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Flashcards in Emergency Procedures Deck (53):

Emergency Shutdown

  • Executed anytime a rapid crew egress is necessary (engine, electrical or fuselage fires in or around helo or severe hard landing)


  • Indications: fire warning light on, smoke, fuel fumes, fire, indication for ground personnel, grinding noise or apparent drive train damage)


*1. Twist grip - Close

*2. Fuel valve - OFF

*3. Battery switch - OFF

*4. Helicopter - Egress and use the fire bottle as reqired to extinguish the fire or get clear of the aircraft

Warning - After exiting aircraft, beware of rotor blades


Abort Start

  • any abnormalities are encountered during the start sequence


  • Igniter failure: TOT fails to rise after twist grip rotated to flight idle, Ng fails to rise above 20%


  • Hung start: Ng rises slowly and stabilizes, TOT rises moer slowly than normal


  • Hot start: TOT exceeds limits, TOT caution light and digital display flash twice per second

Note: 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 necessistate aborting the start to prclude 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.

Note: If a subsequent start is attempted, utilize a GPU

*1. Twist grip - close

*2. Starter -  secure after TOT stabilizes at 400°C or below


Post Shutdown Fire (Internal)

  • internal engine fire that occurs in an engine that is stopped or coasting down


  • Indications: TOT rises above 400°C, flames or smoke coming from engine


*1. Starter - Engage

*2. Fuel valve - OFF

*3. Igniter circuit breaker - Pull

*4. Starter - Secure after fire is extinguished


Engine Failure


  • Immediately upon an engine failure, rotor rpm will decay and the nose will swing to the left due to loss in power and corresponding reduction in torque


  • Heading can be maintained by depressing the right pedal to decrease the tail rotor thrust


  • At and altitude of 75-100 ft, a flare should be established by moving the cyclic stick aft with no change in collective pitch


  • From a 5ft skid height - do not attempt collective reduction but use the available rotor energy and collective to cushion touchdown. Above 5ft skid heights - a partial reduction of collective will maintain rotor rpm until up collective is initiated to cushion touchdown


  • Best glide airspeed is 72 KIAS. Minimum rate of descent airspeed is 50 KIAS. Do not exceed 100 KIAS in sustained autorotation.
  • If time and altitude permit, engine restart may be attempted. The decision to attempt a restart is the pilot's responsibility and is dependent upon the pilot's experience and operating altitude.
  • All autorotative landings should be made into the wind to a suitable landing site.


  • Indications: Nr decrease, rapid settling, left yaw, ROTOR LOW RPM caution light and audio, ENGINE OUT caution light and audio


Engine Failure in Flight

  • a safe landing can be accomplished, provide that altitude and airspeed combination is within safe limits and altitude is sufficient to permit selection of a suitable landing area. Consideration should be given to an engine restart in flight


*1. Autoroate

*2. Shoulder harness - Lock

If time and altitude permit:

*3. Mayday - Transmit

*4. Transponder - Emergency


Engine Failure at High Airspeed and Low Altitude

  • rapid loss of Nr accompanied by a severe nose-tucking tendency will occur

*1. Cyclic - Immediately apply aft

*2. Autorotate

Warning: Rapid cyclic movement should be avoided to preclude mast bumping


Overtorque, Overspeed, Overtemp

  • any overtorque exceeding 110%, overspeed or overtepm is observed -   land as soon as possible


Compressor Stall

  • Indications: popping or rumbling noise, vibrations, rapid rise in TOT, Ng fluctation, loss of power

Warning: Be prepared for complete power loss

*1. Collective - Reduce

Note: Slight power (collective) reduction will often eliminate compressor stalls

*2. ENG Anti-ice switch - OFF

*3. Cabin Heat Valve - OFF

*4. Land as soon as possible

Caution: When accelerating the rotor system during the inital rotor engagement or after power off maneuvers, exceeding 40% torque may induce engine chugging which may induce compressor stall

Note: Mild compressor stalls may occur that will allow powered flight if TOT is within operating limits


Underspeeding Nf/Nr

  • Indications: low Nr, low Nf


*1. Collective - Adjust as required to maintin Nr in operating range

*2. Twist grip - Full open

*3. GOV RPM - Full increase

*4. Check power available with Nr in limits

Note: Power available is considered to be sufficient if level flight can be maintained with Nr at 90% or higher. Do not decelerate below 50 KIAS (minimum power airspeed) while executing a pwer check.

