. LTE accidents recur with troubling regularity and...
Losing tail rotor thrust in a helicopter can be deadly. The tail rotor provides yaw / heading control and prevents a helicopter from spinning out of control, particularly at low speeds. Unfortunately, there are a few phenomena that can reduce tail rotor thrust in exactly these low speed conditions where it’s most needed.
