refer to figure 5-3 for additional information (airspeed limits)
B 100 recommended maximum for Autorotation
R This limit mark not applicable
Transmission Oil Pressure
G 30 to 60 PSI Normal Operation
R 30 PSI minimum
R 70 PSI maximum
G 93 to 110 percent, Normal Operation
Y 49% to 58% continuous operation prohibited
R 93 Percent minimum
R 110 Percent maximum
G 98 to 100 Percent, Normal Operation
R 100 Percent Maximum
15 maximum transient N2 is 110% (Autorotation)
Avoid Steady-State conditions between 78-88% N2
G 0 to 85 percent Normal Opeartions
Y 85 to 100 percent 5 minute Operation
R 100 Percent maximum
Turbine Outlet Temperature Indicator (TOT)
0 C to 810 C Normal
Above 810 c to 927 C Maximum 10 seconds
R 927 maximum 1 second
300 C Minimum
G 300 C to 738 C Normal Operation
Y Above 738 C to 810 C 30 minutes limit
R 810 C Maximum. Above 810 C to 843 C during power transient, 6 second Max
Engine Oil Pressue
R 50 PSI minimum
Y NOTE: disregard yellow and green instrument markings for engine oil pressure
G idle to 78% N1 50-130 PSI
Above 78% to 89% N1 90-130 PSI
Above 89% N1 115-130 PSI
R 130 PSI Maximum
CAUTION: During cold weather start, maximum may go to 150 PSI, but you must remain at engine idle position until normal limits are attained.
Engine Oil Temperature
G 0 C to 107 C continous operation
R 107 C Maximum
NOTE: during cold weather operation the engine may be operated at engine oil temperatures down to -50 C
Y 0 to 65 low fuel
Gas Producer Tachometer indicator
R 105 Percent Maximum
G 62 to 105 percent Normal Operation
Above 105 to 106 percent permissible for 15 seconds
Transmission Oil Temperature limits
110 C - Warning Light On
Transmission Oil Pressure Limits
30 +/- PSI minimum - Warning Light On
NOTE: Light will remain on until 36 PSI is exceeded
a. The helicopter can be started in a maximum wind velocity to 45 knots and a maximum gust spread of 15 knots.
NOTE: Gust spreads are not normally reported. To obtain spread, compare minimum and maximum wind velocities.
b. Maximum wind for hovering is 35 knots crosswind and 30 knots tailwind
c. Maximum wind for mooring is 65 knots parallel to the ground in any direction
The maximum gross weight for towing the helicopter is 3000 pounds on prepared or unprepared surfaces
Fuel Operation limits
a. JP-4. No restrictions are imposed when JP-4 fuel is used
b. JP-5, JP-8, Jet A and Jet A-1. Operations with these fuels are restricted to ambient temperatures of -32 C (-25 F) and above. If fuel other than JP-4 is used, a deceleration check must be performed prior to first flight of the day. If autorotations are to be performed, a decleration check will be done prior to each flight. Refer to Paragraph 8-18.
NOTE: Engine starting difficulties may be encountered if any fuel other than JP-4 is used at ambient temperatures below +5 C (+39 F).
c. Emergency Fuel Aviation gasoline (MIL-G-5572) without Tricreasyl Phosphate (TCP).
(1) The helicopter shall not be flown when emergency fuel has been used for a total accumultaed time of 6 hours. Entry in remarks section of DA Form 2408-13-1 is required for each time emergency fuel is used.
(2) Practice autorotation is prohibited using emergency fuel
Engine starting limitations
During starting if N1 does not reach 58 percent in a total time of 45 seconds (or 60 seconds below 10 C FAT), close throttle and press starter switch until TOT is below 200 C. If engine fails to start on third attempt, abort start and make an entry on DA Form 2408-13-1.
Health Indicator Test (HIT)
HIT is the method by which the aviator in day-to-day flying monintors aircraft engine condition. This is accomplished by the aviator selecting N1 speed (%) predicted upon the existing FAT. The TOT must then be compared to predicted value (Baseline TOT) within a certain tolerance. TOT variation from baseline values are logged by the aviator. This log is part of aircraft records and is an aid to maintenance personnel in monitoring performance trends and troubleshooting the engine. When the difference between recorded and baseline TOT is +/- 20 C or greater, an entry on DA Form 2408-13-1 will be made to notify maintenance. limits for grounding are +/- 40 C.
