Y Jet Bridge Collapses At DEN, Damages Plane

BA · Sat Mar 31, 2007 4:19 pm

Quoting Graphic (Reply 44):
That's a bent wing spar, and that plane is probably done for good

Quoting SLCUT2777 (Reply 47):
Next time DIA and UA would be better off to go with Ogden, UT based FMC-Jetway.

DIA did not want these automated jet bridges as they were skeptical of their reliability due to their complexity.

It was United that insisted on retrofitting five of the gates with these jet bridges and financed them themselves since the airport wasn't willing to do it.

DIA has plenty of FMC Jetways. Infact, two of the five jet bridges that were replaced with these new DewBridge automated dual jet bridges were FMC Jetways that were relatively recently installed. The other three were Stearns jet bridges that the city was planning to replace with FMC Jetways eventually.

antonovman · Sat Mar 31, 2007 4:38 pm

Quoting ChinaClipper40 (Reply 40):
Dual jetways that simultaneously serve both front and rear aircraft doors have been in use at European, Middle East, Asian, and Australasian airports for decades

This is true, I remember seeing my first ones in Amsterdam amost 30 years ago, but what is the 'automated" jetways mentioned a few times on here, are the driverless ?

flyorski · Sat Mar 31, 2007 4:44 pm

Quoting Antonovman (Reply 51):
what is the 'automated" jetways mentioned a few times on here, are the driverless ?

Yes, they are controlled bye lasers finding the aircraft door, and then computers directing the jet way too the aircraft. The computer failed, of maybe the lasers, and this is the result. Ramp workers should be doing this work......

mattnrsa · Sat Mar 31, 2007 5:14 pm

Quoting GlobalDreams (Reply 49):
I thought B15 and B16 could now handle 757 a/c. I only remember seeing a 757 at B15 once tho.

You most likely saw a 757 being tested on the gate. 737s and A319s have also been tested, but, so far, A320s can go on all gates, and 757s can go on B22.

skytony · Sat Mar 31, 2007 7:16 pm

The plane involved is N596UA.

hoya · Sat Mar 31, 2007 7:51 pm

Quoting Skytony (Reply 54):
The plane involved is N596UA.

Ouch, that's one of their newest 757s, delivered in early 1998. Let's hope it's not a write-off.

Yellowstone · Sat Mar 31, 2007 9:29 pm

I just flew through DEN last night, though I didn't see anything of this incident. I did see the dual jetbridge thing though, on gate B15 and whatever one was right across from it. At first, I thought it was some sort of A380 retrofit.

SLCUT2777 · Sat Mar 31, 2007 10:33 pm

Quoting BA (Reply 50):
DIA did not want these automated jet bridges as they were skeptical of their reliability due to their complexity.

Kind of like that automated baggage system that chewed-up luggage that is now gone? biggrin

BTW, that was another Utah based company (forget who it was) that put that infamous design together! laughing

Quoting BA (Reply 50):
It was United that insisted on retrofitting five of the gates with these jet bridges and financed them themselves since the airport wasn't willing to do it.

I think they learned their lesson with this said baggage system! idea

But good old UA was steadfast in their insistence.

Quoting BA (Reply 50):
DIA has plenty of FMC Jetways. In fact, two of the five jet bridges that were replaced with these new DewBridge automated dual jet bridges were FMC Jetways that were relatively recently installed. The other three were Stearns jet bridges that the city was planning to replace with FMC Jetways eventually.

Stearns is Jetway's biggest competitor in this equipment market, and the FMC people were pretty peeved when DIA chose to go with Stearns back in the early 1990s as the airport construction reached fruition. I was recently told by a Jetway employee that DIA wants to retrofit all concourse gates with FMC equipment except for the B concourse which of course is totally dominated by UA..

mkorpal · Sat Mar 31, 2007 11:14 pm

I wonder what they will do if it's determined that they are all unsafe and need to go back to the way they were. That would probably screw up more than just a 757.

boswashsprstar · Sat Mar 31, 2007 11:16 pm

Quoting ChinaClipper40 (Reply 40):
As was simultaneous dual boarding on the DCA-LGA-BOS shuttle for several decades (by simultaneous use of the front door and the drop-down rear stairs on the dedicated 727s that were used on that service for so long).

And indeed, DL still unloads the Shuttle through the drop-down rear staircase in the MD-80s, and US unloads through a wheeled-up staircase to the side rear door of the 319. (This happens always at LGA and sometimes at BOS and DCA--it's easier to do at LGA since passengers at both Shuttle terminals can enter the terminal at ground level and use various passageways to get to the exits without going back upstairs; at DCA and BOS, passengers must walk down the stairs and then walk back up a set of stairs to enter the main gate area.) Neither US nor DL loads the aircraft through the rear door any more.

