TH-67 Chapter 5

Question 1

EXCEEDING OPERATIONAL LIMITS

Answer 1

Intentional use of transient limits is prohibited. Anytime an operational limit is exceeded an appropriate entry shall be made on DA Form 2408-13-1. Entry shall state what limit or limits were exceeded, range, time beyond limits, and any additional data that would aid maintenance personnel in the inspection that is required.

Question 2

MINIMUM CREW REQUIREMENTS

Answer 2

a. VFR configured helicopter is approved for single pilot operations during day, night, and non-icing conditions.
b. Minimum flight crew for VFR operations is one pilot who shall operate the helicopter from the right crew seat. The left crew seat may be used for an additional pilot when approved dual controls are installed.
c. IFR configured helicopter is approved for single pilot VFR, and two pilots (one in right front seat and one in left front seat) for IFR/IMC operations during day, night, and non-icing conditions.
d. A+ Minimum flight crew for VFR operations is one pilot who shall operate the helicopter from the right crew seat. Minimum fight crew for NVG operations is two pilots (one in right front seat and one in left front seat)

Question 3

Instrument markings and placards

Answer 3

The minimum and maximum limits nd the normal and cautionary ranges for the helicopter and its subsystems are indicated by instrument markings and placards. The instrument markings and placards represent careful aerodynamic calculations that are substantiated by flight test data.

Question 4

ENGINE OIL TEMPERATURE AND PRESSURE GAUGE

Answer 4

ENGINE OIL TEMPERATURE

• 0º C - 107º C Continuous Operation
• 107º C Maximum

ENGINE OIL PRESSURE

• 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 idle speed of 60 to 64% until the engine oil temperature is above 0º C and the engine oil pressure is within normal limits.

Question 5

TRANSMISSION OIL PRESSURE AND TEMP

Answer 5

TRANSMISSION OIL PRESSURE

▩ 30 to 50 PSI Continuous Operation

▩ 30 PSI Minimum, 70 PSI Maximum

TRANSMISSION OIL TEMPERATURE

▩ 15º C to 110º C Continuous Operation

▩ 110º C Maximum

Question 6

LOADMETER AND FUEL PRESSURE GAUGE

Answer 6

LOADMETER

▩ 70% Maximum

FUEL PRESSURE

▩ 4.0 PSI Minimum

▩ 4.0 PSI to 30 PSI Continuous Operation

▩ 30 PSI Maximum

► 8 PSI Minimum using TYPE A, A-1, JP-5, JP-8 Fuels below -18 °C (0 °F) to -32 °C (-25 °F)

Question 7

AIRSPEED INDICATOR

Answer 7

NOTE
Autorotation above 100 KIAS 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 KIAS, not to exceed placarded VNE.

Question 8

TURBINE OUTLET TEMPERATURE GAUGE

Answer 8

TURBINE OUTLET TEMPERATURE GAUGE

NOTE
The Red Warning light illuminates when either of the following conditions are exceeded: 810°C to 927°C for 10 seconds or higher than 927°C

▩ 100° to 738° Continuous Operation

▩ 738° to 810° Take-off Power Range (5 minute limit)

▩ 810°C Maximum

810°C to 843°C, 6 second transient limit (Not to be used intentionally)

🔴 927°C Maximum during starting and shutdown, 10 seconds maximum

Question 9

GAS PRODUCER (N1)

Answer 9

GAS PRODUCER

▩ 60 to 105% Continuous Operation

▩ 105% Maximum

105% to 106% transient (15 seconds maximum)

Question 10

DUAL TACHOMETER

Answer 10

ROTOR INDICATOR

▩ 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%, 5 seconds maximum

POWER TURBINE INDICATOR

▩ 97% Minimum Operation

▩ 97 to 100% Continuous Operation

▩ 100% Maximum

N2 75% to 88%
60 seconds maximum (time not cumulative)

Question 11

N2 TRANSIENT OVERSPEED LIMITS

Answer 11

“Student needs to explain graph (figure 5-9, se nederst) verbally”

N2 Transient overspeed limit is 15 seconds maximum. Shaded area represents allowable overspeed.