If power is not sufficient:

*5. Autorotate

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 a more suitable site for autorotation. Terrain permitting, a sliding landing requires the least amount of power.

If sufficient power is available:

*6. Land as soon as possible


Power Required Exceeds Power Available

  • Indications: uncommanded descent with torque at maximum allowed, rotor droop, loss of tail rotor effectiveness


*1. Collective - Adjust as required to maintain Nr in operating range

*2. Twist grip - Full open

*3. Airspeed - Increase/decrease to 50 KIAS (minimum power required airspeed)

*4. Angle of bank - Level wings

*5. Jettison - As required

If impact is imminent:

*6. Level the aircraft to conform to terrain

*7. Cushion the landing


Engine Overspeed (Nf) Rotor RPM (Nr)

  • Indications: Nr increase, Nf increase, Ng increase, TOT increase, right yaw, engine noise increase


*1. Collective - Adjust as required to maintain Nr in operating range

*2. Twist grip - Reduce (to maintain Nf in operating range)

Note: The Nf overspeed must be controlled by continually coordinating collective and twist grip

*3. Collective/twist grip - Readjust

*4. Land as soon as possible


Fuel Control Failure

  • Indications: erratic Nf, Fluctuating Ng and/or TOT


*1. Collective - Adjust as required to maintain Nr in operating range

*2. Twist grip - Adjust (to maintain Nf/Ng in operating range)

*3. Land as soon as possible

Warning: Be prepared for complete power loss


Engine Restart in Flight

  • Engine flameout in flight would most likely result from a malfunction of the fuel control unit or fuel system
  • Decision to attempt an engine restart during flight is the pilot's responsibility and is dependent upon the pilot's experience and operating altitude.
  • Consideration must be given to the cause of the failure prior to attempting restart


*1. Autorotate

*2. Ng - Check

If Ng is below 12%:

*3. Twist grip - Close, perform normal start

If Ng is 12% or above:

*4. Starter - Engage, perform normal start

Note: Ng will not decrease below minimum starting speed within 10 seconds because of rotational inertia plus possible ram air effect. The twist grip can be left in the full open position since fuel flow during the start will be on the normal acceleration schedule

If light-off occurs:

*5. Land as soon as possible


Main Drive Shaft Failure

  • Indications: Nr decrease, Nf indication higher then Nr, left yaw, loud bang/sound of overspeeding engine

*1. Autorotate

*2. Twist grip - Adjust to maintain Nf/ng in operation range

Warning: The engine must continue to operate to provide tail rotor drive. Tail rotor drive effectiveness may be lost if Nf is allowed to go below 80%

When on deck:

*3. Emergency shutdown - Complete


Sprag Clutch Slippage

  • May occur following power-off maneuvers in which Nr and Nf have been split


  • When the twist grip is increased to full open, the pilot may experience the following indications: Nf indication higher than Nr, low torque indication, Ng and TOT indications lower than normal and not responsive to collective


*1. Autorotate

*2. Twist grip - Flight idle

If time and altitude permit:

*3. Twist grip - Smoothly rotate to full open

If Nf/Nr are married:

*4. Collective - Increase

If sprag clutch continues to slip:

*5. Autorotate

*6. Twist grip - Closed

If sprag clutch reengages

*7. Land as soon as possible

Caution: 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.

