1. Power Required exceeds Power Available
LT Robie
NATOPS Officer

2. Lake Tahoe MH-60R
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3. Indications Uncommanded descent with torque at maximum available
Rotor droop
Loss of tail rotor authority
Right yaw

4. When Will it Occur? NOT under normal conditions for a TH-57
Hit torque limits first

5. When Will it Occur? Engine malfunction Engine limited aircraft
Engine Underspeed
Compressor Stall
FCU Failure (possible, but not always)
Engine limited aircraft
Hit Ng or TOT limits or Nr droop

6. Aggravating Factors High G loading High GW High DA Rapid maneuvering
High AOB level turns
High GW
High DA
Rapid maneuvering
Quick stop
Spool up time from lower power to higher power settings
Power off wave off
Loss of wind effect
Descending below a tree line
Change of wind direction
Loss of ground effect
Transition to forward flight from a pinnacle

7. How to Avoid Pr > Pa
Preflight planning to determine expected aircraft performance
Plan for ALL phases of flight
Heaviest load based on fuel for external load ops
Avoid excessive maneuvering, particularly during high DA, hot temperatures, high GW, or marginal power situations
Avoid high descent rates
Requires large power inputs to arrest rate of descent
Keep rotor head loaded
Avoid downwind take offs/landings
Maintain SA of wind speed/direction, especially during low altitude/low airspeed maneuvers

8. EP/Effect on Power
*1. Collective – Lower as required to maintain a minimum of 90% Nr *2. Twist grip – full open *3. Angle of bank – level the wings *4. Airspeed – adjust to 50 KIAS *5. Jettison – as required If impact is imminent: *6. Level skids to conform to terrain *7. Cushion the landing
Decreases Pr
Increase Pa
Decrease Pr

9. Power Available Check
Conducted when any question about engine integrity
“check power available with Nr in limits”
Is level flight possible?
Raise the collective until the VSI is zero or Nr decays to 90%
Adjust airspeed to minimum Pr (~50 kts) as required

10. Pa Not Sufficient VSI is below zero with Nr 90% and min Pr airspeed
Need to autorotate
May use what power is available to set up for auto
DO NOT BRING TWIST GRIP TO IDLE

11. Pa Sufficient for Level Flight
Able to continue flight
Land as soon as possible
Determine how much power is available
Raise the collective until an operating limit is reached (Ng, TOT, Torque, or Nr < 90%)
Allows you to figure out what kind of landing is possible and what is a suitable sight for landing
If Pa is below HIGE torque, you will not be able to hover for a vertical landing
Sliding landings require least amount of power