Engine failure on Trijet...

[swashplate]

Me again, chaps! :)

Always wondered what happens when the centre engine fails on a Trijet. (eg Trident, L1011 etc)

If one of the wing or side mounted engines quits, then obviousley you will have a yaw in the direction of the engine that is still turning. Left fails, Yaw to right. http://www.pprune.org/ubb/NonCGI/eek.gif

But what happens if the CENTRE engine quits?? http://www.pprune.org/ubb/NonCGI/confused.gif

Does the aircraft pitch up, or is there just a reduction of acceleration...??

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Live long and Prosper.....

[747FOCAL]

You go find someplace to land. Northwest had a DC-10 lose the cernter engine out of Seattle a bit back. They were on their way to Amsterdam. Just came back and landed.

[Bellerophon]

swashplate

<font face="Verdana, Arial, Helvetica" size="2">If one of the wing or side mounted engines quits, then obviousley you will have a yaw in the direction of the engine that is still turning. Left fails, Yaw to right.</font>

Er...No, actually...but I'm sure that was just a typo! :)

If the left engine fails, and you do nothing, the aircraft will yaw left, and, in most cases, also start to roll left, due to the secondary effect of the yaw.

In answer to your question, failure of the centre engine, or the boost engine, in a Trident 3 was a non event in terms of pitch change. The effect on the overall performance of the aircraft was however very noticeable with a marked reduction in rate of climb. I'm told the same is true of the L1011 Tristar.

Appearances can be deceptive, remember that the centre engine air intake was mounted much higher, on both the Trident and the L1011, than the engine itself, which was installed much lower down, closer to the centreline of the aircraft, thus reducing the pitch couple effect.

The DC10 was a different story, with the centre engine mounted high up in the tail and capable of exerting a noticeable pitch couple effect.

Even so, whilst a failure of that engine, say during a full power take off, did produce a noticeable nose up pitch change, it was very easily controlled, and not a problem at all.

This pitch couple effect would have proved very useful in the DC10 incident at Sioux City, but unfortunately it was the centre engine that had failed, taking out all three hydraulic systems, thus leaving the crew to manoeuvre the aircraft just using differential thrust from the two wing mounted engines.

On my DC10 conversion course, in the Simulator, the first time I tried that manoeuvre, I didn't even manage to arrive inside the airport perimiter fence!

In my view, those guys did a terrific job on the day!

Edited to correct a mistake, kindly pointed out by the Double Eights

[This message has been edited by Bellerophon (edited 17 May 2001).]

[Cornish Jack]

On the Tristar, the lack of yaw cues for the #2 engine failure was catered for by a #2 engine failure light on the CAWP.

[swashplate]

Belleophon:

ahh...yeesss....thinking about it, that would happen. Me's just a bit confused!

[nilnotedtks]

...same ' engine fail ' lite on the forward glareshield on the DC10 / MD 11. Relied on engine 2 N1 spooling below a set value ( cannot remember but 85% N1 sounds right ) compared to the # 1 and # 3.

[Diesel8]

Bellerophon,

I may have misunderstood you, but I believe the center engine is what failed on the UAL DC-10 that "landed" in Sioux City.

[Cuban_8]

D8,

I too was under the impression that the UAL event concerned the centre engine suffering an uncontained fan disc failure. The a/c was then turned and pitched using the wing mounted engines.

May be wrong though!

Regards,

Cuban_8

[Bellerophon]

Diesel8 & Cuban_8

You’re both right, I’m wrong, I relied on my memory instead of checking. Apologies for the mistake!

It was indeed the centre engine that suffered a catastrophic failure, in the cruise at FL370, leading to the losss of all 3 hydraulic systems, and the crew only able to manoeuvre the aircraft using differential thrust on the two wing engines.

It was a UA DC10, aircraft N1819U, on 19 July 89, at Sioux City, Iowa. More information is available at: http://nasdac.faa/gov/asp/fw_ntsb.asp

I stand by my last two paragraphs however!

I didn’t make it, first time, in the sim. http://www.pprune.org/ubb/NonCGI/frown.gif

They did a terrific job, for real, on the day. :)

[GotTheTshirt]

The Cessna 337 ( two engines push- pull) was sold as the "ultimate twin" because no yaw with engine failure.

It was very quickly discovered that not only did you get no yaw but you got no indication of a engine failure on take-off !!!

At least you go through the fence straight an level !!

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When I die, I want to go like my grandfather did, gently while sleeping, and not like his passengers, screaming in terror, looking for the nearest parachute.

[Jim lovell]

Anyone remember that Eastern L1011 that lost all power going out from Barbados?? On climbout it lost 1 engine then as it turned around to return the other 2 progressively quit until the a/c was completely powerless. The crew managed to restart an engine(think it was the center one)at about 9,000ft and land.

On a tri-jet like a 727/L1011/DC-10 does the center engine provide as much thrust as the other 2? Read somewhere that in the 727 and L1011 the center engine provides only 85-90% as much thrust as the other 2 because of the S-Duct arrangement and the loss of airflow involved. If this is the case then wouldn't it be preferable if you had to lose an engine to lose the number 2??

[FE Hoppy]

Eastern was "o" rings in the oil systems. All were modded after that engineering coup.

center engine on the l1011 gives the same thust as 1 and 3.

You lose less other systems if you lose a wing engine but that is balanced by the assyimitry to worry about.