13.1 EMERGENCY SHUTDOWN
IndicationsFire warning light illuminatedSmokeFuel fumesFireIndication from ground personnelGrinding noises or apparent drive train damage.Procedures*1. Twist grip � Close.*2. Fuel valve � OFF.*3. Battery switch � OFF.(C)*4. Standby attitude indicator � OFF.(C)*5. Rotor brake � Engage immediately.*6. Helicopter � Egress and use the fire bottle as required to extinguish the fire or get clear of the aircraft.WARNING: After exiting aircraft, beware of rotor blades.
13.2 ABORT START
1. Igniter failure:a. TOT fails to rise after twist grip rotated to flight idle.b. Ng fails to rise above 20 percent.2. Hung start:a. Ng rises slowly and stabilizes.b. TOT rises more slowly than normal.3. Hot start:a. TOT exceeds limits.b. TOT caution light and digital display flash twice per second.Note: An excessive rise in TOT, TOT rapidly accelerating through 840 C, and/orthe battery voltage stabilized below 17 volts on starter management,particularly when combined, indicates an increased potential for a hot startand may necessitate aborting the start to preclude an overtemp.Note: If a subsequent start is attempted, utilize an APU.Procedures:*1. Twist grip � Close.*2. Fuel valve � As required.*3. Starter � Secure after TOT stabilizes at 400 C or below.*4. Battery switch �As required.
13.3 POST SHUTDOWN FIRE (INTERNAL)
Indications:TOT rises above 400 C.Flames or smoke coming from engine.Procedures:*1. Starter � Engage.*2. Fuel valve � OFF.*3. Igniter circuit breaker � Pull.*4. Starter � Secure after fire is extinguished.
14.1 ENGINE FAILURE14.1.1 Engine Failure at High Airspeed and Low Altitude
Note: The best glide airspeed is 72 KIAS. The minimum rate of descent airspeedis 50 KIAS. Do not exceed 100 KIAS in sustained autorotation. Note: If time and altitude permit, engine restart may be attempted. The decisionto attempt a restart is the pilot�s responsibility and is dependent upon thepilot�s experience and operating altitude. Note: All autorotative landings should be made into the wind to a suitable landingsite.Indications:Nr decrease.Rapid settling.Left yaw.ROTOR LOW RPM caution light and audio.ENGINE OUT caution light and audio.Procedures:*1. Cyclic � Immediately apply aft.*2. Autorotate.WARNING: Rapid cyclic movement should be avoided to preclude mast bumping.
14.1 ENGINE FAILURE14.1.2 Engine Failure in Flight
Note: The best glide airspeed is 72 KIAS. The minimum rate of descent airspeedis 50 KIAS. Do not exceed 100 KIAS in sustained autorotation. Note: If time and altitude permit, engine restart may be attempted. The decisionto attempt a restart is the pilot�s responsibility and is dependent upon thepilot�s experience and operating altitude. Note: All autorotative landings should be made into the wind to a suitable landingsite.Indications:Nr decrease.Rapid settling.Left yaw.ROTOR LOW RPM caution light and audio.ENGINE OUT caution light and audio.Procedures:*1. Autorotate.*2. Shoulder harness � Lock.If time and altitude permit:*3. Mayday � Transmit on guard.*4. Transponder � Emergency.
14.2 MAIN DRIVE SHAFT FAILURE
Indications:Nr decrease.Nf/Ng rpm increase.Left yaw.Loud bang/noise.Procedures:*1. Autorotate.*2. Twist grip � Adjust to maintain ?f/Ng in operating range.WARNING: The engine must continue to operate to provide tail rotor drive. Tail rotordrive effectiveness may be lost if Nf is allowed to go below 80 percent.When on deck:*3. Emergency shutdown � Complete.
14.3 SPRAG CLUTCH SLIPPAGE
Indications:Nf indication higher than Nr .Low torque indication.Ng and TOT indications lower than normal and not responsive to collective.Procedures:*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.If sprag clutch continues to slip:*5. Autorotate.*6. Twist grip � Closed.If the 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 ontime and altitude.
