Poll: Calling all Multi-Engine Pilots

[JC150]

I was taught in my multi-engine training to wait until reaching Vyse - blue line - before raising the gear.

Last Week, I had the opportunity to fly in a king air and the pilot let me do the takeoff. At blue line I raised the gear and the pilot asks me "Why did you hesitate to raise the gear" to which I responded "I was waiting for blue line" and he tells me "no, after a positive rate you raise the gear". Yesterday, I had a chance to fly in a Cessna 421 and I noticed the owner raised the gear right after positive rate.

So today I called my instructor and asked him about it and he tells me if you raise the gear after positive rate but also below blue line, you won't be able to continue the climb if you have an engine failure, so you will be stuck landing ahead. However, instead of landing ahead with the gear down, you'll be crashing ahead since you raised your gear. So you should keep the gear down until Vyse.

So I'm curious what other multi-engine pilots here do and whether you raise the gear after positive rate, or if you wait until blue line, or if you do something else?

 

[Tarheelpilot]

It depends on the airplane and how they are certified.

For light twins that often can't climb on one engine I'm in the usable runway zone. For stuff that has real v1/v2 speeds it's always positive rate. Stuff in the middle like a king air it just depends on the situation. One answer isn't correct for all twins or even one particular airplane all the time.

 

[Twin_Flyer]

During my multi training I remember my CFI repeatedly saying get to Blue Line. So the procedure was to lift off then accelerate to Blue Line (gear up) then start the climb. It all happens fairly quick in my plane at the weights I normally fly. So I really do think about as much. Liftoff, positive rate then gear up.

 

[Gucci Pilot]

Depends on the airplane. In a jet or turbo prop I raise the gear ASAP after liftoff. In a piston twin, I will more than likely wait until I know I am not going to land in the remaining runway straight ahead, unless obstacle clearance is a factor, then I will do it ASAP. In my jet the take-off performance is calculated based on the gear retraction being initiated within 3 seconds of liftoff.

From the AFH: An important point to remember is that raising the landing gear as early as possible after liftoff drastically decreases the drag profile and significantly increases climb performance should an engine failure occur. An equally important point to remember is that leaving the gear down to land on sufficient runway or overrun is a much better option than landing with the gear retracted. A general recommendation is to raise the landing gear not later than Vyse airspeed.

So even the AFH is basically 50/50 on ASAP after liftoff or once usable runway is no longer available. They mention blue-line as really the latest you should raise it.

 

[GRG55]

Blue line is a pretty low 88 KIAS in the Aztec. I am through that not much after rotation. I use positive rate and only delay retraction in the rare circumstance I happen to still have a lot of runway out front.

 

[denverpilot]

One answer isn't correct for all twins or even one particular airplane all the time.

This.

Even a Turbo Seminole won't climb with a prop windmilling at our altitude, let alone having the gear down, so...

To answer your direct question, yes. We brief gear up is allowed only after true positive rate. But ... we pause before retraction, if there is LOTS of remaining runway.

Example, a short field takeoff effort on the 10,000' runway.

If the gear is down, we're landing. No choice. Choice is made.

Essentially every takeoff in the Seminole at this altitude is an accident chain that's already started.

Vyse does me little good until the windmilling prop won't bring me back to Terra Firma. And it will, most days here.

If there's runway remaining the gear is down.

This is also due to cycle speed. 12-14 seconds, both up and down, as I recall. It won't even be in the wells before you need it again.

In briefings at this altitude, we don't tie it to Vyse. We tie it to whether or not a landing is mandatory or available to us. Once landing is not an option, gear is up, and Vyse is held.

In the Seminole, at this altitude, you're in no-mans-land from gear-up until you've reached a safe return altitude, including any predicted drift-down.

The gear handle is the "committed to fly away" handle in the Seminole. Similar to singles. The performance on one engine, especially with one windmilling, just sucks too much up here.

 

[Mason]

Some aircraft, depending on the gear doors, drag increases during the retraction cycle.

 

[mscard88]

All good replies. As mentioned, depends on the plane as to what procedure one uses.

 

[Fearless Tower]

I'm a positive rate; gear up guy when flying twins. In most twins, I'm above VMC by the time I lift off. The goal is to get to VYSE as quickly as possible. No real advantage in leaving the gear down any longer than necessary.

