Performance Planning

Please download to get full document.

View again

of 111
5 views
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.

Download

Document Related
Document Description
Performance Planning. PPC Requirements. AR 95-1, para 5-2a tells us that the aviator will evaluate: Aircraft performance Departure, enroute, and approach data Notices to Airmen (NOTAM) DA Form 5701-R may be used as an aid to organize performance planning data required for the mission.
Document Share
Document Transcript
Performance PlanningPPC Requirements
  • AR 95-1, para 5-2a tells us that the aviator will evaluate:
  • Aircraft performance
  • Departure, enroute, and approach data
  • Notices to Airmen (NOTAM)
  • DA Form 5701-R may be used as an aid to organize performance planning data required for the mission
  • PPC Requirements
  • This form will be used for:
  • RL progression training
  • Annual ATP evaluations
  • When required during other training and evaluations
  • For evaluation flights, the evaluator will determine the blocks that will be filled out
  • Be safe and do it all
  • CURRENT PA = 2500 ft MSLFAT = 25 deg CGWT = 15000 lbsETF #1 = 1.0ETF #2 = .98MAXIMUMPA = 3000 ft MSLFAT = 30 deg CCRUISEPA = 6000 ft MSLFAT = 25 deg CPLANNING CONDITIONSEngine Torque Factor
  • ETF
  • The comparison of an individual engines torque available to a specification engines (1.0 ETF) torque available at a reference temperature of 35 deg C
  • The ETF must be between .85 to 1.0
  • The ETF indicates degradation of performance based on engine usage
  • Aircraft Torque Factor
  • ATF
  • ATF is the average of the two ETF’s. It indicates the aircraft’s total performance capability based on the condition of the two engines.
  • ATF is also based on 35 deg C and is allowed to range from .90 to 1.0
  • If ATF is outside this range do not fly the aircraft
  • 2500/300025/3015000.991.0.98600025Torque Ratio
  • TR
  • Torque factor chart indicates improved engine and aircraft performance as temperature decreases below +35 deg C
  • Torque ratio will be written to three decimal places
  • Three instances when chart is not needed:
  • If FAT is +35 degrees or above
  • If FAT is -15 or below
  • If ETF is 1.0
  • Chart InfoTorque Factor100% RPM RPage 7A-7.982Chart InfoTorque Factor100% RPM RPage 7A-7.9842500/300025/3015000.991.0.98.9911.0.982600025.9921.0.984Max Torque Available
  • This torque value represents the maximum specification torque available at zero airspeed and 100% RPM R for the operational range of PA and FAT
  • This value may or may not be continuous due to Chapter 5 limitations
  • Max Torque Available
  • The actual MTA figure should be annotated on the PPC, regardless of whether it is above the continuous torque limits
  • Conditions may arise when the pilot may need transient power demands
  • The pilot is responsible for ensuring that Chapter 5 transient limits are applied when using this value, if applicable
  • Max Torque Available
  • Based on flight test data, the MTA chart reflects the maximum torque the engines can produce without exceeding the maximum of any of your three 30 minute engine operating limits:
  • TGT = 851 deg C
  • Ng = 102%
  • Engine Oil Temperature = 150 deg C
  • Max Torque Available
  • MTA is limited by the HMU through Ng limiting
  • A TGT limiter circuit within the DEC causes the HMU to limit fuel to the Ng engine section when TGT reaches 866 +/- 6 deg C (dual engine) and 891 +/- 5 deg C (single engine)
  • Max Torque Available
  • TGT limiting is what will most commonly limit MTA for the PA and FAT combinations that most aviators operate in
  • The HMU also limits fuel to the Ng section during high ambient temperature conditions
  • Max Torque Available
  • At high ambient temperatures, the air becomes less dense, causing the Ng turbine section to operate at higher speeds in order to deliver the same volume of air output to the power turbine wheels (Np)
  • Fuel flow is limited to prevent excessive operating speeds that could damage the Ng turbine wheels
  • Max Torque Available
