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Sioux DC10 Crash Not Due To Hydraulic Failure?  
User currently offlineCedarjet From United Kingdom, joined May 1999, 8124 posts, RR: 54
Posted (8 years 8 months 3 weeks 5 days 22 hours ago) and read 11709 times:

Just saw an excellent documentary about the crash of the United Airlines DC10 in Sioux City called Seconds From Disaster. This is one of the most famous airline disasters ever, not least of all due to the airmanship of Al Haynes, Danny (Denny?) Fitch & co.

The accident happened when the no 2 engine blew up and the fragments destroyed all three hydraulic systems, and the pilots were left with engines 1 and 3 and nothing else to fly the plane, which was also structurally damaged enough that it kept trying to dive to the right. Amazingly, the pilots managed to steer - using assyemtrical thrust - the jet to a runway at Sioux City Iowa. Sadly, the plane rolled over on landing and basically cartwheeled down the runway, killing approx 100 pax (with nearly 200 miraculously surviving).

What was interesting about the Seconds From Disaster documentary is the way they reconstructed the DC10's trajectory after it touched down. They came down very heavily on the right-hand main gear, and the right wing came off and the plane rolled upside down. Although no mention was made of this in the documentary, it occured to me that the reconstruction, stripped of context and the United livery, would have worked equally well for the FedEx and Mandarin MD11 crashes (at Newark and HK respectively) and the Martinair DC10 crash at Faro. It seems that if you land a DC10 or MD11 (known not for nothing as the "Scud" ie you don't know where it's going to come down) heavily on one main gear, the wing comes off and over you go.

So while the UA DC10 was lucky to make it to any kind of runway under control, it seems to me that what did them in was the DC10 / MD11's landing characteristics - and if the same touchdown occured on a Tristar, the wing wouldn't have come off and they would have rolled down the runway on the gear, probably off the end, come to a halt in a cornfield, slides pop out and everyone walks away. Of course there's no way of knowing, and the DC10 is what it is, but I was surprised at the resemblance to other DC10 / MD11 crashes and that no-one has ever remarked on this before.

Any thoughts?


fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz
26 replies: All unread, showing first 25:
 
User currently offlineMidnightMike From United States of America, joined Mar 2003, 2892 posts, RR: 14
Reply 1, posted (8 years 8 months 3 weeks 5 days 22 hours ago) and read 11677 times:

Well, the aircraft lost Hydraulics no problem there, as to the exact reason why they crashed has to with the fact that they were using the engines to control their tracjectory as well as thrust.

By doing this, the aircraft was hovering up & down, by at least 200 feet, when they came down for a landing, they were on the down cycle, and came down on an angle. So not only was it a hard landing, but they also hit the wing.

Of course, the reason for all of this, is that they lost Hydraulics.

If you have never heard Captain Al Haynes speak in person, you are missing out, he is a very humble person and explained the crash in language that everybody can understand.

http://www.aviationexplorer.com/dc10_sioux_city.htm

[Edited 2006-01-09 14:58:58]


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User currently offlineNW727251ADV From , joined Dec 1969, posts, RR:
Reply 2, posted (8 years 8 months 3 weeks 5 days 21 hours ago) and read 11541 times:

The premise of those accounts on the documentary you were watching is sort of wrong. There has always been TWO scenarios for what exactly happened after the DC-10 made contact with the runway. The first appears to be inaccurate and basically plays out the crash the way your described it.

But after looking at very good video of the DC-10 crash you can clearly see that the DC-10 didn't "roll" immediately. In fact I don't understand why anyone says the plane "rolled" because it clearly cartwheeled.

And the reason why the starboard wing broke off has nothing to do with an inherent design fault of the Douglas aircraft. When UA232 lost its hydraulics the only way the plane could then maintain a measurable amount of control was through using varying engine thrust. At the time the #2 engine exploded the DC-10 was making a wide right turn. After the explosion and subsequent loss of all hydraulics that plane was effectively "locked/frozen" in whatever position it was in at the time. The DC-10 continued to make a right hand turn and then entered a strange pattern of phugoidal oscillations going up and down, up and down and the plane wanted to continue to make a right turn. The pilots had to use engine thrust (more on the starboard wing to counter the uncommanded right turn) as a means to control the aircraft. As the DC-10 was coming in for final approach at Sioux Gateway Airport the pilots noticed that the plane was traveling in excess of well over 250 mph. As the plane neared the runway the pilots pulled back on the throttles to slow the aircraft. The "Whoop Whoop" altitude alert sound began to emit and continued to do so until impact. As a result of the pilots cutting power to the engines (which was how they were able to keep relative control of the aircraft and guide it the runway) the DC-10 immediately began to start its uncommanded right-turn tendency as the aircraft entered the runway. This uncontrolled right turn is what in fact caused the starboard wing to impact the runway, followed by the starboard main landing gear. The plane skidded down the runway at 250 mphs and a flash fire broke out. Halfway down the runway the plane finally exploded, broke into four large pieces, the midship section of the DC-10 (the largest of the four pieces) cartwheeled, did a 360 degree turn while in the air, and impacted the ground inverted (backwards) and upside-down in a cornfield. The first class section was destroyed and the economy class section immediately behind the trailing-edge of the wings to the last door on the aft-section of the plane was also destroyed.