Note: Multiple attempts to reengage the sprag clutch are permitted dependent on time and altitude


Sprag Clutch Seizure

  • Indications: Nf/Nr marriend during shutdown, Nf/Nr married above 100% during autorotational flight

Note: In a normal autorotation, Nr and Nf may be matched together between 92 - 96% steady state.

*1. Ensure twist grip is full open

*2. Land as soon as possible

Warning: If suspected during a practice autorotation, execute a waveoff


Imminent Transmission Failure

  • If abnormal transmission temperature or pressure indications are accompanied by the illumination of the TRANS CHIP light or abnormal sound from the transmission area

*1. Land immediately

Warning: Do not autorotate; minimize power changes

*2. Lock harness


Engine Fire in Flight

  • Indications: fire light, smoke, flames

Warning: Be prepared for complete power loss


*1. Confirm existence of fire

If fire exists:

*2. Land immediately

*3. Emergency shutdown - Complete after landing

If fire not confirmed:

*4. Land as soon as possible


Fuselage Fire

*1. Land immediately

*2. Emergency shutdown - Complete

Warning: Fire extinguisher fluid vapors are dangerous; fire extinguisher use should be limited to a well-ventilated area. A moving TH-57 with the cabin vents and windows open is considered to be a well-ventilated area

Note: A sideslip may be desireable to keep the flame from spreading


Fuel Boost Pump Failure

  • Failure of one or both boost pumps will be evidenced by illumination of the FUEL PUMP caution light.


  • If one pump has failed, indicated fuel pressure will be normal (4-30 psi). The failed pump can be identified by alternately pulling the FUEL BOOST FWD and FUEL BOOST AFT circuit breakers and observing any resulting change in indicated fuel pressure


  • If both pumps have failed, indicated fuel pressure will be zero


  • The engine will operate with only one operable boost pump under all conditions of power and altitude; with a dual boost pump failure, the engine-driven fuel pump is only capable of supplying fuel to the engine at altitudes below 6000 ft PA


  • In the event of a single or dual boost pump failure, maintain a level-attitude and balanced flight to the maximum extent possible to precent engine flameout that could be caused by the operating submersible pump being uncoverend and allowing air to be drawn into the fuel lines or by both boost pumps being inoperative and allowing air to be drawn into the engine-driven fuel pump


  • Indications: FUEL PUMP caution light, indicated fuel pressure of zero (dual-pump failure)


*1. Descent - Initiate if above 6000 ft PA and flight permits

*2. Fuel pressure and quantity - Note

Warning: With one or both boost pumps inoperative, minimum fuel is 20 gallson; 10 gallson is unusable

If both boost pumps have failed (fuel pressure at zero)

Warning: Be prepared for complete power loss

*3. Land as soon as possbile

If only one boost pump as failed (fuel pressure 4-30 psi)

4. Land as soon as practical


Suspected Fuel Leakage

  • Indications: unusual fuel usage, fuel fumes in cockpit

*1. Land as soon as possible

If time and altitude permit:

*2. Transmit position and intentions

*3. Unnecessary electrical equipment - Secure

Warning: If an air leak exists in the fuel lines between the boost pumps and engine, turning off all electrical power could cause an engine flameout due to a total loss of boost pump pressure

When on deck:

4. Shutdown - Completed

5. Helicopter - Exit


Mast Bumping

  • Indications: Sharp two-rev knocking

If mast bumping is suspected:

*1. Establish positive G load

*2. Land immediately

During low g maneuvers (below +0.5g) (other than nose high):

*1. Cyclic aft, then center laterally to regain positive g (thrust) on the rotor and maintain Nr

*2. Land immediately

During nose high, low airspeed:

*1. Collective - Judiciously increase, if possible

*2. Pedals - As required

*3. Cyclic - Move to neutral position

*4. Land immediately

During other flight conditions:

*1. If mast bumping is suspected - Land immediately 


Main Generator Failure

  • Indications: loadmeter to zero, MAIN GEN or GEN FAIL caution light on, Dc voltmeter indicates battery voltage

