Iran Air off runway at Arlanda

[Mike Whiskey Romeo]

Flight global now showing a video of this incident which happened on Saturday.

VIDEO: Iran Air A300 engine spouts flame before Stockholm run-off (http://www.flightglobal.com/articles/2010/01/18/337255/video-iran-air-a300-engine-spouts-flame-before-stockholm-run-off.html)

I'm just wondering is there a "best" speed for an incident like this to happen? i.e the crew will have greater rudder authority at higher speed. So should they therefore have a better chance of keeping the machine on the centerline at say 100kts as opposed to say 40kts?.

[framer]

I'm just wondering is there a "best" speed for an incident like this to happen? i.e the crew will have greater rudder authority at higher speed.
There is a speed at which the rudder authority is great enough to keep the a/c on the centerline in order to continue the take-off. It is called Vmcg. This speed will always be lower than V1 which is the speed at which the first stopping action must have been initiated in a Rejected Take-Off.V1 is often called a decision speed but the reality is the decision must have been made a fraction before V1 if the field is critical.
So here's the theory....if your engine falls off prior to V1, you reject which means you no longer have the assymetric thrust problem , if your engine falls off at or subsequent to V1 you are gauranteed to be above Vmcg and therefore have the rudder authority to continue the take-off.
Sometimes you have to increase your V1 in order for it to be above Vmcg.
Does that help?

[framer]

After posting I've just watched the video. In the simulator engine failures at very low speed like this often end up with the same result you see here. The reason I'm told is because pilots are generally not expecting it then, they are waiting for the problem to occur at high speed and they don't react quickly enough to retard the thrust levers. It is more challenging than most of us would have thought.
That information is second hand as I am not a sim instructor, I was told it by one.

[BOAC]

Reminds me of the delightful lady co who set TOGA from a 70% icing run-up and released one brake only on a 737 because "not sure how much acceleration there would be":eek:. Just avoided inspecting the KEF tundra by a matter of cms, probably because unlike framer's "because pilots are generally not expecting it then" one WAS expecting something with her:).

[hetfield]

@Framer

Fully agree!

And the A300 can be a real beast with these engines.

[canadair]

Framer,
must disagree with you on a point.

"I'm told is because pilots are generally not expecting it then, they are waiting for the problem to occur at high speed and they don't react quickly enough to retard the thrust levers."

I am not aware of anyone who is complacent to an engine failure at low speed.
In my case, in the 747, it is quite critical to lose an outboard at low speed, in particular relative to wind.
At 60-80Kts with a mid to light airplane and max or close thrust, it is very hard to keep on the runway, much harder than at higher speeds, as a result we are highly observant at all points from initial thrust set to V1, and of course no less so above.
But we are certainly extremely aware of the weights, thrust, conditions, wind, and potential for failure.
I think you will find most pilots are exactly the same, primed for failure at any point.

In the case above, they obviously lost thrust, (potentially up to 66%) as its a twin, experienced the resultant yaw, perhaps had a less than optimum runway surface in the equation, and while the NW may have departed the surface, it looks like they did get it back, and well done to them.

[Mike Whiskey Romeo]

Thanks framer,

Your posts cleared it up for me. Your second post answered what I was (trying very poorly) to ask originally.

It is interesting that an engine failure at low speed in the take off roll seems trickier to deal with than one closer to rotation speed.

Regards,

Mike

[Nubboy]

Seems to be a popular theme at the moment. Just had a sim session where the low vis engine failure was at low speed. Very nasty, and probably not very nice in real life. Sim instructor said CAA were keen on it at the moment, as it's not a normally expected. or practiced scenario.

[IcePack]

767 needs lots of asymmetric brake, and some tiller if you get a turbine seize at about 60, odd Kts. (with full power). In non sim environments you would probably vacate the rwy. But I guess the probability of that failure at the critical moment is 10mil to 1 so just on the sim then.

[McDoo]

Ice Pack

10 mil to 1? Blimey I'm off to get a lottery ticket right now!