  • The HMU also limits fuel flow to the Ng section during very cold conditions
  • Mach speeds decrease as temperature decreases
  • This limiting is to prevent compressible air flow (mach speeds) from occurring within the compressor inlet section
  • Max Torque Available
  • If MTA is more than 100% dual engine (above 80 KIAS), 120% dual engine (80 KIAS or less), or 135% single engine, then the aircraft is structurally limited
  • The engines are capable of producing the power, but components in the transmission (main module for DE torque and input modules for SE torque) are incapable of sustaining these torque loads continuously without damage
  • Max Torque Available
  • In a structurally limited aircraft, attempting to operate continuously above the allowable torque value in Chapter 5 will result in structural damage to the transmission
  • Maximum torque for a structurally limited aircraft is limited to a 10 second time limitation
  • Max Torque Available
  • If MTA is below 100% dual engine (above 80 KIAS), 120% dual engine (80 KIAS or less), or 135% single engine, then the aircraft is environmentally limited
  • Due to environmental conditions the engines are incapable of producing maximum rated power and transmission torque limits will not be reached
  • Max Torque Available
  • In an environmentally limited aircraft, attempting to demand more torque than MTA, will result in rotor bleed-off
  • Depending on how far the collective is increased beyond this point, will determine how far the rotor will droop
  • The larger the excursion, the greater the reduction in rotor
  • The bigger the splat mark
  • Max Torque Available
  • It is important to understand what the pilot will observe on the torque gauges when maximum power is demanded
  • One scenario would be an aircraft with identical ETF’s, resulting in identical MTA values for both dual and single engine operations
  • Max Torque Available
  • After doing our planning we find out that out Dual Engine MTA is 114%
  • When MTA is demanded the pilot would observe 114% torque on both the #1 and #2 engine torque gauges
  • The respective TGT for each engine would be at the dual engine limiting value (866 +/- 6)
  • TGT limiting would prevent the pilot from receiving more torque
  • Max Torque Available
  • A more common scenario would be having different ETF’s (1.0 and .948) resulting in a different MTA for each engine
  • In this situation when MTA is demanded, the pilot would not see 114% on the torque gauges, as this is only an averaged number between the two engines
  • As the pilot demanded power, torque on both engines would rise evenly to 108%
  • Max Torque Available
  • At this time the #2 engine would reach it’s TGT limiter and would remain at 108% torque
  • If the pilot continues to demand more power, the stronger 1.0 engine would produce up to 114% before reaching it’s TGT limiter
  • Max Torque Available
  • The pilot would observe 114% and 108% respectively, with TGT on both engines at the dual engine limiter
  • Attempting to demand more power in this case would result in rotor bleed-off
  • A torque split will be induced by the pilot when power demanded exceeds that of the weakest engine
  • This is considered normal
  • Max Torque Available
  • With bleed-air extracted, adjust MTA as follows:
  • Eng. Anti-Ice On - Subtract 18% from MTA
  • Heater On - Subtract 4% from MTA
  • Both On - Subtract 22% from MTA
  • This will hold true for SE MTA except the values are half of that stated
  • Max Torque Available
  • These values are different for different helicopter models
  • See the -10 for the values for the UH-60A
  • Also see the -10 if HIRSS is installed and baffles removed
  • This is not a normal configuration
  • Chart InfoMax TQ Avail10 Min LimitBleed Air Off100% RPM RZero AirspeedPage 7A-10112%Chart InfoMax TQ Avail30 Min LimitBleed Air Off100% RPM RZero AirspeedPage 7A-1195%25/302500/300015000.991.0.98.9911.0.982111112110112 X .982 = 110Spec Torque - 112%Spec Torque - 95%112 X .991 = 11195 X .984 = 9395 X .992 = 941/2 MTA = 46%600025.9921.0.984949593Max Allowable GWT OGE/IGE
