Engine Failure in Flight

[USMCmech]

I've also read that if you are flying a carbureted airplane it might be a good idea to put on carb heat simultaneously as you pitch for best glide. Why? Because if ice is the reason for the failure, the engine may cool down too much for that checklist item, when completed later, to do much good.

That is the reason that some people say to run the checklist first. It is a valid concern, but like many of these arguments it is a case of people overthinking to problem.

I agree with waht everybody else is saying. Pitch for best glide, run the checklist, and look for a landing site simutaniously. The engine failure checklist in almost any single only takes about 30 seconds max. You should have praticed this enough times to do it by feel and memory. All the while holding the airplane level and slowing to best glide, while looking for a landing site.

 

[Cutlass1287]

I dont think its likely that your engine would go from perfect health to totally dead instantly from carb ice anyhow.

 

[USMCmech]

I dont think its likely that your engine would go from perfect health to totally dead instantly from carb ice anyhow.

Think again.

Carb Ice is probably the second most comon reason for engine failure (right behind fuel exaustion/starvation).

The most likely scenerio is where you are flying along on a nice fall or spring day with the OAT about 50F. Your carb is slowly iceing up, and when you reduce power to start your descent the throttle plate (which is covered in ice) completely chokes off all airflow in the iced up venturi. THis is why I always add "full throttle" to my engine failure checklist even if the checklist in the POH dosen't mention it.

It happens all the time. Look at the NTSB reports where "engine falied because of undetermined reason" is part of the cause. If you look closely at the weather conditions you will see they are useually an OAT of 55-30F, the most dangerous temps for carb ice. By the time the investigators get there, the ice has melted, and the culprit is never found.

 

[MauleSkinner]

I agree 100% with the general consensus...fly the airplane, pitch to best glide, and run the appropriate checklist (memory or paper, depending on the situation).

While Avbug's comment about the applicability of best glide is probably true for the most part (the only one I had quit cold in a single was at 75 feet and Vx...not sure what I pitched to, but it worked), unfortunately the PTS is worded "Establishes and maintains the recommended best-glide airspeed, ±10 knots."

With regard to Midlife's question, higher-drag airplanes tend to have a lower nose attitude for best glide speed...holding a Stearman in a level flight attitude with the engine out will seriously degrade its already rock-like gliding qualities

Fly safe!

David

 

[midlifeflyer]

I don't honestly know. I've never thought about the pitch attitude during an engine failure.

Unless I'm on instruments, most of the time it's strictly a feel issue, and I probably am not looking inside the cockpit.

Neither am I. I'm talking about cruise level pitch based on visual cues, not the AI (unless in IMC where it works just as well).

The concept is that I've seen many student and low-time pilots spend a heck of a long time (as much as 3-5 seconds) getting to best glide when all they have to do is keep looking out the window as they establish (or maintain) a cruise level pitch attitude while they look for a place to put down and start their troubleshooting.

Thanks. Guess you've been flying long enough that it's so automatic that you don't need to think about it for yourself and aren't worried about how to teach it to others.

 

[midlifeflyer]

With regard to Midlife's question, higher-drag airplanes tend to have a lower nose attitude for best glide speed...holding a Stearman in a level flight attitude with the engine out will seriously degrade its already rock-like gliding qualities

Thanks David. Guess I haven't flown high-enough drag airplanes to see it yet.

 

[Prof. ATP]

I've never thought about the pitch attitude during an engine failure.

For most GA airplanes, the pitch attitude for best glide is very close to nose-on-the-horizon. Best glide is about 6 degrees angle of attack, and the glide angle is about 6 degrees...

I was taught (and teach) glide-grass-gas.

 

[185'er]

Go for best glide speed while doing the checklist. When you get the speed, trim the airplane to help you maintain it. Best glide speed is very important and may make the difference between an on-airport or off-airport landing. Don't forget to practice this occasionally.

 

[avbug]

I dont think its likely that your engine would go from perfect health to totally dead instantly from carb ice anyhow.