1. MAIN GEN FIELD and MAIN GEN RESET circuit breakers - Check in

2. MAIN GEN switch - Reset, then ON

If generator power is not restored:

3. MAIN GEN switch - OFF

Note: Prior to shutting off all electrical power, the pilot must determine the equipment that is essential to the particular flight environments that will be encountered (flight instruments and fuel boost pumps)

4. Unnecessary electrical equipment - OFF

7. Descend below 6000 ft PA

8. Land as soon as practical

If power is restored:

9. Continue flight

Warning: With the battery switch OFF  or battery exhaustion, both fuel boost pumps are inoperative. With one or both boost pumps inoperative, minimum fuel is 20 gallons, 10 gallons is unusable

Note: Be prepared for a possible electrical and/or engine compartment fire because of excessive wiring load or generator meltdown


DC Loadmeter and Voltmeter

If the loadmeter or voltmeter fluctuates erractically, pegs, or goes to zero:

1. Main Generator switch - Reset, then ON

If the problem is corrected:

2. Continue flight

If the problem is not corrected:

3. Main Generator Failure procedures - Execute

Caution: Sustained loadmeter indications greater than 70% may be followed by an electrical fire


Electrical Fire


  • Indications: loadmeter shows excessive load, Dc voltmeter shows excessive load, smoke, fumes, sparks
  • Prior to shutting off all electrical power, the pilot must consider the equipment that is essential to the particular flight environment that will be encountered (flight instruments and fuel boost pumps)


Electrical Fire - Unknown Origin

*1. BATT switch - OFF

*4. MAIN GEN switch - OFF

If fire persists:

*5. Land immediately

If fire extinguishes:

*6 Land as soon as possible

If electrical power is required to restore minimum equipment for continued flight, proceed as follows:

7. All circuit breakers - Pull

9. BATT switch - ON

10. MAIN GEN FIELD AND MAIN GEN RESET circuit breakers - In

11. MAIN GEN switch - Reset, then ON

15. Circuit breakers for essential equipment- In one at a time in order of importance

Note: Ensure corresponding bus supply circuit breakers are in to provide power to desired electrical equipment.

Voltmeter will not indicate battery voltage until battery bus supply and voltmeter circuit breakers are in

Flight operation can be maintained without battery and generator. Instruments powered by the 28 Vdc power, however, will be inoperative. 


Electrical Fire - Known Origin

*1. Affected equipment - Secure

*2. Affected circuit breakers - Pull

If fire persists:

*3. Electrical Fire - Unknown Origin procedure - Execute

If fire extinguishes:

4. Land as soon as practical


Smoke and Fume Elimination

  • Indications: fumes in cockpit, smoke in cockpit, equipment failure

*1. ECS and DEFOG blower - OFF

*2. Vents/windows - Open

*3. Slip or skid aircraft to eliminate smoke and fumes

*4. Land as soon as possible


Hydraulic System Malfunctions


  • With force trim and AFCS ON, the workload necessary to maintain required control is greatly reduced. The aircraft can best be flown when attitude and power adjustments are made smoothly, gradually, and in small increments. IFR speeds of 70-90 knots can easily be managed with no hydraulics if force trim and AFCS are ON. For landing with a hydraulic malfunction, the LAT mode of the AFCS shall be disengaged.

Note: Odd or unusual stick forces will be felt in a boost-off situation. Because of excessive foreces required for control manipulation, a shallow approach with a sliding landing is recommended


Hydraulic System Failure

  • Indicaitons: HYDRAULIC PRESSURE 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 practical

If system is not restored:

5. HYD BOOST circuit breaker - In



10. Land as soon as practical


Hydraulic Power Cylinder Malfunction

  • Indications: Cyclic/collective control displaces to abnormal position, pilot control of cyclic/collective is difficult or impossible


Warning: Hydraulic system will not secure if HYD BOOST circuit breaker is out

*2. Helicopter - Regain control

*3. Airspeed - Adjust (to obtain most comfortable control movenment level)

*4. Land as soon as possible

Warning: In the event of a complete loss of electrical power, the hydraulic system will reeenergize in the malfunction mode. The pilot will be unable to override the hydraulic boost solenoid


High-Frequency Vibration

  • Too fast to count and may be manifested as a buzz in the pedals.