14.4 SPRAG CLUTCH SEIZURE
Indications:Nf/Nr married during shutdown.Nf/Nr married above 100 percent during autorotational flight.Note: In a normal autorotation, Nr and Nf may be matched together between 92 to 96 percent steady state.Procedures:*1. Ensure twist grip is full open.*2. Land as soon as possible.WARNING: If suspected during an autorotation, execute a waveoff before Nr decaysbelow 85 percent.
14.5 ENGINE RESTART IN FLIGHT
Procedures:*1. Autorotate.*2. Fuel valve � Check on.*3. Starter � Engage.CAUTION: If Ng is allowed to fall below a minimum of 15 percent Ng, then close thetwist grip and perform a normal start.Note: Ng will not decrease below minimum starting speed within 10 secondsbecause of rotational inertia plus possible ram air effect. The twist grip canbe left in the full open position since fuel flow during the start will be onthe normal acceleration schedule.If light-off occurs:*4. Land as soon as possible.
14.6 ENGINE OVERSPEED (Nf) ROTOR RPM (Nr)
Indications:Nr increase.Nf increase.Ng increase.TOT increase.Right yaw.Engine noise increase.Procedures:*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 collectiveand twist grip.*3. Collective/twist grip � Readjust.*4. Land as soon as possible.
14.7 UNDERSPEEDING Nf/Nr
Indications:Low Nr.Low Nf.Procedures:*1. Collective � Adjust as required to maintain 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 bemaintained with Nr at 90 percent or higher. Do not decelerate below 50KIAS (minimum power airspeed) while executing a power check.If power is not sufficient:*5. Autorotate.Note: If some usable power exists but level flight cannot be maintained, thatpower, if sufficient, may be utilized to effect a landing or minimize rate ofdescent en route to a more suitable site for autorotation. Terrain permitting,a sliding landing provides the lowest power available.If sufficient power is available:*6. Land as soon as possible.
14.8 FUEL CONTROL FAILURE
Indications:Erratic Nf.Fluctuating Ng and/or TOT.Procedures:*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.
14.9 COMPRESSOR STALL
Indications:Popping or rumbling noise.Vibrations.Rapid rise in TOT.Ng fluctuation.Loss of power.WARNING: Be prepared for complete power loss.Procedures:*1. Collective � ReduceNote: 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.WARNING: When accelerating the rotor system during the initial rotor engagement orafter power off maneuvers, exceeding 40 percent torque may inducecompressor stall or engine chugging.Note: Mild compressor stalls may occur that will allow powered flight if TOT iswithin operating limits.
14.10 SUSPECTED FUEL LEAKAGE
Indications:Unusual fuel usage.Fuel fumes in cockpit.Procedures:*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.
14.11 MAST BUMPING
Indications:Sharp two-rev knocking.Procedures:During high-speed sideward or rearward flight:*1. Cyclic � Immediately apply smoothly toward center.*2. Pedals � Immediately apply as required to align the nose with the direction of travel.*3. Land immediately.During Start/Shutdown:*1. Cyclic � Move to stop bumping.*2. Emergency shutdown � CompleteDuring slope landing:*1. Cyclic � Move to center to stop bumping.*2. Reestablish hover.*3. Land ImmediatelyDuring engine failure at high forward airspeed:*1. Cyclic � Move aft to maintain positive g (thrust).*2. Collective � As required to maintain Nr.*3. 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.WARNING: Should mast bumping occur in flight, catastrophic results are highly probable. Since conditions causing rotor flapping are cumulative, improper pilot response/recovery techniques to flight situations approaching or favorable to mast bumping can aggravate the situation and lead to in-flight mast bumping and mast separation.
14.12 UNCOMMANDED RIGHT ROLL DURING FLIGHT BELOW 1G
Indications:Uncommanded right roll.Reduced cyclic effectiveness.Procedures:*1. Cyclic � Immediately apply aft to establish positive g load on rotor, then center laterally.WARNING: Lateral cyclic is decreasingly effective below 1g and increases main rotorflapping, which can result in mast bumping.When main rotor returns to a positive thrust condition:*2. Controls � As required to regain balanced flight.If mast bumping has occurred:*3. Land immediately.
14.13 ICING
Procedures:*1. ENG ANTI-ICING � ON.*2. PITOT HEAT switches � HEAT.(C)*3. Alternate static port � As required.If unable to remain clear of icing conditions:*4. Land as soon as possible.WARNING: Monitor engine instruments and be prepared for partial or complete powerloss.
