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GE-Walter 601 Operations 


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  This is not to be used as a check list.  This is only to be used as a guide to start the GE-Walter M601 B, D & E Turbines.

AUTO START. (Limiter)

1. Power on.
2. Inverter on if necessary.
3. Fuel on.
4. Fuel pump / pumps on.
5. Condition lever forward to detent.
6. Propeller in feather position.
7. Throttle in idle position.
8. Press start.  Best to keep hand on condition lever in case of overtemp.
9. Carefully monitor the ITT for increasing temp, do not exceed  710.  Rate of increase is important.  If  over temp occurs, pull condition lever to shut off position.
10. Make sure N1 (Compressor rpm) increases to at least 60%.  If not, forward throttle slightly and monitor ITT.
11. After N1 and ITT stabilize, switch on generator.
12. Check oil and fuel pressure.
13. Forward prop to full fine pitch.

Autostart with Push Button (EHT)
1. Fuel On
2. Power on.
3. Fuel pump on.
4. Throttle to Idle.
5. Prop to Feather.
6. Condition Lever to Run position.
7. Press Start, keeping a hand on the fuel condition lever, and be ready to cut the fuel in case of over temp.
8. As the turbine lights, press the EHT button + - two seconds and carefully monitor the ITT. When the ITT slows down or tends to stabilize, release the button to increase the ITT and N1. Repeat this by keeping the ITT between 580 oC and 650 oC. The further into the start, the more abrupt and sensitive the EHT will become.
9. Make sure N1 (Compressor RPM) increases to at least 60%. If  not, advance the throttle slightly and monitor the ITT.
10. After N1 and ITT have stabilized, switch the generator on.
11. Check oil and fuel pressure.
12. Advance the Prop to full fine.

Recommended Practices
It is good practice to start the turbine with headsets off. A possible over temp can be heard quicker than the ITT gauge can display it.


Keep one hand on the Condition Lever and be ready to cut as the button will not prevent an over temp if the throttle is partly open, the batteries are low, or there is high outside temperature and / or elevation. If there is a high turbine temperature (over 150 C) before starting, a wind from the rear, a blockage of the air intakes, or the ISOL valve is in the ISOL mode, these may also cause an over temp.

Important Notice
If the ITT exceeds 735 oC and no more than 800 oC, the turbine must be inspected for damage. (Borescope)

If  ITT exceeds 800 oC, the turbine must be dismantled for inspection and a possible change of all compressor turbine blades.

To continue operation after an over temp could cause a catastrophic failure!

Cold Cycle (motor)

1. Master switch on
2. Fuel on
3. Fuel pump ON
4. Throttle to idle
5. Prop to Feather
6. Condition lever in shut off position
7. Turn the Motor switch on and carefully monitor the 20-second Motor sequence.

If aircraft batteries are used during the Cold Cycle without a GPU, it is possible to worsen the problem by depleting the batteries.

It is possible to cold cycle the turbine for five to eight seconds and abort by switching the Master off. This will save the battery power and should reduce the turbine temperature enough for a successful start.


1. Batteries insufficient power.
2. Limiter not working (electrical).
3. Throttle linkage adjustment incorrect, FCU lever has to be on "0" degree.
4. Adjustment on FCU.
5. High elevation.
6. High outside temp.
7. Strong wind from rear of aircraft.  Turn into wind.
8. If  ITT is 150 C and over, cold cycle turbine to cool off  before attempting a start.


1. Power on.
2. Inverter on if necessary.
3. Fuel on.
4. Fuel pump / pumps on.
5. Condition lever in shut off position.
6. Prop in feather position.
7. Throttle in idle position.
8. ISOL valve on (emergency throttle system).
9. Press start.
10. Monitor N1 (compressor rpm).  When N1 reaches 16 / 18%, feed fuel in by forwarding condition lever,  it could be necessary to forward almost to ident position to light.  Once turbine has lit, reduce fuel by pulling condition lever towards shut off position not to exceed 620 / 680.  Keep adding fuel by forwarding condition lever till such time as the N1 reaches 60 / 63 %.
11. At 60 / 63 % N1 make sure throttle is in idle position and switch ISOL off (normal position).
12. Monitor oil pressure, fuel pressure, ITT,  N1 and torque.
13. Generator on.
14. Forward prop lever to full fine pitch.

If starter generator is fitted with the standard timer LUN 2601-01, it will engage for 20 seconds.  It is necessary to try to achieve 60 / 63 %  N1 before starter disengages to minimize an over temp.  At anytime if there is a possibility or over temp, pull the condition lever to a shut off position.

It is also important to achieve 60 / 63 % N1 before switching ISOL valve off.  A slight bump (compressor stall) will be heard, this is normal.  The lower the N1 is to 60 / 63 % the more abrupt the change over from ISOL to normal mode will be.

