TH67 Operating Limitations And Restrictions

Question 1

Engine oil temperature

Answer 1

0 to 107°C continuous operation

107°C maximum

Question 2

Engine anti-ice limitations

Answer 2

Engine anti-ice shall not be used in ambient temperatures above 4 deg C.

Engine anti-icing shall be ON for flight in visible moisture in temperature 4 deg C or below.

Question 3

Low inlet pressure caution

Answer 3

Caution:

Takeoff with LOW INLET PRESSURE caution light illuminated is PROHIBITED.

Question 4

Engine starter limits

Answer 4

If there is no rise in TOT within the first 20 seconds of engaging the starter, limit starter energizing time to the following:
-External power: 25 seconds ON, 30 seconds OFF, 25 seconds ON, 30 seconds OFF, 25 seconds ON, 30 minutes OFF

-Battery: 40 seconds ON, 60 seconds OFF, 40 seconds ON, 60 seconds OFF, 40 seconds ON, 30 minutes OFF

If there is no rise in TOT within the first 20 seconds of energizing starter, limit starter energizing time to the following:

-External / Battery power: 1 minute ON, 1 minute OFF, 1 minute ON, 1 minute OFF, 1 minute ON, 30 minutes OFF

Question 5

Engine starting limitations

Answer 5

During starting if N1 does not reach 58% in a total time of 45 seconds (or 60 seconds below 10 deg C FAT), close throttle and press starter button until TOT is below 200 deg C. If engine fails to start on third attempt, abort start and make an entry on DA form 2408-13-1. Starter engage time limits above do not apply to engine starting limitations should abort start procedures become necessary.

Question 6

Fuel limitations

Answer 6

Type B or JP-4 may be used at all ambient temperatures with no restrictions.

Type A or A-1, JP-5 and JP-8 may be used in ambient temperatures above -32 deg C. The minimum fuel pressure is 8 PSI at temperatures of -18 deg C to -32 deg C. At temperatures above -18 deg C the minimum fuel pressure is 4 PSI.

If fuels other than Type B or JP-4 are used, a deceleration check must be performed prior to the first flight of each day. A deceleration check must also be performed prior to each flight if Power Off maneuvers are to be performed.

The use of AVGAS in the TH-67 is prohibited.

Question 7

Health indicator test (HIT)

Answer 7

Select an N1 speed based on free air temperature. TOT is compared to a predetermined value (baseline).

If the difference between recorded and baseline TOT is:
+/-20 deg C or greater, an entry in DA form 2408-13-1 will be made

+/-40 deg C or greater is cause for grounding the aircraft

Question 8

Longitudinal center of gravity limits

Answer 8

VMC center of gravity limits are from station 106 to 114.2; forward and aft limits are variable depending on gross weight and configuration.

2425 pounds and below 106.0 - 114.2
At 3200 pounds 106.0 - 111.6
At 3350 pounds 106.9 - 110.8

Question 9

Lateral center of gravity limits

Answer 9

3 inches left of centerline

4 inches right of centerline

Question 10

Weight limitations

Answer 10

Maximum allowable ramp weight is 3,350 lbs
Maximum allowable gross weight for hover/flight is 3,350 lbs
Minimum front seat weight is 170 lbs

Question 11

Flight restriction for high power

Answer 11

VNE 80 knots with >85% to 100% torque applied

Question 12

Aerobatic maneuvers

Answer 12

Aerobatic maneuvers are prohibited. Aerobatic flight is defined to be any intentional maneuver involving an abrupt change in aircraft attitude, an abnormal attitude, pitch angle greater than 30 deg or roll angles greater than 60 deg, or abnormal acceleration not necessary for normal flight.

Question 13

Control movements

Answer 13

Abrupt control movements, including rapid and repetitive anti-torque pedals reversals are prohibited to avoid excessive stresses in the structure. This restriction in no way limits normal control application.

Caution:
For gross weights greater than 3000 lbs and density altitudes greater than sea level, the directional control margin may be significantly reduced while hovering in winds from the right greater than 20 knots or for right sideward flight at speeds greater than 20 knots.

Question 14

Engine oil pressure

Answer 14

50 psi minimum below 78% N1
90 psi minimum from 78% to 94% N1
115 psi minimum above 94% N1. Double wide arc.
50 psi minimum
130 psi maximum
Note: During cold temperature operation the oil pressure may exceed the maximum of 130 PSI. Stabilize the engine at idle speed of 60 to 64% until the engine oil temperature is above 0°C and the engine oil pressure is within normal limits.

Question 15

Transmission oil pressure

Answer 15

30 to 50 PSI continuous operation
30 psi minimum
70 psi maximum

Question 16

Transmission oil temperature

Answer 16

15°C to 110°C continuous operation

110°C maximum

Question 17

Loadmeter

Answer 17

70% maximum

Question 18

Fuel pressure

Answer 18

4 psi minimum
4 to 30 PSI continuous operation
30 psi maximum
8 psi minimum: Type A, A-1, JP-5, JP-8 fuel below -18°C to -32°C.

