Max take off weight
- Internal
- External
- 1451.5kg (3200lb)
- 1519.5kg (3350lb)
Take off power range
85%-100% Torque
Take off power Vne
80 Kt
Vne Speed
Below 3000lb
Above 3000lb
Below 3000lb = 130kts (3000ft density)
Above 3000lb = 122kts(3000ft density)
Altitude Limitations
Below 3000lb
Above 3000lb
below 3000lb=20,000ft (pressure)
above 3000lb = 13,500ft
Engine Model
RR 250-C20
Fuel Pressure Min & Max
8 PSI
50 pSI
Torque Limits
Take off 100%-5mins
Transient 110%-5 second
TOT limits Take off In flight Transient Max Continuous Start and shutdown
- 793 (5 min)
- 737(MCP)
- 793-843 (6 seconds)
- 793-927 (10 seconds)
- 927+ (1 sec)
Max speed for Autorotation
100KIAS
Min front seat weight
150lb (68kg)
During cold operations what should the engine idle speed be set to N1 until oil temp reaches min 0
60-64%
Engage pitot heat in visable moisture and temp below…..
4.4 C
Max pressure alt
20,000ft
Warning lights -Fuel pump
Descend to below 6000ft
Land as soon as practical
Warning lights - Fuel Filter
Land as soon as practical
-Clean before next flight
Common causes of compresser surge (4)
- Rapid increase in fuel flow when RPM increases
- low engine RPM
- Air going into the engine formt he wrong direction (crosswind)
- contaminated or damaged compressor blades
Symptoms of compressor surge (6)
- Loss of thrust
- odd noises
- Vibrations
- RPM fluctuations
- Increased TOT
- Burning gasses out of various orifices
In the Allison 250 engine where is the torque measured from?
-At the engine reduciton gear intermediate pinion
Best ROC speed
47kt
RRPM Limitations
95-100% below 8000ft
-105% Transient for 15s
Gas Producer Limitations
- 104% max
- 105% transient 15seconds
Starter Limitations
- on
- off
- 40s on
- 60s off
- 40s on
- 60s off
- 40s ON
- 30 mins off
Engine oil Temp Limits
Max-107 Degrees