Taxiing can be done in beta range or feather.  When taxiing in feather with low clearance propellers, the propeller blades tend to sweep the taxiway lifting dirt and stones into the air intake.

Make sure the prop has come out of beta range and stabilized before adding power.  (Adding power whilst the transition is taking place from beta to normal mode will result in an over speed of the prop stretching the blades on the power turbine wheel leading to possible failure.)

Add power gently to achieve the necessary take off power.  Monitor the ITT, N1, N2 and torque.

Max ITT take off on calibrated Czech gauges 8 OHM 710C.  It has been found that some American gauges read low by as much as 50 C.

Max  Take-off power 1 minute
ITT  710

Max  N2/Np      2080 rpm
Max  torque      105% +- 132 PSI if using oil pressure gauge.

MAX Continuous
ITT  690
N1/Ng  98.2%
N2/Np  1850 - 2080 rpm
Torque 100% +/- 128 PSI

ITT  660
N1/Ng  97.5
N2/Np  1700 - 1850 rpm
Torque  90%

ITT  710
N1/Ng  99%
N2/Np  2000 rpm


1. Throttle idle.
2. Prop feather for 60 seconds.
3. Electric's off except inverter and battery.
4. Condition lever to shut off position.
5. Inverter and master off. (A good time to check engine oil is soon after shut down.)


In flight, if a reduction in torque and an increasing ITT occurs, the probable cause would be mechanical.  The ISOL will not work and suggest landing.

If a reduction in torque, N1, and/or  ITT occurs and adding of power does not make a change there is a probable problem with the FCU (Fuel Control Unit).  Reduce power to idle (throttle) make sure the condition lever is in the ident position +/- 1/3 forward, select ISOL valve and use condition lever as throttle.

To come out of  ISOL, make sure the throttle is in idle position.  Bring condition lever to the ident position +/- 1/3 forward and select off on the ISOL valve switch.  The throttle can now be forwarded to the necessary power setting.


Minimum ambient air temperature for starting engines without their preheating -20C
Maximum inter turbine temperature during starting from an external power source 700C
Maximum inter turbine temperature during starting from aircraft batteries 735C
Minimum generator speed after spin up of the engine by the starter 18 %
Maximum altitude for engine restarting in flight 13,000 ft
Maximum number of engine starting (turning) attempts from an external power source following at 3 minute intervals 5
The next attempt can be made after one hour.
Voltage of external power source during starting (no load) 20 to 31 V
Allowable voltage drop of aircraft power supply during the initial phase of starting (not over 4 seconds) min. 14 V
Maximum number of starts attempts from aircraft batteries (3 minute intervals)    5

Maximum flight altitude in case of all fuel pumps failure                                  13,000 ft

The engine can be lubricated exclusively with the following oils:

Aeroshell Turbine Oil 500
Aeroshell Turbine Oil 555
Aeroshell Turbine Oil 560
Mobil Jet Oil 11
BP Turbo Oil 2380
Castrol 599


Minimum oil quantity in engine  5.5 L
Maximum oil quantity in engine 7    L
Minimum oil temperature during starting - 12  C
Maximum oil temperature for engine acceleration and normal engine operation 85  C
Minimum oil temperature for engine acceleration and normal engine operation 20  C
Maximum oil consumption 0.1 L / h

Minimum permissible oil pressure

N1/Ng 60%   (17 PSI)   0.12 MPa (1.2 kp/cm2)
N1/Ng 80 - 101.5%   (26 PSI) 0.18 MPa (1.8 kp/cm2)
Maximum permissible oil pressure (39 PSI)  0.27 MPa (2.7 kp/cm2)

For oil temperatures range 20 - 55 C oil pressure can be higher by 43 PSI (0.03 MPa)  (0.3 kp/cm2).  Increase of oil pressure to max. 50PSI (0.35 MPa) (0.3 kp/cm2) is permitted for short time during starting at temperatures below 0 C.

Short-term oil pressure drop to zero                                                            10 seconds


  • Bleed Air for aircraft systems

Air bleed ducts must not be opened with the engine operating at maximum  take-off power or at emergency power.

With air bleed on the gas temperature (ITT) will rise by approximately 30 C.  It is therefore necessary to set the engine operating parameters after the bleed air has been opened so that the maximum inter turbine temperature (ITT) shall not be exceeded.

  • Use of reverse thrust

Reverse thrust may only be used during landing after touch-down.  It is forbidden to use beta or reverse thrust in flight.


  • Electric power sources                                                                               

Normal voltage in DC system                                                           27 to 29.0 V
Maximum load of generator in flight                                                        200 A
Maximum load of  generator on ground (30 min maximum)                 100 A



Diemech Turbines
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DeLand, Florida 32724 U.S.A.
Phone: 1-386-804-1824


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