Question 19

Airspeed indicator

Answer 19

Note: autorotation above 100 knots indicated airspeed will result in high rates of descent and low rotor RPM.
0 to 130 knots continuous operation
130 knots maximum
100 knots maximum for autorotation

VNE for internal gross weight above 3,200 pounds is 78 knots indicated airspeed, not to exceed placarded VNE.

Question 20

Turbine outlet temperature

Answer 20

Note: the red warning light illuminates when either of the following conditions are exceeded: 810 to 927°C for 10 seconds, or higher than 927°C.

100 to 738°C continuous operation
738 to 810°C take off power range (5 minute limit)
810°C maximum
810 to 843°C, 6 second transient (Not to be used intentionally)
927°C maximum during starting and shutdown (10 seconds maximum)

Question 21

Gas producer (N1)

Answer 21

60 to 105% continuous operation
105% maximum
105 to 106% transient (15 seconds maximum)

Question 22

Rotor indicator

Answer 22

90% minimum operation
50 to 60% accelerate through this range
90 to 107% normal operation
107% maximum
Power on transient rotor droop limit is 95% (five seconds maximum)

Question 23

Power turbine indicator (N2)

Answer 23

97% minimum operation
97 to 100% continuous operation
100% maximum
N2 75 to 88%, 60 seconds maximum (time not cumulative)

Question 24

VMC airspeed limitations

Answer 24

At 3000 pounds gross weight and below:
VMC VNE 130 KIAS sea level to 3000 ft density altitude. Decrease VNE 3.5 KIAS per 1000 feet above 3000 feet density altitude. Maximum density altitude 20,000 feet.

Above 3000 pounds gross weight:
VMC VNE 122 knots sea level to 3000 ft density altitude. Decrease VNE 7 KIAS per 1000 ft above 3000 ft density altitude. Maximum density altitude 13,500 feet.

VNE for internal gross weight above 3200 lbs is 78 KIAS, not to exceed placarded VNE.

Question 25

Torque limits

Answer 25

0-85% continuous operation
> 85-100% take off power range (5 minute limit)
100% maximum
Transient torque limit is 100-110% (5 second maximum) INTENTIONAL USE IS PROHIBITED

Question 26

Fuel quantity

Answer 26

Red line is on empty

Question 27

Altitude limitations

Answer 27

3000 lbs gross weight and below
Maximum operating:
- VFR 20,000 feet pressure altitude

Above 3000 lbs gross weight
Maximum operating:
- VFR 13,500 feet pressure altitude

Question 28

Engine RPM limitations warning

Answer 28

Use of the throttle to control RPM is not authorized. (Refer to ch.9, emergency procedures and the flight training guide for exceptions.)

Question 29

Turbine outlet temperature (TOT) limits caution

Answer 29

Exceeding the limits of 810°C TOT or 100% torque may cause N1 topping with resultant rotor droop.

Question 30

Wind limitations

Answer 30

The helicopter can be started in a maximum wind velocity of 45 knots and a maximum gust spread of 15 knots.

Note:
Gust spreads are not normally reported. To obtain spread, compare minimum and maximum velocities.

Maximum wind for hovering is 35 knots crosswind and 30 knots tailwind.

For hover operations at gross weights above 3200 lbs:

• IGE maneuvers: refer to ch. 8
• OGE maneuvers: calm wind only

Question 31

Fuel boost pump limitations

Answer 31

Fuel boost pumps shall be ON during normal operations.

Question 32

Flight restrictions at low “G”s

Answer 32

Flight less than +0.5g is prohibited

Question 33

Flight restrictions for practice autorotations

Answer 33

Practice autorotation landings may be accomplished subject to the following limitations:

• Surface winds must not exceed 20 knots
• Surface crosswind component must not exceed 10 knots as computed from the chart
• Wind gust spread must not exceed 10 knots
• Touchdown autorotations downwind are prohibited
• Airspeed during autorotation shall not be less than that established for minimum rate of descent
• Groundspeed during touchdown should be approximately 5 knots
• Touchdown in a level attitude prior to passing through 70% rotor RPM
• Practice autorotation landings at gross weights above 3,200 lbs are prohibited

Question 34

Slope landing/takeoff limitations

Answer 34

Slope operations shall be limited to slopes of 8 degrees or less.

Question 35

Flight over salt water and near volcanic activity

Answer 35

Caution:
Prolonged hovering over saltwater which results in spray ingestion, indicated by spray on the windshield, should be avoided.

Salt spray ingestion in turbine engines may result in deterioration in performance as well as a loss in compressor stall margin. When aircraft has been operated within 10 miles of salt water or within 200 miles of volcanic activity, appropriate entries should be made on DA Form 2408-13-1 to alert maintenance.

Question 36

Flight in rain, snow, or icing conditions

Answer 36

If flown in rain, snow, or icing conditions, appropriate entries shall remain on DA form 2408-13-1 to alert maintenance.