Never Turn into The Dead Engine?

[letMfly]

After a recent ATCO's radar validation board, I was horrified to learn that the candidate had never heard of turning into dead engines and was never taught the "correct" handling technique at his college. The phraseology for EFATO used to be " turn left or right heading (reciprocal), advise direction of turn". This obviously gives the pilot the option of which way to manouvre and gets the aircraft positioned downwind for a tight circuit if required. I appreciate that high performance or three/four engined aircraft may not need to return quickly, but standard handling of such incidents caters for the worst case scenarios. ie underpowered pistons or engine fires.
On checking with several colleagues, it appears that a fair proportion have never been taught this technique and would base the direction of turn on factors such as avoiding built up areas etc.
Any comments from pilots or ATCOs would be welcome.

[skeptic]

I'm with letMfly on this one. Everyone knew from an early age that this was a dangerous practice because Biggles said so, and he should know. Imagine my surprise on starting a twin rating course to find the chief instructor at London Flight Centre (Lydd) had never even heard of this advice!. Mind you, he was a gash hand anyway.

Evidently years ago there was likely not to be enough rudder authority to overcome the asymmetric torque and the thrust of the good engine on the outside of a turn could roll you over. I bet Wellingtons and Beauforts and suchlike did this.

A go around in a Seneca can require some wing down to assist the rudder if I remember right, so clearly there is aturning moment at high poweer that the rudder alone cannot cope with. Imagine the result if you needed sustained go around power in a turn (perhaps to avoid terrain) and you were already turning the "wrong" way. Perhaps it is good advice after all. Certainly sounds like good airmanship to consider it?

[TeaCup]

RTO, I presume in your training you are not at gross in old light twins, if you had it at gross with a aft COG and get to much Angle of Bank into the dead engine you may have "fun" getting it out. Not to pretty if kind of close enough to the ground as not being able to close both thotalls to get out of it. There will be some negitive engery turning into the live donk, but at least you will be incontrol and wont end up on your back or pulling power to get the wings level. I too didn't think much of it either, untill you have a go at that. cheers.;)

[Crossunder]

Old wive's tales if you ask me!
If you make a turn, you'll have to bank both ways every time. Doesn't matter much whether you bank into dead engine on your way into or out from a turn? Never had any trouble turning into dead engine...

[Captain Stable]

I wouldn't say never turn towards the dead engine - but you certainly should be aware of the dangers and exercise caution - otherwise it may be a turn you never get out of.

I wouldn't agree either with Crossunder - it most certainly is not a case of old wives' tales.

[john_tullamarine]

Another consideration is the effect of bank on Vmca which is quite significant.

If the aircraft is at low speed, as it probably would be, then bank into the dead engine will result in an increase in realworld Vmca ... bank too far ..... Vmca increases substantially ...... if the increase is to a speed in excess of where you are at the moment .... then you might very well be surprised to find that the situation takes a turn for the worst .... so to speak ....

[witchdoctor]

Only advice I ever got was don't walk into a LIVE one!

[PaperTiger]

it most certainly is not a case of old wives' talesIf discussing the Beech 18 it's more likely an old widow's tale :uhoh:. Applies to a lot of older twins, the modern ones are thankfully more benign.

[411A]

...with limited rudder authority. CV240 comes to mind. Some of these old birds would not climb with BOTH engines at METO power, especially if operators (many) overloaded same and used dry takeoff power...generally BAD results.

[5milesbaby]

Every year us ATCO's in the UK have to go through a simulated day of emergency training, and every year there are new 'best' practices quite often contradicting one another.

I wouldn't be too suprised that your friend didn't know what you said. We cannot be taught specific emergencies, as each are always different from the next. In this example, is the dead engine out or on fire? I know an FO friend who told me never turn into a dead engine UNLESS its flaming, then ALWAYS turn into it or risk burning the tail. I know another who disagrees.

An ATCO's job is to aid you fully to safety, however not being pilots (well most of us), we will ask very early on if there are any special handling requirements we need to know. Alternatively, we are also prepared for the occasional 'sorry cannot do that', and so immediately have to alter plans, but thats what we are trained for, expect the unexpected...... :ouch:

[bookworm]

Another consideration is the effect of bank on Vmca which is quite significant.

If the aircraft is at low speed, as it probably would be, then bank into the dead engine will result in an increase in realworld Vmca ... bank too far ..... Vmca increases substantially

Slightly confused by this, John.

From a regulatory point of view, Vmca is defined with a bank limit and presumably the assumption is non-turning flight, so it doesn't make sense to talk about it as a function of bank in a turn. But assuming we forget the bank limit and consider Vmca as simply the lowest speed at which we can retain control...

What's the limiting factor? Do we run out of aileron authority earlier if we turn into the dead engine? Presumably it's not rudder authority. How does bank angle affect it?

[Onan the Clumsy]

I made the mistake of mentioning this on my MEI checkride and the examiner - a legend of sorts in the area and a career that dated back to WWII said "What nonsense. Watch me."

Then we did a series of steep turns, in both directions at pattern altitude with him pointing at the ASI saying "So long as you keep your speed up, it doesn't mattter which way you turn. It's all about speed."

