Great observation and investigation!
I just had something happen to me that almost made me walk away from Jets completely! (Emotional reaction of course). So here is my story!
At the end of 2017 I changed careers and have been travelling more than I ever have before. Weekends have turned into valuable family time and flying got moved to the back of the list. My son convinced me to get my BVM Cougar flying and I finally made the effort to sneak in the shop and get some work done. I have always had build procedures and practices that have always made my projects successful. On this day I had completed my K140G2 install and was going over things when my neighbor stopped by and got me all fired up to beat the rain and get a test run in. This is when I got excited and forgot to follow my own procedures. Normally I would disconnect the 4mm fuel line to the turbine and use a container to capture the fuel as I tested the fuel pump and purged all the air out of the line before connecting it back. (I have done this on every turbine I have owned and never had one hiccup at startup)
Except for this day. I was too excited and in a hurry to beat the rain that I had sold myself that it was Ok to skip this step. I continued on with pre-start up and placed my Extinguisher in the same spot I always do, knee pad in the same place, transmitter ect.
Start #1. no fire "low gas"
Start #2. no fire "low gas"
Start #3. no fire "low gas"
Not familiar with ever seeing this on my engine test, I moved on to trouble shooting things. I had changed all the tank lines and put the start up failures to air in the line and getting suction going from the tank. As I inspected the lines I noticed that the 4mm discharge from the fuel pump was kinked. I replaced that section and started all over again. (Sill didn't purge/test fuel pump).
Start #4. Engine is spooling up and then **FIRE** **FIRE** **FIRE**
My first hot start ever in 5 years!!! AS fast as I can remember I closed the ball valve to the fuel supply, killed the motor and jammed the throttle to cooling mode, grabbed the extinguisher and hit it!!!!!!! FIRE under control....Turbine in cooling mode kept the incipient fire that was still burning going down the thrust tube....I grabbed my shop blower and forced air down the intakes to help cool the engine down. Once this was accomplished the small incipient fire went out completely. It took me about 1 hour to calm my nerves to inspect the damages. I put the jet back on the bench and was just blown away at what I had found. The fire was put out so fast that it did no damage to plane at all. The lower former had slight discoloration but that was about the extent of the "Damages". Now for the wake up call...Upon inspection of the aircraft, I noticed that when I lowered the tail to inspect the plane in detail, jet fuel poured out of the rear. I had fuel in the fuselage below the thrust tube. A LOT OF IT!!! As I pulled the motor to clean things up, fuel pours out of the turbine as well. Honestly, I have no idea how the whole tail section didn't go up in flames!!!!!! This really set me back emotionally....The whole week I was out of town I really considered getting out of jets. The only thing that changed my mind was the challenge not to give up so easily. Guys deal with hot starts all the time. I made a mistake and I owned up to it. It was completely my fault and had it burned down to the ground I would have to live with the fact that I took a shortcut and almost paid the ultimate price. So what did I do? I placed the turbine in the vertical position to drain out and let the fuse dry (tail section) out as well. When I came back a week later (after calming my nerves) I put everything back together and did what I always do. Followed my rules and she fired up on the first start!!! Nerves gone and I am now ready to move on.
So what did I learn?????
Turbine waiver process works. This should be the minimum training you get before operating a turbine.
Safety Equipment is a HUGE Investment. I haven't used my fire extinguisher in 5 years and when I needed it she was there!!!! (inspected yearly)
Knowing your equipment!!! shut off valves, engine kills, cooling mode!!!
Turbines are a huge investment. have your personal checklist, follow it!
Don't rush, listen to your jet when she / he (gender bias jet) is talking to you.
Learn how to handle emergencies!!!
Most important, this is a hobby. Take your time and do it right.