TD 25

Question 1

Explain why hovering OGE requires more power than IGE hover.

Answer 1

Induced flow velocity is increased causing a decrease in AOA. A higher blade pitch angle is required to maintain the same AOA as in IGE hover. The increased pitch angle also creates more drag. More power to hover OGE than IGE is required by this increased pitch angle and drag.

Question 2

Define Translating Tendency

Answer 2

During hovering flight, the counterclockwise rotating, single-rotor helicopter has a tendency to drift laterally to the right. The translating tendency results from right lateral tail-rotor thrust exerted to compensate for main rotor torque (main rotor turning in a counterclockwise direction).

Question 3

To compensate for translating tendency the helicopter design usually includes one or more of the following:
A
B
C
D

Answer 3

A. Flight control rigging may be designed so the rotor disk is tilted slightly left when the cyclic control is centered.
B. Transmission may be mounted so the mast is tilted slightly left when the helicopter fuselage is laterally level.
C. The collective pitch control system may be designed so the rotor disk tilts slightly left as collective pitch is increased.
D. Programmed mechanical inputs/automatic flight-control systems/stabilization augmentation systems.

Question 4

CAUTION INDICATIONS - ENG CHIP (SYSTEM 1 or 2)

ON GROUND
1. Affected engine – 
2. Single engine emergency shutdown – 
IN FLIGHT
1. OEI flight condition – 
2. Affected engine – 
1. Alternative:
3. Single engine emergency shutdown – 
2. Alternative:
3. Twist grip (affected engine) – 

CAUTION THE SECOND ALTERNATIVE ENABLES THE CREW TO USE THE AFFECTED ENGINE FOR LANDING IF NECESSARY. BE PREPARED FOR
ENGINE FAILURE. MONITOR N1, TOT, TORQUE, OIL PRESSURE AND
TEMPERATURE OF AFFECTED ENGINE CLOSELY. IF THE PARAMETERS
FLUCTUATE OR THEIR LIMITS ARE EXCEEDED PERFORM SINGLE ENGINE EMERGENCY SHUTDOWN IMMEDIATELY.

4. LAND AS SOON AS

Answer 4

ON GROUND
1. Affected engine – Identify
2. Single engine emergency shutdown – Perform
IN FLIGHT
1. OEI flight condition – Establish
2. Affected engine – Identify
1. Alternative:
3. Single engine emergency shutdown – Perform
2. Alternative:
3. Twist grip (affected engine) – Rotate slowly to IDLE, check
indications
CAUTION THE SECOND ALTERNATIVE ENABLES THE CREW TO USE THE AFFECTED ENGINE FOR LANDING IF NECESSARY. BE PREPARED FOR
ENGINE FAILURE. MONITOR N1, TOT, TORQUE, OIL PRESSURE AND
TEMPERATURE OF AFFECTED ENGINE CLOSELY. IF THE PARAMETERS
FLUCTUATE OR THEIR LIMITS ARE EXCEEDED PERFORM SINGLE ENGINE EMERGENCY SHUTDOWN IMMEDIATELY.
4. LAND AS SOON AS PRACTICABLE