C3101 EP's Flashcards
Abnormal Starts
The Abort Start procedure is intended for use when any abnormalities are encountered during the start sequence.
An excessive rise in TOT, TOT rapidly accelerating through 840 °C,
and/or the battery voltage stabilized below 17 volts on starter engagement
particularly when combined, indicates an increased potential for a hot start
and may necessitate aborting the start to preclude an overtemp.
In the event of a mechanical failure in the engine or control linkage, the twist grip may not secure fuel flow to the
engine. Turning the fuel valve off will provide the only means of securing fuel flow if the twist grip fails to control
TOT.
Failure to utilize a GPU/battery cart on subsequent start attempts may result
in hot start.
Abort start under the following conditions:
1. Battery voltage stabilized below 17V.
2. TOT fails to rise after twist grip rotated to flight
idle and Ng fails to rise above 20 percent (igniter
failure).
3. TOT rises more slowly than normal and Ng rises
slowly and stabilizes (hung start).
4. TOT exceeds limits and TOT caution light flashes
twice per second (hot start).
5. Engine Oil Pressure remains at 0 PSI.
6. Rotors not turning by 25 percent Ng.
7. Transmission Oil Pressure not indicated by 30
percent Nr.
*1. Twist grip — Close.
*2. Starter — OFF after TOT stabilizes at 400 °C or
below.
Engine Overspeed
Indications: 1. Nr increase. 2. Nf increase. 3. Ng increase. 4. TOT increase. 5. Right yaw. 6. Engine noise increase.
*1. Twist grip — Reduce (to maintain Nf/Nr in
operating range).
*2. Collective/twist grip — Coordinate.
*3. Land as soon as possible.
Sprag Clutch Slippage
Indications: When the twist grip is increased to full open, the pilot may experience the following: 1. Nf indication higher than Nr. 2. Low torque indication. 3. Ng and TOT indications lower than normal and not responsive to collective.
*1. Autorotate.
*2. Twist grip — FLT IDLE.
If time and altitude permit:
*3. Twist grip — Smoothly rotate to full open.
If Nf/Nr are married:
*4. Collective — Increase.
Note
Multiple attempts to reengage the sprag clutch
are permitted dependent on time and altitude.
If sprag clutch continues to slip:
*5. Autorotate.
*6. Twist grip — Closed.
If the sprag clutch reengages:
*7. Land as soon as possible.
After completing the autorotative landing, ensure
the twist grip is secured. Failure to do so may
result in sudden reengagement of the sprag
clutch, causing severe damage to the drive
system.
Hydraulic System Failure
Indications:
- HYDRAULIC PRESSURE caution light.
- Increased force required for control movement.
- Feedback in control.
1. Airspeed — Adjust (to obtain most comfortable control movement level). 2. HYDRAULIC BOOST switch — Check ON. 3. HYD BOOST circuit breaker — Pull. If system is restored: 4. Land as soon as practicable. If system is not restored: 5. HYD BOOST circuit breaker — In. 6. HYDRAULIC BOOST switch — OFF. 7. FORCE TRIM (FT) — ON. 8. -C- FCS STAB — ON. 9. -C- ALT — OFF. 10. Land as soon as practicable.
Hydraulic Power Cylinder Malfunction
Indications:
1. Cyclic/collective control displaces to abnormal
position.
2. Pilot control of cyclic/collective is difficult or
impossible.
*1. HYDRAULIC BOOST switch — OFF.
Hydraulic system will not secure if HYD BOOST
circuit breaker is out and the pilot will be unable
to maintain control of the aircraft.
*2. Helicopter — Regain control.
*3. Airspeed — Adjust (to obtain most comfortable
control movement level).
*4. Land as soon as possible.
In the event of a complete loss of electrical
power -B- or a loss of electrical power to
the ESS No. 2 bus (e.g., failure of the Main
Generator and Main Battery), -C- , the hydraulic
system will reenergize in the malfunction mode.
The pilot will be unable to override the hydraulic
boost solenoid.
Compressor Stall
Indications:
- Popping, rumbling or loud banging.
- Abnormal vibrations.
- Rapid rise or fluctuations in TOT.
- Torque fluctuations with yaw kicks.
- Ng fluctuation.
- Loss of power.
This emergency may result in engine failure.
*1. Collective — Lower.
Note
Power (collective) reduction will often eliminate compressor stalls. *2. ENG Anti-ice switch — ON. *3. Cabin Heat Valve — ON. *4. Check power available. Note
Power available is considered sufficient if level
flight can be maintained with Nr at 90 percent
or higher.