  • This is the most weight the aircraft is able or allowed to pick up to a 10’ hover height for IGE operations or to an OGE altitude (70’ for UH60) for OGE operation
  • This weight is limited by either engine capability or aircraft structural design
  • Max Allowable GWT OGE/IGE
  • The Max GWT for UH60A without provisions for Engine Output Shaft STUD BALANCE MWO or without the wedge mounted pitot static probes is 20,250 lbs
  • The Max GWT for UH60L or UH60A with the MWO provisions and wedge mounted pitot static probes is 22,000 lbs
  • Max Allowable GWT OGE/IGE
  • If the Max GWT IGE or OGE is 20,250/22,000 lbs (as applicable), then your aircraft is structurally limited
  • Although the engines may be capable of lifting more weight, the airframe is not
  • When the Max GWT value is 20,250/22,000 lbs, attempting to operate at a weight above that value will result in exceeding a structural design limitation and airframe damage is likely
  • Max Allowable GWT OGE/IGE
  • If the Max GWT IGE or OGE is less than 20,250/22,000 lbs (as applicable), then your aircraft is environmentally limited
  • Although the airframe is capable of lifting up to the Chapter 5 limit, the engines cannot provide enough power to lift that weight for the given environmental conditions
  • Max Allowable GWT OGE/IGE
  • When the Max GWT value is less than 20,250/22,000 lbs, attempting to operate at a weight above that value will result in rotor droop (environmental limitation), but no airframe damage should result
  • Unless you crash from low rotor RPM!
  • Chart InfoHoverClean Config.100% RPM RZero WindPage 7A-1521,250 lbs2500/300025/3025/3015000.991.0.98.9911.0.98211111211021250/22000600025.9921.0.984949593GO/NO GO Torque OGE/IGE
  • This value is essentially a weight check
  • At a 10’ hover height, this is the torque that will determine if you are at or below your maximum weight that the engines are capable of lifting to an IGE or OGE altitude
  • Bottom line…GNG is the hover torque for Max Allowable GWT for the day
  • GO/NO GO Torque OGE/IGE
  • If your Max GWT OGE is at the Chapter 5 maximum (ie. 20,250/22000), then only one GNG value will be needed and this will represent both IGE and OGE capability
  • If you can lift maximum weight to OGE altitudes, then you can obviously do it at IGE altitudes
  • GO/NO GO Torque OGE/IGE
  • In this scenario, if the torque required to maintain a stationary hover is at or below the GNG IGE/OGE value, the pilot has confirmed aircraft weight to be at or below Max GWT and any maneuver requiring OGE power or less may be attempted
  • GO/NO GO Torque OGE/IGE
  • If the torque required to maintain a stationary hover is above the GNG IGE/OGE, you cannot operate in compliance with the -10 because you are exceeding the aircraft’s maximum structural gross weight
  • This requires an entry to made to DA Form 2408-13
  • The helicopter shall not be flown until corrective action is taken
  • GO/NO GO Torque OGE/IGE
  • If your Max GWT is less than the Chapter 5 maximum (20,250/22,000), then a GNG value is required for both IGE and OGE
  • If the torque required to maintain a stationary hover exceeds the GNG OGE, but does not exceed the GNG torque IGE, then only IGE maneuvers may be attempted
  • GO/NO GO Torque OGE/IGE
  • Maneuvers requiring OGE power are:
  • Perform fast rope insertion
  • Perform rappelling procedures
  • Perform rescue-hoist operations
  • Perform STABO operations
  • Perform external load operations
  • Basically, if it hangs under the aircraft don’t do it
  • GO/NO GO Torque OGE/IGE
  • Theoretically, if the torque required to hover exceeds the GNG OGE, you should not be able to exceed the GNG IGE for and environmentally limited aircraft since your MTA will equal your GNG IGE and rotor bleed off will develop when engines hit the TGT limiter at 866 +/- 6
  • GO/NO GO Torque OGE/IGE
  • Remember, all hover checks are done at an altitude of 10’
  • If you are performing external load operations plan a GNG value that will place the load at 10’ AGL (usually 30’ or 40’)