14.14 ENGINE FIRE IN FLIGHT
Indications:Fire light.Smoke.Flames.Procedures: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.
14.15 FUSELAGE FIRE
Procedures:*1. Land immediately.*2. Emergency shutdown � Complete.WARNING: Fire extinguisher fluid vapors are dangerous; fire extinguisher use shouldbe 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 desirable to keep the flame from spreading.
14.16 ELECTRICAL FIRE14.16.1 Electrical Fire � Unknown Origin
Indications:Loadmeter shows excessive load.Dc voltmeter shows excessive load.Smoke.Fumes.Sparks.Procedures:*1. BAT switch OFF.(C)*2. STANDBY GEN switch OFF.(C)*3. STBY ATT IND switch OFF in VMC.*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 � Out.(C)8. Check BAT RELAY circuit breaker � In.9. BAT switch � ON.10. MAIN GEN FIELD and MAIN GEN circuit breakers � In.11. MAIN GEN switch � Reset, then ON.(C)12. STBY GEN RELAY circuit breaker � In.(C)13. STBY GEN switch � ON.(C)14. STBY ATT IND switch � 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 powerto desired electrical equipment. Note: Voltmeter will not indicate battery voltage until battery bus supply andvoltmeter circuit breakers are in. Note: Flight operation can be maintained without battery and generator.Instruments powered by the 28 Vdc power, however, will be inoperable.
14.16 ELECTRICAL FIRE14.16.2 Electrical Fire � Known Origin
Indications:Loadmeter shows excessive load.Dc voltmeter shows excessive load.Smoke.Fumes.Sparks.Procedures:*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.
14.17 SMOKE AND FUME ELIMINATION
Indications:Fumes in cockpit.Smoke in cockpit.Equipment failure.Procedures:*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.
14.18 MAIN GENERATOR FAILURE
Indications:Loadmeter to zero.MAIN GEN or GEN FAIL caution light � On.(B) Dc voltmeter indicates battery voltage.(C) Voltmeter indicates 0. WARNING: With the battery switch OFF or battery exhaustion, both fuel boost pumpsare inoperative. Descend below 6,000 feet pressure altitude. WARNING: With one or both boost pumps inoperative, minimum fuel is 20 gallons; 10gallons is considered unusable.Note: Prior to shutting off all electrical power, the pilot must determine theequipment that is essential to the particular flight environment that will beencountered (e.g., flight instruments and fuel boost pumps). (C)Note: In the TH-57C, time of operation of ESS No. 2 bus on battery power isapproximately 40 minutes with pitot heat OFF and an 80 percent chargedbattery (approximately 35 minutes with pitot heat ON). To conserve batterypower as needed for extended flights or for use of landing lights atdestination, turn off unnecessary electrical equipment on the ESS No. 2 andNON ESS Bus. (C)Note: With the NORMAL/RECOVER switch in NORMAL, failure of the maingenerator will result in illumination of the FUEL PUMP caution lightbecause of loss of power to the nonessential bus. (C)Note: Resetting the BUS/TIE RELAY circuit breaker will cause the main batteryto power the nonessential bus, accelerating main battery depletion.Procedures:1. GEN FIELD and GEN RESET circuit breakers � Check in.2. MAIN GEN switch � Reset, then ON.If generator power is not restored:3. MAIN GEN switch � OFF.4. Unnecessary electrical equipment � OFF.(C)5. NORMAL/RECOVER switch � Recover as desired.6. Descend below 6,000 feet.7. Land as soon as practical.If power is restored:8. Continue flight.(C)Note: In the TH-57C, with the loss of the main battery after a main generatorfailure, the HSI and both RMIs will be inoperative for TACAN, LOC, andVOR approaches; however, the RMIs will still provide relative ADFbearing. VMC should be attained as soon as possible. Note: Be prepared for a possible electrical and/or engine compartment firebecause of excessive wiring load or generator meltdown.
14.19 STANDBY GENERATOR FAILURE (C)
Indications:STBY GEN FAIL caution light.Procedures:1. STBY GEN circuit breaker � In. Check voltmeter for indication.2. STBY GEN switch � OFF, then ON.If power not restored:3. Land as soon as practical.If power restored:4. Continue flight.
