EP NWC Flashcards
ENGINE MALFUNCTION IN FLIGHT
WARNING: A decrease in Nr will reduce the efficiency of the tail rotor, potentially resulting in an uncommanded right yaw.
WARNING: Flying with greater than 110 percent torque with one engine inoperative may result in unrecoverable decay of Nr in the event of a dual-engine failure.
WARNING: With engine anti-ice on, up to 18% torque available is lost. Torque may be reduced as much as 49% with improperly operating engine inlet anti-ice valves.
ENGINE HIGH-SIDE FAILURE IN FLIGHT
INDICATIONS
TRQ is 10% or greater than other engine.
2. Ng is 5% or greater than other engine.
3. Np is matched within 5% of other engine.
4. Nr is at or above 103%.
CAUTION: If an Np overspeed condition is reached (120%), the overspeed system will flame out the engine and the auto-ignition system will relight the engine. If Nr is not controlled and Np accelerates back to 120%, the overspeed system will flame out the engine again and the auto-ignition system will reset the igniter 5-second timer. The Np overspeed/auto-ignition system will continue cycling until Np/Nr is controlled. A yaw kick may be experienced each time the engine relights.
NOTE: With high collective settings, Nr may increase slowly, making high-side failure confirmation difficult. Reducing collective will reveal increasing Nr and verify high-side failure.
NOTE: Ng does not pass through the EDECU and is a highly reliable signal.
NOTE: Torque signal may be erratic or drop off for high side conditions driven by EDECU failure.
ENGINE HIGH-SIDE FAILURE ON DECK
None.
ENGINE TORQUE OR TGT SPIKING/FLUCTUATIONS
warning: PCL movement during engine fluctuations may precipitate an engine failure. Consider performing APU Emergency Start procedure prior to manipulating the PCL. Maintaining
a low power setting when moving the PCL will minimize the Nr decay rate if the malfunctioning engine fails.
COMPRESSOR STALL
WARNING: If the Ng decay relight feature attempts to relight the engine, subsequent compressor stalls may occur and damage the engine. A yaw kick may be experienced each time the engine relights. The engine must be manually shut down
ENGINE HIGH-SPEED SHAFT FAILURE
INDICATIONS: Indicates failure of the high-speed shaft. Np is greater than Nr by more than 3% and engine torque is below 10%.
CAUTION: Following a high-speed shaft failure, the engine will overspeed, the Np overspeed system will flame out the engine, and the auto-ignition system will activate the relight feature. The engine Np governor will eventually bring Np down toward 100%. The engine must be manually shut down to prevent further damage.
ABORT START
INDICATIONS:
Abort engine start if any of the following limits are exceeded:
1. Ng does not reach 14% within 6 seconds after starter initiation.
2. No oil pressure within 30 seconds after starter initiation (do not motor engine).
3. No light-off within 30 seconds after moving PCL to IDLE.
4. ENG STARTER advisory disappears before reaching 52% Ng.
5. TGT is likely to exceed 851 °C before idle speed is attained.
CAUTION: During aborted starts, failure to immediately stop fuel flow may result in engine overtemperature.
ENGINE MALFUNCTION DURING HOVER/TAKEOFF
None.
DUAL-ENGINE FAILURE
WARNING: Rotor rpm decays rapidly following a dual-engine failure or the loss of the second engine after a single-engine failure. Delay in lowering the collective will result in loss of rotor rpm and may cause catastrophic failure of the rotor system due to dynamic instability at low rpm.
WARNING: Altitude hold will remain engaged unless deselected. If the collective TRIM RLSE switch is not depressed, the AFCS will attempt to maintain aircraft altitude. AFCS commanded collective movement could result in a catastrophic loss of Nr.
WARNING: Flying with greater than 110 percent torque with one engine inoperative, may result in unrecoverable decay of Nr in the event of a dual-engine failure. (If both engines fail, generators will drop off line at approximately 80 percent Nr, resulting in loss of both pilot and copilot mission and flight displays.)