  • GO/NO GO Torque OGE/IGE
  • GNG is computed using maximum forecast conditions
  • When the actual temperature is less than maximum, the torque required to hover at a given GWT is less
  • To ensure that OGE capability exists and/or structural limitations are not exceeded, reduce GNG by 1% for each 10C that actual temperature is less than maximum forecast
  • GO/NO GO Torque OGE/IGE
  • The colder temperatures would allow the same 20,250/22,000 pound aircraft to hover at these weights with less torque
  • Therefore operating at the higher (original) GNG torque value would mean you are actually hovering an aircraft weighing more than the Chapter 5 limits allowed
  • Chart InfoHoverClean Config.100% RPM RZero WindPage 7A-1592%Chart InfoHoverClean Config.100% RPM RZero WindPage 7A-1596%2500/300025/3015000.991.0.98.9911.011211111211021250/2200092/96600025.9921.0.984949593Predicted Hover Torque
  • With current conditions at takeoff, and at takeoff GWT, this is the estimated torque required for a stationary 10’ hover in zero wind conditions
  • For external load operations, record the predicted torque required to hover at a height that will place the load at 10’ AGL (usually 30’ or 40’)
  • Predicted Hover Torque
  • If actual hover torque does not agree with predicted hover torque it is not a non-flying condition
  • As long as you are still below GNG OGE or IGE you may still fly
  • Predicted Hover Torque
  • One of the following conditions has occurred:
  • Your actual weight is more or less than you predicted
  • Current conditions have changed since you computed your PPC (FAT, PA, GWT, Wind, etc.)
  • Remember, your hover values are based on a no wind condition
  • An error was made during computation of PPC
  • Chart InfoHoverHigh Drag100% RPM RZero WindPage 7A-1658%2500/300025/3015000.991.0.98.9911.0.98211111211021250/2200092/9658600025.9921.0.984949593Velocity Never to Exceed (Vne)
  • The maximum permitted airspeed as a function of temperature, pressure altitude, and aircraft weight
  • Exceeding this airspeed may cause the rotor system to encounter the effects of retreating blade stall
  • Stall has not been encountered in one G flight up to the airspeeds shown on the Vne chart in the -10
  • Velocity Never to Exceed (Vne)
  • Exceeding this airspeed may also cause advancing blade compressibility (-10C and colder), and/or aircraft structural damage
  • This airspeed cannot be obtained in level flight
  • Velocity Never to Exceed (Vne)
  • If Vne minus 15 KIAS is a lesser value than MAX RANGE IAS, this lower value will be the recommended maximum turbulence penetration airspeed
  • The 15 knot speed reduction reduces the likelihood of the pilot exceeding Vne due to airspeed fluctuations associated with turbulence
  • Chart InfoAirspeedNO ESSS100% RPM Page 5-14180 KIAS2500/300025/3015000.991.0.98.9911.0.98211111211021250/2200092/9658600025180.9921.0.984949593Cruise Speed IAS/TAS
  • These airspeeds are dictated by the mission or chosen by the pilot within aircraft limits
  • Indicated airspeed is the airspeed shown on the pitot static airspeed indicator that has been calibrated for standard sea level pressure and is uncorrected for airspeed system errors
  • Cruise Speed IAS/TAS
  • Calibrated airspeed is the indicated airspeed corrected for position and instrument error
  • Calibrated airspeed would be equal to true airspeed (TAS) at standard pressure at sea level
  • The error is usually small and may be computed with reference to the -10
  • Cruise Speed IAS/TAS
  • TAS is calibrated airspeed corrected for error due to density altitude
  • Since the airspeed indicator is calibrated for the dynamic pressures corresponding to airspeeds at sea level conditions, variations in air density must be accounted for
  • Cruise Speed IAS/TAS
  • When determining the IAS to be used for the PPC, the pilot should use the speed that the aircraft will be at for the majority of the flight profile
  • When determining single engine (SE) cruise speed, the pilot has the option of choosing any speed that falls within the MIN/MAX SE envelope.