Maximum gross weight is 3200 pounds
a. Refer to airspeed operating limits chart (figure 5-3) for forward airspeed limits
b. Sideward flight limits are 35 knots
c. Rearward flight limits are 30 knots
d. Recommend maximum indicated airspeed for autorotation is 100 knots
e. Maximum indicated airspeed with any door removed is 100 knots
Cockpit and cabin door restrictions
a. Helicopter will not be flown without cabin doors unless heavy duty rear electronics compartment soundproof blanket (P/N 206-070-893-7), or its approved equivalent, has been installed. Helicopter will not be flown with only one cockpit door or one cabin door removed.
b. Whenever any OH-58A/C helicopter is operated without its cabin doors:
(1) All soundproof blankets must be in serviceable condition and firmly attached. Pilot must verify.
(2) If the rear cushions (bottom and back) are modified per MWO 55-1520-228-30-30, they may remain installed provided seat belts and shoulder harnesses are installed, properly fastened and tightened.
(3) Loose equipment or compnents must be removed or secured
c. Doors shall not be opened in flight
Flight restriction with Float landing Gear Installed
a. Airspeed Limit. Float landing great installed - Rearward and sideward airspeed limit is 30 knots. Figure 5-3
b. Altitude LImitation
(1) maximum operating - 15,000 feet altitude
(2) Flight to lower altitude - increase pressure 0.5 PSI per 1000 feet below base altitude, to minimum operating altitude
(3) Flight to higher altitude - Limit climbing flight to 8000 feet differential pressure altitude. Above 8000 feet differential pressure altitude, reduce float pressure 0.5 PSI per 1000 feet.
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 degrees or roll angles greater than 60 degrees, or abnormal acceleration not necessary for normal flight.
CAUTION: For gross weights greater than 3000 lbs and density altitudes greater than seal 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 anit-torque pedal reversals are prohibited to avoid excessive stresses in the structure. This restricion in no way limits normal control application.
Ten percent of total pedal travel, full right to full left, is considered adaquate for safe control. The rearward airpseed limit is 30 knots and sideward limit is 35 knots except that control is marginal for certain combinations of relative wind velocity and azimuth angles (meansured clockwise from the nose of the helicopter). See chapter 8 for description of the marginal wind velocity and azimuth angles.
Flight restrictions at low "G's"
Flight at less than +0.5g is prohibited
Flight restrictions for practice autorotation landings
Practice autorotation landing may be accomplished subject to the following limitations.
a. A qualified OH-58A/C IP must be in position to take control of the aircraft
b. Reported surface winds must not exceed 20 knots
c. Surface crosswind component must not exceed 10 knots. Wind gust spread must not exceed 10 knots.
d. Touchdown rotor RPM must not be less than 64%
e. Ground speed at touchdown should be approximately 5 knots
f. Airpseed during glide shall not be less than that established for minimum rate of descent
CAUTION: In any event, relatively long ground runs with the collective up, or any tendancy to float for long distance prior to skid contact should be avoided. If vibrations are encountered after touchdown immediate lowering of the collective is recommended.
g. Upon ground contact, collective pitch must be reduced smoothly to bottom stop without delay while maintaining cylic pitch near center position. Appliction of aft cyclic should be avoided.
h. Touchdown autorotations downwind are prohibited
Flight restriction for high power
NOTE: In aircraft equipped with IR exhaust stacks, rate of climb in excess of 1000 ft/min may result in divergent aircraft pitch oscillation which can reach 20 to 30 degree attitudes. This divergence can be alleviated by either increasing airspeed during steady climbs or decreasing rate of climb. Climb rates in excess of 100 ft/min should be avoided
Slope landing / Take-Off limitations
Slope Operations shall be limited to slopes of 8 degrees or less
CAUTION: Caution is to be exerciesed for slopes greater than 5 degrees since rigging, loading, terrain and wind conditions may alter the slope landing capability. See Rollover characteristics in FM 1-203.
Flight Under Instrument Meteorological Conditions (IMC)
This aircraft is restricted to Visual Flight conditions. Flight into instrument meteorological conditions will be conducted on an emergency basis only.
Flight Restrictions in falling or blowing snow
Flight in falling or blowing snow is prohibited except for those helicopters with reverse flow inlet fairing installed. Helicopters having the above features may be flown in falling or blowing snow provided reverse flow inlet fairing are installed and the following criteria is met.
a. Visibility reduced by now must be atleast 1/2 mile.
b. Prior to inital take off and each subsequent take off, inspect the engine as specified in CH 8, section V, paragraph 8-34
Flight in Sand and Dust conditions
During operations in heavy sand or dusty conditions without the new improved nozzles will result in lower inlet particle separator (IPS) efficiency which in turn severely shortens the engine life.
Flight in Rain, Snow and Icing conditions
If flown in rain, snow or icing conditions, appropriate entries should be made on DA Form 2408-13-1 to alert maintenance
a. Intentional flight into severe or extreme turbulence is prohibited
b. Intentional flight into moderate turbulence is not reommended when report or forecast is based on aircraft above 12,500 pounds gross weight
c. Intenional flight into thunderstorms is prohibited