Quite an informative lesson really.

On another note, with an EFATO, other considerations come into play, such as the already mentioned avoiding built up areas. Others might include turning INTO the stiff crosswind to reduce the amount of turn needed, heading for a parllel runway, heading for an alternate runway, heading for an alternate airport or lake or parking lot, etc etc etc. For instance, if you leave Love Field on 18, you've got 17 at Redbird directly ahead of you. No turns necessary.

[You Aint Seen Me. Roit!]

I'm with Onan on this one.

In the case of an EFATO, my SOP is to climb straight ahead to 500' AGL and increase speed to 90kts and only then begin the turn and then not greater than Rate 1. The speed helps to reduce the effect of asymmetric thrust and not exceeding Rate 1 means I maintain as much (vertical) lift as possible.

If you can't climb on 1 engine whilst flying in a straight line you have to ask yourself whether you should be there in the first place irrespective of whether you are at MAUM or not.

I think I'm right in saying that VMCa calculations allow for 5 degrees of bank toward the live engine in order to maintain controlled flight in a straight line. If we're talking about a minimum speed where controlled flight can be maintained in the turn it would be a figure greater than VMCa - I think:confused:

Where's Alex Wittingham when you need him!:D

[englishal]

Vmc is calculated using a 5° bank into the dead engine, thus reducing rudder required. If you now fly straight and level, you'll need more rudder and will be slipping through the air reducing performance on what could already be a dangerously under-performing aircraft. If you're at Vmc with a 5° bank and you now level the wings, you'll be below Vmc [or Vmc raises] and loose control, or at least you won't have enough rudder authority to remain in control with full power on the good engine.

For a fairly simplistic view....

Bank into the dead engine and you increase your chances of not coming out alive. Vmc will be higher as you have more forces to overcome with the rudder [weight of the dead engine for starters].

Bank into the live engine and you're chances are better, before the aircraft can loose control it has to overcome the forces keeping the live engine down for example.

I for one would not bank into the dead engine especially at low airspeed and trying to maintain altitude or climb unless there was no other option. You can be pretty sure that most ME fatalities during an EFATO are the result of the aircraft speed dropping below Vmc and the aircraft loosing control, so no point in exacerbating your problems by turning the wrong way.

I would be very dubious about attempting a go-around in a Seneca [any of them] on a single engine. The POH states that this is "Not recommended" anyway.

Rgds
EA:D

[john_tullamarine]

The certification Vmca figure is required and determined to give the pilot a fighting chance of maintaining control in the initial management of a critical engine failure - typically during the initial takeoff phase of flight. As we all know - hopefully (?) - it has nothing to do with whether the aircraft can climb or not. If the V2/Vtoss were to be unduly compromised by Vmca considerations, then the probability of a safe outcome is minimal or zero.

Certification Vmca has no direct relevance to continued OEI flight at altitude.

Now, putting the certification Vmca (i.e. the number quoted in the flight manual) to one side .... if one were to do the Vmca testing with a variety of bank angles (while maintaining a straight flight path), then the observation would be that the Vmca dataset so determined (what I refer to as "realworld" Vmca .. as opposed to the very specific certification value) was strongly dependent on (i.e. varies significantly with variations in) bank angle. As bank is increased into the operating engine, Vmca decreases ... and as bank is increased away from the operating engine, Vmca increases. This is to do with the effects of sideslip and directional stability on yawing moments and, consequentially, the rudder deflection required to make up the difference if one is to achieve a straight flight path.

There is also the high hazard consideration of what might happen to control with high sideslip angles ..... this is a related but separate issue and dictates that, at lower speeds, one doesn't want big bank angles ... regardless of the direction of bank.

If the pilot intends to manoeuvre at lowish speeds, then the effect of bank on the realworld Vmca becomes extremely pertinent to the discussion if the aircraft is permitted to operate in a manner where there is any significant sideslip .... Vmca departure, especially in dynamic circumstances, can be a real "gotcha".

If the pilot is manoeuvring at speeds sufficiently high to remain well above the region where Vmca variation is going to affect the operation, and the bank angles flown (considering airspeed) are sufficiently modest to keep the sideslip reasonably controlled - (i.e. something not too far removed from co-ordinated flight), then I don't see that it really matters which way we choose to bank (turn).

As in most things to do with flying, there are a lot of factors at play and most times explanations of why this or that happens or this or that technique is the better .... necessarily presume simplifying assumptions which are not disclosed. This consideration, I suggest, is the genesis of many of the "old wives' tales" represented as rock solid truths in circumstances sufficiently removed from the conditions of the original tale such that the underlying assumptions inherent in the original may no longer be relevant or applicable ........

Rant over ..... have a nice day ..... :ok:

[fireflybob]

A very interesting thread which reminds me of the Airtours (that's British Airtours, by the way, NOT what is now MyTravel!) B707-436 which crashed during training at Prestwick many years ago. All the crew escaped but the aircraft was destroyed.

One of the interesting things in the accident report was that VMCA wings level was 40 kt (yes that's FORTY knots) higher than with 5 degrees of bank towards the live engine. Not that the crew were likely to know this since, at that time, there was nothing in the Flight Manual to tell them.

