Chapter 9, 11 Flashcards
While operating in a salt spray environment, a TGT rise of 20C or more for a constant torque is indicative of what? 40C?
20*C is an indication of engine performance degradation and possible salt encrustation
40*C is an indication of engine performance degradation that may result in compressor stalls
What is considered the gate position in dip-to-dip?
aircraft wings level, nose into the wind, and on final approach to the hover
During the dip-to-dip pattern, what are three things you cannot do?
- Do not decelerate below 50 KIAS until within 90 of the wind line.
- Do not descend below 90’ until into the wind.
- Do not uncouple the rotorhead with large reduction in collective during the maneuver.
When can you engage hover coupler?
When helo reaches the hover altitude/attitude with less than 5 KGS
What three things are required for hover checks?
- synchronize RADALT/BARALT
- check TGT/torque
- state OEI intentions
What is considered a steady coupled hover?
70’ hover with less than 4 KGS
Delay a minimum of _________ at trail before initiating departure or raising to seat.
two seconds
Dip-to-Dip: At night or IMC, turns shall not be initiated until when?
stabilized flight at 150’
In what configurations can the Stokes litter be used?
the SAR/MEDEVAC or Logistics/VERTREP configurations
it does NOT fit in the cabin in the SUW or ASW config.
What (generally) is the aircrewman doing during the rig for rescue checklist?
preparing the SAR equipment bag, Level “A” med kit, rescue equipment, raft/floatations, smokes, and stowing the Simula seat (as req.)
List the SAR safety precautions. “SHH ASH”
SMOKES
- do not fly low over Mk 58, second candle can eject up to 50’
- avoid cutting hands on sharp edges of Mk 58
- do not remove pull ring from Mk 58 until launching (battery exposed and seawater will activate)
- Mk 25 shall not be launched in a hover
- red phosphorous in smokes is highly caustic, do not inhale
HOVER
- TGT rise of 20C = salt encrustation, TGT rise of 40C = poss. compressor stalls
- hover alt. may be adjusted 40-90’
- maintain 1 rotor diameter between parachute and rotor downwash
- hoist may oscillate during recovery which may disengage RAD ALT
HOIST
- cable must be grounded to discharge static electricity prior to pickup
- cable abrasion during hoist can lead to cable failure
- personnel hoist shall not be attempted with a damaged hoist cable
ALL AIRCREW
- when cabin door is open, everyone in cabin shall wear crew harness or remain strapped in seat
- if lost ICS, notify copilot and use hand signals
SWIMMER
- swimmer shall not be required to enter the water to effect the recovery of inanimate objects
- with RIB aux, hoist devices may contact the fwd part of the fuel tank and cause damage or injury
HOIST OPERATOR
- there shall be a hoist operator in the cabin if a swimmer is deployed
- shall wear heavy duty glove during hoist
The swimmer shall enter the water and assist the survivor on all rescues except when…
the PIC determines that circumstances will unnecessarily expose the swimmer to danger
Name four conditions existing at the scene of a rescue that could dictate procedures to be followed.
- sea state
- water temperature
- condition of the survivor
- proximity to other units
At what sea state is it recommended that the swimmer deploy on the hoist?
Douglas sea states of 3 or above
SAR lost ICS hand signals for the following:
Forward, Back
Right, Left
Up, Down
Hoist Up, Down
Ready for Fwd Flight
Req. Crew Hover
Forward: Elbow bent 90*, fingers extended pointing up
Back: Elbow bent 90*, fingers extended pointing down
Right: Elbow bent 90*, fingers extended up and perform waving motion
Left: Left arm extended, fingers extended
Up/Down: Palm motioning up or down
Hoist up/down: thumb up or down
Ready for fwd flight: circular motion, point forward
Req. crew hover: tap helmet, point aft
Is the wind line rescue pattern required?
No. With a visible horizon, NVD aircrews may maneuver the aircraft into the wind without use of the wind line rescue pattern in order to maintain sight of survivor.
