Blue-line Debate

RiddlePilot

RiddlePilot

New Member
Recently I've had run-ins with several Riddle instructors on the topic of blue-line during engine-out flight. Their contention is that no matter the performance, you should always fly at blue-line when an engine is inoperative. Fair enough. However, my contention is that if you can gain performance by flying a few knots below blue-line, you should do it.

I'm interested in hearing some thoughts from other multi pilots about how engine-out ops should be conducted. Keep 'er at blue-line, or experiment a bit?
 
You can tell them that they are wrong. Blue Line represents Vyse at Max Weight at Sea Level. If you are not at max weight or are at a higher density altitude, then you can improve your rate of climb, or slow your rate of descent by flying at a slower airspeed. The question is how much slower? The Seminole (I am assuming this is what you use at Riddle) unfortunately does not have charts in the POH that give any guidance.

As a general rule, I avoid flight below Vxse. There is usually no useful benefit in going there, and it can obviously be dangerous if you get too slow. At max weight Vyse will always be between the published Vyse and Vxse. At lower weights, you should still probably be able to optimize performance (climb rate) between the speeds published for max weight, especially in a light twin where the weight does not really vary that much. The larger twins that can carry hundreds of pounds of cargo should have a more complete POH that contains charts for this (Vxse and Vyse vs Wt. and D.A.).

Initially when you first loose an engine, it is a good idea to just go for the blue line, get the airplane cleaned up and either trouble shoot or feather the engine. Once that is done, if you really need the performance, it is obviously ok to try to find the airspeed that will give you the best climb rate.

If your instructors would rather fly into terrain than slow down a few knots and clear it on takeoff, that is their business.
 
In the Apache Vxse is three (3) MPH over REDLINE.

The point is if you need the angle (i.e. need to get up and out of someplace to clear an obstacle) you fly the correct aispeed or in better phraseology "do what it takes." but "experimenting" in a real situation will get you killed. Go out and practice it at altitude (will simulate a higer DA to boot) and learn what the airplane will and won't do.

This blind adherance to "blue line" is simply a holdover from their own training and shows a lack of understanding of multiengine opeations.
 
The info is much appreciated, guys. Just wondering if I was the crazy one. Actually, I've had no less than two ERAU guys tell me that they're superior instructors because they went to ERAU, and teach 100% by the book in this sort of situation. Argh!
 
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In the Apache Vxse is three (3) MPH over REDLINE.



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At first I thought you were talking about Vne! Then I remembered Vmc - it's been awhile since I burned twice as much gas /ubbthreads/images/graemlins/wink.gif
 
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In the Apache Vxse is three (3) MPH over REDLINE.

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Yeah, the Seneca is 5 mph over redline. Not too much room to play with there.
 
Now you mean during the climb or straight and level flight as well?
 
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Now you mean during the climb or straight and level flight as well?

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Well the debate was what to do with bricky Seminoles in PRC's high DA environment. As you know, no climb unless you have turbos. /ubbthreads/images/graemlins/smile.gif But, do you accept a 200 fpm descent at blue-line, or do you go a few knots below in order to hold level?

Anyhoo, that brings up another topic: If you were straight-and-level with some excess airspeed, do you reduce power on the operating engine to maintain blue-line, or do you maintain max power and keep that extra airspeed? My answer is based on common sense, but I'm very surprised at just how many folks say that you should reduce power.
 
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Now you mean during the climb or straight and level flight as well?

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Well the debate was what to do with bricky Seminoles in PRC's high DA environment. As you know, no climb unless you have turbos. /ubbthreads/images/graemlins/smile.gif But, do you accept a 200 fpm descent at blue-line, or do you go a few knots below in order to hold level?

Anyhoo, that brings up another topic: If you were straight-and-level with some excess airspeed, do you reduce power on the operating engine to maintain blue-line, or do you maintain max power and keep that extra airspeed? My answer is based on common sense, but I'm very surprised at just how many folks say that you should reduce power.

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You situation depends. What's my performance like at this moment? Am I at El Centro, California (elevation minus 55') on a cold day with lots of performance? Then sure, I'll take care of the remaining engine and not run it full-bore for no reason. It's a judgement call based on the situation at hand.

Remember, the words "never" and "always" rarely belong in the description of handling an emergency.
 
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You situation depends. What's my performance like at this moment? Am I at El Centro, California (elevation minus 55') on a cold day with lots of performance? Then sure, I'll take care of the remaining engine and not run it full-bore for no reason. It's a judgement call based on the situation at hand.

Remember, the words "never" and "always" rarely belong in the description of handling an emergency.

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You're absolutely right. With a normally aspirated twin anyhow, you probably won't have much extra airspeed (if any) during straight-and-level. But for example, in the turbo twin I did my MEI in, we'd run the operating engine at 32", which is decently lower than the maximum of 36-37". With that sort of power setting, we would get about 10-15 KIAS above blue-line in level flight.

Thanks for bringing that up though...I hadn't mentioned anything about how you're treating your good engine at the time.
 
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But, do you accept a 200 fpm descent at blue-line, or do you go a few knots below in order to hold level?


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As long as the brick is still controlable, I'm doing whatever I can to hold altitude. If that means going a little below blue line, so be it. If I get within 10 knots of Vmc, however, I might reevaluate.

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If you were straight-and-level with some excess airspeed, do you reduce power on the operating engine to maintain blue-line, or do you maintain max power and keep that extra airspeed?