If power is insufficient to maintain level flight:
*5. Autorotate.
*6. Twist grip — Flight Idle.
Note
If some usable power exists but level flight
cannot be maintained, that power, if sufficient,
may be utilized to effect a landing or minimize
rate of descent enroute to suitable site for
autorotation.
If power is sufficient to maintain level flight:
*7. Land as soon as possible.
Note
Depending on time, altitude, and suitability of the
landing site the pilot may attempt to increase the
twist grip after the compressor stall has cleared
to affect a power on landing. Increasing the twist
grip may re-aggravate the compressor stall.
Engine Failure
Indications: 1. Nr decrease. 2. Rapid settling. 3. Left yaw. 4. ROTOR LOW RPM caution light and audio. 5. ENGINE OUT caution light and audio. 6. GEN FAIL -B- or MAIN GEN FAIL -C- caution light.
*1. Autorotate.
*2. Shoulder harness — Lock.
If time and altitude permit:
*3. Mayday — Transmit.
*4. Transponder — Emergency.
*5. Engine Restart in Flight procedure — as required.
Engine Restart
The decision to attempt an engine restart during flight is the pilot’s responsibility and is dependent upon the pilot’s
experience and the operating altitude. Ensure autorotation is established and maintained until power is restored.
Consideration must be given to the cause of the failure prior to attempting restart. If able, engage starter within 10
seconds of power loss.
*1. Ng — Note.
If Ng is below 12 percent:
Note
Ng will not decrease below minimum starting
speed within 10 seconds because of rotational
inertia plus possible ram effect. The twist grip
can be left full open, since fuel flow during the
start will be on the normal start acceleration
schedule.
*2. Twist grip — Close.
*3. Starter — ON.
*4. At 12 percent Ng, Twist grip — Full open.
If Ng is 12 percent or above:
*5. Starter — ON.
*6. At 58 percent Ng, starter — OFF.
If light-off occurs:
*7. Land as soon as possible.
Note
Main generator and BUS/TIE RELAY -C- may
need to be reset.
Main Driveshaft Failure
Indications: 1. Nr decrease. 2. Nf indication higher than Nr. 3. Left yaw. 4. Loud bang/sound of overspeeding engine. 5. Low torque.
*1. Autorotate.
*2. Twist grip — Adjust, if necessary, to maintain Nf
in operating range.
The engine must continue to operate to provide
tail rotor drive. Tail rotor authority may be lost if
Nf
is allowed to go below 80 percent.
Note
The Nf governor should bring the Nf back to
100% with the twist grip full open.
When on deck:
*3. Emergency shutdown — Complete.
Torquemeter Malfunction
Torquemeter Wet Line Rupture
If the torquemeter needle is unusually low or falls to zero with a corresponding digital readout, it is probable that
the torque line has ruptured. A restrictor fitting in the wet line will slow the rate of engine oil loss, but will not stem
the flow.
Indications:
1. Low needle indication and digital readout.
- Monitor engine oil instruments.
- Land as soon as possible.
Torquemeter Electrical Failure
The torquemeter incorporates a transducer between the wet line and the gauge. If the needle falls to zero and the
digital readout is extinguished, the cause is a loss of electrical power to the indicator.
Indications:
- Needle reads zero torque.
- Digital readout extinguished.
If circuit breaker was not popped or does not reset:
1. Monitor engine instruments.
2. Land as soon as practicable.
Note
Some minor torque fluctuation is normal and
should not be cause for concern.
Loss of Tail Rotor Thrust
Indications:
1. Pedal input has no effect on helicopter trim.
2. Right yaw (left sideslip).
3. Left roll of fuselage along the longitudinal axis.
4. Loud bang.
Delayed-Onset Indications:
1. High frequency vibrations.
2. Whining, grinding.
3. Yaw kicks, often during power changes.
4. Restricted or difficult movement of pedals.
5. Unusual pedal positions.
In a hover:
*1. Twist grip — Flight idle.
*2. Cyclic — Eliminate drift.
*3. Collective — Increase to cushion landing.
Transition to forward flight or hover/air taxi:
*1. Twist grip — Flight idle.
*2. Cyclic — Eliminate sideward drift.
*3. Collective — Increase to cushion landing.
At altitude:
*4. Autorotate.
If yaw is not controllable:
*5. Twist grip — Flight idle immediately.
If yaw is controllable:
*6. Continue powered flight and set up to a suitable
landing area at or above minimum rate of descent
autorotational airspeed.
Autorotation may be the safest option. Attempting
to control a loss of tail rotor thrust in powered
flight requires considerable skill and may result in
loss of aircraft control.