  • May come from the engine or accessory gearbox components, improper drive shaft alignment, malfunctioning couplings, dry or excessively worn bearings, or an out-of-track or damaged tail rotor


  • If associated with a malfunctioning tail rotor, the time from onset of vibration to complete loss of tail rotor thrust may be extremely limited. Recognition of suspected failure of the tail rotor drive system relies heavily on pilot judgment. Indications of impending failure include, but are not limited to, sudden increase in amplitude of vibrations, unusual noises and T/R CHIP caution light


*1. ECS - OFF

If vibrations continue:

*2. Land as soon as possible

Warning: 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 tial 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 practical


Complete Loss of Tail Rotor Thrust

  • Involves a break in the drive system, such as a severed driveshaft, or damage to/loss of the tail rotor, where thrust produced is minimal or nonexistent


  • Indications: Pedal input has no effect on helicopter trim, right yaw (left sideslip), left roll of fuselage along the longitudinal axis, loud bang


  • Delayed-onset indications: high frequency vibrations, whining, grinding, yaw kicks (often during power changes), restricted or difficult movement of pedals, unusual pedal positions

In a hover:

*1. Twist grip - Close

*2. Cyclic - Eliminate drift

*3. Collective - Increase to cushion landing

Transition to forward flight or hover-air taxi:

*1. Twist grip - Close

*2. Cyclic Eliminate sideward drift

*3. Collective - Increase to cushion landing

At altitude:

*1. Collective - Reduce to minimize yaw

*2. Cyclic - Adjust for best airspeed to control yaw

Warning: Airspeed indications during side-slip are unreliable. At airspeeds below approx. 50 knots, the sideslip 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 50-72 KIAS may provide the best opportunity to maintain level flight. Due to yaw stiffness provided by the vertical fin at higher airspeeds, it may be possible to continue at faster airspeeds in cruise or descent depending on power requirements.

A non-typical nose down 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.

If yaw is not controllable:

*3. Autorotate

*4. Twist grip - Clsoed prior to flare

If yaw is controllable:

*5. Continue powered flight and set up to a suitable landing area at or above minimum rate of descent autorotational airspeed

*6. Autorotate

*7. Twist grip - Closed prior to flare

Warning: 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 ten 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, consideratoin should be given to leaving twist grip open until pulling collective at the bottom of the autorotatoin to allow control of yaw with twist grip.


Fixed Pitch Right Pedal (Low Power)

  • Probable causes: pedals locked in fixed position because of FOD, control linkage failure during a right-pedal applied situation
  • Helicopter reaction: pilot will be unable to control right yaw with pedal input. If power is increased, it will tend to aggravate the degree of yaw or sideslip

In a hover:

*1. Collective - Decrease to effect a power-on landing

If rate of rotation is excessive or landing surface is unsuitable for a power-on landing:

*2. Twist grip - Reduce as nose approaches windline

*3. Cyclic - Eliminate drift

*4. Collective - Increase to cushion landing

At altitude:

1. Maintain airspeed and engine rpm to streamline the aircraft

2. Plan an approach to a smooth level surface into the wind or with a slight left crosswing if possible

3. Establish a shallow approach, maintaining 60 KIAS until on final

Note: In such an approach profile, it isnot unusual for the nose to be yawed slightly to the left

4. At 50-75 ft AGL and when the landing area can be made, start a slow deceleration to arrive over the intended landing point with minimum forward speed required for directional control

5. At approximately 2-3 ft skid height, increase collective to slow the rate of descent and coordinate twist grip to maintain nose alignment

Warning: If necessary, a waveoff should be made early in the approach, using cyclic to increase forward airspeed. if it becomes necessary to use large collective inputs to wave off near the deck, thenose will yaw right and possible enter uncontrolled flight.