Explanation:

• N2 transient overspeed is dependant upon engine torque.*
• 0 - 32% Engine torque: 107% Engine RPM.*
• 32% - 100% Engine torque: gradually decreases to decreases to 103% Engine RPM at 100% torque.*

Question 12

TORQUE METER

Answer 12

▩ 0 to 85% Continuous Operation

▩ > 85 to 100% Take-off Power Range (5 minute limit)

▩ 100% Maximum

Transient Torque Limit is 100 to 110% (5 seconds maximum)
INTENSIONAL USE IS PROHIBITED

Question 13

FUEL QUANTITY GAUGE

Answer 13

▩ On Empty

Question 14

ALTITUDE LIMITATIONS

Answer 14

a. 3000 pounds gross weight AND BELOW

Maximum operating

• VFR: 20,000 feet PRESSURE altitude
• IFR: 14,000 feet PRESSURE altitude
  b. ABOVE 3000 pounds gross weight

Maximum operating

• VFR: 13,500 feet PRESSURE altitude
• IFR: 8,000 feet PRESSURE altitude

Question 15

ENGINE RPM LIMITATIONS

Answer 15

⚠ WARNING
Use of the throttle to control RPM is not authorized. Refer to Chapter 9 Emergency Procedures and the USSAWC flight training guide for exceptions.

Question 16

TURBINE OUTLET TEMPERATURE (TOT) LIMITS (Caution, Para 5-20)

Answer 16

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

Question 17

WIND LIMITATIONS

Answer 17

WIND LIMITATIONS

a. 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.

b. Maximum wind for hovering is 35 knots crosswind and 30 knots tailwind.
c. For Hover operations at gross weights above 3200 lbs:

1. IGE maneuvers - refer to chapter 8
2. OGE maneuvers - calm wind only.

Question 18

FUEL BOOST PUMP LIMITATIONS

Answer 18

Fuel boost pumps shall be ON during normal operations.

Question 19

IFR STANDBY GENERATOR LIMITS

Answer 19

Prolonged operation of standby generator while it is the primary power supply to essential #1 buss is prohibited at airspeeds less than 50 KIAS (V_MINI) to assist with generator cooling.

NOTE
With main generator on, standby generator load-meter should indicate 10% or less. Momentary testing of standby generator under full bus load is permitted on ground or in air.

Question 20

ENGINE ANTI-ICE LIMITATIONS

Answer 20

a. Engine anti-ice shall not be used in ambient temperatures above 4ºC.
b. Engine anti-ice shall be ON for flight in visible moisture in temperature 4ºC or below.

Question 21

LOW INLET PRESSURE

Answer 21

⚠ CAUTION
Takeoff with LOW INLET PRESSURE caution light illuminated is PROHIBITED.

Question 22

ENGINE STARTER LIMITS

Answer 22

a. If there is no rise in TOT with in the first 20 seconds of energizing, 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

b. If there is a rise in TOT within the first 20 seconds of energizing the 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 Minute - OFF

Question 23

ENGINE STARTING LIMITATIONS

Answer 23

During starting if N1 does not reach 58% in a total time of 45 seconds (or 60 seconds below 10ºC FAT), close throttle and press starter button until TOT is below 200 ºC. If engine fails to start on third attempt, abort start and make 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 24

FUEL LIMITATIONS (PART 1)

Answer 24

a. Turbine Fuel ASTM D-1655, (Type B) or MIL-T-5624 (JP-4) may be used at all ambient temperatures with no restrictions.
b. Turbine fuels ASTM-D 1655, (Type A or A- 1), MIL-T-5624, (JP-5) or MIL-T-83133, (JP-8) may also be used at ambient temperatures above -32 ºC (-25 ºF). The minimum fuel pressure is 8 PSI at temperatures of -18 ºC (0 ºF) to -32 ºC (-25 ºF). At temperatures above -18 ºC (0 ºF) the minimum fuel pressure is 4 PSI. This helicopter is equipped with a fuel pressure gage which has a red triagle at 8 PSI and a red line at 4 PSI to reflect these minimums.

Question 25

FUEL LIMITATIONS (PART 2)

Answer 25

c. 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. d. Helicopters equipped with airframe mounted fuel filter do not require the use of anti-icing additive at any ambient temperature. Refer to Allison 250-C20 series Operation and Maintenance Manual for AVGAS Mix, Cold Weather Fuel, and Blending Instructions **NOTE** Engine starting difficulties may be encountered if any fuels other than Jet B or JP-4 are used at ambient temperatures below +5 ºC e. The use of AVGAS in the TH-67 is **prohibited**.

Question 26

HEALTH INDICATOR TEST (HIT)

Answer 26

The HIT is the method by which the aviator in day-to-day flying monitors the aircraft engine condition. This is accomplished by the aviator selecting a N1 speed (%) predicated upon the existing FAT. The TOT must then be compared to a predicted value (Baseline TOT) within a certain tolerance. TOT variation from baseline values are logged by the aviator. This log is a part of the aircraft records and is an aid to the maintenance personnel in monitoring performance trends and in troubleshooting on the engine. When the difference between the recorded TOT and the baseline TOT is +/- 20 ºC or greater, an entry on DA Form 2408-1 3- 1 will be made to notify maintenance. A difference of +/- 40 ºC or greater is cause for grounding the aircraft.