14.20 INVERTER FAILURE (C)14.20.1 FCS Inverter Failure (C)
Indications:FCS light flashes.Loss of pitch/roll servos.Loss of FCS.Note: FORCE TRIM will function.Procedures:If FCS inverter voltage is less than 111 volts:1. FCS circuit breaker (ESS-1, lower panel) � Pull.2. Establish VMC.
14.20 INVERTER FAILURE (C)14.20.2 Avionics Inverter Failure (C)
Indications:Ac voltage drop.RMI � Needles failing in the VOR position.Yaw servo failure.Procedures:1. AVIONICS INV circuit breaker (ESS-2, upper avionics panel) � Pull.Note: Further flight in IMC is possible, but must be accomplished without RMIs and yaw servo.
14.21 DC LOADMETER AND VOLTMETER
If the loadmeter or voltmeter fluctuates erratically, pegs, or goes to zero:1. Generator � Cycle.If the problem is corrected:2. Continue the flight.If the problem is not corrected:3. Use Generator Failure procedures.CAUTION: Sustained loadmeter indications greater than 70 percent may be caused byan electrical fire.
14.22 HYDRAULIC SYSTEM MALFUNCTIONS14.22.1 Hydraulic System Failure
Note: Odd or unusual stick forces will be felt in a boost-off situation. Because of excessive forces required for control manipulation, a shallow approach with a sliding landing is recommended.Indications:HYDRAULIC PRESSURE light.Increased force required for control movement.Feedback in control.Procedures:*1. Airspeed � Adjust (to obtain most comfortable control movement level).*2. HYDRAULIC BOOST switch � Check ON.*3. HYD BOOST circuit breaker � Out.If system is restored:4. Land as soon as practical.If system is not restored:5. HYD BOOST circuit breaker � In.6. HYDRAULIC BOOST switch � OFF.(C)7. FORCE TRIM (FT) � On.(C)8. AFCS STAB � ON.(C)9. AFCS ALT � OFF.10. Land as soon as practical.
14.22 HYDRAULIC SYSTEM MALFUNCTIONS14.22.2 Hydraulic Power Cylinder Malfunction
Note: Odd or unusual stick forces will be felt in a boost-off situation. Because of excessive forces required for control manipulation, a shallow approach with a sliding landing is recommended.Indications:Cyclic/collective control displaces to abnormal position.Pilot control of cyclic/collective is difficult or impossible.Procedures:*1. HYDRAULIC BOOST switch � OFF.WARNING: Hydraulic system will not secure if HYD BOOST circuit breaker is out. *2. Helicopter � Regain control.Adjust airspeed as desired to obtain most comfortable control movement level.*3. Land as soon as possible.WARNING: In the event of a complete power failure in the TH-57B or a failure of theESS No. 2 bus in the TH-57C, the hydraulic system will reenergize in themalfunction mode. The pilot will be unable to override the hydraulic boostsolenoid.
14.23 JAMMED FLIGHT CONTROLS AND OTHER FLIGHT CONTROL MALFUNCTIONS
Aircraft experiencing a control malfunction during ground operations will be inspected immediately by qualifiedtechnicians prior to further flight operations or continued turnup/maintenance action. If jammed or restricted flightcontrols are experienced on the ground by a pilot or maintenance personnel, no attempt shall be made to free thecontrols. Light pressure shall be held against the restriction or jam while a thorough inspection of the flight controlsystem is being conducted.Pilots of aircraft that have just returned from a flight during which a control malfunction was experienced will requestan immediate flight control system inspection.
14.24 TAIL ROTOR MALFUNCTIONS14.24.1 Complete Loss of Tail Rotor Thrust
Probable causes:Tail rotor drive shaft severed.Loss of tail rotor blades.Helicopter reaction:In this situation, the nose of the helicopter will swing rapidly to the right in a hover with an accompanying sideslipin forward flight.Procedures:In a hover:*1. Twist grip � Close.*2. Cyclic � Eliminate drift.*3. Collective � Increase to cushion landing.During transition to forward flight:*1. Twist grip � Close.*2. Cyclic � Eliminate sideward drift.*3. Collective � Increase to cushion landing.At altitude:If right rotation is controllable by reducing power and maintaining airspeed of 50 to 72 knots, proceed as follows:*1. Set up for autorotation to suitable landing area.*2. Autorotate.*3. Twist grip � Close.If right rotation is uncontrollable at reduced power settings and airspeed of 50 to 72 knots:*4. Autorotate.*5. Twist grip � Close.