How many yards downwind should you establish a steady hover from the survivor?
50 yards
Night/IMC: In the event of a loss of visual contact with the swimmer, the hoist operator shall…
cycle the rescue light. The swimmer shall illuminate the strobe light or ignite a flare to aid in reestablishing visual contact.
List the five basic rescue methods for overland SAR.
- landing to effect a rescue
- rescue via one or two wheels
- rescue via hoist
- rappelling
- direct deployment
Which overland sar rescue method is preferred?
landing to effect a rescue
more expeditious, reduces pilot/crew fatigue, and is the safest method of recovery
When the landing site is a combination of cross slope and up and down slope, which landing limit should you use?
the most restrictive
What is the required power margin for VERTREP per NATOPS?
6% between HOGE and CRP
What is power available defined as?
a continuous XMSN torque limit or TGT limiting with contingency power selected
VERTREP: What four things will the PNAC check once the load has been lifted off the deck?
Ng, TGT, torque, and Nr prior to transitioning to forward flight
The signals received from the LSE and aircrewman are advisory in nature with the exceptions of…?
“HOLD” and “WAVEOFF”
How is formation bearing maintained at night?
by vertically aligning the closest stabilator light and the tail cone light on the lead aircraft
What is the horizontal separation between helos if only two form lights are distinguishable? 1? 4?
Two: 2-4 rotor discs (optimal)
One: > 4 rotor discs (too far)
Four: < 2 rotor discs (too close)
When can you execute simulated EPs over unprepared surfaces where an autorotative state is entered?
if recovery is made at no less than 500’ AGL / 40 KIAS
What is the recommended / optimum airspeed for practice autos? for max glide?
80-85 KIAS optimum
100 KIAS max glide
What is your target Nr in the descent during practice autos? Why?
Nr 101-105%
aids in mitigating the effects of the EDECU attempting to govern the engines
What are the three waveoff criteria in the descent during practice autos?
- Nr > 110%
- Aircraft is not over the runway by 300’
- Aircraft is not aligned with the runway by 200’
Autos: What is the maximum nose-up attitude during the flare / power recovery?
35 deg.
What are the four types of FCF profiles?
A - Full systems check.
B - Engine check.
C - Controllability / drive train check.
D - AFCS check.
What is ground effect? When is the MH-60R considered to be in ground effect?
when rotor disc is within one rotor diameter of the ground. the ground reduces the amount of recirculated air through the rotor disc, increasing efficiency of lift production and reducing power req.
60R in ground effect at 45’ on RADALT (bc its on the bottom of the aircraft)
Describe blowback
with increasing forward airspeed, the rotor disc tilts aft.
the advancing blade experiences higher velocity relative wind than the retreating blade which creates more lift on the advancing side. phase lag causes max displacement to occur 90* after applied force so max upward flapping occurs at the 12 o’clock position and downward flapping at 6 o’clock.
Below 30 KIAS, the stabilator is at what position?
42* trailing edge down
At what airspeeds is translational lift experienced?
17 - 30 KIAS
Describe the effects of translational lift
as the flow of air moves through the rotor more horizontally, the rotor operates more efficiently. in forward flight, the rotor encounters undisturbed air versus recirculating vortices in a hover.
horizontal airflow reduces induced drag which decreases induced power required. profile and parasite drag effect power requirements at higher airspeeds which means the greatest benefit of translational lift is noticed at lower airspeeds
Explain the cause(s) of retreating blade stall. When is it most likely to occur?
as airspeed increases, the relative wind on the advancing blade increases but decreases on the retreating side.
as the in-air velocity of the retreating blade decreases with increasing forward airspeed, the AOA must be increased to equalize lift to provide stabilized flight. flapping aggravates the lift distribution on the retreating blade further and eventually the blade stalls.
most likely to occur when operating at high speed, gross weight, density altitude, and power
Name the methods of eliminating retreating blade stall
“PSA RAG”
“PSA RAG”
pitch (collective)
severity (decrease)
airspeed (decrease)
rotor rpm (increase)
altitude (decrease)
gross weight (decrease)
Explain Loss of Tail Rotor Authority
LTA is a power issue
the tail rotor can no longer produce enough thrust to react against the high torque and the helo will spin to the right
Define Loss of Tail Rotor Effectiveness
A wind issue - the inability of the tail rotor to provide sufficient thrust to maintain yaw controllability.