SINGLE-ENGINE FAILURE IN FLIGHT
INDICATION:
Warning light is activated by the vertical instrument when Ng decreases below 55%. In the event of an isolated Ng signal failure, the ENG OUT light will be illuminated with the engine operating normally.
ENGINE AIR RESTART
WARNING: If APU is unavailable, and a crossbleed start is necessary, maximum torque available
will be reduced during the start sequence. Depending on operating conditions, level flight may not be possible. Ensure AIR SOURCE ECS/START switch is placed to ENG for crossbleed starts.
CAUTION: For a crossbleed start, the donor engine should indicate the maximum Ng safely obtainable. Receiving engine Ng less than 24% prior to advancing PCL to IDLE may result in a hot start.
NOTE: Either a single- or dual-engine restart may be attempted following dual-engine
failure. Decision should be based on applicability of respective start envelopes and considerations of longer time to idle when executing a dual-engine restart.
NOTE: In the event of an alternator failure, the Ng signal may be unavailable. Engine start will not be possible without ac power provided to the ignition exciter.
APU EMERGENCY START
None.
HUNG DROOP STOPS
NOTE: While operating in cold weather, consideration should be given to turning the BLADE DEICE POWER switch to ON. This will activate the droop-stop heaters and aid the droop stops in seating.
LOW ROTOR RPM WARNING
INDICATIONS:
Warning light is activated by the vertical instrument when Nr is less than 96 percent.
MAIN TRANSMISSION MALFUNCTION
WARNING: Possible indications of main transmission imminent failure may include: yaw attitude excursions with no control input, an increase in power required for a fixed collective setting, failure of a main generator or hydraulic pump, increased noise, increased vibration levels, or abnormal fumes in the cabin.
WARNING: Operation of the main gearbox with no oil pressure may result in failure of the tail rotor drive takeoff pinion gear and subsequent loss of tail rotor drive.
NOTE: Consideration should be given to performing the applicable steps of the Immediate Landing/Ditching emergency procedure and transiting at a minimum power airspeed and low altitude flight profile (approximately 80 feet and 80 KIAS) to permit a quick flare followed by an immediate landing/ditching.
NOTE: A loss of all main transmission lubricating oil may result in unreliable temperature indications from the main transmission temperature gauge and temperature sensor (caution).
NOTE: Continued operations in the precautionary range for temperature and pressure are acceptable provided that the ambient conditions and flight regime of the aircraft correspond with the guidance set forth in the transmission limitations section of Chapter 4.
TAIL/INTERMEDIATE TRANSMISSION MALFUNCTION
WARNING: High power settings require maximum performance of the tail rotor drive system and may precipitate ultimate drive failure.
WARNING: Consideration should be given to transiting at an altitude sufficient to enter an autorotation and performing the applicable steps of the Immediate Landing/Ditching emergency procedure.
NOTE: An INT XMSN OIL HOT or TAIL XMSN OIL HOT caution occurring simultaneously with a WCA MISCOMPARE alert may be an indication of a mission computer/backup computer card failure.
LOSS OF TAIL ROTOR DRIVE ALTITUDE AND AIRSPEED SUFFICIENT TO ESTABLISH AUTOROTATION
WARNING: Attempting to continue flight with uncontrolled yaw rates and forward speed will result in a total loss of aircraft control regardless of PAC inputs.
WARNING: Altitude hold will remain engaged unless deselected. If the collective TRIM RLSE button is not depressed, the AFCS will attempt to maintain aircraft altitude through the collective trim servo. AFCS commanded collective movement can result in an accelerated yaw rate.
LOSS OF TAIL ROTOR DRIVE ALTITUDE AND AIRSPEED NOT SUFFICIENT TO ESTABLISH AUTOROTATION
CAUTION: Altitude may have to be adjusted based on rate of yaw and/or turn.
