NATOPS Chapter 2 Tail Rotor HSM-50

Question 1

Provides directional control by

Answer 1

varying pitch of TR blades

Question 2

TR is __ actuated, but requires __ to operate the pitch change shaft, which moves the ___, changing blade pitch angle through ___

Answer 2

mechanically; hydraulic pressure; pitch change beam; pitch change links

Question 3

TR quadrant transmits TR cable movement to the

Answer 3

TR servo

Question 4

__ connected to the quadrant allow cable tension to be maintained if either TR cable becomes severed

Answer 4

2 spring cylinders

Question 5

if both cables are severed, __ will counter TR servo pilot valve to position TR to neutral for fly home capability

Answer 5

2 separate centering springs

positions pedals

Question 6

Describe the TR

Answer 6

bearingless, crossbeam TR blade system

Question 7

TR flexible spar allows

Answer 7

tail rotor blade flap and pitch change

Question 8

Blades are canted

Answer 8

20 degrees upward

Question 9

TR provides __ % of lift in a hover which helps __

Answer 9

2.5; lower nose attitude in hover because the TR is aft of the aircraft CG

Question 10

TR indexing system

Answer 10

positions blades during pylon folding and prevents TR from windmilling in winds up to 60 knots when tail folded

Question 11

Describe TR blades

Answer 11

built around 2 composite spars to form 4 blades

Question 12

Nose snap with loss of drive is less noticeable at __ airspeeds

Answer 12

faster

Question 13

Indication of functioning TR when attempting to verify drive failur

Answer 13

application of right pedal brings nose right

Question 14

3 types of TR Control Malfunctions

Answer 14

1. Cable failure
2. Servo failure
3. Restricted flight controls

Question 15

Cable failure indications

Answer 15

TR QUADRANT light

Question 16

Cable failure airspeeds for GW 19,500 lbs

Answer 16

25 AND 145 KIAS

Question 17

Cable failure below/above 25/145; between 25/145

Answer 17

Nose yaws right; nose yaws left

Question 18

TR Servo Failure indications

Answer 18

Lose No 1 Hyd Pump and Backup Pump; retain boost and mechanical system

Question 19

TR Servo Airspeeds

Answer 19

40 TO 120

Question 20

Servo Failure Recommended Landing

Answer 20

Running landing above 40 KIAS

Question 21

Restricted Flight Control Scenarios

Answer 21

FOD, mechanical failure, servo hardover

Question 22

Hardover failure can put __ lbs of force on pedals

Answer 22

250 lbs

Question 23

Stuck left

Answer 23

high power setting; normal landing

Question 24

Stuck right

Answer 24

low power setting, running landing/auto

Question 25

LTE

Answer 25

inability of TR to provide sufficient force to maintain yaw controllability

Question 26

LTE occurs when

Answer 26

full pedal input is insufficient to provide directional control

Question 27

Tail rotor thrust is a function of

Answer 27

operating rpm and tail rotor AOA

Question 28

Two primary directional control mechanisms of TR

Answer 28

AOA and weather vaning tendency of fuselage

Question 29

LTE and winds from the right

Answer 29

• winds from right decrease AOA of TR, reducing effectiveness and requiring additional left pedal to maintain heading
• additional left pedal depletes main rotor power and reduces directional control authority
• so, in high power, right crosswind situations, may lose TR effectiveness

Question 30

LTE and winds from the left

Answer 30

• winds from left increase AOA of TR –> increase TR AOA –> increase in TR effectiveness
• if left wind excessive, disturbed airflow around TR may develop, resulting in loss of effectiveness

Question 31

Weather Vaning

Answer 31

winds in 120 to 240 region

nose will weathervane into wind

Question 32

TR VRS

Answer 32

• 210 to 330
• can cause TR to operate within its own recirculated airflow
• causes TR thrust variations that can initiate yaw rates
• if right yaw builds from this, may get into weather vaning and see yaw rate accelerate

Question 33

Main Rotor Disc Vortex Interaction

Answer 33

• 280 to 330, less frequently 30 to 80
  can cause main rotor vortex to be directed onto TR, resulting in changes of AOA to TR
• TR thrust can vary unpredictably

Question 34

Loss of TL

Answer 34

• results in increased power demand and additional anti-torque requirements
• if occurs in right turn, right turn will be accelerated; if near max power available –> Nr decay
• can be caused by insufficient attention to wind direction and velocity

Question 35

Right sideward flight and LTE

Answer 35

same effect as right crosswind

Question 36

Factors increasing likelihood of LTE

Answer 36

high gross weight, high DA, arresting high descent rate

Question 37

Recovering from LTE

Answer 37

1. Lower collective to reduce tq/arrest right yaw (if too high of descent rate, arresting descent may reinitiate LTE)
2. Forward cyclic to increase airspeed, and if necessary, turning in direction of rotation (causes reduction in TR thrust req and produces streamlining effect)
3. At low speeds/hover, full left pedal may stop right yaw (may take a few seconds/rotations to work). Neutralizing pedals or adding right pedal will only accelerate yaw rate

Question 38

Spring tension feature

Answer 38

with loss of both cables, provides positive pitch on TR equivalent to the antitorque requirements (left pedal) for a midposition collective setting