TD31 DQ

What is Transverse Flow Effect?

In forward flight, air passing through the rear portion of the rotor disk has a greater downwash angle

than air passing through the forward portion. This is due to the fact the greater the distance air flows over the

rotor disk, the longer the disk has to work on it and the greater the deflection on the aft portion. Downward

flow at the rear of the rotor disk causes a reduced AOA, resulting in less lift. The front portion of the disk

produces an increased AOA and more lift because airflow is more horizontal. These differences in lift

between the fore and aft portions of the rotor disk are called transverse flow effect

Rotor RPM Limitations

WARNING LIGHT INDICATIONS - ROTOR RPM

Conditions/Indications

NRO low

• NRO ____ or less -

• Audio signal -

NRO high

• NRO ______ or above -

• Audio signal at _______ or above -

Procedure

NRO low/NRO high

1. Rotor RPM indicator - Check

2. Collective lever -

95% steady light

low-pitch beeping tone

106% flashing light and warning gong

110% flashing light and steady high-pitch tone

Adjust as necessary to maintain NRO within normal range

TAIL ROTOR DRIVE FAILURE - HOVER

1. Both TWIST GRIPS - Rotate to IDL
   and simultaneously

2. Landing attitude - Establish

3. Collective lever - Apply as necessary
   After landing:

4. Double engine emergency shutdown - Perform