LTE: AOA Reduction
060* - 120*
in a right crosswind, AOA of the tail rotor for a given pitch setting tends to decrease which reduces effectiveness and requires additional left pedal to maintain heading.
LTE: Weather Vaning
120* - 240*
winds in this region tend to weather-vane the nose of the aircraft into the wind
if a yaw rate has already been established, weathervaning will act to accelerate the yaw rate as the tail passes through the wind
LTE: Tail Rotor VRS
210* - 330*
winds in this region can cause the tail rotor to operate within its own recirculated airflow. this causes tail rotor thrust variations that can initiate yaw rates
LTE: Main Rotor VRS
280* - 330*
winds in this region can cause the main rotor vortex to be directed onto the tail rotor resulting in changes in AOA to the tail rotor. tail rotor thrust can vary unpredictably resulting in high pedal workload to maintain directional control
How can you recovery from LTE?
“CAL”
“CAL”
1. collective lower - reduces torque and assists in arresting right yaw
2. airspeed increase - fwd cyclic and turn in direction of rotation as req.
3. left pedal apply
At what roll rate and airspeed does tail rotor spar loading / damage occur?
30 deg. per second and 75 KIAS
When executing high roll rate maneuvers to the left, what should you be cognizant of?
left roll rates (> 30*/sec above 75 KIAS) can combine with induced tail rotor gyroscopic and flapping loads to cause excessive tail rotor spar loading.
when executing high roll rate maneuvers to the left, collective should be lowered concurrently to control transient torque increases and reduce tail rotor spar loading
What can cause main rotor flapping margins to be exceeded and droop stop pounding to occur?
inducement of less than 1g flight by rapid application of forward cyclic
Describe the phenomena associated with rolling pullouts.
the weight vector of the aircraft increases in a rolling pullout due to centrifugal acceleration (g-loading)
lift produced by the rotor system must be increased proportionally to the g-load to arrest descent and establish level flight.
this can result in a situation where power required for recovery greatly exceeds total power available in the rotor system and a mushing occurs.
during mushing the aircraft will continue to descend rapidly even with max power applied, longitudinal cyclic control will feel sluggish, increased 4 per vibes, and retreating blade stall may occur.
Name the four flow states of a rotor system.
normal thrusting
vortex ring
autorotative
windmill brake
Describe vortex ring state
an aerodynamic condition where a helicopter may be in a vertical descent with max power required and little or no cyclic authority
tip vortices are created by air curling up from the bottom of the rotor system and rejoining the air entering the rotor from the top. they consume engine power but produce no useful lift. when the helo descends vertically, it settles into it’s own downwash, which greatly enlargens the tip vortices. VRS is a state where most of the engine power is wasted accelerating vortices around the rotor.
When is the effect of VRS measurable?
at descent rates greater than 700 FPM and airspeeds between 0-20 KIAS
worst at descent rates of 1500 FPM and airspeeds of 5-10 KIAS.
What is fully developed VRS characterized by?
an unstable condition where the helicopter experiences uncommanded pitch and roll oscillations, has little or no cyclic authority, and achieves a descent rate that may approach 6,000 FPM.
How do you recover from VRS?
- Decrease collective pitch.
- Increase forward airspeed.
- Enter autorotation if altitude permits.
The autorotative state can be achieved at descent velocities between approx. ________FPM and ________FPM at 19,000 lbs. gross weight.