The accident report made very interesting reading (especially for training/instructor pilots). If they had applied a little bit of bnk towards the live engine they might have got away with it!

[StrateandLevel]

VMCa for a light twin is a certification speed measured under specified conditions. It does not vary with anything. If the conditions vary then the speed you are measuring is no lionger VMCa as defined!

If a pilot wishes to turn towards the live engine because he is struggling to control the aircraft at minimal speed he should request the circuit direction he requires. It is an emergency and it is the ATCOs job to give him what he asks for, questions can be asked later.

[DFC]

Here's my 2 cent worth;

As was stated above, if one can bank the aircraft towards the live engine safely then by default, having banked towards the failed engine, that bank can be reduced back to zero.

While VMCA defines the lowest speed where a test pilot has demonstrated an ability to control a brand new aircraft with the most critical engine failed and the other at maximum power, I as a pilot while being aware of that speed am much more interested in the best rate of climb speed called "blue line speed". It is only at that speed that I can put maximum vertical distance between my aircraft and any obstacles.

However, enough about light twins.

SIDs make no allowance for obstacle clearance. Obstacle clearance is the responsibility of the operator. Thus when departing airports with obstacles, while following the SID on two engines, a B737 will be well capable of clearing all the obstacles. However, if the aircraft suffers an engine failure, the rate of climb will be drastically reduced. If the aircraft is no longer able to clear the obstacles on one engine, the operator will have calculated what is called an "emergency turn".

Example, departing an airport with mountains straight ahead and to the left of the departure track. On two engines, the aircraft can safely climb over the mountains and follow a SID that takes it in that direction (left). However, to allow for the reduced rate of climb, an emergency turn may be specified which will require the aircraft to turn right in the event of an engine failure in order to maintain obstacle clearance at the reduced rate of climb.

Now...if turning into the dead engine can be a problem, how does the CAA allow operators to fly from such airports where regardless of which engine fails, the aircraft will have to turn right?

Regards,

DFC

[bookworm]

As bank is increased into the operating engine, Vmca decreases ... and as bank is increased away from the operating engine, Vmca increases. This is to do with the effects of sideslip and directional stability on yawing moments and, consequentially, the rudder deflection required to make up the difference if one is to achieve a straight flight path.

Any chance of a little more detail here?

I can see that the optimum (zero-slip) straight-and level situation is (say) 5 degrees into the operating engine with corresponding rudder input. If I bank 15 degrees (to 10 degrees into dead engine, or 20 degrees into operating engine) without changing the rudder input, don't I turn just as if I were in a 15 degree bank?

For the same rate of turn, why should I run out of control authority (is it rudder or aileron?) in one direction before the other?

[JW411]

I think what you are all missing is that the aircraft that gave rise to this advice are pretty well extinct.

For example, I am given to believe that the difference betwen VR and V2 on the Mosquito was around 70 knots.

Just imagine that! That is a very long way with a very small rudder!

[englishal]

I think the best advice in a light twin, is not to turn into a dead engine if at all possible, this is what I was taught for my ME rating. Of course if you're on an object clearance departure and you have no choice, then of course you must turn into a dead engine. It is possible, but you just have to be very aware of your airspeed, and how Vmc changes with various flight attitudes and I imagine that in an already underperforming twin, the tendancy to let speed decay trying to maintain altitude will be rather high.

The effects of speed dropping below Vmc are quite dramatic. For the FAA ME rating you have to give a Vmc demo to the examiner, which consists of flying straight and level on one engine [ie. 5° bank], then pulling the nose up and letting the airspeed decay, maintaining full power on the critical engine [if applicable]. In the region of Vmc at ["Actual" Vmc], you basically loose control, the nose suddenly yaws away from the good engine fairly quickly even with full oposite rudder input. The only way recover is to increase airspeed, & / or reduce power on the good engine...no other options.... Not good if you're close to the ground.

Vmc is a complicated subject, I remember being grilled on it by the examiner for the oral exam, though I must admit I probably couldn't recite all the forces involved now. It varies with angle of bank, whether your gear is down or not, whether the flaps are down or not, altitude, etc etc. The best thing is to keep well above it, especially close to the ground or in the region known as 'Coffin Corner' where stall speed and Vmc co-incide.

I would still be unwilling to turn into a dead engine unless I had to !

Cheers
EA:D

[what cessna?]

The emergency training we got on our radar course simulated an aircraft ewith engine failure.

We were taught to expect a reduced rate of turn, expect the crew to turn into the dead engine and aviod vectoring over built up areas if you're trying to get back to the runway.

But the list is not exhaustable and situations vary.

At the end of the day if the crew have experienced a problem an the controller passes instructions and information appropriately to the condition, it is still the commanders choice to take the advice.

I'm assuming that most of you out there would state quickly to the controllers if you wanted to turn the other way.

[Tinstaafl]

As long as I'm above Vmc I have no problems turning towards or away from the dead engine. Since Vyse or Vxse usually are the lowest speeds seen then control difficulties aren't really a problem.