Really? I guess you've had enough carb ice related failures to know.

I've had it stone cold and dead fairly quickly in ice and ended up landing in that condition because it couldn't be restarted. Perhaps a few more tries and I'll find out you're really right.

Thanks. Guess you've been flying long enough that it's so automatic that you don't need to think about it for yourself and aren't worried about how to teach it to others.

No, it's done intuitively, and the student should understand it intuitively. The first few hours in the pattern with a primary student, I use the same airspeed for takeoff, approach, and landing. The student only memorizes or knows one airspeed, one feeling, one way to fly, intially. The student understands that speed, knows the power settings, the feel power on and power off, the trim settings, by feel, without thinking. I can cover up the instruments and have the student set the speed and uncover them to show the student he or she can achieve it. Each time.

After that, the student will always think something is wrong if the engine is working properly, because I'll never let him go long without an engine failure.

As far as the attitude, I think it's a wrong way to look at it. I don't care about the attitude; that could vary with loading, weight, whatever...but what's on the dial, and what's in the hand and in the ear, I do care about. If the airplane feels like it's at best glide and I can confirm it by checking, fine.

Best glide is only important if you need to glide. Most of the time you're looking at a landing site beneath you, if it's a complete power failure. In that case, minimum sink is much more important.

How many people teach minimum sink?

 

[MauleSkinner]

How many people teach minimum sink?

Well, speaking as a glider instructor...

I noticed the other day that the Aviat Husky lists a minimum sink speed in the AFM...first I've seen it in a power plane...kind of refreshing!

Fly safe!

David

 

[Lead Sled]

Well, speaking as a glider instructor...

I noticed the other day that the Aviat Husky lists a minimum sink speed in the AFM...first I've seen it in a power plane...kind of refreshing!

Speaking as another glider instructor...

I'm currently flying an Astra and they even give you the best L/D speed - it's not listed as such, but that's what it is none the less. We could always introduce the concept of "Speed to Fly".

If I were king of the world, I would require a certain amount of training in gliders, aerobatics, and tailwheels for EVERY fixed-wing pilot. There'd be a whole lot less crash'n going on. But hey that's just me and I'm not the king of the world.

'Sled

 

[dmrogers]

...I have always been taught to immeadiately pitch for Best Glide when the engine fails, and then start looking for a place to land and turning. After you have that under control, you start running your restart checklist, and then your shutdown checklist.

Now I am at a school where they want you to immeadiately run your checklist, and then if it wont restart pitch for best glide, and look for a place to land and turn.

How were you guys taught? How would you do it in an emergency as PIC?

A wiser man than myself once said:

Aviate, navigate, investigate, communicate.

My aerobatics instructor gave me the “evacuate” option as well.

 

[MauleSkinner]

I'm currently flying an Astra and they even give you the best L/D speed - it's not listed as such, but that's what it is none the less. We could always introduce the concept of "Speed to Fly". 'Sled

You'd not only have to adjust your McCready ring for anticipated climb rate, but also keep track of massive changes in TAS over the 40,000-ft altitude range for best penetration speed in that Astra

Fly safe!

David

 

[Cutlass1287]

Really? I guess you've had enough carb ice related failures to know.

Actually I have had one, and the engine did in fact die as soon as I pulled the power, and I had to make a power off 180 (this happened abeam the numbers). I guess this kind of condradicts my earlier speculation.

 

[avbug]

In that particular case, you created the engine failure by closing the throttle. Had you opened the throttle again and resupplied the engine with fuel and air, you may have experienced a restart. By applying carburetor heat with full power for ten or fifteen seconds prior to power reduction, you would have avoided the situation).

The most conducive condition to the formation of ice is when the airflow is highest and the temp drop the greatest; high power settings (for venturi icing). Icing with the throttle completely closed occurs adjacent and just downstream of the throttle plate as the gap between the plate and wall is blocked, and the idle jet is occluded.

Generally speaking, idle descents in a piston airplane are bad form.