For me, gear retraction is my abort/go point in the takeoff.

 

[James331]

Positive rate

Very few situations Id raise it once I was out of runway, but there are a few instances.

 

[PPC1052]

So today I called my instructor and asked him about it and he tells me if you raise the gear after positive rate but also below blue line, you won't be able to continue the climb if you have an engine failure, so you will be stuck landing ahead.

I'm neither multi rated, nor a King air driver, but I know that this is false for a King Air B200. It's more than capable of climbing single engine once it gets to Vr. The POH specifically states to retract the gear at positive rate of climb. I will also add that the emergency procedure for a single engine failure post Vr calls for the pilot to continue the climb. So, that is probably why it calls for gear up at positive rate of climb. By that point, you're going (or at least should be) anyway.

Now, for a less capable multiengine plane, what he says may be true.

 

[mscard88]

I'm neither multi rated, nor a King air driver, but I know that this is false for a King Air B200. It's more than capable of climbing single engine once it gets to Vr. The POH specifically states to retract the gear at positive rate of climb. Now, for a less capable multiengine plane, what he says may be true.

Yup. Just depends on the plane and the certification it's built under.

 

[brcase]

I always liked the phrase "Fly it like you are already on one", if the plane is not as close as is practical to being configured the way you want it when the engine quits, then it is probably time to change your configuration.

 

[bradg33]

I've always been a "positive rate, gear up" guy, even in singles. It's just a habit I developed and haven't wanted to change. The airport I fly out of doesn't have friendly options on either end of the runway, so I want as much altitude as I can get as quickly as I can get it. That happens best with the gear up. Further, when launching into IMC, I'd rather have the configuration change done before I get into the soup, rather than pretty much right as I get there. I'm in the process of buying a twin right now, and I have no reason to believe I'll change that when I get it.

 

[stratobee]

My gear comes up as soon as possible. I can see no emergency landing you can't walk away from in a gear up situation. I can see plenty of situations where gear down in single engine scenario that can't walk away from.

 

[bobmrg]

I was taught in my multi-engine training to wait until reaching Vyse - blue line - before raising the gear.

Last Week, I had the opportunity to fly in a king air and the pilot let me do the takeoff. At blue line I raised the gear and the pilot asks me "Why did you hesitate to raise the gear" to which I responded "I was waiting for blue line" and he tells me "no, after a positive rate you raise the gear". Yesterday, I had a chance to fly in a Cessna 421 and I noticed the owner raised the gear right after positive rate.

So today I called my instructor and asked him about it and he tells me if you raise the gear after positive rate but also below blue line, you won't be able to continue the climb if you have an engine failure, so you will be stuck landing ahead. However, instead of landing ahead with the gear down, you'll be crashing ahead since you raised your gear. So you should keep the gear down until Vyse.

So I'm curious what other multi-engine pilots here do and whether you raise the gear after positive rate, or if you wait until blue line, or if you do something else?

Refer the instructor to 23.66, which establishes minimum climb performance with an engine out for certification.

Bob

 

[Kritchlow]

I don't see the logic why the airplane wouldn't climb below blue line. The rate may be lower than at blueline, but it will likely still climb.
You may need to get the gear up to actually achieve blueline.

 

[JC150]

The way my flight school is teaching it, even if it is -30 degrees out at sea level and you have performance to climb, if you have an engine failure below blue line, you're supposed to abort and land ahead. Even if that means into the trees.

My instructor says you don't raise the gear until blue line (roughly 50' AGL) and at that point if you had an engine failure you would try to do a pattern. But the flight school I'm at teaches not to touch the gear until blue line, any failure prior to blue line means you land ahead.

 

[Kritchlow]

The way my flight school is teaching it, even if it is -30 degrees out at sea level and you have performance to climb, if you have an engine failure below blue line, you're supposed to abort and land ahead. Even if that means into the trees.

My instructor says you don't raise the gear until blue line (roughly 50' AGL) and at that point if you had an engine failure you would try to do a pattern. But the flight school I'm at teaches not to touch the gear until blue line, any failure prior to blue line means you land ahead.

So... they teach that if you're 5 kts under best rate of climb, you are better off landing into the rugged terrain ahead?
Pretty poor airplane that gets ZERO climb that close to blueline.. What is VxSe in some of these airplanes i wonder..??