  • Cruise Speed IAS/TAS
  • The pilot may wish to consider using at least 80 KIAS or higher. 80 KIAS provides the minimum rate of descent for autorotation and would ensure sufficient airspeed available to arrest the rate of descent should the other engine become inoperative
  • Cruise Speed IAS/TAS
  • Autorotative decelerations initiated at speeds below 80 KIAS will most likely result in aircraft damage
  • Although it will not always be possible, an airspeed should be used that will maintain cruise flight at or below your continuous torque available SE
  • Torques above your continuous value will limit you to 30 minutes of operation if that power setting is maintained
  • Chart InfoCruiseClean Config6000ft. PA30 deg CPage 7A-60115 KTASChart InfoCruiseClean Config6000ft. PA30 deg CPage 7A-6096 KTAS2500/300025/3015000.991.0.98.9911.0.98211111211021250/2200092/9658600025180.9921.0.9849495931001158096Cruise Torque
  • This is the torque required to maintain the Cruise Speed (IAS or TAS) that you have selected for the mission
  • Chart InfoCruiseClean Config6000ft. PA30 deg CPage 7A-6044%Chart InfoCruiseClean Config6000ft. PA30 deg CPage 7A-6038 X 2 = 76%2500/300025/3015000.991.0.98.9911.0.98211111211021250/2200092/9658600025180.9921.0.98494959310011580964476Cruise Fuel Flow
  • This is the predicted fuel flow (burn rate) that the aircraft will have at Cruise Torque
  • With bleed-air extracted, adjust fuel flow as follows:
  • Eng. Anti-Ice On - Add 100 lbs/hr
  • Heater On - Add 12 lbs/hr
  • Both On - Add 112 lbs/hr
  • Cruise Fuel Flow
  • This will hold true for SE MTA Fuel Flow except the values are half of that stated
  • These values are different for different helicopter models
  • See the -10 for the values for the UH-60A
  • Also see the -10 if HIRSS is installed and baffles removed
  • This is not a normal configuration
  • Chart InfoCruiseClean Config6000ft. PA30 deg CPage 7A-60775 lbs/hr1100/2 = 550 lbs/hrChart InfoCruiseClean Config6000ft. PA30 deg CPage 7A-602500/300025/3015000.991.0.98.9911.0.98211111211021250/2200092/9658600025180.9921.0.98494959310011580604476775550Continuous Torque Available
  • This is the most torque the engines can produce and remain out of all of your 30 minute engine operating limits
  • You will be at the top of one or more of your continuous limitations:
  • TGT - 810C
  • NG - 99%
  • Eng Oil Temp - 135C
  • Continuous Torque Available
  • As far as pre-mission flight planning, this torque value is pretty limited in it’s application
  • A more practical value would be a continuous airspeed which could be used for determining times enroute and flight plan speeds
  • Continuous Torque Available
  • As a technique, the pilot may obtain a continuous airspeed by tracing the Continuous Torque available line upward until you intersect your aircraft GWT
  • Read horizontally to indicated airspeed
  • This will provide the pilot with a speed value to fly as quickly as possible to his/her destination, while remaining outside of any 30 minute limits
  • Continuous Torque Available
  • Notice that unlike the ATF lines, there is only one Continuous Torque line on your cruise charts
  • The Continuous Torque line in the cruise chart represents an averaged ATF of .95 or greater
  • If the aircraft ATF is lower than .95, the Continuous Torque value will be less than the PPC indicates, but we have no means to compute how much less
  • Continuous Torque Available
  • Notice also that the Continuous Torque line stops at approximately 70-80 KIAS
  • For torques below these speeds, read vertically down from where the Continuous Torque line terminates to obtain this value
  • DO NOT interpolate below the line
  • Continuous Torque Ava
    Search Related
    We Need Your Support
    Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

    Thanks to everyone for your continued support.

    No, Thanks