Note: If nose swings right after touchdown, follow the turn with cyclic to prevent the aircraft from rolling over.


Fixed Pitch Left Pedal (High Power)

  • Probably causes: pedals locked in fixed position because of FOD, control linkage failure during a left-pedal applied situation


  • Helicoper reaction: pilot iwll be unable to control left yaw with pedal input. If power is decreased, it will tend to aggravate the degree of yaw or sideslip

In a hover:

If rate of rotation os not excessive and landing surface is smooth and firm:

*1. Collective - Decrease to effect a power-on landing

If rate of rotation is excessive or landing surface is unsuitable for a power-on landing:

*2. Twist grip - SLowly reduce while increasing collective to stop rotation.

*3. Collective - Coordinate with twist grip to maintain heading and allow aircraft to settle

At altitude:

1. Maintain airspeed and engine rpm to streamline the aircraft.

2. Plan an approach to a smooth, level surface into the wind or with a slight left crosswind if possible.

3. Establish a normal approach and maintain 60 KIAS during the initial part of the approach.

4. On final approach, maintain engine rpm within limits and begin a slow deceleration in order to arrive at a point approximately 2 feet above the intended touchdown area as effective translational lift is lost.

5. Apply collective pitch to slow the rate of descent and align the helicopter with the intended landing path. If
the aircraft is not aligned after pitch application, adjust the twist grip to help further with the alignment. Allow
the aircraft to touch down at near zero groundspeed maintaining alignment with the twist grip.

Note: In a fixed−pitch left−pedal situation, it may be possible for the pilot to slow the aircraft to a hover and effect such a recovery.


Loss of Tail Rotor Effectiveness

*1. Pedals — Maintain full left pedal.

*2. Collective — Reduce (as altitude permits).

*3. Cyclic — Forward to increase airspeed.

If spin cannot be stopped:

*4. Autorotative landing — Execute.


Ng Tachometer or Turbine Outlet Temperature System

If Ng or TOT falls to zero or fails to rise and fall with corresponding power changes:

1. Monitor other engine instruments.

2. Avoid high power settings.

3. Land as soon as practical.

Note: Failure of the Ng tachometer generator is usually accompanied by actuation of the ENG OUT warning horn and caution light.



  • If the torquemeter needle is unusually low or falls to zero with a corresponding digital readout, it is probable that thetorque line has ruptured. Loss of engine oil will be kept to a minimum by a restrictor fitting in the system.

*1. Monitor engine instruments.

*2. Land as soon as possible.

  • 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.

1. Monitor engine instruments

2. Check TRQ circuit breaker — In

3. Land as soon as practical

Note: Some minortorque fluctuation is normal and should not be cause for concern.


Engine or Transmission Oil Pressures

On ground:

The engine shall be shut down if transmission oil pressure exceeds 70 psi or engine oil pressure exceeds 150 psi.


If either gauge fluctuates erratically, engine oil pressure does not indicate within normal range, or transmission oil pressure is not within 30 to 70 psi:

*1. Land as soon as possible.

Warning: With suspected transmission malfunctions, the pilot should make an approach with minimum power change to minimize changes to transmission torque.

Note:  Check the transmission oil pressure with the twist grip full open. Illumination of the TRANS OIL PRESS caution light is common, while the twist grip is at flight idle, after power off maneuvers; however, the gauge should indicate positive transmission oil pressure.
There is no detrimental effect to the transmission system with oil pressure
between 50 to 70 psi with transmission temperature within limits. Pressure indications between 50 to 70 psi shall be documented on a MAF upon completion of flight.


Engine or Transmission Oil Temperatures

If either oil temperature gauge indicator exceeds red line limitations:

*1. Land as soon as possible. 

