Limits Flashcards
Exceeding Operational Limits
Anytime an operational limit is exceeded, an appropriate entry shall be made on an MAF. The entry shall state what limits were exceeded and include range, duration, and any additional data that would aid maintenance personnel.
The flight display’s digital readout will display “XXX” in red when a TGT or torque limit is exceeded.
If a limit is exceeded to the extent that a red “XXX” is indicated, the crew shall land as soon as practicable.
Engine Limitations
The engines are limited by Ng, Np, TGT, oil pressure and oil temperature. Specified temperature limits ensure that engines are operated at internal temperatures that will not shorten the service life expectancy of engine components.
Engine Starter Limitations, Starter Cycle
Engine starter limits are presented in Figure 4-2. A start cycle is defined as starter initiation, acceleration of the output drive, and starter dropout. A 60-second delay between start attempts is required any time a start is aborted, except during emergencies.
Engine Start Limitations
The single and dual engine start envelopes are presented in the Figure 4-3. For crossbleed starts, the receiving engine shall be at or above 24% Ng prior to advancing the PCL to IDLE.
Engine starts with the main rotor blades or tail pylon folded is prohibited.
The start TGT limit is 851C until idle speed is attained.
Engine Idle Limitations with Gust Lock Engaged
Engine operation with gust lock engaged is prohibited.
TGT
0-810 Continuous Green 810-851 30 mins Yellow 851-878 10 mins Red 878-903 2.5 mins Red 903-949 12 seconds Red 949 Maximum Red
Power Turbine Speed
<96 Avoid Red 96 to 105% Continuous Green (Yellow above 101%) 105 to 117% 20 Seconds Yellow 117 to 120% 12 Seconds Yellow 120% Max Red
During engagement, extended operations in the 20 to 40% and 60 to 75% ranges may cause engine damage.
Main Rotor Speed
<96% Avoid Red 96 to 101% Continuous Green 101 to 120% Precautionary Yellow 120% Max Red >120, 123% max FCF only Red 127% Overspeed Latch Red
Dual Engine Torque <80 KIAS
0 to 120% Continuous Green
120 to 144% 10 Seconds Yellow
144% Max Red
Dual Engine Torque >80 KIAS
0 to 106% Continuous Green
106 to 127% 10 Seconds Yellow
127 Max Red
Dual engine torque limits apply when both engines are above 65% torque
Single Engine Torque Limits
0 to 135% Continuous Green
135 to 144% 10 Seconds Red
144% Max Red
Gas Generator Speed
0 to 102.2% Continuous Green
>102.2 to 106% 2.5 mins Yellow
>106 to 107% 12 Seconds Red
107% Max Red
Transmission Temperature
-50 to 105C Continuous Green
105 to 120C Precautionary Yellow
120C Max Red
Transmission Pressure
20 psi Minimum Red 20 to 30 psi Idle and Transient Yellow 30 to 65 psi (45 to 60 psi in level flight) Continuous Green 65 to 130 psi Precautionary Yellow 130 psi Max Red
Engine Oil Temp
-50 to 135C Continuous Green
135 to 150C 30 Mins Yellow
150C Max Red
Engine Oil Pressure
22 psi Minimum Red 22 to 26 psi Precautionary Yellow 26 to 100 psi Continuous Green 100 to 120 psi Precautionary Yellow 120 psi Max Red
Normal idle range is 22 to 55 psi
Minimum Planned Fuel on Landing
Minimum planned fuel on landing shall be no less than 600 lbs.
APU Limitations
The APU is not intended for routine in-flight use. Operations of the APU in flight shall be limited to essential operations only. Acceptable in-flight use includes emergency procedures, single engine training, practice autorotations, and powering the ECS in extreme temperature operations.
Transmission Limitations
The transmission is limited by Nr, torque, oil pressure, and oil temperature. Operation is governed by whichever limit is reached first.
Engine torques over 150% are displayed as red XXX.
Transmission Oil Temperature Limitations
During any operating condition, no maintenance action is required if main transmission oil temperature is in the precautionary range continuously for 5 mins or less.
Prolonged hovering in hot weather, 86F (30C), may cause main transmission oil temperature to rise into the precautionary range. Operation in the precautionary range for less than 30 mins during any one flight under this condition is acceptable and no maintenance action is required.
Transmission Oil Pressure Limitations
During steady state level pitch attitudes (i.e., level flight), the transmission oil pressure should be 45 to 60 psi. The following conditions do not constitute an immediate emergency situation, but may be indicative of a degraded lubrication system. Any discrepancy shall be documented on a MAF.
1) Steady pressure outside of 45 to 60 psi, but within the normal limits of 30 to 65 psi.
2) Fluctuations not to exceed a range of 10 psi, within the normal limits of 30 to 65 psi.
During transient pitch or steady state nose high pitch attitudes (autorotations, downwind hovering, rearward flight, slope up landings, etc.) transmission oil pressure fluctuations (including momentary fluctuations below 30 psi and transient drops below 20 psi for up to one second) are acceptable. Operating with pressure fluctuations below 30 psi shall be limited to 30 mins.
During rotor engagement, a zero oil pressure indication may indicate a no-oil-flow condition through the oil lubrication system. Operating with a no oil pressure indication shall be limited to les than 1 minute and shall be documented on a MAF.
