Limits Flashcards
Minimum Nf RPM (Power-on)
97%
Maximum continuous Nf RPM (Power-on)
100%
Avoid Range Nf (Steady State Operation)
71-88% with engine torque greater than 33%
- Holding Nf in this range for a cumulative 60 seconds requires turbine replacement and should be avoided.
- Flight within this range shall be included on a MAF to ensure documentation and include duration
Steady State definition (Nf)
Holding Nf within a 2% range
Idle Ng RPM
62+/-2%
Normal Operating Range Ng RPM
60-105%
Maximum Transient Ng RPM
106% for 15 seconds
Minimum Engine Oil Pressure
- 50 psi with Ng below 79%
- 90 psi with Ng between 79-94%
- 115 psi with Ng above 94%
Maximum Engine Oil Pressure
130 psi, except for temporary conditions up to 150 psi immediately following a cold-weather start
Engine Oil Temperature
0-107 degrees C
Nf Overspeeds
Determined on a sliding scale depending on TOT, Nf percentage, and duration
Engine Oil Temperature Gauge Colors
Green-0-107 degrees C
Red-107 degrees C
Engine Oil Pressure Colors
Red-50 psi Yellow-50-90 psi Green-90-115 psi (Single Wide Arc) Green-115-130 psi (Double Wide Arc) Red-130 psi
Transmission Oil Pressure Colors
Green-30-50 psi
Red-30, 70 psi
Transmission Oil Temperature Colors
Green-15-110 degrees C
Red-110 degrees C
Loadmeter Colors
Red-70%
Fuel Pressure Colors
Red-4.0 psi
Green-4.0-30 psi
Airspeed Colors
Green-0-130 knots
Red-130 knots
Blue-100 knots
Fuel Quantity Colors
Red-1.03 gallons/empty
Torque Colors
Green-0-85%
Yellow-85-100%
Red-100%
Turbine Outlet Temperature Colors
Green-100-738 degrees C Yellow-738-810 degrees C Red-810 degrees C Red circle-843 degrees C Red triangle-927 degrees C
Gas Producer Colors
Green-60-105%
Red-105%
Dual Tachometer Power Turbine Indicator Colors
Red-97%
Green-97-100%
Red-100%
Rotor Indicator Colors
Yellow-50-60%
Red-90%
Green-90-107%
Red-107%
Turbine Outlet Temperature (During Start)
Temperature Range: Time Limit:
- Up to 810 degrees C -No Limit
- 810-927 degrees C -10 seconds maximum
- 927 degrees C -Maximum
Turbine Outlet Temperature (During Power Transient)
Temperature Range: Time Limit:
- Up to 738 degrees C -No Limit
- 738-810 degrees C -5 minutes
- 810-843 degrees C -6 seconds
- 843 degrees C -Maximum
Minimum fuel reserve requirement (B/C)
10 gallons
Minimum Nr (Power-on)
97%
Maximum continuous Nr (Power-on)
100%
Normal operating range Nr (Power-off)
90-107%
Transmission Oil Pressure Limits (Continuous Operation)
30-50 psi
Minimum Transmission Oil Pressure Limits
30 psi
Maximum Transmission Oil Pressure Limits
70 psi
Transmission Oil Pressure Limits that dictate a MAF
50-70 psi
Transmission Oil Temperature Limits
15-110 degrees C
Maximum torque (Continuous Operation)
85%
Military power limit
100% for 5 minutes
Maximum transient torque
100-110 for 5 seconds
Allowable fuel boost pump pressure
4.0-30 psi
Standby generator speed limit
Prolonged operation of the standby generator while it is the primary power supply to the essential No. 1 bus is prohibited at speeds below 65 KIAS.
Rotor brake limit
Should be applied between 38-30 % Nr during normal operations
Starter limitation Note
If a light-off occurs within the first 20 seconds of the start sequence, the starter may be operated for 60 seconds within a 60 second cooling period. Three such attempts can be made in a 30-minute period, then wait 30 minutes to allow the starter to cool.
Starter limits
External Power: Battery: 25 seconds-ON 40 seconds-ON 30 seconds-OFF 60 seconds-OFF 25 seconds-ON 40 seconds-ON 30 seconds-OFF 60 seconds-OFF 25 seconds-ON 40 seconds-ON 30 minutes-OFF 30 minutes-OFF
Airspeed limit Note
All airspeed values are calibrated airspeed except when the indicated airspeed is specifically stated.