If either oil temperature gauge fluctuates or falls to zero:

*2. Land as soon as practical.


Nr and Nf Tachometer Malfunction

  • If the tachometer indications fluctuate erratically or peg and all other instruments and lights are normal, land as soon 
  • as practical, utilizing the remaining engine and performance instruments to monitor flight performance.


Pitot-Static Instruments

  • If the airspeed, vertical speed, or altimeter fluctuates erratically or gives apparently false indications while power and attitude instruments are normal

*1. PITOT HEAT switch(es) — HEAT.

If icing conditions are present:

*3. Icing procedures — Execute.

If icing conditions are not present:

*4. Land as soon as practical.


Gyro Instruments

  • If the directional or attitude gyro precesses or otherwise malfunctions, shift the scan to the standby compass(directional gyro malfunction) or to a partial panel scan utilizing other flight instruments to maintain heading,airspeed, and altitude (attitude gyro malfunction). 
  • If IFR, attempt to reestablish VMC conditions. Remain VFR andcontinue the flight. Report the discrepancy upon return to base.

Warning: TH−57B control/trim characteristics prohibit safe instrument flight.


Fuel Quantity Indicator

  • If the fuel quantity indicator drops to zero or fluctuates, utilize elapsed time to judge available remaining fuel. Land as soon as practical.


Emergency Descent

*1. Collective — Reduce (to minimum pitch).

*2. Airspeed — 130 KIAS (122 KIAS Maximum with AFCS on).

Note: During recovery, Nr may tend to overspeed.


Lost Plane Procedures

The primary requirements when lost are as follows:

1. Confess.

2. Climb.

3. Conserve.

4. Communicate.

5. Conform.

6. Consult local area maps for landmarks.

7. Land if necessary and ask available persons for information.


Inadvertent Entry Into Instrument Meteorological Conditions

If inadvertent IMC flight should occur while in a formation flight and the lead aircraft is lost from sight or upon command of the lead, immediately take the following action (Figure 14-1):

1. Aircraft numbers two and four will commence a standard rate turn away from the flight. They will call passing through 90° of turn and will turn 170°.

2. Aircraft number three will climb 500 feet on the present heading. After completing the climb, the aircraft will reverse heading 170° away from the flight leader. When aircraft number four reports passing through the 90°, upon completing the reversal turn, descend to the initial altitude.

3. The flight leader, upon receiving the radio call of aircraft number two passing through 90° of turn, will reverse course 180° on the same side as aircraft number two.

4. It is essential that all aircraft maintain the airspeed of the flight when the dispersal was commenced. The flight will regroup when in a clear area.



  • Operation of the engine during icing conditions could result in ice formations on the compressor front support. If icewere allowed to build up, airflow to the engine would be affected and engine performance decreased. 
  •  The anti−ice system in this helicopter is to be used as a preventative measure only. Once ice has accumulated, the anti−ice system cannot be used as a corrective measure (will not deice).
  • Intentional flight in any known icing condition (<4 °C in visible moisture) is prohibited. 


*2. PITOT HEAT switches — HEAT.

*4. Descend or climb to a warmer temperature or vacate clouds/moisture.

If unable to get clear of icing conditions:

*5. Land as soon as possible.

Warning: Monitor engine instruments and be prepared for partial or complete power loss.



  • A safe autorotative approach and landing is dependent upon variables such as pilot capability, density altitude, airspeed, gross weight, proximity of suitable landing area, and wind direction and velocity. This does not preclude operation in the restricted height velocity area during emergencies or pressing operational requirements.
  • Heading is maintained by applying right pedal to decrease the tail rotor thrust. Autorotative rotor rpm will vary with ambient temperature, pressure altitude, g loading, and gross weight. High gross weights, increased g loads, and higher altitudes and temperature will cause increased rotor rpm that can be controlled by increasing collective. Do not exceed 100 KIAS in sustained autorotation.

