Accidental diesel in Rotax 912

[Fitter2]

Power kerosene was probably very similar to what was known as "tractor vapourising oil", or TVO, here in UK, which is probably no longer available. I understand it was "cut" somewhere between petrol and paraffin. I was privileged (!) to learn to drive on a little grey Ferguson tractor which ran on it, it had a compartmentalised tank for petrol and TVO and a changeover fuel tap. I loved the smell of it when running on TVO. I also learned not to touch HT leads while the engine is running in the rain, but that's a different story.

I can vouch from personal experience that TVO tractors will run on 'water contaminated' V-bomber fuel (AVTUR), the tractors at the RAFGSA Club at Upavon in the 1960's ran very happily on fuel supplied from Gaydon.

[Rotor Kop]

I had to check the date to make sure it is not 1st April
Cannot believe someone dances with death like this.......should have his/her licence revoked permanently.
4 years or so down the line - is this person still alive?

[tecman]

RK..I had a similar reaction and wondered the same thing. Reading the thread for the first time, I'm puzzled about why a couple of recent posters are not seeing the gravity of the situation, and the consequential weight of the criticism of the OP. Most of us can just about understand the initial fuel mix-up but the really dumb thing was to go flying without having a comprehensive engine inspection by a Rotax expert engineering facility. That shows such poor knowledge and judgement that both some re-training and, probably, punitive measures (licence suspension?) would be justified. But it might be true that our North American cousins are right in saying 'you can't fix stupid'.

[Mariner9]

This place is incredible sometimes.

The OP wrote:

I should re-assure those expressing concern that the aircraft was flown after the diesel accident, and after a change of fuel and oil, only after consultation with engineers and in view of the fact that there was, at first, no apparent damage.

So the OP inspected the engine himself and found nothing wrong, and also took expert advice from un-named Engineers, possibly the aforesaid Skydrive or Conair. Entirely sensible and proportionate precautions that I would have done myself in the circumstances.

I guess my licence should be revoked too

[frontlefthamster]

Mariner:

From the first post:

the oil pressure had fallen to the red line and the temperature was rising rapidly. After the tank, lines and carburettors had been flushed and the oil changed the cruising oil pressure dropped from 4 to 2 bar... and there was some debris in the filter

You said:

the OP inspected the engine himself and found nothing wrong

So, yes, nothing wrong. Apart from red line oil pressure, rising temperature, and debris in the filter. (I haven't mentioned the nearly-four-fold increase in oil consumption because presumably that only showed up as the aircraft continued to be flown with its damaged engine).

I guess my licence should be revoked too

So yes, my opinion would be that it should.

[tecman]

Any engineer who told him to fly the aircraft without an internal examination of the engine was no expert and, by the way, the OP never claimed 'expert' advice. Any pilot who took such dumb advice was negligent. The subsequently detected engine problems merely underline the folly.

[Mariner9]

The OP says he had

consultations with Engineers

. (My bold)

None of the above posters can possibly know who the engineers were, or what that consultation involved.

You are passing judgement on the basis of assumptions, and with the benefit of hindsight.

[tecman]

No, I'm passing judgement on the basis of what he wrote in the posts. It's immaterial how many opinions he sought; no authoritative source(s) would have dispensed the advice to fly the aircraft without internal inspection of the engine. Neither would a responsible pilot with a basic understanding of the engine operation have flown the aircraft in the circumstances described. That's the key argument.

[abgd]

A few observations:

There's relatively little on the internet about putting diesel in petrol engines, because cars are largely immune from it because diesel pumps won't fit in petrol tanks. All the articles are swamped by ones about what happens if you put petrol in a diesel tank. If you google "diesel in a petrol engine" with quotes, the articles tend to suggest that it's no big deal other than the engine stopping and maybe needing to clean the spark plugs and fuel lines.

My thoughts as to what would happen, are that the engine would simply stop as the diesel wouldn't burn/evaporate as readily. I can follow all the arguments about carbon deposits but wouldn't have any intuition as to how bad it would be likely to be. After all, you burn oil directly in 2-strokes. Extra energy in the fuel? But is that a problem if it's not burning properly. Detonation? It's easy to find that diesel engines suffer detonation if you get petrol in the fuel, but why would it happen the other way round?

If I made such a mistake, my thoughts are that I can't work out what would happen from first principles, so I would be to go and see an engineer and accept their advice. That's the point of an expert - they know things you don't. I think the point that a motor-glider pilot is likely to be more comfortable with engine failures including EFATOs (tow line breaks) than a regular power pilot is a reasonable one to make too.

So, it seems the OP got bad advice, but assuming that he did go and talk to an engineer, I think any character assassination should be directed at the engineer. Though could it be that (s)he talked to an automotive engineer who might be expected to have a different take on things, as the consequences of an engine failure are likely to be less severe? A suck-it-and-see approach would be a whole lot more reasonable for a car engine.