Loss of Tail Rotor Effectiveness

Apr 26, 2018

Loss of Tail Rotor Effectiveness

LTE is a critical; low-speed aerodynamic
flight characteristic which can result in an
uncommanded rapid yaw rate which does not subside
of its own accord and, if not corrected, can result
in the loss of aircraft control.

LTE is not related to a maintenance malfunction
and may occur in varying degrees in any single
main rotor helicopters at airspeeds less than 30 knots.

CONDITIONS UNDER WHICH LTE MAY
OCCUR:

Any maneuver which requires the pilot to
operate in a high-power, low-airspeed environment
with a front left quartering wind, left crosswind or tailwind creates an environment
where unanticipated right yaw may occur.

Additional factors that place you at risk would be high gross weight/density altitude, or allowing the RPM to drop below the operating range.

There is greater susceptibility for LTE in
right turns. This is especially true during flight at
low airspeed since the pilot may not be able to stop
rotation. The helicopter will attempt to yaw to the
right. Correct and timely pilot response to an
uncommanded right yaw is critical. The yaw is usually
correctable if additional left pedal is applied
immediately. If the response is incorrect or slow,
the yaw rate may rapidly increase to a point where
recovery is not possible.

Recovery is achieved by flying into clean air, if altitude and environment allows. In a hover, a hovering autorotation is the best option.