UH-60 Limitations Flashcards
TRANSMISSION OIL PRESSURE
Precautionary 65-130 PSI
Continuous 30-65 PSI
Idle/Transient 20-30 PSI
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MAIN TRANSMISSION
OIL TEMPERATURE
Precautionary 105-140 C
Continuous -50-105 C
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ENGINE OIL TEMPERATURE
30-Minute Limit 135-150 C
Continuous -50-135 C
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ENGINE OIL PRESSURE
5 Minute Limit 100-120 PSI
Normal Operation 26-100 PSI
Idle 22-26 PSI
Above 90% Ng 35 PSI minimum
TURBINE GAS TEMPERATURE
12 Second Transient 903-949 C 2.5 Minute Transient 878-903 C (Contingency Power) Start Abort Limit 851 C 10 Minute Limit 851-878 C 30 Minute Limit 810-851 C Normal 0-810 C
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ENGINE Ng
12-Second Transient 102-105%
30-Minute Limit 99-102%
Continuous 0-99%
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AIRSPEED LIMITS
Maximum 193 Knots
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MAIN ROTOR OVERSPEED
- 127%
- 137%
- ** 142%
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ENGINE % RPM 1-2
12-Second Transient 105-107%
Transient 101-105%
Continuous 95-101%
Transient 91-95%
Avoid Operations In 20-40% and
60-90% Range Except During
Start And Shutdown
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MAIN ROTOR % RPM R
Power On
Transient 101-107%
Continuous 95-101%
Transient 91-95%
Power Off (Autorotation)
Maximum 110%
Transient 105-110%
Normal 90-105%
ENGINE % TORQUE
10-Second Transient
Dual-Engine
Above 80 KIAS 100-144%
80 KIAS or Below 120-144%
Single-Engine 135-144%
Continuous
Single-Engine 0-135%
Dual-Engine
Above 80 KIAS 0-100%
80 KIAS or Below 0-120%
ENGINE STARTER LIMITS
The pneumatic starter is capable of making the number of consecutive start cycles listed below, when exposed to the environmental conditions specified, with an interval of at least 60 seconds between the completion of one cycle and the beginning of the next cycle. A starting cycle is the interval from start initiation and acceleration of the compressor, from zero rpm, to starter dropout. The 60 second delay between start attempts applies when the first attempt is aborted for any reason, and it applies regardless of the duration of the first attempt. If motoring is required for an emergency, the 60-second delay does not apply.
At ambient temperatures of 15°C (59°F) and below, two consecutive start cycles may be made, followed by a 3-minute rest period, followed by two additional consecutive start cycles. A 30-minute rest period is then required before any additional starts.
At ambient temperatures above 15° up to 52°C (59° up to 126°F), two consecutive start cycles may be made. A 30-minute rest period is then required before any additional start cycles.
PNEUMATIC SOURCE INLET LIMITS
The minimum ground-air source (pneumatic) required to start the helicopter engines is 40 psig and 30 ppm at 149°C (300°F). The maximum ground-air source to be applied to the helicopter is 50 psig at 249°C (480°F), measured at the external air connector on the fuselage.
ENGINE START LIMITS
CAUTION
Engine start attempts at or above a pressure altitude of 701C 701D/CC 18,000 feet or 700 20,000 feet could result in a Hot Start.
Crossbleed starts shall not be attempted unless the #1 ENG ANTI-ICE ON or #2 ENG ANTI-ICE ON advisory does not appear, and operating engine must be at 90% Ng SPEED or above and rotor speed at 100% RPM R. When attempting single-engine starts at pressure altitudes above 14,000 feet, press the start switch with the ENG POWER CONT lever OFF, until the maximum motoring speed (about 24%) is reached, before going to IDLE. Engine starts using APU source may be attempted when within the range of FAT and pressure altitude of Figure 5-4.
FUEL LIMITATIONS
a. Fuel boost pumps shall be off except as required by emergency procedures and the following limitations: Boost pumps shall be on when operating with JP-4 or equivalent (as specified in Operator’s Manual) at 5000 feet pressure altitude and above; when operating in crossfeed with JP-4 at any altitude.
CAUTION
Due to fuel volatility, when converting from JP-4 to JP-5/JP-8, three helicopter refueling operations must be completed before performing operations with fuel boost pumps off.
b. When a helicopter operating with JP-4 is restarted within 2 hours of engine shutdown and the air temperature is above 21°C (70°F), a minimum of 2 minutes of dual engine ground operation at 100% RPM R is required prior to takeoff to purge possible hot fuel from engine nacelle area.
