1. UH-60L FAMILIARIZATION CW4 Sandbakken
Good afternoon. I am CW4 Sandbakken. The purpose of today’s class is to familiarize you with the UH-60L aircraft. The topics discussed in this class are required subjects for UH-60L qualification IAW TC Some of you may already be qualified in the UH-60L, so if you have any additional information or experiences you would like to share, or if you have any questions please feel free to interject at any time.
CW4 Sandbakken 1

2. UH-60A VS UH-60L T700-GE-700 Main Transmission (28000 Series) ECU POU
History Recorder
T700-GE-701C
IDGB Series)
DEC
ODV
History Counter
Additional Nr & Coll Position Sensor for Droop
Updated CDU & SDCs
The UH-60L helicopter is the same as the UH-60A helicopter except for: (brief slide) 2

3. T700-GE-701C Compressor Rotor Assembly Hot Section Module
Centrifugal Impeller & Rectangular Throat Diffuser
Compressor Rear Shaft/Gas Generator Shaft
Hot Section Module
Stage One Turbine Nozzle
Gas Generator Turbine Rotor
Gas Generator Stator
Power Turbine Module
The T700-GE-701C weighs about 456 lbs. and has a shaft horsepower rating on a standard day at sea level of: SHP max continuous
1800 SHP intermediate (30 minute)
1890 SHP intermediate (10 minute)
1940 SHP contingency (2.5 minute)
COMPRESSOR ROTOR ASSEMBLY:
Centrifugal Impeller: Backwall thickness increased
Throat Diffuser: Reduces speed of air better than 700C resulting in greater air compression & air
temperature entering the combuster
Compressor Rear Shaft: Vent holes in rear shaft relocated aft of compressor/turbine spline & half
the spline teeth have been removed to better cool the #4 Bearing
HOT SECTION MODULE:
Stage One Turbine Nozzle: 2 vanes of each segment are welded together for a stronger joint, more
heat resistant, improved strength, & better corrosion resistance. Also has a
better aerodynamic design for better airflow onto 1st stage turbine blades
Gas Generator Turbine Rotor: Comprised of a new material that is more heat resistant, new
aerodynamic design, more cooling designs (serpentine drill), & also
“floating” blades in a tongue & groove design to preclude vibration problems
Gas Generator Stator: Basically same modifications as Gas Generator Turbine Rotor 3

4. IMPROVED DURABILITY GEAR BOX (IDGB)
Major Improvements
New upper housing w/ mount for hyd pump
Tail T/O flange has larger pinion shaft
Provisions for rotor brake
Oil filler cap & dip stick more forward on G/B
All internal gears upgraded
IDGB mast shaft life increases 5-fold
Large increase in lube/scavenge volume flow
Breather ports installed on upper housing
MAIN TRANSMISSION SYSTEM:
Brief Slide! 4

5. DIGITAL ELECTRONIC CONTROL (DEC)
DEC replaces ECU
Two power sources
Primary: Engine alternator
Secondary: 400 Hz, 120 Vac airframe power
Loss of alternator only results in loss of Ng signal & eng out audio and light (Airframe power causes no high side failure & no loss of Np or TQ indications
DEC replaces the analog ECU. Is mounted in the same location as the ECU. It provides the same basic functions as the ECU. 5

6. Torque & overspeed sensor Torque signal from other engine
DEC Inputs
Engine alternator
Thermocouple harness
Np sensor
Torque & overspeed sensor
Torque signal from other engine
Collective stick position sensor (New- in mixing unit)
Nr sensor (New- on left accessory module)
Demand speed from engine trim switch
Feedback from HMU (Linear Variable Differential Transformer LDVT)
- The input from the alternator is for power. Should the alternator (or the power winding) fail the DEC will continue to function as long as their is airframe power.
- An average of the seven thermocouple harness probes provide the TGT signal to the DEC where it is relayed to the cockpit. This signal is required by the DEC for: (1) TGT limiting (to include a resetting feature for “contingency” power (2.5 minutes)) (2) Hot Start Prevention (activated when Ng<60%, Np<50%, and TGT >900 °C). HSP may be overridden in an emergency by pressing and holding either of the Np overspeed test buttons during start (hold until Np > 60%. If HSP is activated (1) PCL- OFF, (2) IGNITION- OFF, and wait until TGT is <300 °C or for 25 seconds.
- Np signal is used for: (1) Np governing (keeps Np set at reference speed set by pilot + 1%) (2) Np Overspeed Protection System (set to trip at % (25,000 RPM) as sensed by Torque and Overspeed Sensor on engine). If overspeed is sensed, the Overspeed Protection Relay activates the Overspeed Solenoid in the Overspeed Drain Valve (ODV) and fuel is cycled back to the HMU causing the engine to flame out. A signal is also sent to the Delay On Drop Out Circuit to turn on ignition (for 5 seconds) for engine relight once the overspeed condition is corrected. 6

7. DEC Signals to Cockpit Np Torque TGT Signal fault validation
Validates input signals & DEC functions
If signal failure occurs, identified by fault code displayed on torque meter after engine shutdown
Np- Initial indication is at 4000 RPM versus 6000 RPM with the ECU
Torque-Trq signal locked to zero until Np reaches 35%. This eliminates torque spikes.
TGT-Has a 71 °C bias (engine is running hotter than indicated)
Fault Validation Codes: If failure occurs the fault code will be displayed on the torque meter after
engine shutdown. The code will be displayed for 4 seconds and off for and 2
seconds off, in numerical sequence beginning with 15% in increments of 10% up to 125%. Fault codes observed will be annotated on the Examples of fault codes are as follows: DEC %
TGT CHANNEL %
HOT START PREVENTER CHANNEL %
Nr % 7