3,125
4,450
What are the regions of the rotor disc in a steady state autorotation? What % is each one?
prop - 30%
auto - 45%
stall - 25%
Which of the three regions of the rotor disc create lift in an autorotation?
the prop region creates usable lift
the auto region produces forward-tilting force that creates lift and pro-rotational force that overcomes blade drag and keeps the rotor spinning at a constant rpm
the stall region creates only drag
What is the minimum rate of descent airspeed in an actual autorotation? max glide?
min ROD = 75 KIAS
max glide = 95 KIAS
Why do we practice shooting autos 5 KIAS faster than the optimum descent and distance values?
allows the aircraft speed to slow toward an ideal condition instead of away from it
Why do heavier aircraft descend slower in a steady-state autorotation than a lighter one?
heavier aircraft can have a greater rate of exchange of potential energy (alt. and weight) into kinetic energy (rpm) of the rotor system.
a rotor system with more kinetic energy needs more collective pitch to govern it to the optimum rpm. more collective pitch means more lift, therefore a smaller rate of descent for heavier aircraft.
essentially, you have to govern Nr more with collective in a heavier aircraft therefore decreasing your descent rate.
What is the relationship between Nr and descent rate in an autorotation?
as rotor rpm increases, descent rate increases
What is the static rollover angle?
28 deg.
What is the critical rollover angle?
12 deg. (also the cross-slope landing limit)
where full lateral cyclic input is required to trim the wheels level with the slope without sliding
What is the main contributor to dynamic rollover?
the buildup of angular velocity of the helicopter cg about the wheel touching the ground
lateral translation (drift) converted to angular motion (roll rate)
What is the most effective corrective action to prevent dynamic rollover?
smooth reduction of collective
Slope landings should be executed as slow, controlled, ________ descents. The PAC should place the ________ wheel on the ground first.
vertical; upslope
What is the best indication of the salt spray environment?
the amount of salt water spray observed on the windshield
if the spray is sufficient to require the use of the windshield wipers, the engines are ingesting a very significant amount of salt water
The probability of salt ingestion into the engine is greatest in winds of ______ to ______ knots. In this condition there are _________ on the water and moderately heavy salt spray is lifted off the water.
8 to 12 knots; whitecaps
At wind velocities of _____ to ______ knots and higher, salt spray is generated, but it is blown aft and underneath the engines so that the rate of salt ingestion is small.
15 to 20 knots
The ________ drag of an external load will __________ fuel consumption significantly.
parasite; increase
What are the most probable causes of one-per-revolution vibrations? How is it felt in the aircraft?
- Main rotor blades out of track
- Worn or loose rod end bearings
- Malfunctioning blade damper
felt as a vertical vibration
How are tail rotor drive shaft vibrations felt in the aircraft?
as a “buzz” in the pedals or a “tickling” in the nose similar to that of a feather
Instrument Takeoff Procedure
- Select hover mode on FD
- Smoothly increase collective to takeoff power and maintain hover attitude. Allow AFCS to maintain heading.
- Smoothly increase collective to climb out power. Thru 20’ on RADALT, nose over 5 deg and accelerate forward. Feet off the pedals.
- Est. 500 fpm rate of climb.
- Maintain accel. up to 90 KIAS.
Practice Autos: During the flare and power recovery, a wave off shall be executed if:
- The aircraft balloons in excess of 50’
- There is excessive lateral drift
- An excessive sink rate develops
- Rotor speed exceeds 115% Nr
- Recovery not initiated by 60’ AGL
- Any condition indicating potential tail slide
During an autorotation, an Np indication that exceeds 109% or remains matched with Nr for several seconds is an indication of __________________.
an LDS malfunction
If this occurs, initiate a waveoff immediately. Lowering collective to minimum with an engine LDS malfunction will cause Np and Nr to rise rapidly and may cause activation of the Np overspeed protection system.