However, I have seen B6 arrange to have passengers load through the back (walk down terminal stairs, across the ramp, back up a wheeled set of stairs) in attempts to make up time on delayed aircraft. Not clear how much good it really does them, but they do a pretty good job of getting the waiting passengers jazzed up about how they can pro-actively help to get their flight out on time.

md80fanatic · Sat Mar 31, 2007 11:39 pm

And you people wanted automated freighters? banghead

PC12Fan · Sat Mar 31, 2007 11:41 pm

Quoting UnknownUser (Reply 12):
The bridge does not have the capability to hook up to the rear door of the 757.

How many words do pictures say? scratchchin

UnknownUser · Sat Mar 31, 2007 11:48 pm

Quoting PC12Fan (Reply 61):
How many words do pictures say?

Wow, my mistake. Suppose it has been close to a year since I passed through DEN.

copter808 · Sun Apr 01, 2007 12:39 am

Quoting Flyorski (Reply 48):
Maybe time to wake up and realize that computers have a much lower rate of success then employees.

Actually, I think you'll find the opposite to be true. Computers are actually far more reliable than humans--once they are properly set up and maintained. Computers can do a better job of flying than a human crew too. What they can't do yet is think and reason. Humans are there as a backup and because nobody, including myself, wants to fly on an airplane without a human crew. Same thing with freighters, as long as they fly over MY house, I want a human on board!

Jetways have been running into airplanes for years! With the traditional jetway, the damage is usually far less as they do not pass over any critical aircraft structures.

Would this type accident happen with a human at the controls? Probably, sooner or later.

RDUDDJI · Sun Apr 01, 2007 12:41 am

Quoting Skytony (Reply 54):
The plane involved is N596UA.

I don't have Unimatic running, but I believe that's an Over Water 57, and it might be one of the ETOPS 57's. Ouch.

adizzy · Sun Apr 01, 2007 1:23 am

It looks as if it just came to rest on the wing of the 757. It does not seems as if the wing was carrying any extra weight on it. If that is true maybe it is just one of the flaps that will need replacing. Also, i think the speed at which it came crashing down will affect the amount of damage done to the jet.

globaldreams · Sun Apr 01, 2007 1:59 am

Quoting JumboBumbo (Thread starter):
don't have Unimatic running, but I believe that's an Over Water 57, and it might be one of the ETOPS 57's. Ouch.

it is indeed an ETOPS 757.

InnocuousFox · Sun Apr 01, 2007 2:05 am

Quoting RDUDDJI (Reply 23):
Anyway, I was not a fan of going to those jetways, not because of the automation, but because of the mechanics. The lack of structural support under the heavy extension just doesn't jive with me. I know the extension is anchored by the last pylon, but it just doesn't look right to me. Add a few months of moving those anchored supports around, and well, it ain't gettin' any stronger...

I agree... it was the cantilevered design that bailed. This was going to happen regardless of the control system.

Quoting BR715-A1-30 (Reply 20):
That just goes to show ya.. You can't beat a good ole pair of eyes and human response.

Which is a pretty ignorant thing to say, really. Yeah sure

Quoting Flyorski (Reply 48):
Maybe time to wake up and realize that computers have a much lower rate of success then employees.

At what?

Quoting Flyorski (Reply 52):
Ramp workers should be doing this work......

Completely irrelevant... it could have been caused just as easily by a stuck button on the controls in the cab... and then you would have to say "Ramp workers should be pushing these things into place with their bare hands instead of relying on motors and electronic controls."

Holy hell... is everyone knee-jerk ignorant today?

Quoting Zvocio79 (Reply 45):
the article says that it was a structural failure, but then it says that a malfunctioning sensor caused the accident........weird?

It could be that the sensor failure caused it to overextend, for example, overloading the cantilever system and causing it to collapse.

graphic · Sun Apr 01, 2007 3:15 am

Quoting ADiZzy (Reply 65):
It looks as if it just came to rest on the wing of the 757. It does not seems as if the wing was carrying any extra weight on it.

The wing was definetly carrying the weight of the extension.

airbazar · Sun Apr 01, 2007 3:18 am

For all the naysayers out there, there's nothing wrong with the design of the "over-wing" jet bridge. It's been used for years at different airports and IIRC this is the first time I've ever seen anything like this happen. AMS has had them for years. If you guys think the design is unsafe because of the apparent lack of structural support under the long extension then I suggest you never set foot on any of the hundreds of suspension bridges that exist all over the World. Accidents like this occurre because of human error or lack of maintence, not because the design is flawed.

InnocuousFox · Sun Apr 01, 2007 4:06 am

Quoting Airbazar (Reply 69):
If you guys think the design is unsafe because of the apparent lack of structural support under the long extension then I suggest you never set foot on any of the hundreds of suspension bridges that exist all over the World.

