NATOPS Chapter 11

Question 1

Normal Hover Attitude

Answer 1

4-5* nose up
2-3* left wing down

Question 2

Ground Effect

Answer 2

When the rotor disk is within one rotor diameter of the ground

Question 3

Blowback

Answer 3

Retreating blade sees less relative wind

Question 4

Translational Lift

Answer 4

Approximately 17 -30 knots

Question 5

Blade Stall Recovery

Answer 5

Decrease collective
Decrease Severity of Maneuver
Decrease Airspeed
Increase rotor RPM
Decrease Altitude
Decrease Gross Weight

Question 6

Tail Rotor

Answer 6

Tractor Tail rotor canted at 20% providing 2.5% of total lift in a hover.

Question 7

Loss of Tail Rotor Authority

Answer 7

LTA is an issue of power. Seen at high gw/high DA. Left pedal will be sluggish or you can droop.

Question 8

Nr drooping

Answer 8

As Nr droops, torque increase while power available to the main rotor and tail rotor decrease. Eventually the tail rotor cannot produce enough anti-torque and the helicopter will spin right.

Question 9

Loss of Tail Rotor Effectiveness

Answer 9

LTE is the inability of the tail rotor to provide sufficient force to maintain yaw controllability. A function of operating rpm and tail rotor angle of attack. Relative winds, low-speed/high power maneuvering, gross weight, and high da are all factors.
High power… lots of left pedal

Question 10

Tail rotor winds

Answer 10

Winds from the right, decrease AoA and reduce effectiveness
Winds from the left, increase AoA and improve effectiveness

Question 11

AoA Reduction Winds

Answer 11

060-120 relative

Question 12

Weather Vaning

Answer 12

120-240 relative
Aircraft wants to nose into the wind

Question 13

Tail Rotor Vortex Ring State

Answer 13

210-330 relative
Tail rotor operates in its own recirculated airflow

Question 14

Main Rotor Disk Vortex Interaction

Answer 14

280-330 relative
Main rotor vortex directed to the tail rotor changing Tail Rotor AoA

Question 15

Hover/Air Taxi

Answer 15

Right sideward flight can increase airflow across the tail, reduction in AoA

Question 16

Recovery from LTE

Answer 16

Lower the collective to stop the right yaw
Gain forward airspeed, if necessary turn in direction of rotation
At very low airspeeds, full left pedal may stop it

Question 17

Tail Rotor Spar Damage

Answer 17

Left turns in excess of 30* per second above 75 KIAS may cause damage to the spar

Question 17

AoA Reduction Winds

Answer 17

060-120 relative

Question 18

AoA Reduction Winds

Answer 18

060-120 relative

Question 18

4/rev vibration

Answer 18

Indication that the lift generation of the rotor has been exceeded. Correct by reducing collective

Question 19

AoA Reduction Winds

Answer 19

060-120 relative

Question 19

Main Rotor Flapping

Answer 19

Inducement of less than 1G flight may exceed main rotor flapping margin and cause droop stop pounding

Question 20

AoA Reduction Winds

Answer 20

060-120 relative

Question 20

Power Required Exceeds Power Available

Answer 20

At High DA, high GW.

Add +100 DA for every 10% humidity above 40%.

Question 21

AoA Reduction Winds

Answer 21

060-120 relative

Question 21

Vortex Ring State

Answer 21

Encountered: Greater than 700fpm descents 0-20KIAS @1500fpm descent 5-10KIAS Leads to uncommanded pitch and roll oscillations and descent rate may approach 6000'

Question 22

AoA Reduction Winds

Answer 22

060-120 relative

Question 22

Vortex Ring State Recovery

Answer 22

Decrease Collective Pitch Increase forward airspeed Enter Autorotation if altitude permits.

Question 23

AoA Reduction Winds

Answer 23

060-120 relative

Question 23

Autorotational Airspeed

Answer 23

Enter at max 100 KIAS Min rate of descent 75 KIAS Max glide 95 KIAS

Question 24

AoA Reduction Winds

Answer 24

060-120 relative

Question 24

Autorotation Nr

Answer 24

Actual- In the approach close to 100, in the flare as much NR as possible Practice- As close to 100 as possible to provide faster engine spool up when Nr droops below 100%

Question 25

AoA Reduction Winds

Answer 25

060-120 relative

Question 25

Dynamic Roll over

Answer 25

Ground contact, and a rolling motion. Opposite cyclic may not be enough to correct, and may exaserbate the problem by adding lift into the equation

Question 26

AoA Reduction Winds

Answer 26

060-120 relative

Question 26

Sloped Landing Considerations

Answer 26

Consideration should be given to setting the parking brake. With parking brake increased risk of dynamic rollover Without increased risk of rolling out of zone Land with upslope wheel first, the keep the rotor disk level Extreme aft cyclic may cause droop stop pounding, or main rotor blades striking the tail pylong

Question 27

Salt water power deterioration

Answer 27

20*C indication of engine performance degradation and possible salt encrustation 40*C indication of engine performance degradation which may cause compressor stall Look for TGT and Torque relationship

Question 27

Salt Water ingestion

Answer 27

Greatest in winds of 8-12 knots due to sea spray being lifted Small risk in winds 15-20 knots as spray is blown under the aircraft Lower hover alt = greater risk of ingestion

Question 28

Flight with external loads

Answer 28

Know the riding characteristics Oscillations can be minimized with smooth control inputs There is a best airspeed for a load Be wary of loads aerodynamic properties

Question 29

Performance in Icing

Answer 29

If unanticipated icing is encountered first consideration should be exiting icing conditions

Question 30

Main rotor vibrations

Answer 30

1 per rev - main blades out of track, or worn or loose control rod bearings ground 1 per - static imbalance of main rotor, or improper landing gear strut servicing 1.44 per rev - SAS and pilot induced oscillations longitudinally 4 per rev- asymmetrical blade loading. vertical and lateral shakes

Question 31

Ground Resonance

Answer 31

Caused by out of phase lead lag tendency, or system dampers. Can occur within 3 seconds and produce violent vibrations. Will continue to build until take off or main rotor is disengaged.

Question 32

Tail Rotor Vibrations

Answer 32

Tail shake 5hz - felt as a random impulse around yaw axis Tail Drive Shaft Vibes (high freq) - caused by an unbalanced driveshaft, buzz in the pedals or tickling in the nose 1 per 20hz- tail rotor imbalance, loose hardware or damage.

Question 42

AoA Reduction Winds

Answer 42

060-120 relative