Writing this post is also a way of studying the procedures I’ll be carrying out tomorrow. It might be interesting for you, and will certainly be a set of notes for me too.
There are a few interesting aspects of starting a turboprop engine, that you might not expect if you are primarily a piston driver.
Having the Avionics turned off during a start is normal, and in this case, the inverters as well. Turning off the generator to start an engine didn’t make sense at first, however, until I remembered that these are generators and not alternators.
These generators only put out 100amps of their capacity when the Gas Generator (Ng) is at 49%. This number increases to full capacity (200amps) as Ng approaches 63%. Our procedures require running up the engines to 68% before turning on the generators after a start, and not using them during the first engine start. The generator being on at low RPM would actually be a load in this case, so waiting for Ng to get above 68% ensures they’ll be at full capacity to meet the load and will begin charging (recovering) the battery at that point.
Going Flying: I’m going flying in the morning, and this is the machine I’ll be taking up. Flying the Cheyenne 1 is the next opportunity that I wouldn’t have, had I not spent a ridiculous amount of money on my Twin Comanche.
The PA30 Twin Comanche experience led to the King Air C90; Dash-8s with Piedmont; B-25 Panchito; Westwind, Astra, and G280 with FlightSafety and as a contractor; and now this.
While this particular opportunity is in the negotiation phase and certainly not a sure thing yet, I’m forever appreciative of my supportive wife for ensuring I was always in a position to pursue my dreams and experience life in the fullest. It is one thing to be lucky, and another to be ready to strike when the opportunity arose. Let there also be a shout out to my friends, who just happen to be in the room when the opportunities arise, and point me out. Not the first time a friend has hooked me up.
Tomorrows flight will allow me to get more familiar with the start sequence for these engines. I’ll also get in another T/O and landing, and a bit of flying in the pattern. I’ll get to practice the landing sequence, speeds, and sight pictures. Might also get an instrument approach in there as well.
So, let’s start this thing up:
Starting a TurboProp:
- Ensure Avionics/AP-FD and Inverters are OFF
- Turn ON gen bus ties, non-essential bus, and battery master switches.
- Set cockpit lighting as required.
- Turn on the seat belts and no smoking signs.
- Leave the battery master switch ON
- Check volts between 24 and 28
- Right Side Start
- Fuel pump #2 ON; check pressure; OFF
- Switch to Fuel pump #1 ON; check pressure
- Ignition switch ON; nothing happens until condition lever advances
- Starter switch ON; Observe the starter operating limits
- When Ng stabilizes above 12%, condition lever to RUN; check ignition light.
- Monitor ITT and Ng. If ITT exceeds 1090°C for more than 2 sec; condition lever to STOP.
Note: If Ng exceeds 20% immediately after engaging the starter, a sheared shaft is indicated, and the starter must be turned OFF immediately.
Note: If gas gen fails to light w/in 10 sec after moving condition lever to RUN, pull the condition lever to STOP, and turn OFF starter and the ignition. Clear the engine
Note: discontinued start requires a motoring run to clear engine - Ng stabilizes at idle (52% Ng), starter and ignition OFF.
- Advance the power levers to 68% Ng. Min of 68% Ng, generator ON.
Note: Be sure min Ng of 68% before its generator is turned ON.
Note: Do not go to GENERATOR without going to the OFF position momentarily. - Check that the oil pressure is reading in the green arc.
- Right Side Hydraulic Pump Check:
- Gear selector DOWN. If the hydraulic pump is functioning properly, gear lever will automatically return to neutral. The second hydraulic pump can be checked during shutdown.
- When the ammeter reads 100 or less, the battery is charged sufficiently; GEN OFF
- Repeat the above procedures to start the second engine, w/o hydraulic pump check.
NOTE: When starting the engines below an ambient temperature of 0°F, sufficient time at engine
idle should be given to warm up the hydraulic fluid. Prior to takeoff, the landing gear handle should be cycled down while each. engine is running separately and the handle should return within 20 seconds. If the handle does not return, the pump is inoperative and flight must not be initiated.
ENGINE CROSS-START (ONE ENGINE OPERATING): To start the second engine through use of power from the generator of the operating engine, turn ON the fuel pump and the ignition of the engine to
be started.
Turn OFF the generator of the engine that is operating. Advance the power lever of the operating engine to attain 68% Ng. When the Ng of the operating engine is at 68%, turn ON the starter of the second engine. Monitor Ng and ITT on the operating engine and advance the power lever to maintain 68% Ng and ITT within its limits. After the second engine reaches 10% Ng, turn ON the generator of the first engine started. After the Ng of the second engine stabilizes above a minimum of 12%, advance its condition lever to RUN.
Check for the illumination of the ignition light. Monitor ITT and Ng for normal readings as in the Normal Start procedure. If the start is proceeding normally, when the Ng stabilizes at idle, turn the starter and ignition OFF. At a minimum of 68% Ng, turn ON the generator of the second engine.
Fly safe, one and all. I’ll report back on how I did later on.
Frank