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While having that extra airpseed is a good thing, keep in mind you've already lost one engine. I'm of a mind to power back a little to take care of my one remaining engine.
 
The NTSB investigator will say "Well, he did an off-airport landing and ended up a fatality, but he held blue line +/- 1 knot! Woo!"
 
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Anyhoo, that brings up another topic: If you were straight-and-level with some excess airspeed, do you reduce power on the operating engine to maintain blue-line ...

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ABSOLUTELY not. When you lose an engine in a light twin you lose 50% of your thrust but generally upwards of 80% of your performance. Why on earth would you bleed off speed and give up any ofthat tiny 20% of remaining performance? Speed = options (mainly potential altitude). If you bleed that speed off chances are you're going to have a rough time (i.e. not) getting it back if you need it.

Keep that airspeedas long as possible. When the time comes it'll either bleed off for you or you can exchange it for whatever you need.
 
I think that's a Riddle/PRC phenomenon.

Seminoles and Duchesses (is "Duchessae" the plural?) have such poor high altitude performance that you spend 99% of your time at or near blue line at a slow descent. So basically anyone training up in PRC really hasn't had the option of exceeding the blue line speed until your CFI failed your engine at a high altitude and you're descending within the airport traffic area.

That's just my opinion though!

Procedurally, on the MD-88, if we have a engine failure at V1, we'll leave the aircraft configured at flaps 11 (standard takeoff config), do a 180 knot pattern and return to landing.

If we're going to 'clean up' and divert to our takeoff alternate (if we take off below landing minimums and can't get back in), we'll configure for a clean configuration and fly fast -- but then even an MD-88 near max gross weight on a single engine vastly outperforms a Seminole with a emaciated/starving CFI and a 115 lb student on the Top Ramen diet.
 
Here's my .02 worth.
Perhaps the harping on blue line is for the purpose of evaluating the pilots control of airpspeed. It is an accuarate measurement of performance, can the pilot fly a specified airspeed or is he just haphazardly flying the airplane. I require on a single engine that the pilot flies blue line or the briefed ( per the POH ) Vyse +5 -0 to the circleing altitude or to 500 AGL then accelerate to normal climb speed, if that performance is not available climb at Vyse untill manuevering altitude then take what ever speed you can get untill time to land ... again no slower than Vyse untill short short final.
My caution here would be without manufacturer's data on anything other than blue line ( Vyse ) that is the target airspeed to fly. On most light twins the actuall Vyse for varying weights is a small range. The danger of flying lower and closer to Vmca is that we train to recognize a static Vmc demo NOT a Dynamic Vmc event ... which is what you could encounter here. One could get Vmc as much as 15 kts. higher than the publishd red line if not precisely flying on one engine. Lets be carefull out there.

Jim
 
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Initially when you first loose an engine, it is a good idea to just go for the blue line, get the airplane cleaned up and either trouble shoot or feather the engine. Once that is done, if you really need the performance, it is obviously ok to try to find the airspeed that will give you the best climb rate.

If your instructors would rather fly into terrain than slow down a few knots and clear it on takeoff, that is their business.

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Two issues here
1. With an engine malfunction you don't have time to troubleshoot ( unless you are at cruise ), Do the Procedure at least up to Feathering. You need the Performance NOW not after trouble shooting. You don't need to find the airspeed that will give you the best climb rate ... the manufacturer has already done that ... blue line baby. Now once you move into larger twins there won't be a blue line on the Airspeed inicator, you will define Vyse on your pre flight performance card.
2. A ridiculous statement ... what instructor would rather fly into terrain ...? I say you are more apt to get into trouble NOT flying Vyse, if a few knots work better today then a few more work better tommorrow ... until you roll it in uncontrolled.

Jim
 
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One could get Vmc as much as 15 kts. higher than the publishd red line if not precisely flying on one engine. Lets be carefull out there.

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Jim ... which is why I really wish "redline" wasn't painted on the ASI. Instead of teaching "redline" we should be teaching "loss of directional control awareness." It's all to easy to look at the ASI and say "hey I'm cool, I'm over redline by X kts/mph" when depending on a variety of factors you could be much closer to loss of directional control than yourealize.

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I think that's a Riddle/PRC phenomenon.

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Could very well be. I think, also, its a problem with the way the "system" is set up. Most MEIs have what 50 hours or 100 hours of multi time at best? So you have people who have very little "real world" experience flying multis turning around and teaching low time pilots how to fly 'em. So naturally they stick to "the book" and never quite reach a "correlative" level of understanding in order to teach at that level in the multi. I dunno I could be way off but it's just an opinion. /ubbthreads/images/graemlins/wink.gif
 
I like how the blue line is easy to see on the ASI, in an emergency it's easier to put the white needle on the blue line than it is to focus on finding 'the' airspeed 1.87kts lower than blueline... Especially if you don't KNOW in advance what that speed is
 
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Could very well be. I think, also, its a problem with the way the "system" is set up. Most MEIs have what 50 hours or 100 hours of multi time at best? So you have people who have very little "real world" experience flying multis turning around and teaching low time pilots how to fly 'em. So naturally they stick to "the book" and never quite reach a "correlative" level of understanding in order to teach at that level in the multi. I dunno I could be way off but it's just an opinion. /ubbthreads/images/graemlins/wink.gif

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Tell ya the truth though, when I was working on my Private-multi, I had a Riddle-PRC instructor with 400-500 multi saying that I should reduce power to maintain blue-line at all times. I hope they're still not teaching that. /ubbthreads/images/graemlins/tongue.gif
 
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