Makes no sense.

 

[GRG55]

The way my flight school is teaching it, even if it is -30 degrees out at sea level and you have performance to climb, if you have an engine failure below blue line, you're supposed to abort and land ahead. Even if that means into the trees.

My instructor says you don't raise the gear until blue line (roughly 50' AGL) and at that point if you had an engine failure you would try to do a pattern. But the flight school I'm at teaches not to touch the gear until blue line, any failure prior to blue line means you land ahead.

They are clearly trying to keep a margin of safety above Vmc; presumably the thinking is a wings level impact with both throttles closed is a better alternative for occupants than trying to save the plane by keeping one engine at full throttle and inadvertently rolling it at low airspeed and altitude. There is some merit to that.

What is the spread between Vmc and blue line on the planes they are training in?

 

[JC150]

They are clearly trying to keep a margin of safety above Vmc; presumably the thinking is a wings level impact with both throttles closed is a better alternative for occupants than trying to save the plane by keeping one engine at full throttle and inadvertently rolling it at low airspeed and altitude. There is some merit to that.

What is the spread between Vmc and blue line on the planes they are training in?

It's a piper seminole Vmca 56 Vyse 88

 

[JC150]

So... they teach that if you're 5 kts under best rate of climb, you are better off landing into the rugged terrain ahead?
Pretty poor airplane that gets ZERO climb that close to blueline.. What is VxSe in some of these airplanes i wonder..??

Makes no sense.

Correct, they teach that blue line is essentially the equivalent to "v1" or go/no go decision speed. Once you hit blue line you may raise the gear. Before blue line, it doesn't matter, their policy is to land ahead.

 

[denverpilot]

The way my flight school is teaching it, even if it is -30 degrees out at sea level and you have performance to climb, if you have an engine failure below blue line, you're supposed to abort and land ahead. Even if that means into the trees.

I'll bet money they're teaching to the specific aircraft. What are you flying?

It's still weird tying the gear to blue line because blue line itself is by definition only accurate with the gear up and prop feathered in most light twins. The line itself represents a specific configuration, by the strict definition of Vyse.

Looking over the Turbo Seminole chart and extrapolating sea level at -30F... because that's off the bottom of the chart...

At max gross, with gear UP, flaps up, cowl flap closed on inop engine, prop FEATHERED on inop engine, and banked 3-5 degrees into the operative engine...

You're still only going up a little over 200'/min.*. Pitiful.

Piper doesn't even publish the numbers for gear DOWN and prop WINDMILLING. Mostly because there's no point. It's almost always DOWN. If your airplane has a number, awesome. Most don't.

An interesting book challenge for you: You SURE your airplane will go up with the gear down and prop windmilling at -30F? I bet you think it will! If it's a typical trainer, I bet it won't.

Take a look at your chart and see if it'll really climb even at -30F gear down and prop windmilling. Mine won't. Even at sea level and -30F. 250' minus gear drag and prop drag, is going to be a negative number.

Light twin performance sucks so hard on one engine, with a prop windmilling and the gear down, that it could pull a large basketball through a small straw.

It's all about performance. The airplanes you and I are flying simply won't go up at all, with the gear down and a prop windmilling even at blue line.

Thus, you have to pitch it down and land it.

Up here, even with the gear up, you might be headed down with gear up and one windmilling. From there it's just a guesstimate on descent rate vs altitude for number of seconds until impact. Most often those numbers look bad enough that you're pitching down, slowing, and landing that one too.

* I've never seen this airplane hit Piper book numbers for single engine performance even in the prescribed configuration. Neither has anyone else who's flown any Seminole. LOL. It's almost always worse.

Great topic.

 

[denverpilot]

PS was typing when you responded that it was the Seminole. I suspect you're flying the non-Turbo but the numbers are nearly identical for a Sea level -30F scenario.

 

[denverpilot]

By the way...

Just doing a little POH dive here...

Piper specifically says...

ENGINE FAILURE DURING TAKEOFF (Below 75 KIAS)
Throttles... CLOSE both immediately
Stop straight ahead
(With an added section for if inadequate runway remains where they tell you to steer not to hit things. DUH... And kill masters and fuel.)

