TH-73A Limits

gas generator speed (N1)

minimum: 51%

cautionary (autorotation only) 51 - 60%

continuous operation 60 - 100.1%

take off ( 5 minutes) 100.1 - 103.2%

maximum takeoff ( 5 min) 103.2

transient (30 sec) 103.6%

IDLE N1 may decrease below ___ when the generator and other aircraft systems are turned on. This is normal

60%

Power Turbine speed (N2)

min 95%

cautionary 95-101%

continuous operation 101 - 103%

maximum 103%

transient (10 seconds) 108%

An N2 indication of ___ corresponds with an actual value of ___ to ___. the N2 transient region begins as ___. protracted operation at N2 values of ___ should be avoided to minimize the possibility of N2 overspeed.

103%

102.5 to 103.49%

103.01%

103%

Inter-Turbine Temperature (ITT) NORMAL OPERATION

Maximum continuous 755 C

take-off (5 min) 755 - 810 C

Max takeoff (5min) 810 C

Transient (5sec) 860

Inter-Turbine Temperature (ITT) STARTING

Maximum 870

transient (2 seconds between 980 C and 1090 C) 1090 C

a linear variation applies above ___ C, ___seconds, and ___C, ___ seconds

870 C

ten seconds

980 C

two seconds

Engine torque (TRQ)

Maximum continuous 100%

takeoff (5min) 100 - 108.5%

maximum takeoff (5min) 108.5%

transient (6 seconds) 115%

Rotor limitations (NR) POWER ON

minimum 95%

cautionary 95 - 101%

continuous operations 101 - 103%

maximum 10%

transient (10 sec) 108%

Rotor limitations (NR) POWER OFF

transient (10 sec) 80%

minimum 90%

continuous operation 90 - 110%

maximum 110%

fuel pressure

cautionary 0 - 7 psi

continuous operation 7 - 25 psi

maximum 25 psi

minimum fuel

planned fuel reserve shall be no less than 142 lbs in the No. 1 cell. satisfies the 20 minutes of flight fuel per CNAF M3710.7. Irrespective of planning, minimum fuel on landing shall be no less than 50 lbs in the No. 1 cell

sidewards flight and x-wind hovering when indicated fuel quantity is less than lbs may result in ________

22

engine flameout

engine oil pressure

minimum 40 psi

cautionary (with N1 < 72%) 40 - 80 psi

continuous operation 80 - 1110 psi

maximum 110 psi

engine oil temperature

minimum OAT for starting -25 C

continuous operation 10 - 115 C

maximum 115 C

transient (5 min with N1 at 61 +- 1%) 127 C

during cold starting conditions the oil pressure can temporarily exceed ___; it reduces as oil temperature increases

110 psi

transmission oil pressure

minimum 30 psi

continuous operation 30 - 55 psi

cautionary 55 - 70 psi

maximum 70 psi

transmission oil temperature

minimum OAT for starting -25 C

continuous operation 0 - 115 C

maximum 115 C

starter duty cycle ON BATTERY

40 sec on, 60 sec off

40 sec on, 60 sec off

40 sec on, 30 MINUTES off

starter duty cycle WITH EXTERNAL POWER

25 seconds on, 30 seconds off

25 seconds on, 30 seconds off

25 seconds on, 30 MINUTES off

Generator load limitations

continuous operation 0 - 200A

Maximum 200 A

transient (5 seconds) 300 A

Auxiliary generator load limitations

continuous operation 0 - 150A

Maximum 150 A

Transient (5 sec) 150 A

Hydraulic system limitations FLUID PRESSURE

minimum 1200 psi

cautionary 1200 - 1400 psi

continuous operation 1400 - 1600 psi

maximum 1600 psi

Vne (Max IFR airspeed)

lesser of 145 KIAS or Vne(power on)

Vmini (MINIMUM IFR airspee)

60 KIAS

Vmin APP (Min IFR approach speed)

60 KIAS

Vmax (Max IFR approach airspeed)

130 KIAS

Minimum airspeed in autorotation (without close external references)

60 KIAS

Maximum airspeed with torque between 100% and 108.5% (takeoff power range)

75 KIAS

Vne with one or both doors open or removed

85 KIAS

Vne during doors opening and closing operation

70 KIAS

Maximum speed for searchlight extension, orientation and retraction

120 KIAS

Vne with searchlight extended

no change with respect to the basic NFM

Vne with external loads attached to cargo hook:

from sea level to 5000 ft:

above 5000 ft

100 KAIS

decrease 3 kt for every 1000 ft from 100 KIAS

maximum forwards speed at touchdown after engine failure

50 kt

maximum operating altitude

15000 ft (4572 m)

minimum ambient air temperature

-13 F (-25 C)

maximum sea level ambient air temperature

122 F (50 C)

the maximum ambient air temperature for operation decreases with pressure altitude at the standard lapse rate of ___ C (___F) every ___ ft (___ m) up to ____ ft (___ m)

2 C (3.6F)

1000 ft (305 m)

1500 ft (4572 m)

slope takeoff and landing limitations

nose up operations 12 deg

side-up operations 10 deg

nose down ops 2 deg

nose down (unobstructed tail) 5 deg

weight limitations

Maximum gross weight for ground operations (towing and take off prohibited) 6393 lb (2900 kg)

Maximum gross weight 6283 lb (2850 kg)

Minimum gross weight for flight 3803 lb (1725 kg)

Maximum gross weight with external load attached to a cargo hook 6944 lb (3150 kg)

AUTOMATIC FLIGHT CONTROL SYSTEM MINIMUM USE HEIGHT

MUH with both helipilot operative:

fly attentive below 500 ft AGL

fly manually below 250 ft AGL

AUTOMATIC FLIGHT CONTROL SYSTEM MINIMUM USE HEIGHT

MUH with one helipilot inoperative (SAS 1or SAS 2)

fly attentive below 500 ft AGL

fly manually below 500 ft AGL

flight with one helipilot inoperative

max airspeed 130 KIAS

max rate of climb 750 fpm

fly attentive up to ___ KIAS and/or + rate of climb, and above ___ , fly manually in all other conditions

130 KIAS

750 fpm

500 ft AGL

Flight director modes MUH

All FD modes when in cruise, climb, and descent: 500 ft AGL

All FD modes during approach: 50 ft AGL

instrument landing system approach

steepest approach gradient: 3 deg

maximum rate of descent: 1000 ft/min

Flight director engaged, or coupled, with an helipilot inopertive

max airspeed 100 KIAS

fly attentive above 500 ft AGL

fly manually below 500 ft AGL

baggage compartment limitations

maximum load 250 lbs (113 kg)

maximum unit load 102 lb/sq-ft (500 kg/m²)

bleed air heater operations

bleed air shall be off during takeoff and landig and shall be off in all flight conditions requiring max engine power available

rotor brake limitations

limited to ground operations and shall only be applied after engine shutdown and rotor ROM (NR) below 40%

hoist limitations

maximum hoist load 450 lbs (204 kg)

maximum available hoist cable length 164 ft (50 m)

cargo hook operations:

cargo hook loading limit

from -1000 ft to 9000 ft: 3086 lbs (1400 kg)

above 9000 ft: decrease 110 lbs (50 kg) every 100 ft from 3086 lbs (1400 kg)

Prohibited maneuvers

aerobatic maneuvers

protracted operations in the AVOID areas of the height velocity diagram

intentional entry into retreating blade stall