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Emergency - Mental Planning

Roger Lee

By Roger Lee
in Landing and Flying

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Roger Lee

Roger Lee

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For fun and emergency mental planning. Remember fail to plan, plan to fail. 

 

Let's say you're cruising along and a throttle cable breaks and you don't know what happened.  Now the engine is shaking. So you instinctively pull back the power and the shake gets worse.

 

Your next move?

 

 

This will be a two parter when I get a  correct response and the second part will fit right in.

 

 

So then after you do the right thing what are your actions or considerations? 

 

If I say more I'll give it away.

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gbigs

gbigs

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Posted

For fun and emergency mental planning. Remember fail to plan, plan to fail. 

 

Let's say you're cruising along and a throttle cable breaks and you don't know what happened.  Now the engine is shaking. So you instinctively pull back the power and the shake gets worse.

 

Your next move?

 

 

This will be a two parter when I get a  correct response and the second part will fit right in.

 

 

So then after you do the right thing what are your actions or considerations? 

 

If I say more I'll give it away.

 

This happened to my wife when she was flying with her CFI in their trainer (CTLS with 912ULS).  The throttle stuck open after the cable kinked or broke (verified after pulling throttle back and no change ).... They were about two miles away from the airport.  He flew in on base (after calling the Tower) and arched in on final.  Then he turned the engine off and landed normally knowing the runway was 5,000 feet long (KVGT).

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Roger Lee

Roger Lee

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Hi Al,

 

Perfect answer.  "When the cable breaks it goes full throttle. You need to balance out the carbs by adding throttle."

 

Okay now Rotax says only 5 minutes above 5500 rpm. Let's say your WOT rpm is 5700 rpm. Now what do we fly for 5 minutes and land? Do shut down the engine?

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Anticept

Anticept

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It's not possible to land at full throttle unless you want to push the prop in (and probably flip over) or land up the side of a steep mountain.

 

Roger: Get as much altitude as possible (which also controls engine RPM) until near a place that you can land safely, then turn off engine and close fuel valve for descent. BUT, shut down the engine only if you have to (you might still need it, so try not to destroy the engine; don't turn one emergency into two), and remember the parachute (if equipped) if the situation requires.

 

"Two things that are useless are altitude above you and runway behind you."

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Roger Lee

Roger Lee

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My question is Rotax says 5 minutes above 5500 rpm. What about 5700 rpm for 20-30 minutes to a safe landing site?

Who's for getting altitude and shutting down the engine or just flying at 5700 for 20 minutes? 

If you decided to fly for those 20 minutes what would happen to the engine?

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Al Downs

Al Downs

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If there is not a place to land nearby it doesn't matter what Rotax says. I think there is a good chance the engine the engine would be fine. In any case I am looking for a place to land as soon as I can and when I am close enough to land I would shut down, slow down and land. This is where plenty of altitude would help so you have time to slow down and set up  safe landing.

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Roger Lee

Roger Lee

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Hi Alo,,

 

You've been peeking :clap-3332: 

 

In fact running at that 5700 rpm for 20-30 minutes won't hurt the engine. So fly to a safe place like a runway set yourself up and shut down the engine to land. Just remember no go arounds. :fainting-1344: 

 

 

This has been tested and there is plenty a safety factor there. 

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Roger Lee

Roger Lee

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I'm not 100% sure they would categorize this as an over speed. Maybe.

Here are the test parameters from Rotax no matter what 912 they use (UL or certified)

 

After the endurance run the engine is torn down all parameters must be within serviceable limits.

Part 1 A 30-hour run consisting of alternate 5 minute periods at Take-off Power and speed
and Maximum Best Economy Cruising Power or Maximum Recommended Cruising Power conditions.

Part 2 A 20-hour run consisting of alternate periods of 1.5 hours at Maximum Continuous
Power and speed and 0.5 hour at 75% Maximum Continuous Power and 91% Maximum Continuous speed.

Part 3 A 20-hour run consisting of alternate periods of 1.5 hours at Maximum Continuous
Power and speed and 0.5 hour at 70% Maximum Continuous Power and 89% Maximum Continuous speed.

Part 4 A 20-hour run consisting of alternate periods of 1.5 hours at Maximum Continuous
Power and speed and 0.5 hour at 65% Maximum Continuous Power and 87% Maximum Continuous speed.

Part 5 A 20-hour run consisting of alternate periods of 1.5 hours at Maximum Continuous
Power and speed and 0.5 hour at 60% Maximum Continuous Power and 84.5% Maximum Continuous speed.

Part 6 A 20-hour run consisting of alternate periods of 1.5 hours at Maximum Continuous
Power and speed and 0.5 hour at 50% Maximum Continuous Power and 79.5% Maximum Continuous speed.

Part 7 A 20-hour run consisting of alternate 2.5 hour periods at Maximum Continuous
Power and speed and Maximum Best Economy Cruising Power or Maximum Recommended Cruising Power condition

 

 

 

​Bottom line it will get you to where yo need to go.

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Al Downs

Al Downs

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Until something like the cable happens to you or someone you know, it isn't something that crosses your mind. Ours broke half way from the end of the sheilding and the point where it connects. About a 2 inch area where nothing can touch or damage it. Never could figure out how or why it broke but was really glad it was in the pattern. When it happens it feels like you are in a paint shaker and it confuses the hell out of you. More throttle doesn't seem right but once you understand what is going on, it is the  correct action. Every pilot flying the plane needs to be educated on this because to does happen.

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Anticept

Anticept

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I'm not 100% sure they would categorize this as an over speed. Maybe.

Here are the test parameters from Rotax no matter what 912 they use (UL or certified)

 

 

You made me pop open the MM. Line maintenance manual doesn't even have an overspeed or time entry for anything less than 5800rpm. Chapter 5-50-00 paragraph 3.4

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Runtoeat

Runtoeat

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FWIW, I would first add throttle and climb (aviate), then I would look for "nearest" on my GPS and set a course (navigate), then I would call on 121.5 and declare an emergency and press my beacon "on" (communicate).  Once at a safe altitude and over the "nearest", shut down and circle for a landing.  All the while keeping the 'chute deployment as "plan B" backup.

 

This is a really good "what if" safety exercise.  The thought of a broken throttle causing the carbs to function unevenly didn't occur to me.  Thanks Roger.

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ausctls

ausctls

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Roger Lee, on 29 Jul 2016 - 11:35 AM, said:

My question is Rotax says 5 minutes above 5500 rpm. What about 5700 rpm for 20-30 minutes to a safe landing site?

Who's for getting altitude and shutting down the engine or just flying at 5700 for 20 minutes? 

If you decided to fly for those 20 minutes what would happen to the engine?

I would probably just increase the prop pitch to prevent over revving.

Then turn it off when an ALA was in sight.

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