Question 27

LONGITUDINAL CENTER OF GRAVITY LIMITS

Answer 27

a. VMC Center of gravity limits are from station 106.0 to 114.2; however, the aft limits are variable depending upon gross weight and aircraft cnnfigl-lrat\_tion.,Refer tc? Center of Gravity vs. Cross Weight Chart in Chapter 6. ``` **NOTE** Station 0 (datum) is located 55.16 inches fonvat'd of forward jack point centerline. ``` b. IMC Longitudinal CG limits are from station 106 to 110 at GW of 2400 pounds to 3200 pounds and 106.1 to 110.0 at gross weights above 3200 pounds. Refer to Chapter 6. c. DOOR(S) OFF (1) No change from basic helicopter CG with only the aft cabin door(s) OFF. (2) With one or both forward doors off, the longitudinal CG limits are the same as with doors on. (3) Actual weight change shall be determined after doors, etc., have been removed and ballast readjusted, if necessary, to return basic weight center of gravity to within allowable limits.

Question 28

LATERAL CENTER OF GRAVITY LIMITS

Answer 28

**NOTE** Lateral CG limits vary depending on longitudinal CG location. Refer to Lateral vs. Longitudinal CG limits chart in Chapter 6. a. 3.0 inches left of helicopter centerline. b. 4.0 inches right of helicopter centerline.

Question 29

WEIGHT LIMITATIONS

Answer 29

a. Maximum allowable ramp weight is 3,350 lbs. b. Maximum allowable gross weight for hover/flight is 3,350 lbs. c. Mimimum front seat weight is 170 lbs. **NOTE** Use Ballast as required to maintain weight CG within limits.

Question 30

VMC AIRSPEED LIMITATIONS

Answer 30

**NOTE** All airspeeds values are Indicated Airspeed (IAS), except when Calibrated (CAS) is specifically states. a. At 3,000 pounds gross weight AND BELOW: VMC V_ne 130 KIAS sea level to 3,000 feet DENSITY ALTITUE. Decrease V_ne 3.5 KIAS per 1,000 feet above 3,000 feet DENSITY ALTITUDE. Maximum DENSITY ALTITUDE 20,000 feet. b. ABOVE 3,000 pounds gross weight: VMC V_NE 122 KIAS sea level to 3000 feet DENSITY ALTITUE. Decrease V_NE 7.0 KIAS per 1000 feet above 3000 feet DENSITY ALTITUDE. Maximum DENSITY ALTITUDE 13500 feet. c. V_NE for internal Gross Weight above 3200 pounds is 78 KIAS, not to exceed placarded VNE.

Question 31

IMC AIRSPEED LIMITATIONS

Answer 31

a. Minimum climb (V_YI) - 70 KIAS b. Minimum speed (V_MINI) - 50 KIAS c. Maximum speed (V_NEI) - 110 KIAS or placarded V_NE, whichever is less. d. Maximum speed (V_NEI) - 78 KIAS above 3200 lbs or placarded V_NEI, whichever is less.

Question 32

FLIGHT RESTRICTION FOR HIGH POWER

Answer 32

V_NE 80 Knots with above 85% to 100% Torque applied.

Question 33

COCKPIT AND CABIN DOOR RESTRICTIONS

Answer 33

**⚠ WARNING** Airspeeds in excess of airspeed limitations door(s) off will cause cyclic fore and aft stick reversal and fuselage buffeting a. Aft Door(s) off V_NE 87 Knots or placarded airspeed, whichever is less, power ON or OFF. **NOTE** With both forward doors removed, the aircraft is approved for day and night VFR operations only. IFR flight is prohibited. b. Forward doors off V_NE 110 Knots or placarded airspeed, whichever is less, power ON. c. Forward doors off V_NE 100 Knots or placarded airspeed, whichever is less, power OFF. d. With one or both forward doors off, both rear sliding windows must be closed above 70 KIAS.

Question 34

AEROBATIC MANEUVERS

Answer 34

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

Question 35

CONTROL MOVEMENTS

Answer 35

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

Question 36

FLIGHT RESTRICTIONS A LOW "G"s

Answer 36

Flight at less than +0.5g is PROHIBITED.