So I know I wrote a lot (LOL) but the gist is the reason for the right wing breaking off is because of the non-correctable tendency for the DC-10 to want to make a right turn because the plane had "locked" itself in a right turn formation when the #2 engine exploded. Once power was cut to the engines (which allowed the pilots to somewhat straighten out the aircraft) the DC-10 immediately went into a right turn just before touching down. I don't think the design of the DC-10 had anything to do with it. If I recall correctly, the crash of Eastern Air Lines Flight 401 which was an L-1011 TriStar was almost identical to United 232. The starboard wing impacted the Everglades followed by the right main gear. About 60% of the starboard wing broke off including the landing gear. The L-1011 slewed 180 degrees and eventually came to rest inverted and basically completely destroyed.


User currently offlineCasInterest From United States of America, joined Feb 2005, 4636 posts, RR: 2
Reply 3, posted (8 years 8 months 3 weeks 5 days 20 hours ago) and read 11419 times:

When you read the articles on the crash, keep in mind the following.
1. The plane was still trimmed for 400+ mile per hour flight.
2. The plane was in right turn.
3. When it slammed into the runway it was going 250 mph + with a decent of over 1000 feet per minute. It was going way faster and harder than most planes could land.
4. When they put other crews into simulators with the same circumstance. Nearly all of them crashed it.

There was no design flaw. It was a defect in the fan blade of the #2 engine that caused the disaster.



Older than I just was ,and younger than I will soo be.
User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 4, posted (8 years 8 months 3 weeks 5 days 20 hours ago) and read 11366 times:

Quoting CasInterest (Reply 3):
4. When they put other crews into simulators with the same circumstance. Nearly all of them crashed it.

Not nearly.... ALL of them crashed and no one ever got close to the airport.



"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 5, posted (8 years 8 months 3 weeks 5 days 20 hours ago) and read 11313 times:

Quoting NW727251ADV (Reply 2):
At the time the #2 engine exploded the DC-10 was making a wide right turn. After the explosion and subsequent loss of all hydraulics that plane was effectively "locked/frozen" in whatever position it was in at the time.

With no hydraulic power the primary flight control surfaces should have faired. Hydraulic power is used to move and hold them in position. There could have been damage caused by the engine disk that froze the rudder and elevators but loss of hydraulic power did not lock them.


User currently offlineConcordeBoy From , joined Dec 1969, posts, RR:
Reply 6, posted (8 years 8 months 3 weeks 5 days 19 hours ago) and read 11150 times:

Quoting Cedarjet (Thread starter):
Just saw an excellent documentary about the crash of the United Airlines DC10 in Sioux City called Seconds From Disaster.

There was also a feature film called "A Thousand Heros" made of the incident.


User currently offlineCruzinAltitude From United States of America, joined May 2004, 415 posts, RR: 1
Reply 7, posted (8 years 8 months 3 weeks 5 days 17 hours ago) and read 10950 times:

Has anyone here seen A Thousand Heroes? If so, how was it. Now that I know a movie has been made about it I'll have to check it out.

I have always thought the events of that flight would make the best aviation movie ever. There is no need to over dramatize it, it is chock full of Drama. Id love to see a quality script and director pull it off. With today's special effects it would be one of the most intense movies of all time.


User currently offlinePositiverate From United States of America, joined May 2005, 1590 posts, RR: 8
Reply 8, posted (8 years 8 months 3 weeks 5 days 16 hours ago) and read 10847 times:

Quoting NW727251ADV (Reply 2):
So I know I wrote a lot (LOL)

That was a great explanation of what happened. Well written.


User currently offlineYYZYYT From Canada, joined Apr 2005, 955 posts, RR: 0
Reply 9, posted (8 years 8 months 3 weeks 5 days 16 hours ago) and read 10776 times:

Quoting CruzinAltitude (Reply 7):
Has anyone here seen A Thousand Heroes? If so, how was it. Now that I know a movie has been made about it I'll have to check it out.