I had this very thing happen to me at about 80 kias during a full pwr take off in an A320.
You're right though - it did take tiller as well as full rudder and some opposite brake to keep it on the tarmac...:ouch:

[framer]

Canadair,
I think i too might disagree with me on that point ha ha.....I'm not sure though. In real life I know I am very aware of thrust assymetry at low speeds (737) , even just from spool up and TOGA , but I have flown with quite a few guys/gals that seem to not worry about it much and take a fairly cavalier attitude towards setting the thrust even in crosswinds. I know of one 737-800 that departed the runway a year or so ago with no failure whatsoever, they just didn't take care in setting the thrust and hit TOGA while still turning and Bingo....off the strip. Also I probably didn't make it very clear in my post but when I said that the pilots were expecting a problem at a higher speed I was referring to a mind-set for the simulator where most of the failures occur around V1. Therefore they are a bit caught out with the low speed failure.
Mike;
Glad it helped, with topics like these there is always conjecture over the finer points. It's one reason why they are educational to pilots young and old, you get to see different points of view. I'm actually a little surprised that nobody has disagreed with my definitions of the speeds considering I was quite rough and ready in the explanations and wasn't quoting directly from a book. you'd be amazed at how many different points of view there can be on a fairly black and white subject.
Have a good day, Framer

[Max Angle]

I have got a lot of sympathy for that Iran air crew, even on a dry runway you need to close the other engine very, very quickly to contain it, far easier to deal with at high speed. A powerful twin with an engine out at very low speed is a monster.

[Anders Nilsson]

EP-IBB left ESSA 22/1 at 17:00 local time.

Anders

[hollingworthp]

I recall my first low speed engine failure in the sim (a bizjet so tail mounted engines with far less assymetry) and it certainly took me by surpise to have to use assymetric braking in addition to full rudder. A good training exercise.

[FullWings]

I remember doing a sim training module involving an engine failure on a contaminated runway, about 4 secs after pressing TOGA: the power was a goodly part of maximum but we were only doing 30-40Kts. Even though we had briefed and were expecting it, it was a big job to remain on the paved surface.

The critical point seemed to be in retarding the thrust levers as quickly as possible - any delay and you were in the weeds.

[338C]

A number of readers have quite rightly pointed out:
The cavalier attitude exhibited by some when setting thrust:
The need to promptly reduce thrust on the live engine.

This event is not regularly practiced in the simulator however:
It happens more frequently than a real failure at V1;
Is a novel event for many when it does occur;
It has a high "surprise" element when it happens.

Should the simulator training syllabus be amended to include this event?

Should the engines be accelerated to a higher N1 or EPR setting than is currently recommended before the auto throttle system is engaged?

[M609]

Report is out: http://www.havkom.se/virtupload/reports/RL%202012_21.pdf (Swedish only...)

[Fargoo]

http://www.havkom.se/virtupload/reports/RL%202012_21e.pdf

English version

[sleeper]

And the report in english?
sorry, already posted.

[Centaurus]

even on a dry runway you need to close the other engine very, very quickly

One potentially deadly scenario usually giving spectacular results in the 737 simulator is give a fuel governor failure while taxiing. The engine goes to full power while the throttle stays at idle. When it happens the first alert is a rising engine noise on one side for no apparent reason. Things happen so quickly from then on it is best to cut both start levers immediately before control is lost and the aircraft swerves into another aircraft or into an obstruction. There is no time to go through the classic identification sequences and trying to remember whose area of responsibility it is. It's all over Red Rover in 5-10 seconds unless you cut that engine. That is why it is better to cut both engines in case the wrong engine is identified

[hetfield]

The Swedish Havarikommission (SAIB) released their final report (http://www.havkom.se/virtupload/reports/RL%202012_21e.pdf) concluding the probable causes of the incident were:

Operational

- Deficiencies in the certification process for large aircraft with wing-mounted engines with regard to requirements for yaw stability in the event of sudden loss of engine power in the speed range below VMCG.Ooops!

Does that mean, beside these lovely but over 40 years old planes, ALL LARGE AIRCRAFTS WITH WING-MOUNTED engines are affected?

[Capn Bloggs]

There is no time to go through the classic identification sequences and trying to remember whose area of responsibility it is. It's all over Red Rover in 5-10 seconds unless you cut that engine. That is why it is better to cut both engines in case the wrong engine is identified

Tut tut! Must follow the QRH! := :} Commonsense (wash ya mouth out with soap, Bloggs!) is not allowed. :)

[BOAC]

Which is why you close the other throttle PDQ. In any case, Vmcg refers only to rudder control, not to brakes and nosewheel steering

EDITED for dysleckseer

[proxus]

I'm slightly surprised nobody has mentioned the term Vmcg. Directional control is not possible below 114kts on the A300 after loss of one engine during take off roll.

It was mentioned in post #2 :D