Question 37

FLIGHT RESTRICTIONS FOR PRACTICE AUTOROTATIONS (part 1)

Answer 37

a. Reported surface winds must not exceed 20 Knots. b. Surface crosswind component must not exceed 10 Knots as computed from the crosswind component chart. (figure) c. Wind gust spread must not exceed 10 Knots.

Question 38

FLIGHT RESTRICTIONS FOR PRACTICE AUTORATIONS (part 2)

Answer 38

d. Touchdown autorotations downwind are PROHIBITED. e. Airspeed during autorotation shall not be less than that established for minimum rate of descent. f. Groundspeed at touchdown should be approximately 5 Knots. g. Touchdown in a level attitude prior to passing through 70% rotor RPM. Upon ground contact, collective pitch shall be reduced smoothly while maintaining the cyclic near the neutral or centered position. If skid "chatter" is encountered, a SLIGHT increase in collective may temporarily used to stop the chatter. Continue reducing the collective as soon as practical when the "chatter" stops.

Question 39

FLIGHT RESTRICTIONS FOR PRACTICE AUTOROTATIONS (part 3)

Answer 39

h. Practice autorotational landings at gross weights above 3200 pounds are PROHIBITED. ⚠ **CAUTION** Relatively long ground runs with the collective up, or any tendency to float for long distance prior to skid contact SHALL be avoided. If abnormal vibrations are encountered before or after touchdown, immediate lowering of the collective is recommended (after skids are on the ground) to dampen vibrations. Under normal conditions, the collective will be smoothly and slowly lowered to the full down position after the skids are on the ground. The cyclic will remain near neutral with aft cyclic inputs avoided.

Question 40

SLOPE LANDING/TAKEOFF LIMITATIONS

Answer 40

Slope operations shall be limited to slopes of 8 degrees or less. ⚠ **CAUTION** Caution is to be observed for slopes greater than 5 degrees since rigging, loading, terrain and wind conditions may alter the slope landing capability.

Question 41

ENVIRONMENTAL RESTRICTIONS: _FLIGHT UNDER IMC_

Answer 41

a. General Limitations 1. The anti-collision light may be turned **OFF** during flight in or near visible moisture to prevent reflections and possible pilot vertigo. 2. Keep cabin glass clean to prevent halataion. 3. Maximum precision approach angle is 4.7 degrees. b. Rate of climb/descent. **NOTE** Maximum rate of climb and descent during flight in IMC conditions is 1000 feet per minute. c. Required Equipment. d. The followiung equipment must be operative prior to entering IMC conditions: 1. Cyclic Force Trim System 2. Main Generator. 3. Standby Generator. 4. Battery Protection Circuit. 5. Pilot's Flight Instruments. 6. Copilot's Flight Instruments. 7. Standby Attitude Gyro-automatically provided by approved standby battery source in the event of primary power loss. 8. Two communication systems. 9. Two navigation Systems appropriate to the routes flown. 10. Other equipment as required by the operating rules.

Question 42

ENVIRONMENTAL RESTRICTIONS: _Flight restrictions in falling or blowing snow_

Answer 42

a. Flight in falling and/or blowing snow is prohibited unless the Particle Separator Engine Air Induction System Kit and the Deflector Kit are installed to reduce the possibility of engine flameout. b. If the Particle Separator Kit is installed, the following limitations apply to flight in falling and/or blowing snow: 1. Hover flight is limited to 20 minutes after which the helicopter must be landed and checked for snow and/or ice accumulation. 2. Flight operations are prohibited when visibility is less than 1/2 statute mile.

Question 43

ENVIRONMENTAL RESTRICTIONS: _Flight over salt water and near volcanic activity_

Answer 43

⚠ **CAUTION** Prolonged hovering over salt water which results in spray ingestion, indicated by spray on the windshield, should be avoided. Salt spray ingestion in turbine engines may result in deterioation 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 44

ENVIRONMENTAL RESTRICTIONS: _Flight in sand and dust condition_

Answer 44

a. Operations in heavy sand or dusty conditions without the improved nozzles will result in lower inlet particle separator (IPS) efficiency which in turn severely shortens the engine life. b. If the inlet air barrier filter is installed and the AIR INLET PRESSURE caution light illuminates or the Engine Air Alternate Switch is turned on, appropriate entries shall be made on DA Form 2408-13-1 to alert maintenance.

Question 45

ENVIRONMENTAL RESTRICTIONS: _Flight in rain, snow or icing conditions_

Answer 45

If flown in rain, snow, or icing conditions, appropriate entries shall be made on DA Form 2401-13-1 to alert maintenence.