Is that the one which was all about the emergency response on the ground? I saw that many years ago. It wasn't bad at all (for a made-for-t.v.-movie, that is) but it was somewhat light on the goings-on in the air...


User currently offline777236ER From , joined Dec 1969, posts, RR:
Reply 10, posted (8 years 8 months 3 weeks 5 days 16 hours ago) and read 10744 times:

Quoting CasInterest (Reply 3):
There was no design flaw. It was a defect in the fan blade of the #2 engine that caused the disaster.

Sorry, but siting three hydraulic lines next to one another in a turbine-burst-critical area with no fuses is a design flaw in itself. Bear in mind a L-1011 had a tyre burst at FL290, which damaged all four (the DC-10 only had three) systems. Thanks to a fuse in hydraulic system D, there was enough fluid, and consequently enough pressure, for the F/O to land the aircraft.

Combine this with a dodgy cargo door, and a serious lack of foresight with the slat mechanics, and you see just how McDD cut corners on the DC-10.


User currently offlineLitz From United States of America, joined Dec 2003, 1765 posts, RR: 0
Reply 11, posted (8 years 8 months 3 weeks 5 days 13 hours ago) and read 10540 times:
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Quoting CasInterest (Reply 3):
3. When it slammed into the runway it was going 250 mph + with a decent of over 1000 feet per minute. It was going way faster and harder than most planes could land.

Consider this .. the fastest landing aircraft is most likely the space shuttle ...

It lands at 213-226 mph ... with an initial sink rate of 10,000 feet per minute, reduced to around 1000fpm at final approach (well, the only approach; there ain't no go around), then further reduced to 9fpm @ the final flare and touchdown ...

(ie: the performance is roughly equivalent to what you'd expect from a brick with wings)

UAL232 was way outside even THOSE boundaries. It's an absolute miracle they got it on the ground in one piece and on a runway, to boot.

It's completely unsurprising that it broke apart after hitting the ground, however. The speed and sink rate were far outside of the operating envelope that Douglas had ever even visioned for the worst emergency.

Consider this : when investing the wreckage, they initially coudln't find the Right MLG ... they eventually DID find it -- it was still in the hole it had punched THROUGH the runway; it had broken off @ that point, which helped cause the right wing to dip, catch, and the eventual cartwheel.

- litz


User currently offlineNW727251ADV From , joined Dec 1969, posts, RR:
Reply 12, posted (8 years 8 months 3 weeks 5 days 12 hours ago) and read 10501 times:

Quoting Positiverate (Reply 8):
That was a great explanation of what happened. Well written.

Thank you. I appreciate that  Smile


User currently offlineCosmicCruiser From United States of America, joined Feb 2005, 2255 posts, RR: 15
Reply 13, posted (8 years 8 months 3 weeks 5 days 12 hours ago) and read 10431 times:

Quoting Cedarjet (Thread starter):
It seems that if you land a DC10 or MD11 (known not for nothing as the "Scud" ie you don't know where it's going to come down) heavily on one main gear, the wing comes off and over you go.

Actually any airplane will lose it's gear when you hit well over the design limits. It wasn't designed to land on a carrier and as I posted once before the MD-10 (DC-10) that had the right main fail at MEM hit not only in a crab but 37% over design limits! I won't comment on EWR for other reasons.
"Scud"? whoa, I'm gonna start getting scared to go to work...I need combat pay.


User currently offlineLevg79 From United States of America, joined Sep 2003, 994 posts, RR: 0
Reply 14, posted (8 years 8 months 3 weeks 5 days 12 hours ago) and read 10395 times:

Quoting Cedarjet (Thread starter):
killing approx 100 pax (with nearly 200 miraculously surviving).

Killing 112 with 184 surviving to be exact

Quoting CasInterest (Reply 3):
When they put other crews into simulators with the same circumstance. Nearly all of them crashed it.

As stated above, all of the DC-10 pilots crashed in the simulator. The closes that anyone was able to get to the airport was about 10 miles.

Quoting CruzinAltitude (Reply 7):
Has anyone here seen A Thousand Heroes? If so, how was it. Now that I know a movie has been made about it I'll have to check it out.

I have always thought the events of that flight would make the best aviation movie ever. There is no need to over dramatize it, it is chock full of Drama. Id love to see a quality script and director pull it off. With today's special effects it would be one of the most intense movies of all time.

