H9-11 Emergencies and Hazards Flashcards
Chapter 11 Helicopter Emergencies and Hazards ........11-1 Introduction..................................................................11-1 Autorotation .................................................................11-2 RPM Control ............................................................11-3 Risk Management during Autorotation Training ....11-3 Straight-In Autorotation ...........................................11-4 Technique (How to Practice)................................…
During power off auto rotations, upward movement of the collective reduces or raises the RPM?
Reduces
During power off auto rotations, downward movement of the collective reduces or raises the RPM?
Increases
11-6 Autorotation with Turns should be aborted if.. (4)
-if the helicopter is not in a stabilized approach to landing profile (i.e., it is not aligned as close as possible into the wind with the touchdown point, after completing the 180-degree turn)
-if the rotor rpm is not within limits;
-if the helicopter is not at a proper attitude/airspeed;
-or if the helicopter is not under proper control at 200 feet AGL.
11-7 Upon arriving into the course line prior to the flare, the scan should focus almost entirely outside. The scan should include….(3)
-The horizon for attitude, ground track, and nose alignment
-the altitude to set the flare and for closure (groundspeed)
-the instrument cross-check of airspeed, rotor rpm, and engine rpm in the descent.
??? H.11-7 Name some things a pilot operating a helicopter needs to take into account when recovering from an aborted autorotation. (5)
- Higher rate of descent.
- Reduced rotor RPM builds in autorotation.
- Low initial rotor RPM response in autorotation.
- The requirement for a higher flare height.
- Reduced engine power performance.
What is Vortex Ring State?
An aerodynamic condition in which a helicopter may be in a vertical descent with 20 percent up to maximum power applied.
11-10 What is the Vuichard Recovery (1.5)
-In most helicopters, lateral cyclic thrust combined with an increase in power and lateral antitorque thrust will produce the quickest exit from the hazard.
-eliminating the descent rate as opposed to exiting the vortex.
11-10 What is windmill brake state?
the vortex ring state and the corresponding descent rate is allowed to progress to what is windmill brake state
-the point where the airflow is completely up through the rotor, the only recovery may be an autorotation.
How should a tandem helicopter get out of VRS?
Tandem rotor helicopters should maneuver laterally to achieve clean air in both rotors at the same time.
11-10 Retreating blade stall is a factor in limiting a helicopter’s never-exceed speed (VNE) and its development can be felt by (3)
-a low frequency vibration,
-pitching up of the nose,
-and a roll in the direction of the retreating blade.
11-11 List some things that can cause retreating blade stall (4)
- High weight, low rotor RPM.
- High density altitude.
- Turbulence.
- Steep abrupt turns.
11-11 As altitude is increased, higher blade angles are required to maintain lift at a given airspeed. Thus, retreating blade stall is encountered at a ______ forward airspeed at altitude.
lower
Most manufacturers publish charts and graphs showing a VNE decrease with altitude.
11-12 For dynamic rollover to occur the following three factors must be present. (3)
For dynamic rollover to occur the following three factors must be present:
1. A rolling moment
2. A pivot point other than the helicopter’s normal CG
3. Thrust greater than weight
11-11 if a pilot at high weight and high DA is about to conduct a high reconnaissance prior to a confined area operation where rolling into a steep turn causes onset of RBS, the recovery is to ______
Roll out of the turn.
11-12 Role tilt range of the average rotor.(dynamic rollover)
5-8 degrees
How to recover from dynamic rollover?
Reduce collective.
11-12 The following conditions are most critical for helicopters critical rollover with counterclockwise rotor rotation (4)
- Right side skid or landing wheel down.
- Right lateral center of gravity (CG).
- Crosswinds from the left.
- Left yaw inputs.
11-13 Dynamic rollover is possible even during normal takeoffs and landings on relatively level ground, if one wheel or skid is on the ground and
thrust (lift) is approximately equal to the weight of the helicopter.
At what angle will a rotor blade stall?
15 degrees
11-16 list ways a pilot can recognize a low rotor RPM situation (3)
-besides the indicator decreasing will also notice a change in torque that produces yaw
-a noticeable decrease an engine noise
-an increase in vibration at higher airspeed or in turns
11-16 to recover from the low rotor RPM condition the pilot must simultaneously (3)
- Lower the collective.
- Increase throttle if available.
- Apply aft cyclic to maintain a level attitude.
What are the two categories of antique failure?
- Failure of the power drive portion of the tail rotor disc.
- Mechanical control failure.
11-16 Tail rotor drive system failures include (3)
- Driveshaft failures.
- Tail rotor gearbox failures.
- Complete loss of the tail rotor.
11-17 the landing profile for a stuck left pedal is best described as
(Auto rotation makes things worse )
-A normal to steep approach angle to arrive approximately 2 to 3 feet landing gear height above the intended landing area as translational lift is lost
11-17 the landing profile for a stuck, neutral or stuck right pedal is
A low powered approach terminating with a running or roll on landing
-Approach profile can be described as a shallow to normal approach angle
What are the angles for weathercock stability?
120 to 240 degrees
What are the angles for main rotor disc interference?
285 to 315 degrees
What are the angles for tail rotor vortex ring state?
210 to 330 degrees
11-20 main rotor disc interference increases or decreases the angle of attack of the tail rotor
Increases that increasing tail of thrust.
Right rudder must be added
After the vortex passes, the angle of attack of a tail rotor will reduce. Be ready to compensate for that reduction.
11-21 list some things that could be done done to reduce the onset of LTE
-avoid tailwinds below airspeed of 30 knots
-avoid OGE operations and high-power demand situations below air speed of 30 knots at low altitude
-The especially aware of wind direction and velocity when hovering at winds of about 8 to 12 kn
-Be aware that if a considerable amount of left pedal is being maintained, a sufficient amount of left pedal may not be available to counteract any anticipated right yaw
-Execute right turns slowly. this limits the effects of rotating inertia and decreases loading on the tail, rotor to control yawing.