Note: Avoid abrupt control movement during high speed autorotation to prevent

  • Any increase of rotor rpm, above that specified for maximum glide, will result in increased rate of descent. At an altitude of 75 to 100 feet, a flare should be established by moving the cyclic stick aft. This will decrease both airspeed and rate of descent and cause an increase in rotor rpm that is dependent upon the rate at which the flare is executed.
  • Increased rotor rpm is desirable because more energy will then be available to the main rotor when collective is applied. Sites for autorotative landings should be hard, flat, smooth surfaces clear of approach and rollout obstructions. During landing, the helicopter should be held in skids−level attitude. After touchdown, decrease collective slowly to full down.

Note: The best glide airspeed is 72 KIAS. The minimum rate of descent airspeed is 50 KIAS.
*1. Autorotate.

*a. Autorotation — Establish.

*(1) Collective — Full down immediately.

*(2) Pedals — Center ball.

*(3) Airspeed — 50 KIAS minimum rate of descent, 72 KIAS maximum glide range.

*(4) Nr — Maintain between 90 to 107 percent (94 to 95 percent optimum).

*(5) Heading — Turn into wind or toward best landing area.

*b. Autorotative landing — Execute.

*(1) Cyclic — Flare as required (to reduce rate of descent and groundspeed).

*(2) Collective — Increase as required (to cushion landing).

*(3) Cyclic — Level skids prior to touchdown.


Landing in the Trees

  • An autorotation into a heavily wooded area should be accomplished by executing a normal autorotation and full flare.
  • The flare should be executed so as to reach a zero rate of descent and zero groundspeed as close to the top of the trees as possible. As the helicopter settles, increase collective to maximum.

*1. Autorotate.

*2. Shoulder harness — Lock.

If time and altitude permit:

*3. Mayday — Transmit.

*4. Transponder — Emergency.

*5. Twist grip — Close.

*6. Battery — OFF.


Ditching - Power On

Once the decision has been made to ditch:

1. Passengers and crew — Alert.

2. Shoulder harness — Locked.

3. Mayday — Transmit.

4. Transponder — Emergency.

5. Perform normal approach to hover/taxi 3 to 5 feet above the water.

6. Doors — Jettison.

7. Nonessential personnel — Execute emergency egress.

8. Helicopter — Move to a safe distance away.

9. Vertical landing — Perform.

10. Twist grip — Close.

11. Collective — Increase slowly to maximum pitch.

12. Cyclic — Maintain helicopter upright as long as possible.

13. Emergency egress — Execute.

14. Lifevest — Inflate (when well clear of helicopter).


Ditching - Power Off

*1. Autorotate.

*2. Shoulder harness — Lock.

If time and altitude permit:

*3. Mayday — Transmit.

*4. Transponder — Emergency.

*5. Doors — Jettison.

Warning: Do not abandon helicopter until rotor blades have stopped. Do not inflate lifevest until well clear of the helicopter.

*6. Underwater egress — Execute.


Underwater Egress

*1. HABD — As required.

*2. ICS cords — Disconnect.

*3. Doors — Jettison.

*4. Place hand on known reference point.

*5. Harness — Release.

*6. Exit helicopter.

After egress:

*7. Swim clear of helicopter and inflate LPU.

Warning: Do not inflate LPU until outside helicopter.
Water pressure may prevent opening the doors until the cabin fills with water.

Failure to disconnect ICS cords can impede egress.
If entanglement or disorientation delays egress, hold onto a reference point with one hand. Using the other hand, place HABD in your mouth, clear water from your mouthpiece, and continue with egress.

To prevent injury while ascending to the surface and breathing from the HABD, continually exhale to vent the expanding air from your lungs.

Orientation of the HABD is critical. It must angle away from the crewmember’s head. Otherwise, during a crash, the head may impact the HABD, causing serious injury and/or incapacitation.

Note: If time does not permit placing HABD in your mouth before submerging, attempt emergency egress while holding your breath.