LOSS OF TAIL ROTOR CONTROL
WARNING: Servo hardovers in the yaw channel may result in loss of tail rotor control. Consideration should be given to securing the SAS/BOOST and/or TRIM as necessary.
WARNING: Following the appearance of the #1 TAIL RTR SERVO caution without the associated BACK UP PUMP ON and #2 TAIL RTR SERVO ON advisories, the aircraft will demonstrate normal yaw responses in flight regimes that do not require excessive tail rotor performance; however, at slower airspeeds, below approximately 40 KIAS, more pronounced effects of loss of tail rotor control may become more apparent.
WARNING: After touchdown, rapid reduction of collective or PCLs may cause excessive and uncontrollable yaw rates.
WARNING: If an uncontrolled right yaw develops at too low of an airspeed, loss of waveoff capability may result. Increasing collective may increase the yaw to unrecoverable rates. Performing Loss Of Tail Rotor Drive (Altitude And Airspeed Not Sufficient To Establish Autorotation) procedure may be required.
WARNING: If the tail rotor control cables are damaged, the hydraulic transients associated with switching the TAIL SERVO switch from NORM to BKUP may cause catastrophic damage to the tail rotor controls.
NOTE: A momentary uncommanded right yaw will occur when the tail rotor servo switches from normal to backup in a hover. The rate and magnitude will primarily depend on power required and wind direction and magnitude.
TAIL ROTOR QUADRANT CAUTION
CAUTION: If the helicopter is shut down and/or hydraulic power is removed with one tail rotor cable failure, disconnect of the other tail rotor cable will occur when force from the boost servo cannot react against control cable quadrant spring tension. The quadrant spring will displace the cable and servo piston enough to unlatch the quadrant cable.
HYDRAULIC SYSTEM WARNING
The HYD warning will occur as a result of several compounded hydraulic malfunctions. The order in which the hydraulic emergency will present itself should allow the pilot early indications of the impending failure.
1 and #2 HYD PUMP Failure
None.
1 PRIMARY SERVO OR #1 TRANSFER MODULE LEAK
WARNING: Failure to ensure BACKUP HYD PMP switch is in AUTO or ON position prior to landing with a #1 RSVR LOW or #1 HYD PUMP caution present will result in loss of tail rotor directional control when the weight on wheels switch is activated.
NOTE: Be prepared for loss of tail rotor control.
2 PRIMARY SERVO OR #2 TRANSFER MODULE LEAK
NOTE: Failure to ensure BACKUP PUMP switch is in AUTO or ON position prior to landing with a #2 HYD PUMP caution present will result in loss of pilot assist servos when the weight on wheels switch is activated.
NOTE: Be prepared for loss of the pilot-assist servos.
BOOST SERVO HARDOVER
CAUTION: Up to 75 pounds of left pedal force will be required when hovering with boost servos off with starboard crosswinds. This value is significantly reduced with port crosswinds.
CAUTION: Landings with boost servos off on all single spot air-capable ships should only be attempted if there is no large landing platform (LPD or larger) or shore base available.
CAUTION: Landing with aft cyclic movement corresponding with a nose up pitch rate has a significant effect on the instantaneous descent rate of the tailwheel and may cause an overload that ultimately contributes to the failure of the tail strut. If sufficient space and a suitable landing site exists,
a landing may be conducted with slight forward drift not to exceed 5 KGS.
AFCS DEGRADED CAUTION
WARNING: Altitude hold may be disengaged due to a malfunction in the engine torque indication system, resulting in false high torque indication for both engines and high torque signals to the AFCS.
NOTE: Backup pump initiation with AFCS heading hold engaged may cause heading hold failure. Should the malfunction occur, pressing one of the fail advisory mode reset pushbuttons will restore system operation.
NOTE: If the AFCS DEGRADED caution appears during a night/IMC coupled hover or automatic approach, consideration may be given to continuing hover/approach if not disoriented or unstable.