ENGINE FAILURE DURING TAKEOFF (75 KIAS or above)

If engine failure occurs during liftoff during takeoff ground roll or after lift-off with gear still down and 75 KIAS has been attained:
If adequate runway remains, CLOSE both throttles immediately, land if airborne and stop straight ahead.
If runway remaining is inadequate for stopping, decide whether to abort or continue. If decision is made to continue, maintain heading and when climb is established, retract landing gear, accelerate to 88 KIAS, and feather inoperative engine prop (see Engine Securing Procedure).

Irony: They forget to tell you to kill the masters and fuel on this second above 75 KIAS checklist. Boo. Bad editor. No donut.

So... Piper says 75 is the speed to use for go/no-go on the entire takeoff including gear retraction. Not blue line.

By the way, since y'all asked:
(In KIAS)

Vmc 57
Shirt field takeoff (25 flap): 67 through 50', accel to Vxse or Vyse after 50'.
Engine failure abort: 75
Short field takeoff (no flap) through 50': 75, accel to Vxse or Vyse after 50'.
Vxse 82
Vyse 88
max gear retracting 100
Vfe 111
Max gear extending and Vfe 140
Vno 170
Vne 202

Yellow arc: 170-202
Green arc: 60-170
White arc: 56-111

And you can't open the storm window above 129. Haha.

PS (edit): Anyone else notice that if you put two items together... Piper says 67 knots climb for short field (25 flap) or 75 climb (0 flap) accelerating to 88... BUT if you lose an engine below 75 you abort and land?

She's all right zzzere in zeeee booooook. Go figure.

 

[denverpilot]

More fun... straight out of the Seminole POH again...

Normal Procedures amplified section...

In all three paragraphs on normal, short field without flaps, and short field with flaps...

"... retracting the landing gear when a gear-down landing is no longer possible on the runway."

Now you can go ask your school why they don't follow the manufacturer's recommendations in the AFM, @JC150.

(Evil grin... I want him to do it!) haha.

 

[MauleSkinner]

I've always retracted the gear at my go/no go point in light twins.

Assuming the airplane will adequately climb on one, retracting the gear is one component required to make that happen. Feathering the prop, retracting flaps, and closing cowl flaps may also be part of the equation. How long does it take to do all that stuff, and how much altitude will you lose while accomplishing all that in addition to flying the airplane? (Remember your drag demos?) That's the altitude at which I retract the gear.

For a King Air with autofeather, it's pretty much positive rate. In a dirty 414 at higher elevations and terrain considerations, it's been as high as 400 feet.

Your flight school/instructor have their reasons for doing it the way they do, and more than likely those reasons revolve around keeping pilots who are, by definition not proficient, as safe as possible.

 

[Kritchlow]

I've always retracted the gear at my go/no go point in light twins.

Assuming the airplane will adequately climb on one, retracting the gear is one component required to make that happen. Feathering the prop, retracting flaps, and closing cowl flaps may also be part of the equation. How long does it take to do all that stuff, and how much altitude will you lose while accomplishing all that in addition to flying the airplane? (Remember your drag demos?) That's the altitude at which I retract the gear.

For a King Air with autofeather, it's pretty much positive rate. In a dirty 414 at higher elevations and terrain considerations, it's been as high as 400 feet.

Your flight school/instructor have their reasons for doing it the way they do, and more than likely those reasons revolve around keeping pilots who are, by definition not proficient, as safe as possible.

Enlighten me... I just cannot imagine a situation where one would wait until 400' to pull gear.

The only time I can think of that I would wait past positive rate is if I could still land. Unless it's a very long runway, and you are in a very light airplane, even that is unlikely.

 

[MauleSkinner]

Enlighten me... I just cannot imagine a situation where one would wait until 400' to pull gear.

The only time I can think of that I would wait past positive rate is if I could still land. Unless it's a very long runway, and you are in a very light airplane, even that is unlikely.

Do you prefer touching down gear up or gear down ?

 

[Kritchlow]

Do you prefer touching down gear up or gear down ?

Touching down where??? 400 feet you're not landing on the runway.
And even if there was a great clear way ahead, you would likely have time to put the gear back down from 100 feet.

 

[Tarheelpilot]

The way my flight school is teaching it, even if it is -30 degrees out at sea level and you have performance to climb, if you have an engine failure below blue line, you're supposed to abort and land ahead. Even if that means into the trees.

