NATOPS Chapter 4 Limits HSM-50

Question 1

Exceeding Operating Limitations

Answer 1

Anytime an operational limit is exceeded, an appropriate entry shall be made on a MAF. The entry shall state what limits were exceeded and include range, duration, and any additional information that would aid maintenance personnel.

The flight display’s digital readout will display XXX in red when a torque or TGT limit is exceeded.

If a limit is exceeded to the extent that a red XXX is flashing, the crew shall land as soon as practicable.

Question 2

Engine Limitations

Answer 2

The engines are limited by Ng, Np, TGT, oil px and oil temp. Specified temperature limitations ensure that engines are operated at internal temperatures that will not shorten the service life expectancy of engine components.

Question 3

Engine Starter Limitations

Answer 3

1. The single and dual engine start envelopes are present in Figure 4.1-3. For crossbleed starts, the receiving engine shall be at or above 24% Ng prior to advancing PCL to IDLE

A start cycle is defined as starter initiation, acceleration of the output drive, and starter dropout. A 60 second delay between start attempts is required any time a start is aborted, except during emergencies.

Question 4

Engine Start Limitations

Answer 4

1. The single and dual engine start envelopes are presented in figure 4-3. For crossbreed starts, the receiving engine shall be at or above 24% Ng prior to advancing PCL to idle.
2. Engine start with the main rotor blades or tail rotor pylon folded is prohibited.
3. The start TGT limit is 851 deg C until idle speed is attained

Question 5

Engine idle limitations with gust lock engaged

Answer 5

Engine operation with gust lock engaged is prohibited

Question 6

TGT

Answer 6

0-810 continuous green
810-851 30 min yellow
851-878 2.5 min (10 min for max power and limiter checks only) red
878-903 2.5 min red
903-949 12 sec red
949 max red

Question 7

Np

Answer 7

<96% avoid red
96 to 105% continuous green (yellow above 101%)
105 to 117% 20 sec yellow 
117 to 120% 12 sec yellow
120% max red

CAUTION
during engagement, extended operations in the 20 to 40% and 60 to 75% ranges may cause engine damage

Question 8

Nr

Answer 8

<96% avoid red
96-101% continuous green
101 to 120% precautionary yellow
120% max red
>120% max for FCF only, red
127% overspend latch red

Question 9

Dual engine torque <80 KIAS

Answer 9

0 to 120% continuous green
120 to 144% 10 sec yellow
144% max red

Question 10

Dual engine torque >80 KIAS

Answer 10

0 to 106% continuous green
106 to 127% 10 sec yellow
127% max red

NOTE
dual engine tq limits apply when both engines are above 65% tq

Question 11

Single engine torque

Answer 11

0 to 135% continuous green
135 to 144% 10 sec red
144% max red

Question 12

Ng

Answer 12

0-102.2% continuous green
>102.2-106% 2.5 min yellow
>106-107% 12 sec red
107% max red

Question 13

XMSN Temperature

Answer 13

-50 to 105 continuous green
105 to 120 precautionary yellow
120 max red

Question 14

XMSN Pressure

Answer 14

20 psi min red
20 to 30 psi idle and transient yellow
30 to 65 psi (45 to 60 psi in level flight) continuous green
65 to 130 psi precautionary yellow 
130 psi max red

Question 15

Engine oil temperature

Answer 15

-50 to 135 continuous green
135 to 150 30 min yellow
150 max red

Question 16

Engine oil pressure

Answer 16

22 psi minimum red
22 to 26 psi precautionary yellow
26 to 100 psi continuous green
100 to 120 psi precautionary yellow
120 psi max red

Question 17

Engine Start Cycle

Answer 17

<16 deg 3x60sec, 1x30 min

16 to 52 deg, 60 sec, 30 min

Question 18

Engine Motor (ignition off)

Answer 18

Any temp - 2 min on, 5 off; 2 min on, 30 min off

NOTE

1. A start cycle is defined as starter initiation, acceleration in Ng, and dropout
2. Times for motoring are cumulative within a 5 min period

Question 19

Minimum planned fuel on landing

Answer 19

Minimum planned fuel on landing shall be no less than 600 pounds

Question 20

APU Limitations

Answer 20

The APU is no intended for routine in flight use. Operation of the APU in flight shall be limited to essential operations only. Acceptable in flight use includes emergency procedures, single engine training, practice autorotations, and powering the ECS during extreme temperature operations.

Question 21

ORM Process

Answer 21

1. Identify Hazards
2. Assess Hazards
3. Make Risk Decisions
4. Implement Controls
5. Supervise and watch for change