What is the uncontrolled right yaw recovery technique?
- Apply left pedal.
- Simultaneously apply cyclic control to increase airspeed.
- If able, reduce power.
11-22 if the drive shaft or belt breaks, the lack of any load on the engine results in an overspeed. in this case you should
The throttle must be closed.
11-22 an impending hydraulic failure can be recognized by (3)
- A grinding or howling noise from the pump or actuators.
- Increased control forces and feedback.
- Limited control movement.
11-22 what do you do any event of hydraulic failure?
-check RFM for Best answers
In most Aircraft …
-Airspeed needs to be reduced in order to reduce control forces
-hydraulic switch and circuit breaker should be checked and recycled
-If hydraulic power is not restored, make a shallow approach to a running or roll on landing
What are hydraulic accumulators?
A store of pressure that can be used for a short time while in an emergency if the hydraulic pump fails.
11-22 in the event of a high side failure (governor or fuel control failure)
The engine and rotor RPM tend to increase above the normal range due to the engine being commanded to put out too much power.
Close the throttle and enter auto rotation
11-22 in the event of a failure on a low side (governor or fuel control failure)
The engine output is allowed to go below the collective and normal RPM may not be attainable, even if the throttle is manually controlled
-The collective has to be lowered to maintain RPM
-Running or roll on landing maybe performed at the engine can maintain sufficient road to RPM
-If there’s enough power, enter auto rotation
11-22 before responding to any type of mechanical failure, Pilot to confirm that the Rotor RPM is not responding to flight control input. If the RPM can be maintained in the operating range, the failure is in the…
Instrument and not mechanical.
11-22 low frequency vibration vibrate at how many cycles per minute, and usually from where
-100 to 500 cycles per minute
-from the main rotor disc
11-22 list some causes of low frequency vibrations
-out of track or out of Balance main rotor blades
-Damaged blades
-Worn bearings
-Dampers out of adjustment
-Worn parts are possible cause
11-23 at what frequency or medium and high frequency vibrations
1000 to 2000 cycles per minute.
11-23 list some causes of medium and high frequency vibrations (3)
- Engine and transmission cooling fans.
- Accessories such as air conditioner compressors.
- Driveline components.
11-23. Most Taylor vibrations fall into a high frequency range at how many cycles per minute.
2100 cycles per minute or higher
-Can be felt through the tail as long as there are no hydraulic actuators to dampen out the vibration
-often felt in the pilots feet which leads to numbness
11-23 what is the tail rotor to main rotor rotation ratio
6:1
11-23 HUMS
Health and usage monitoring system
Monitors vibrations in the aircraft and offers records and corrective actions
What are the angles for main rotor disc interference (LTE)?
285 to 315 degrees.
What are the angles for tail rotor vortex ring state?
210 to 330 degrees.
How does main rotor disc interference affect the angle of attack of the tail rotor?
Increases that increasing tail of thrust. Right rudder must be added.
After the vortex passes, the angle of attack of a tail rotor will reduce. Be ready to compensate for that reduction.
What are some actions to reduce the onset of LTE?
- Avoid tailwinds below airspeed of 30 knots.
- Avoid OGE operations and high-power demand situations below airspeed of 30 knots at low altitude.
- Be especially aware of wind direction and velocity when hovering at winds of about 8 to 12 knots.
- Be aware that if a considerable amount of left pedal is being maintained, a sufficient amount of left pedal may not be available to counteract any anticipated right yaw.
- Execute right turns slowly to limit the effects of rotating inertia and decrease loading on the tail rotor to control yawing.
What are the steps for uncontrolled right yaw recovery?
- Apply left pedal.
- Simultaneously apply cyclic control to increase airspeed.
- If permitted, reduce power.
What should be done if the drive shaft or belt breaks?
The throttle must be closed.
What should you do in the event of hydraulic failure?
Check RFM for best answers.
In most aircraft, airspeed needs to be reduced to reduce control forces, hydraulic switch and circuit breaker should be checked and recycled. If hydraulic power is not restored, make a shallow approach to a running or roll on landing.
What happens in the event of a high side failure (governor or fuel control failure)?
The engine and rotor RPM tend to increase above the normal range due to the engine being commanded to put out too much power. Close the throttle and enter auto rotation.
What happens in the event of a low side failure (governor or fuel control failure)?
The engine output is allowed to go below the collective and normal RPM may not be attainable, even if the throttle is manually controlled. The collective has to be lowered to maintain RPM. Running or roll on landing may be performed if the engine can maintain sufficient RPM. If there’s enough power, enter auto rotation.
What should a pilot confirm before responding to any type of mechanical failure?
Confirm that the rotor RPM is not responding to flight control input. If the RPM can be maintained in the operating range, the failure is in the instrument and not mechanical.
What is the frequency range for low frequency vibrations?
100 to 500 cycles per minute, usually from the main rotor disc.
What are some causes of low frequency vibrations?
- Out of track or out of balance main rotor blades.
- Damaged blades.
- Worn bearings.
- Dampers out of adjustment.
- Worn parts are possible causes.
What is the frequency range for most tail rotor vibrations?
2100 cycles per minute or higher.
Can be felt through the tail as long as there are no hydraulic actuators to dampen out the vibration, often felt in the pilot’s feet which leads to numbness.
What is the tail rotor to main rotor rotation ratio?
6:1.
What does HUMS stand for?
Health and usage monitoring system.
Monitors vibrations in the aircraft and offers records and corrective actions.
