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Instructor Tour > TH-73A Limits > Flashcards

TH-73A Limits Flashcards

1
Q

Introduction Blurb

A

Compliance with the operating limitations in section 1 of this manual is mandatory. The helicopter must also be operated in accordance with the appropriate operating rules.

If aircraft structural, rotor or engine limitations are exceeded, record the fact on a maintenance action form, including limits exceeded, range, time beyond limits, and any additional data that would aid maintenance.

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2
Q

Gas Generator Speed (N1)

A

Minimum 51%
Cautionary (autorotation only) 51 to 60%
Continuous operation 60 to 100.1%
Take-off (5 minutes) 100.1 to 103.2%
Maximum take-off (5 minutes) 103.2%
Transient (30 seconds) 103.8%

N:
-Transient must not be used intentionally
-IDLE N1 may decrease below 60% when the generator and other aircraft systems are turned on. This is normal.

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3
Q

Power Turbine Speed (N2)

A

Minimum 95%
Cautionary 95 to 101%
Continuous operation 101 to 103%
Maximum 103%
Transient (10 seconds) 108%

C:
-As N2 indication of 103% corresponds with an actual value of N2 of 102.50% to 103.49%. The N2 transient range begins at 103.01%. Protracted operation at N2 values of 103% should be avoided to minimize the possibility of N2 overspeed.

N:
-Transient must not be used intentionally.

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4
Q

Inter-Turbine Temperature (ITT)

A

Normal Operation

Maximum continuous 755 deg C
Take-off (5 minutes) 755 to 810 deg C
Maximum take-off (5 minutes) 810 deg C
Transient (5 seconds) 860 deg C

Starting

Maximum 870 deg C
Transient (2 seconds between 980-1090 deg) 1090 deg C

N:
-A linear variation applies above 870 deg C, ten seconds, and 980 deg C, two seconds
-Transient must not be used intentionally

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5
Q

Engine Torque (TRQ)

A

Maximum continuous 100%
Take-off (5 minutes) 100-108.5%
Maximum take-off (5 minutes) 108.5%
Transient (6 seconds) 115%

N:
-Transient must not be used intentionally

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6
Q

Rotor Limitations (NR) Power-On

A

Minimum 95%
Cautionary 95-101%
Continuous operation 101-103%
Maximum 103%
Transient (10 seconds) 108%

N:
-Transient must not be used intentionally.

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7
Q

Rotor Limitations (NR) Power-Off

A

Transient (10 seconds) 80%
Minimum 90%
Continuous operation 90-110%
Maximum 110%

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8
Q

Fuel Pressure Limitations

A

Cautionary 0-7 psi
Continuous operation 7-25 psi
Maximum 25 psi

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9
Q

Minimum Fuel Limitations

A

Minimum fuel on landing shall be no less than 50 lb in the No. 1 cell.

W:
-Sideward flight and crosswind hovering when indicated fuel quantity is less than 22 lb may result in engine flameout.

N:
-The No.1 and No.2 fuel cells each contain 9 lb of unusable fuel.

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10
Q

Engine Oil Pressure Limitations

A

Minimum 40 psi
Cautionary (with N1 <72%) 40-80 psi
Continuous operation 80-110 psi
Maximum 110 psi

N:
-During cold starting conditions the oil pressure can temporarily exceed 110 psi; it reduces as oil temperature increases.

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11
Q

Engine Oil Temperature Limitations

A

Minimum OAT for starting -25 deg C
Continuous operation 10-115 deg C
Maximum 115 deg C
Transient (5 minutes with N1 at 61 +/-1% 127 deg C

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12
Q

Main Transmission Oil Pressure

A

Minimum 30 psi
Continuous operation 30-55 psi
Cautionary 55-70 psi
Maximum 70 psi

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13
Q

Main Transmission Oil Temperature

A

Minimum OAT for starting -25 deg C
Continuous operation 0-115 deg C
Maximum 115 deg C

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14
Q

Engine Starter Limitations

A

The engine starter duty cycle is the following:

On battery:
1. 40 seconds on, 60 seconds off.
2. 40 seconds on, 60 seconds off.
3. 40 seconds on, 30 minutes off.