8. Hot Start Preventer Prevent overtemps during start
Requires 400 Hz, 120 Vac for operation
Requires signals from Np sensor, Ng winding, & Thermocouple Harness (TGT)
HSP activates ODV shutting off fuel flow if:
Ng < 60%
Np < 50%
TGT >900° C
BRIEF SLIDE!! 8

9. Transient Droop Improvement (TDI)
Engines more responsive
Signals required:
Nr (New on left accessory module)
Collective position sensor (New w/ 2 in mixing unit)
Engine torque signal
TDI is 4:1 over T700-GE-700
The Nr and collective signals are routed to rate circuits in the DEC and compared with Np and TRQ signal values. When the Nr and collective rate signals exceed predetermined values they are combined and passed to the Torque Motor Amplifier. A large Nr drop rate, and a significant increase of collective both result in a greater input signal. A priority signal is then processed to quickly trim the Torque Motor in the HMU to compensate for the demand.
If a sensor fails or a malfunction occurs then the system reverts back to the basic load demand system similar to that provided by the ECU. 9

10. TGT Limiting Dual engine limiting value: 866 + 6° C
Contingency power limiting value: ° C
When other engine is inoperative
When torque on other engine is below 50%
Provides more power for single engine operation
DEC commands HMU to limit fuel flow
TGT limiting does not prevent overtemp during compressor stalls, engine starts, or LOCKOUT
Expect transient increases above limiting value when demanding max power
BRIEF SLIDE!!
- System is basically the same as the 700C. 10

11. Np Overspeed Protection System
Primary electrical source is alternator. Secondary source is 400Hz airframe power.
Tripped when Np reaches % (25,000 rpm)
Requires input signal from Trq & Np overspeed sensor
When an overspeed is sensed, the Overspeed Relay activates solenoid in ODV and sends signal to Delay On Drop Out (DODO) circuit to turn on ignition
ODV shuts off fuel causing flameout (fuel returns to HMU)
When RPM drops below %, fuel returns to engine
When Overspeed Solenoid Valve closes, ignition comes on for 5 seconds for restart
BRIEF SLIDE!! 11

12. OVERSPEED DRAIN VALVE (ODV)
Replaces the POU
Mounted on the rear of accessory of engine
Houses 2 valves and the Overspeed Solenoid Valve
Three primary functions:
Sends main fuel to 12 nozzles (no start fuel system on 701C)
Purges fuel from main fuel manifold on shutdown
Np Overspeed Protection/Hot Start Preventer
BRIEF SLIDE!! 12

13. HISTORY COUNTER Replaces History Recorder (not interchangeable)
Requires either alternator or 400Hz airframe power
All computations conducted in DEC
Provides permanent record of engine parameters
Engine operating hours-Begins when Ng > 50%
Low Cycle Fatigue (LCF), mechanical stress-Ng exceeds 95% after being >50%
(LCF) Thermal-Ng exceeds 95% after being >86%
Time Temp Index-TGT 90% of max cont (apprx 770°C)
Tracks many other items. Stored for 5 prev flights
Req inputs from Np, Ng, TGT (if any fail all stop)
BRIEF SLIDE!! 13

14. UH-60L OPERATING LIMITS ENGINE TORQUE
12-Second Transient
Dual-Engine
Above 80 KIAS %-144%
80 KIAS or below %-144%
Single-Engine %-144%
Maximum Continuous
Single-Engine %-135%
Above 80 KIAS %-100%
At or below 80 KIAS %-120%
BRIEF SLIDE!!

15. 12-Second Transient 903º - 949º C 2.5-Minute Transient 878º - 903º C
TGT LIMITS
12-Second Transient º - 949º C
2.5-Minute Transient º - 903º C
Start Abort Limit º C
10-Minute Limit º - 878º C
30-Minute º - 851º C
Normal º - 810º C
BRIEF SLIDE!!

16. Engine Oil Temperature
Maximum ° C
30-Minute Limit ° C
Continuous ° C
Engine Oil Pressure
Maximum PSI
5-Minute Limit PSI
Normal Operation PSI
Idle PSI
Minimum PSI
BRIEF SLIDE!!

17. Transmission Oil Temperature
Maximum ° C
Precautionary ° C
Continuous ° C
Transmission Oil Pressure
Maximum PSI
Precautionary PSI
Continuous PSI
Idle and Transient PSI
Minimum PSI
BRIEF SLIDE!!

18. EMERGENCY PROCEDURES DEC LOCKOUT Single Engine Failure
% Trq Split Between Engines 1 and 2
- DEC LOCKOUT: Done exactly the same as with the ECU
- SINGLE ENG FAILURE: TGT limiting system is reset to a higher limiting value for “Contingency power”. Limiter resets from °C to °C.
- % TRQ SPLIT BETWEEN ENGINES 1 AND 2: If TGT of one engine exceeds the limiter (872 °C with low power engine above 50% TRQ or 896 °C with low power engine below 50% TRQ), retard PCL on that engine to reduce TGT. Set approximately 10% torque below the other engine.

19. PERFORMANCE PLANNING Maximum Torque Available-10 Minute Limit
Dual-Engine Torque Limits Above 80 KIAS (Helicopters prior to S/N not equipped w/ improved main rotor flight controls)
GIVE PPC CLASS!!

20. SUMMARY T700-GE-701C Improved Durability Gearbox (IDGB)
Miscellaneous Aircraft Improvements
Operating Limitations
Emergency Procedures
Performance Planning
BRIEF SLIDE!!

21. CONCLUSION
This class was not designed to create T700-GE-701C engineers, but to merely familiarize you with the UH-60L Model aircraft and to highlight the differences between the UH-60A and the UH-60L.
BRIEF SLIDE!!

22. QUESTIONS ?