I own a copy of that movie after ConcordeBoy suggested it to me a while ago. It doesn't use special effects, rather it shows the actual crash of actual UA 232 that was shot by the amateur cameraman on that fateful day. It shows everything, the initiation of the disaster prevention program in Sioux City, beginning of flight 232, the crash and the immediate aftermath. A decent movie for somebody familiar with the crash.

I wish I had a chance to hear Al Haynes speak. Does anyone know if it's still possible, and where?

Leo.



A mile of runway takes you to the world. A mile of highway takes you a mile.
User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 15, posted (8 years 8 months 3 weeks 5 days 9 hours ago) and read 10226 times:

Quoting 777236ER (Reply 10):
Bear in mind a L-1011 had a tyre burst at FL290, which damaged all four (the DC-10 only had three) systems.

Do you have any details on this L-1011 incident. The only tire incident at altitude I know about is the 1983 Saudia incident where two children were killed when the wheel failed (not a tire) and ruptured the pressure deck.


User currently offlineDc10rules From United States of America, joined Jun 2005, 99 posts, RR: 0
Reply 16, posted (8 years 8 months 3 weeks 5 days 6 hours ago) and read 9723 times:

What channel was this on? Id love to catch it on a replay sometime.

Thanks


User currently offlineMrMcCoy From United States of America, joined Sep 2005, 377 posts, RR: 2
Reply 17, posted (8 years 8 months 3 weeks 5 days 5 hours ago) and read 9695 times:

Uhh, that plane tapped into the ground at near full speed (and increasing due to a last ditch effort to turn the aircraft to the left) and at over -3000!! I'd say the circumstances were pretty remarkable considering what happened.

I'm a tristar fan, but I really think thats an unfair claim to make against the DC-10. There was more factors involved that just a "hard contact" on the gear.



It only takes five years to go from rumor to standard operating procedure.
User currently offlineKITH From United States of America, joined Mar 2004, 378 posts, RR: 1
Reply 18, posted (8 years 8 months 3 weeks 5 days 5 hours ago) and read 9439 times:

As far as movies go, the most gut wrenching scene about UA 232 though it never specifically mentions it is FEARLESS with Jeff Bridges. -Matt in KITH

User currently offlineLTU932 From Germany, joined Jan 2006, 13864 posts, RR: 50
Reply 19, posted (8 years 8 months 3 weeks 5 days 4 hours ago) and read 9210 times:

Quoting 777236ER (Reply 10):
Combine this with a dodgy cargo door, and a serious lack of foresight with the slat mechanics, and you see just how McDD cut corners on the DC-10.

Well, isn't there a chance that it also could be MX or maybe even GE be at fault if the aircraft had been delivered to UA with the in reply 3 mentioned defect of the Number 2 engine fan blade?

Quoting CasInterest (Reply 3):
There was no design flaw. It was a defect in the fan blade of the #2 engine that caused the disaster.



Quoting NW727251ADV (Reply 2):
So I know I wrote a lot

Nonetheless very informative. Thanks for sharing.  Smile


User currently offline777236ER From , joined Dec 1969, posts, RR:
Reply 20, posted (8 years 8 months 3 weeks 4 days 18 hours ago) and read 7463 times:

Quoting 474218 (Reply 15):
Do you have any details on this L-1011 incident. The only tire incident at altitude I know about is the 1983 Saudia incident where two children were killed when the wheel failed (not a tire) and ruptured the pressure deck.

http://aviation-safety.net/database/record.php?id=19801222-2

Quoting LTU932 (Reply 19):
Well, isn't there a chance that it also could be MX or maybe even GE be at fault if the aircraft had been delivered to UA with the in reply 3 mentioned defect of the Number 2 engine fan blade?

GE were at fault, but were the same engine fitted to an L-1011, 112 people would be alive.


User currently offlineAeroWeanie From United States of America, joined Dec 2004, 1609 posts, RR: 52
Reply 21, posted (8 years 8 months 3 weeks 4 days 14 hours ago) and read 7325 times:
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A couple of points that no one has mentioned so far:

1) The rudder went hard over when the hydraulics failed. Asymmetric thrust was used by the crew to counter the yaw.

2) While the crew did a great job handling the airplane, they failed to realize that a decrease in thrust would cause the airplane to pitch down.

When they got over the runway, the pilots pulled back thrust to set the airplane down. This caused the airplane to pitch down and roll, causing the gear to fail and the wing to break off.

The DHL pilots in Baghdad learned from this experience and didn't reduce thrust until the aircraft was on the ground. They didn't have to counter a hard over rudder. If they had had this problem too, they would have been OK, as by not reducing thrust until after touch down, they wouldn't have rolled.


