Limits Chapter 4 Flashcards
(46 cards)
Exceeding Operating Limitations
Anytime an operational limit is exceeded, an appropriate entry shall be made on a MAF. The entry shall state what limits were exceeded and include range, duration and any additional data that would aid maintenance personnel
The flight displays 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 Limits
The engines are limited by Ng, Np, TGT, oil px, and oil temp. Specified temp limits ensure that the engines are operated at internal temps that will not shorten the service life expectancy of engine components
Engine Starter Limits
Engine starter limits are 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 Limits
The single and dual engine start envelopes are figure 4-2.
For crossbreed starts, the receiving engine shall be at or above 24% Ng prior to advancing PCL to idle
Engine starts are prohibited with the main rotors blades or tail pylon folded
The start TGT limit is 851 C until engine idle speed is attained
Engine Idle limits with Gust lock engaged
Engine operation with gust lock engaged is prohibited
TGT limits
0-810 continuous green 810-851 30 mins yellow 851-878 2.5 mins (10 mins max power and limiter checks only) red 878-903 2.5 mins red 903-949 12 seconds red 949 max red
Np Limits
<96% avoid red 96%-105% cont green (yellow above 101%) 105%-117% 20 seconds yellow 117%-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.
Nr Limits
<96% avoid red 96%-101% cont green 101%-120% precautionary yellow 120% max red >120% 123% max for fcf red 127% overspeed latch red
Dual engine torque <80 KIAS
0-120% cont green
120-144% 10 seconds yellow
144% max red
Dual engine torque >80 KIAS
0-106% cont green
106-127% 10 seconds yellow
127% max red
Dual engine torque limits apply when both engines are above 65% torque
Single engine Torque
0-135% cont green
135-144% 10 seconds yellow
144% max red
Ng Limits
0-102.2% cont green
102.2-106% 2.5 mins yellow
106-107% 12 second red
107% max red
Transmission Px
20 psi min red 20-30 psi precautionary yellow 30-65 cont green. 45-60 psi in level flight 65-130 precautionary yellow 130 max red
Transmission Temp
-50-105 cont green
105-120 precautionary yellow
120 max red
Engine oil Temp
-50-135 cont green
135-150 30 mins yellow
150 max red
Engine oil Px
22 min red 22-26 precautionary yellow 26-100 cont green 100-120 precautionary yellow 120 max red
22-55 normal idle range
Engine Start limits
Starter engaged/starter disengaged
<16 C First cycle 60 seconds Second cycle 60 seconds Third cycle 60 seconds Fourth cycle 30 mins
16-52 C
First cycle 60 seconds
Second cycle 30 mins
Engine Motor (Ignition Off) Starter Engaged/Starter Disengaged
2 mins 5 mins
2 mins 30 mins
- A start cycle is defined as starter initiation, acceleration, dropout
- Times for motoring are cumulative within a 5 min period
Min planned fuel on landing
Min planned fuel on landing shall be no less than 600 lbs
APU limits
APU is not meant for routine in flight use. Operation of the APU in flight shall be limited to essential operations only. Acceptable in flight use includes emergency procedures, single engine training, practice auto rations, powering the ECS during extreme temperature operations
Transmission Limits
The Transmission is limited by Nr, Torque, oil temp, oil px. Operation is governed by whichever limit is reached first.
Engine torques over 150% are displayed as red “XXX”
Transmission Oil temp limits
During an operating condition, no maintenance action is required if main transmission oil temp is in the precautionary range continuously for 5 mins or less
Prolonged Hovering in hot weather, 86 F/30 C may cause main transmission oil temp 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 Px Limits
During Steady State level pitch attitudes (level flight) transmission px 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
- Steady pressure outside of 45-60 psi but within the normal limits of 30-65
- Fluctuations not to exceed 10 psi range, but within the normal limits of 30-65
During transient pitch or steady state nose up attitudes (autos, rearward flight, downwind hovering, slope up landings) transmission oil px fluctuations (momentary fluctuations below 30 psi and transient drops below 20 psi for less than 1 second) are acceptable. Operating with px fluctuations below 30 psi shall be limited to 30 mins
No Oil Flow condition
During Rotor engagement, a zero oil px indication may indicate a no oil flow condition through the oil lubrication system. Operating with a no oil pressure indication shall be limited to less than 1 min and shall be documented on a MAF