Uh... those are supported at both ends... not just one. There IS a limit to how far you can go in ONE direction depending on the strength of the support on the attached end.

glideslope · Sun Apr 01, 2007 4:27 am

Does anyone know how long the weight was on the wing? Would it make a difference?

FriendlySkies · Sun Apr 01, 2007 4:54 am

Quoting Glideslope (Reply 71):
Does anyone know how long the weight was on the wing? Would it make a difference?

The most significant damage occurred when the bridge hit the wing, probably causing the spar to bend (or possibly fracture). Length of time on the wing would make a difference, as the stress would be constantly applied.

I really hope this isn't a w/o, UA needs every plane in their fleet...

aviatortj · Sun Apr 01, 2007 9:07 am

Hopefully UA takes the advise of the a.net structural engineers and writes this plane off. Based on the pictures, there is no possible way this plane could fly again. Yeah sure

LeonB1985 · Sun Apr 01, 2007 9:18 am

Quoting Deltajet757 (Reply 22):
The wing looks fine to me. It probably has some minor scrapes, scratches, etc. here and there. The plane should be back in the air pretty soon. Nevertheless it still needs to be checked just to make sure. Hopefully there aren't any punctures or big dents.

Wow, aged 13-15 and an expert on aircraft maintenace!

adizzy · Sun Apr 01, 2007 11:23 pm

I think the we are not giving the 757 wing enough credit for how much weight it can actually carry. I think that the damage will not be as much as everyone is predicting.

However, with that said.....does anyone know whether or not the bridge cam plummeting down or did it gradually lower and come to rest of the wing?

If it came plummeting down- i would say that it would have suffered severe damage - not because the bridge is heavy b tut he fact that the weight of the bridge would seems much higher when momentum is taken into account. If it gradually lowered- i would think the wing would be fine... because the weight would distribute throughout the wing more evenly-rather than only in one spot!

UnitedFlyer · Wed Apr 04, 2007 10:14 am

anyone know what the extent of the damage to the 757 is?

christao17 · Wed Apr 04, 2007 11:13 am

Quoting UnitedFlyer (Reply 76):
anyone know what the extent of the damage to the 757 is?

Nope, nobody actually knows... but many are willing to speculate regardless of their qualifications!

phelpsie87 · Wed Apr 04, 2007 11:43 am

Quoting Graphic (Reply 38):
Well since you asked:

Smart guy huh? Haha, well, I do stand corrected, but I am sure you realize that I meant UA. But thanks for the heads up.

zenarcade · Wed Apr 04, 2007 1:23 pm

Arent wing spars designed to flex or is this only upward to accomodate forces produced by lift?

graphic · Wed Apr 04, 2007 3:02 pm

Quoting Phelpsie87 (Reply 78):
Smart guy huh? Haha, well, I do stand corrected, but I am sure you realize that I meant UA. But thanks for the heads up.

Actually all you asked was to see an A320 with double bogeys, i believe when you said "Show me an A320 with double bogeys." So I did. TED/UA was nowhere in that statement.

robsawatsky · Wed Apr 04, 2007 3:10 pm

Quoting InnocuousFox (Reply 69):
Uh... those are supported at both ends... not just one. There IS a limit to how far you can go in ONE direction depending on the strength of the support on the attached end.

Well, try a cable-stayed or various other cantilever bridge designs or dozens of other structural designs using cantilevers then. It isn't as if mechanical engineers have never designed anything using the same physical principles before. If the structure isn't strong enough or designed with proper fail-safe considerations it doesn't matter what it looks like to the untrained eye it can still fail.

If a more standard jetbridge support had collapsed and damaged the fuselage would the concept be abandoned or would the problem be investigated, identified and fixed?

ADent · Wed Apr 04, 2007 6:06 pm

Quoting Zenarcade (Reply 79):
Arent wing spars designed to flex or is this only upward to accomodate forces produced by lift?

Commercial A/C are designed to at least +2.8 and -1.0 g. So the each wing half is designed to take at least 1/2 the MTOW - but it has to be evenly spread. A point load or too far outboard and you can fail it.

(A380 is supposedly good for +3.8/-1.5)

LimoJet · Fri Apr 06, 2007 5:04 am

Any updates on the condition of this aircraft?

adizzy · Sat Apr 07, 2007 9:07 pm

Anyone from United have any info?

777den · Wed Apr 11, 2007 12:39 am

the aircraft returned to normal service yesterday after a wing teardown and inspection

hoya · Wed Apr 11, 2007 3:45 am

Good to hear there was little damage!

BA · Wed Apr 11, 2007 8:01 am

Quoting 777DEN (Reply 85):
the aircraft returned to normal service yesterday after a wing teardown and inspection

Glad to hear that.

I wonder what will happen to these five automated dual jet bridges...

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