User currently offlineJohnJ From United States of America, joined Jun 2000, 1659 posts, RR: 2
Reply 22, posted (8 years 8 months 3 weeks 4 days 13 hours ago) and read 7255 times:

Quoting NW727251ADV (Reply 2):
But after looking at very good video of the DC-10 crash you can clearly see that the DC-10 didn't "roll" immediately. In fact I don't understand why anyone says the plane "rolled" because it clearly cartwheeled.

Here's the description of what happened right from the proverbial horse's mouth (Capt. Al Haynes):

"We came pretty close to the runway. We got the right wing tip in the center of the runway, the right main gear off to the side. We touched down on the right wing tip, the wing flap fairing, the #3 engine, the one on the right side, the right wing gear, and the nose wheel, all pretty much simultaneously. The right wing broke off--that's the reason for the fire here, spilling all the fuel. The right main gear separated from the airplane. The left gear stayed on. And the airplane slammed on the ground, and we did not hit and cartwheel, like all the news says. We hit and slid on the ground, on the left main gear and the right wing stub. Slid along sideways, for about 2000' or so, when the left wing came up. Also, on impact, the tail broke off, the entire tail section of the aircraft broke off, so there's no weight in the tail at all. So when the left wing came up--probably because of our speed--the tail came up. the aircraft went up on its nose, bounced on the runway three times, on the nose, leaving radome marks on the runway. We went upside down and airborne about right here. We were thinking--even that tape that you see there, that's all we have in the way of tape, and nobody really remembers, and there was so much fire and smoke that nobody could tell. We hit right about here, and upside down. And fortunately for us, the cockpit broke off, and unfortunately for the first-class cabin. And then the aircraft went over on its back and skidded to a halt right over here."


User currently offlineCedarjet From United Kingdom, joined May 1999, 8124 posts, RR: 54
Reply 23, posted (8 years 8 months 3 weeks 4 days 12 hours ago) and read 7224 times:

Quoting 474218 (Reply 15):
Do you have any details on this L-1011 incident. The only tire incident at altitude I know about is the 1983 Saudia incident where two children were killed when the wheel failed (not a tire) and ruptured the pressure deck.

There is apparently strong evidence that the two children were sucked out of the Tristar at (nearly) cruising altitude but both survived the fall and were brought up in a fishing community in the Persian Gulf, where locals said the two children had fallen from the sky. A miracle rivalled only by that Yugoslavian flight attendent who fell from 33,000 feet when her DC9 blew up eh.

And on the subject of the Tristar, there was an incident in the 70s at San Diego when a Delta Tristar lost all elevator control during the takeoff roll - in fact the aircraft rotated on it's own before VR / rotate, and climbed steeply without accelerating, indeed as it maintained a severe nose-up position the airspeed fell towards the verge of a stall. By varying thrust they regained some control of the aircraft's attitude and managed to land at LAX. Interesting that all the big widebodies of the 70s have been involved in incidents where most or all of the controls have failed inflight, ie 747 (Japan Air Lines crash in Japan in August 1985), L1011 (Delta incident as above), DC10 (AA near-disaster over Detroit 1972, Turkish Airlines crash in Paris 1974, Sioux City 1989). I guess the A300 can join the club (Baghad SAM strike, 2003).



fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz
User currently offlineNW727251ADV From , joined Dec 1969, posts, RR:
Reply 24, posted (8 years 8 months 3 weeks 4 days 12 hours ago) and read 7180 times:

Quoting JohnJ (Reply 22):
Here's the description of what happened right from the proverbial horse's mouth (Capt. Al Haynes):

I've read that dialogue before and plus I have Air Disaster, Vol. 2 so I am very informed about the crash. Nonetheless the plane cartwheeled plain and simple. Imma have to claim ignorance here and go against Capt. Haynes. You must have never seen the video of the crash. Nobody can tell me that I didn't see a 400,00lb DC-10 flipping over the air and back down to the ground. There is a HUUUUGE difference between a "roll" and a "cartwheel". I just looked at the video earlier today to see if there was in fact a roll and the plane clearly cartwheeled. Why would so many people say so if it did appear to be a roll?


25 GEEDO : hero defined: Capt. Haynes and his crew The absolute calm in their voices in the audio clips I've heard from this tragedy demonstrate the level of pro
26 474218 : Cederjet & 777236ER, I had lunch today with my old manager. In 1983 he was the lead engineer on the Lockheed team that investigated the Saudia wheel i
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