14.24 TAIL ROTOR MALFUNCTIONS14.24.2 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:The pilot will be unable to control right yaw with pedal input. If power is increased, it will tend to aggravate the degreeof yaw or sideslip.Procedures:In a hover:If rate of rotation is 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 � 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 crosswind if possible.3. Establish a shallow approach, maintaining 60 KIAS until on final.Note: In such an approach profile, it is not unusual for the nose to be yawedslightly to the left.4. At 50 to 75 feet AGL and when the landing area can be made, start a slow deceleration to arrive over theintended landing point with minimum forward speed required for directional control.5. At approximately 2 to 3 feet 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, the nose will yaw right and possibly enter uncontrolled flight.Note: If nose swings right after touchdown, follow the turn with cyclic to prevent the aircraft from rolling over.
14.24 TAIL ROTOR MALFUNCTIONS14.24.3 Fixed Pitch Left Pedal (High Power)
Probable causes:Pedals locked in fixed position because of FOD.Control linkage failure during a left-pedal applied situation.Helicopter reaction:The pilot will be unable to control left yaw with pedal input. If power is decreased, it will tend to aggravate the degreeof yaw or sideslip.Procedures:In a hover:If rate of rotation is 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 is possible for the pilot to slow the aircraft to a hover and effect such a recovery.
14.24 TAIL ROTOR MALFUNCTIONS14.24.4 Loss of Tail Rotor Effectiveness
Procedures:*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.
14.25 EMERGENCY DESCENT
Procedures:*1. Collective � Reduce (to minimum pitch).*2. Airspeed � 130 KIAS (122 KIAS Maximum with AFCS On).Note: During recovery, Nr may tend to overspeed.
14.26 LOST PLANE PROCEDURES
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.
14.28 SINGLE INSTRUMENT INDICATIONS14.28.1 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 actuationof the ENG OUT warning horn and caution light.
14.28 SINGLE INSTRUMENT INDICATIONS14.28.2 Torquemeter
If the digital torquemeter indication is unusually low or falls to zero with a corresponding digital readout, it is probable that the torque line has ruptured. Loss of engine oil will be kept to a minimum by a restrictor fitting in the system.Procedures:*1. Monitor engine instruments.*2. Land as soon as possible.The digital torquemeter incorporates a transducer between the wet line and the gauge. If the indicator falls to zero and the digital readout is extinguished, the cause is a loss of electrical power to the indicator.Procedures:1. Monitor engine instruments.2. Check TRQ circuit breaker � In.3. Land as soon as practical.Note: Some minor torque fluctuation is normal and should not be cause forconcern.
14.28 SINGLE INSTRUMENT INDICATIONS14.28.3 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.Airborne: 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 anapproach 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. Note: There is no detrimental effect to the transmission system with oil pressurebetween 50 to 70 psi with transmission temperature within limits. Pressure indications between 50 to 70 psi shall be documented on a MAF uponcompletion of flight.
14.28 SINGLE INSTRUMENT INDICATIONS14.28.4 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.
14.28 SINGLE INSTRUMENT INDICATIONS14.28.5 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.
14.28 SINGLE INSTRUMENT INDICATIONS14.28.6 Pitot-Static Instruments
If the airspeed, vertical speed, or altimeter fluctuates erratically or gives apparently false indications while power andattitude instruments are normal, proceed as follows:1. PITOT HEAT switch(es) � On.Monitor cruise power settings and nose attitudes to maintain altitude and airspeed. If pitot heat does not remedy thesituation, accomplish the following:(C)2. Alternate static source knob � Pull.3. Land as soon as practical.
14.28 SINGLE INSTRUMENT INDICATIONS14.28.7 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 and continue the flight. Report the discrepancy upon return to base.WARNING: TH-57B control/trim characteristics prohibit safe instrument flight. If inadvertently IMC, regain VMC as expeditiously as possible.