With external power:
1. 25 seconds on, 30 seconds off.
2. 25 seconds on, 30 seconds off.
3. 25 seconds on, 30 minutes off.

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15
Q

Generator Load Limitations

A

Continuous operation 0-200 A
Maximum 200 A
Transient (5 seconds) 300 A

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16
Q

Auxiliary Generator Load Limitations

A

Continuous operation 0-150 A
Maximum 150 A
Transient (5 seconds) 150 A

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17
Q

Hydraulic Fluid Pressure Limitations

A

Minimum 1200 psi
Cautionary 1200-1400 psi
Continuous operation 1400-1600 psi
Maximum 1600 psi

18
Q

Vne (Power-ON/OFF)

A

See Figure 4.12-3

19
Q

Vne (Max. IFR airspeed)

A

Lesser of 145 KIAS or Vne (Power On)

20
Q

Vmini (Min. IFR airspeed)

A

60 KIAS

21
Q

Vmin APP (Min. IFR Approach airspeed)

A

60 KIAS

22
Q

Vmax APP (Max. IFR Approach airspeed)

A

130 KIAS

23
Q

Minimum airspeed in autorotation (without close external references)

A

60 KIAS

24
Q

Maximum airspeed with torque between 100 and 108.5% (take-off power range)

A

75 KIAS

25
Q

Vne with one or both doors open or removed

A

85 KIAS

26
Q

Vne during doors opening and closing operation

A

70 KIAS

27
Q

Maximum speed for searchlight extension, orientation and retraction

A

120 KIAS

28
Q

Vne with searchlight extended

A

No change with respect to the basic NFM

29
Q

Vne with external loads attached to cargo hook

A

From sea level to 5000 ft 100 KIAS
Above 5000 ft Decrease 3 kt every 1000 ft

Controllability and stability of the load may limit the airspeed of the rotorcraft with an external load. Particular rotor-craft load combination flight characteristics may reduce the limits above.

N:
-Caution should be exercised, when carrying external cargo, as the handling characteristics and controllability may be affected by the size, weight, and shape of the cargo load, as well as by the length of the sling.

30
Q

Maximum forward speed at touchdown after engine failure

A

50 KGS

31
Q

External Hoist Maximum Operating Limit Speed (Vne)

A

Hoist operation (cable reeling-in/out, load raising or lowering) is permitted with aircraft in stationary hover only.

Aircraft horizontal translation with external hoisted load outside the aircraft cabin is approved up to 8000 ft density altitude (Hd) in accordance with the wind/ground speed azimuth envelope.

The VS shall be limited to +/-200 ft/min.

At altitudes higher than 8,000 ft, flight with external load outside the aircraft cabin is prohibited.

Flight with external hoisted load shall be limited to reach a place suitable for load recovering.

Hoisting or lowering an empty litter in open position is prohibited.

32
Q

Maximum operating altitude

A

15000 ft (4572 m) Hp

33
Q

Minimum ambient air temperature

A

-13 deg F (-25 deg C)

34
Q

Maximum sea level ambient air temperature

A

122 def F (50 deg C)

35
Q

Tell me about adiabatic lapse rate.

A

The maximum ambient air temperature for operation decreases with pressure altitude at the standard lapse rate of 2 deg C (3.6 F) every 1000 ft (305 m) up to 15,000 ft (4572 m)

36
Q

Nose-up operations

A

12 deg

37
Q

Side-up operations

A

10 deg

38
Q

Nose-down operations

A

2 deg

39
Q

Nose-down operations (unobstructed tail)

A

5 deg

40
Q

Maximum Gross Weight for ground operations (towing and Take-off prohibited)

A

6393 lb (2900 kg)

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