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Engines out - but why?


MarkHurst

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If you check out this video, at the 8 mins mark my left engine fails. It won't restart. Then the 10 mins mark the right engine fails too. I still don't know what happened here. I can see the temperature is 0C here, so ice is a possibility even though the weather was clear-ish. I have had the engines flame-out in icing conditions before but they will usually start again. The GG would (apparently) not spin up here, although I don't know if this is a reliable indication (in the sim) of what was wrong. I should have tried immediately switching to continuous ignition, but I doubt that would have worked as the engines wouldn't start manually anyway. I wish I had tried switching on intake de-ice, which seems like the only possibility. I'm not sure this accounts for why the engines wouldn't start when I was back on the ground, but perhaps the intakes stay iced up for a while. I am pretty sure I checked the ice load gauge in the config page and it was zero, but I don't know if this shows engine icing.

 

I am open to suggestions. I'd be disappointed to discover this was just a bug :(

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  • Aerosoft

I watched it and have even discussed it with the main dev Finn. 

 

It is hard to say what happened but seeing the conditions and the fact one failed after the other engine icing is most likely. There is no reason to assume it is a bug. Keep in mind this is an old product and we think any problem would be known by now.

 

SUPERB video's btw.

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43 minutes ago, Mathijs Kok said:

I watched it and have even discussed it with the main dev Finn. 

It is hard to say what happened but seeing the conditions and the fact one failed after the other engine icing is most likely. There is no reason to assume it is a bug. Keep in mind this is an old product and we think any problem would be known by now.

 

 

Thanks Mathijs, I'm just about to re-fly that leg with the same weather as I am convinced it will turn out to be intake ice.

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13 minutes ago, Herman said:

Mark, did this resolve the issue for you?

 

No, I have tried without success to repeat the problem, both in the same route and weather conditions (three times) and in a test scenario I set up when I was looking at icing before. So I can't say yet whether it was intake ice but I am still assuming it is so. I have definitely had engines stop before in icing conditions, but it may be that there's a random element in the algorithm too. I will avoid setting the engine de-ice on for now so when happens again I can check it out. I'm sure it will happen again before I get around the world!

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Hi Mark

 

Next time open the Checklist/Config panel (Sh+2) and go to the config page.

You might be able to see that also structural icing is starting to occur on the bar graph.

 

Like Mathijs said - it´s most probably engine icing, which fit´s to Your OAT readings.

 

Parameters that adds a chance for engine icingcausing wngine failure are:

(OAT between ÷10-2°C AND (Any kind of precipitation OR Visibility below 1700 meters )) OR Structural icing building up

 

Tor clear the engines, You must either apply engine de-icers, or get into warmer air (above 2°C) inorder to thaw the engine inlets, which only happens gradually

 

Best regards

Finn.

 

 

 

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18 hours ago, Finn said:

Parameters that adds a chance for engine icingcausing wngine failure are:

(OAT between ÷10-2°C AND (Any kind of precipitation OR Visibility below 1700 meters )) OR Structural icing building up

 

Tor clear the engines, You must either apply engine de-icers, or get into warmer air (above 2°C) inorder to thaw the engine inlets, which only happens gradually

 

Thanks Finn. If precipitation is required for engine icing that will explain why I was not getting it on my test runs. I will try again with rain.

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  • 2 weeks later...

Hi Mark.

 

Have seen the video you posted, the exact same thing happened to me yesterday while flying my first leg with my brand new Otter (the short nosed 100 wheels variant) in (Around the world in 80 days) some 20 minutes after take off from Calcutta, on my way to Hong Kong, 12,500 ft. Just as I entered Bangladeshi airspace, over the bay of Bengal, in clear weather and hot climate (didn't see the OAT to be honest), my starboard engine did the same thing as your port engine, I got the same warning lights on the panel coming on (something pneumatic etc.). No way to restart no matter, fiddled with all the electrics -including complete off then on- in hoping to reset whatever was happening to no avail, and my stall warning was on like a school break bell. In the end I had to use the same thing you did after landing, i.e. go to the checklist and reset ready for take-off!  only I did it at 5,400 ft. so I have lost 7,100. I am still very new with this aircraft (only bought it on the evening of 24 October) so I disabled the failures and icing from the extended checklist in order to be able to go on with the leg. 

 

Please login to display this image.

.I apologise for piggybacking on your thread but I think this is an appropriate venue to report this.

 

Best wishes.

 

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3 hours ago, kalizzi said:

.I apologise for piggybacking on your thread but I think this is an appropriate venue to report this.

 

No worries. I think disabling the icing is a mistake though, on the assumption that it is behaving logically. I have yet to determine whether I had engine intake icing but that's where I'd put my money. The icing is one of the things that makes flying the Twin Otter interesting and I have taken pains to make it more realistic by adding in (and fixing) the freeware 'icev10' gauge.

 

Anyway, I need to get to Calcutta myself and then be on my way East from there this weekend, so maybe we shall see more of the same...

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Cheers, I did exactly that. flicked up all the de-icing switches and everything ran smoothly ever since, touch wood. I paid attention to my OAT and it is -9 to -10 C so what you are saying makes solid sense. I have never flown the model before and all my rl experience is with piston engines, never a turboprop. Oh by the way, the school bell I heard is a fire alarm apparently so I must have "fouled" up real bad. But there was no smoke or fire coming out visually, though. Safe flying mate and we should get together for a beer if we concur at the same place en route. :cheers_s:

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