• Airspeed indications during side-slip are
unreliable. At airspeeds below approximately
50 knots, the side-slip may suddenly become
uncontrollable, and the helicopter will begin an
unrecoverable vertical axis “flat spin”.
• If attempting to achieve higher airspeeds, care
must be taken to avoid excessive cyclic inputs
coupled with large power settings that could lead
to mast bumping or rapid nose tucking.
Note
• Depending on the nature of the failure and degree
of damage, airspeeds between 50 to 72 KIAS
may provide the best opportunity to maintain
level flight.
• A non-typical nosedown attitude may be required
to achieve a desired airspeed due to increased
drag on the tail.
• Turns to the right may provide greater
controllability of airspeed and potentially minimize
altitude loss.
• Banking to the left will aid in counteracting torque.
*7. Autorotate.
*8. Twist grip — Rotate to flight idle prior to
touchdown.
• In the autorotation, maintain airspeed above
minimum rate of descent airspeed until flare to
avoid loss of yaw control.
• Once the engine is secured, in the absence
of torque, the lift produced by the vertical fin
may tend to yaw the nose to the left at faster
speeds. As airspeed slows and Nr decays, the
decelerating rotorhead and swashplate friction
will create additional left yaw, increasing the
chance for rollover. Depending on landing profile,
consideration should be given to leaving twist grip
open until pulling collective at the bottom of the
autorotation to allow control of yaw with twist grip.
Vibration Identification
11.17.1 Low-Frequency Vibrations
Low-frequency vibrations, one per revolution and two per revolution, are originated by the main rotor.
One-per-revolution vibrations are of two basic types: vertical or lateral. A vertical one-per-revolution vibration is
caused by one blade developing more lift than the other blade at the same point or, simply, an out-of-track condition.
A lateral one-per-revolution vibration is caused by an unbalance of the main rotor because of either a difference or
weight between the blades (spanwise unbalance) or the misalignment of the blades (chordwise unbalance).
Rigidly controlled manufacturing processes and techniques eliminate all but minor differences between blades,
resulting in blades that are nearly identical; these minor differences may affect the flight vibration level and are
reduced by adjustments of the trim tabs, blade pitch settings, or small balance adjustments.
Sometimes during steep turn maneuvers, one blade may pop out of track, causing a vertical one-per-revolution
vibration. This condition generally indicates an excessive trim tab setting differential and is corrected by rolling the
blade and reducing some of the trim tab differential.
Two-per-revolution vibrations are inherent with the two-bladed rotor systems and a low level of vibration is always
present. The normal two-per-revolution threshold is approximately 100 to 110 knots and becomes more pronounced
with additional speed.
11.17.2 Medium-Frequency Vibrations
Medium-frequency vibrations at frequencies of four per revolution and six per revolution are other inherent
vibrations associated with the main rotor system. An increase in the level of these vibrations is caused by a change
in the capability of the fuselage to absorb vibrations or a loose airframe component vibrating sympathetically at
that frequency.
11.17.3 High-Frequency Vibrations
High-frequency vibrations can be caused by anything in the aircraft that rotates or vibrates at a speed equal to or
greater than that of the tail rotor.
High-frequency vibrations are much too fast to count and feel like a buzz. These frequencies may come from the
engine, improper drive shaft alignment, couplings improperly functioning, bearings dry or excessively worn, or an
out-of-track tail rotor. If excessive high-frequency vibrations exist, it is recommended that the aircraft land and a
crewmember attempt to locate the source. The area where the highest amplitude of the vibration exists is generally
the area from which the vibration is originating.
High Frequency Vibration
Procedures:
*1. ECS — OFF.
If vibrations continue:
*2. Land as soon as possible.
• Be prepared to execute Complete Loss of Tail
Rotor Thrust procedures.
• Increased power settings required to accomplish
a normal approach may ultimately precipitate
the complete failure of a malfunctioning tail
rotor. Be prepared for uncommanded right yaw
in the event of complete loss of tail rotor thrust
during the approach. Consideration should be
given to maintaining an autorotative profile or
low-powered approach.
If vibrations cease:
3. Land as soon as practicable.
Fuel Control Failure
If TOT is fluctuating, it will be fluctuating in the same
direction as Ng due to erratic fuel scheduling.
Indications:
1. Erratic Nf /Nr.
2. Fluctuating Ng and/or TOT.
Procedures:
*1. Collective — Adjust as required to maintain Nr in
operating range.
*2. Twist grip — Adjust as required to maintain Nf
in
operating range.
*3. Land as soon as possible.
This emergency may result in engine failure.