My instructor says you don't raise the gear until blue line (roughly 50' AGL) and at that point if you had an engine failure you would try to do a pattern. But the flight school I'm at teaches not to touch the gear until blue line, any failure prior to blue line means you land ahead.

What they are doing is making decisions for you because they don't want the liability of you making them for yourself and in the process they are not teaching you what you really need to know to be a proficient multi engine pilot. You should find a new school. Those people suck and are shorting your education.

 

[Kritchlow]

To me the arguement is silly.
Some say not to raise gear until Vyse (blueline), even though they have already accelerated to Vxse.

Please explain the logic in that.

 

[flydigital]

Piston twins: Positive rate, out of runway, gear up. Engine failure before gear up, throttle to idle, land/stop straight ahead, otherwise, full rich, full prop, full throttles, Vyse, clean up, identify, verify, feather, etc...

I can get the blue line philosophy even though its a bit foreign IME, but it would depend on the airplane, gross weight, density altitude and the runway available. On a short runway with any chance of climb out/return, I would rather have a clean configuration ASAP.

 

[Tarheelpilot]

I've always retracted the gear at my go/no go point in light twins.

Assuming the airplane will adequately climb on one, retracting the gear is one component required to make that happen. Feathering the prop, retracting flaps, and closing cowl flaps may also be part of the equation. How long does it take to do all that stuff, and how much altitude will you lose while accomplishing all that in addition to flying the airplane? (Remember your drag demos?) That's the altitude at which I retract the gear.

For a King Air with autofeather, it's pretty much positive rate. In a dirty 414 at higher elevations and terrain considerations, it's been as high as 400 feet.

Your flight school/instructor have their reasons for doing it the way they do, and more than likely those reasons revolve around keeping pilots who are, by definition not proficient, as safe as possible.

I think your math skills need some help if you're leaving gear hanging through 400'. I understand where you're coming from but that's a lot of ground behind you and lost energy leaving the drag out that long. There is a point of negative return leaving that gear hanging.

 

[denverpilot]

I think your math skills need some help if you're leaving gear hanging through 400'. I understand where you're coming from but that's a lot of ground behind you and lost energy leaving the drag out that long. There is a point of negative return leaving that gear hanging.

I suspect you're right on this, but we could actually DO that math, make a table, and prove it, for any particular aircraft if we had:

(Note: Some of these are going to be negative in light training twins.)

1. Rate of climb, both engines operative, gear down.
2. Rate of climb, one engine inop, gear down, prop windmilling.
3. Rate of climb, one engine inop, gear up, prop windmilling.
4. Rate of climb, one engine inop, gear up, prop feathered.

Piper is so unimpressed by numbers 2 and 3 in the Seminole, that they won't even tell us what they were during flight test. LOL!

So we'd have to agree on those two numbers before we proceeded to make a climb profile chart and downrange distance chart for sucking the gear up at 100', 200', 300', and 400' AGL.

Toss some ideas out. I can run that math and post it. The chart/spreadsheet is pretty easy to make, if we agree on those two numbers.

Anyone want to toss a Pressure Altitude, temperature, and four numbers out there for any typical trainer? We can run those too.

One number I can debunk pretty quick though, is retraction at 100' AGL. Here's why...

Assuming say, whatever configuration the aircraft is in, it's going down 500'/min after losing one engine, which seems a reasonable swag at a windmilling prop and the gear up...

(Feel free to disagree and change that number, it's midnight and caffeine ingestion stopped hours ago... I suspect on most days at my DA that descent rate number is higher than that even with the gear up, but I'd have to go dig out some drag demo notes at higher altitudes.)

Anyway...

You're 12 seconds from impact at 100' AGL at 500'/min down.

The gear on the Seminole takes 14 seconds to cycle down as I recall. (Where the hell did I put that AFM last night? Haha... it has wandered off upstairs somewhere...)

Won't work.

Retracting it at 100' AGL you'd better leave your hand on it until you have another 50' up... which, you would, if you train like we do to leave your hand on it while it's in-transit, upward and downward... and be ready to slap it back down immediately on a power loss. Even then, it might not make it.