14.28 SINGLE INSTRUMENT INDICATIONS14.28.8 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.
14.29 IMMINENT TRANSMISSION FAILURE
If abnormal transmission temperature or pressure indications are accompanied by the illumination of the TRANSCHIP light or abnormal sound from the transmission area:*1. Land immediately.WARNING: Do not autorotate; minimize power changes.*2. Lock harness.
14.31 OVERTORQUE/OVERSPEED/OVERTEMP
If any overtorque exceeding 110 percent, overspeed, or overtemp is observed, land as soon as possible.
14.32 FUEL BOOST PUMP FAILURE
Indications:FUEL PUMP caution light.Indicated fuel pressure of zero (dual-pump failure).Procedures:*1. Descent � Initiate if above 6,000 feet PA and flight permits.*2. Fuel pressure and quantity � Note.WARNING: With one or both boost pumps inoperative, minimum fuel is 20 gallons; 10gallons is considered unusable.If both fuel boost pumps have failed (fuel pressure at zero):WARNING: Be prepared for complete power loss.*3. FUEL BOOST circuit breakers � Pull.*4. Land as soon as possible. If only one boost pump has failed (fuel pressure 4 to 30 psi):*5. Failed boost pump � Identify.WARNING: Do not pull circuit breakers in an attempt to identify the failed boost pumpuntil below 6,000 feet PA.If unable to identify failed boost pump or FUEL LOW caution light is illuminated:*6. Ensure both boost pump circuit breakers are in.*7. Land as soon as possible.If able to identify failed boost pump:8. Failed boost pump circuit breaker � Pull.9. Land as soon as practical.WARNING: If an air leak exists in the fuel lines between the boost pumps and engine,a total loss of boost pump pressure could cause an engine flameout.
14.34 HIGH-FREQUENCY VIBRATION
Indications:Buzz in the pedals. Possible Causes: engine or accessory gearbox components, improper drive shaft alignment, malfunctioning couplings,dry or excessively worn bearingsout-of-track or damaged tail rotor (sudden increase in amplitude of vibrations, unusual noises, and illumination of T/R CHIP light.)Procedures:*1. Land immediately.If tail rotor drive system failure is suspected:*2. Complete Loss of Tail Rotor Thrust procedure � Execute.WARNING: Increased power settings required to accomplish a normal approach may ultimately precipitate the complete failure of a malfunctioning tail rotor. Beprepared 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.
14.35 VORTEX RING STATE
Indications:Rapid descent rate increase.Increase in overall vibration level.Loss of control effectiveness.Procedures:*1. Collective � Decrease.*2. Cyclic � Forward to gain airspeed.WARNING: Increasing collective has no effect toward recovery and will aggravatevortex ring state. During approaches at less than 40 KIAS, do not exceed800 feet per minute.If impact is imminent:*3. Level skids to conform to terrain.
14.36 POWER REQUIRED EXCEEDS POWER AVAILABLE
Indications:Uncommanded descent with torque at maximum allowed.Rotor droop.Loss of tail rotor effectiveness.Procedures:*1. Collective � Adjust as required to maintain Nr in operating range.*2. RPM switch � Full increase.*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.
14.37 ROTOR BLADE STALL
Indications:Progressively increasing two--per--revolution vibrations.Loss of longitudinal control and severe feedback in the cyclic.Violent vertical nose oscillations independent of cyclic position.Procedures: (one or a combination of the following)*1. Severity of maneuver � Decrease. *2. Collective pitch � Decrease.*3. Altitude � Descend.*4. Rotor RPM � Increase.CAUTION: Entry into severe blade stall can result in structural damage to the helicopter.
15.1 AUTOROTATION
Procedures:*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.Note: Avoid abrupt control movement during high-speed autorotation to prevent overcontrolling.Note: The best glide airspeed is 72 KIAS. The minimum rate of descent airspeedis 50 KIAS.
15.1 AUTOROTATION15.1.1 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 on guard.*4. Transponder � Emergency.*5. Twist grip � Close.*6. Battery � OFF.Note: Avoid abrupt control movement during high-speed autorotation to prevent overcontrolling.Note: The best glide airspeed is 72 KIAS. The minimum rate of descent airspeedis 50 KIAS.