Vne FCS OFF
130 KIAS
Vne FCS ON
122 KIAS
Sideward/rearward
Density Altitude Feet Max Sideward Max Rearward
0-1,000 ft 25 15
1,000-2,000 ft 20 15
2,000-4,000 ft 15 15
4,000-6,000 ft 10 10
6,000-10,000 ft 5 5
Maximum rate of climb
50 KIAS
Minimum IFR speed (Vmini)
65 KIAS
Maximum airspeed with any combination of doors off
110 KIAS
Maximum autorotational airspeed
100 KIAS
Turbulence penetration airspeed
80 KIAS
Maximum operating altitude:
FCS OFF: 3,000-pound gross weight and below
20,000 ft pressure altitude
18,000 ft density altitude
Maximum operating altitude:
FCS OFF: Above 3,000-pound gross weight
16,000 ft pressure altitude
13,000 ft density altitude
Maximum operating altitude:
IFR or FCS ON: 3,000-pound gross weight and below
11,500-foot pressure altitude
13,500-foot density altitude
Maximum operating altitude:
IFR or FCS ON: Above 3,000-pound gross weight
8,500-foot pressure altitude
11,000-foot density altitude
Climb/Descent Rate of Climb Limit in IMC
1,000 ft/min
Acceleration Limit
Upper: +2.5 G’s
Lower: +0.5 G’s
@maximum gross weight
Maximum gross weight internal
3,200 lbs
Maximum gross weight external
3,350 lbs
Rotor Engagement/Disengagement Wind Limits
Front 45 to 45 - up to 40 kts max
45 to 45 both sides - up to 25 kts max
Back 45 to 45 - up to 17 kts max
Longitudinal Center-of-Gravity Limits
- Cg limits with FCS OFF are from station 106.0 to 114.2.
- Cg limits with FCS ON are from station 106.75 to 112.5.
- Cg limits with front doors removed are from station 106.0 to 110.0.
- The aft limit varies, depending on gross weight, for all operations.
Minimum Crew Requirements
- The minimum flightcrew consists of one pilot and a qualified observer.
- The minimum flightcrew for IFR operations is two pilots, with at least one being an instrument-rated pilot.
- The minimum flightcrew for Confined Area Landing and External Cargo operations is one pilot, one
qualified observer, and an aircrewman.
No aircrewman required if both pilots are NATOPS qualified in model. - The minimum crew weight is 180 pounds.
Minimum Flight Crew Requirements
One pilot and a qualified observer
Minimum Flight Crew for IFR operations requirements
Two pilots, with at least one being an instrument-rated pilot
Minimum Flight Crew for Confined Area Landing and External Cargo operations requirements
One pilot, one qualified observer, and an aircrewman. No aircrewman required if both pilots are NATOPS qualified in model.
Minimum crew weight
180 lbs
Required Equipment for IMC Flight
Operation in instrument meteorological conditions is prohibited in a TH-57B.
1. Cyclic force trim system.
2. MINISTAB flight control system (pitch and roll).
3. Main generator.
4. Standby generator.
5. Battery protection circuit.
6. Instantaneous vertical speed indicator.
7. Two attitude indicators (one automatically powered by approved standby battery source in the event of
power loss).
8. One operable communication system.
9. One operable navigation system appropriate to the routes to be flown.
10. Radar altimeter.
11. Other equipment as required by the operating rules.
Prohibited operations
- The TH-57B is prohibited from operating IMC or in icing conditions.
- The TH-57C is prohibited from operating in icing conditions.
- IFR operations are prohibited with any doors removed or with an external load.
- Asymmetrical doors off flight prohibited.
Prohibited maneuvers
- Aerobatic maneuvers.
- Protracted operations in the AVOID and CAUTION areas of the height velocity diagram (Figure 4-6).
- Fully developed vortex ring state.
- Intentional entry into blade stall.
- Hovering turns exceeding a rate of 45° per second.
Required Equipment for Night Flight
- All instrument and circuit breaker panel lights.
- All exterior lights.
- Operable communication radio.
- Attitude gyro.
- Radar altimeter.
Required Equipment for Overwater and Shipboard Operations
- Radar altimeter.
2. Vertical Speed Indicator.