Even if it's closer to 10 seconds, that means for a straight ahead landing you have it back out at 16' AGL and that number doesn't account for the new drag of the gear hanging out, that just increased the descent rate.

As the gear comes out, and both throttles are closed, and two props are now windmilling... the decent rate probably doubles to 1000'/min. Or more.

I suspect ... the TRANSIT time is why Piper specifically says to leave it out until there's nothing left to land on. You need more than 100' of altitude loss at 500'/min down, to get the wheels back down and locked.

Can't make great guesses as to when the rate goes from 500'/min down to 1000'/min down, but roughly, you enough time that you'd lose 200' of altitude before you had three green lights.

This also assumes you'd be trying to climb, to get the 500'/min. If you're landing, you're pushing the nose over and forcing that high descent rate. Gear won't be back out before you "arrive" at the runway.

Methinks there's method to Piper's POH/AFM madness. Thus, why they say for every takeoff type, to leave it down until there's nothing remaining to land on.

It's not about climb performance, the controlling variable appears to be gear extension speed vs how fast you need to come down to even attempt to land. Can't make the gear pump run any faster.

Select gear down and you need 14 seconds to get it there, and you need to force a high descent rate to get back down to the remaining runway.

 

[Fearless Tower]

Piston twins: Positive rate, out of runway, gear up. Engine failure before gear up, throttle to idle, land/stop straight ahead, otherwise, full rich, full prop, full throttles, Vyse, clean up, identify, verify, feather, etc...

Word of caution: Be careful about pulling the throttles strait back to idle if you have an engine failure before gear up. You need to lose the nose and gradually pull the power back, otherwise you will drop like a rock and destroy the airplane like a couple of CFIs who tested the FAAs recommended technique and wrecked the airplane.

 

[MauleSkinner]

Touching down where??? 400 feet you're not landing on the runway.
And even if there was a great clear way ahead, you would likely have time to put the gear back down from 100 feet.

Touching down on whatever happens to be in front of you when you lose an engine and the airplane descends while you retract flaps, feather the prop, and close cowl flaps. How long does that take to do, especially while ensuring that the flying pilot is maintaining proper control of the airplane? (The flying pilot, btw, is also you.)

Factor in some rising terrain and an unfamiliar airplane, and 400 feet goes by fast.

Yeah, I could put the gear back down from 100 feet, but if I know I'm going to touch down if an engine fails, why retract it?

 

[Fearless Tower]

Touching down on whatever happens to be in front of you when you lose an engine and the airplane descends while you retract flaps, feather the prop, and close cowl flaps. How long does that take to do, especially while ensuring that the flying pilot is maintaining proper control of the airplane? (The flying pilot, btw, is also you.)

Factor in some rising terrain and an unfamiliar airplane, and 400 feet goes by fast.

Yeah, I could put the gear back down from 100 feet, but if I know I'm going to touch down if an engine fails, why retract it?

Think about what you are suggesting. If you at at say 300' AGL in such a twin, you are beyond the runway. Having the gear down may not be all that helpful if you do abort and land off airport.

Leaving the gear out to 400' is really only penalizing yourself.

Only place I've seen guys leave the gear down that long was in jets/TPs departing from contaminated runways and that was for a very different reason.

 

[MauleSkinner]

I think your math skills need some help if you're leaving gear hanging through 400'. I understand where you're coming from but that's a lot of ground behind you and lost energy leaving the drag out that long. There is a point of negative return leaving that gear hanging.

I didn't understand calculus in college, and failed Differential Equations.

I can do the math when the AFM says I'll descend 900 fpm with the gear in transit, prop windmilling, flaps dragging, and cowl flaps open.

I can estimate how long it'll take to fix those conditions and figure out how much altitude I could lose, maybe adding a few feet so I don't have to dodge trees in the process.

Where are my math skills lacking?

 

[MauleSkinner]

Think about what you are suggesting. If you at at say 300' AGL in such a twin, you are beyond the runway. Having the gear down may not be all that helpful if you do abort and land off airport.

Leaving the gear out to 400' is really only penalizing yourself.

Only place I've seen guys leave the gear down that long was in jets/TPs departing from contaminated runways and that was for a very different reason.

Gear up or down off airport is a whole nuther question...that's why I posed it to Kritchlow, and probably why he didn't answer it.

I just don't believe in crashing fly able airplanes.