Help wanted at JetBlue.... pics!

singpilot · 09:10 PM

Well, the pics have leaked out.

JetBlue is probably looking for a ground service lineman at Burbank. I'll bet they had to let one go for not connecting the scissors link on one of their birds.

The nosegear took up it's own direction separate from the plane.

The rest is on videotape.

I would have uploaded the pics, but PelicanParts has a bug. They say a .bmp is OK until after you have uploaded it, then it says nopecando.

stevepaa · 09-29-2005, 09:00 PM

What is the scissors link and why would a ground person touch the mechanics of a plane?

singpilot · 09-29-2005, 09:00 PM

OK, changed the format. In this pic, taken on the runway at LAX, you can see the scissors (the angled, hinged bars) unhooked from the steering motor directly above it. Sorta hangs the last guy that touched it. The guy that unhooked the tug in Burbank after pushing it back.

BlueSkyJaunte · 09-29-2005, 09:09 PM

Whoops!

We watched that live (as did half the rest of the USA, I guess), and I just kept thinking, "Somebody's gonna lose his job..."

Given the fireworks associated with the nosegear upon touchdown I'm surprised everything looks so unscorched.

Joeaksa · 09-29-2005, 09:12 PM

Quote:

Originally posted by stevepaa
What is the scissors link and why would a ground person touch the mechanics of a plane?

The link is detached to allow the plane's nosewheel to turn any direction. It should be reattached after towing to let the pilot have nose wheel steering and to center the nosewheel.

Kinda bad if its not hooked up...

JoeA

singpilot · 09-29-2005, 09:15 PM

These are high tensile aluminum and the axles are titanium. While they look bad, the amount of energy required to grind these down is amazing.

stevepaa · 09-29-2005, 09:20 PM

Thanks Joe, man I just never noticed the tug guy actually altering something there. Was that true for 707s and 747s.

But if he didn't reconnect, how did the pilot steer the plane onto taxiway and turn for takeoff?

bryanthompson · bryanthompson's Garage

I bet they will retrofit a sensor or something to keep that from happening again. A big red light next to the other big red lights, maybe?

competentone · 09-29-2005, 09:29 PM

Quote:

Originally posted by stevepaa
But if he didn't reconnect, how did the pilot steer the plane onto taxiway and turn for takeoff?

Additionally, didn't the pilot do a walk-around inspection on his plane before climbing onboard? Wouldn't the condition you describe be something that should have been seen?

air-cool-me · 09:59 PM

Quote:

But if he didn't reconnect, how did the pilot steer the plane onto taxiway and turn for takeoff?

Differential braking and power application...

keep a little power in and just drag the left brake and the nose swings around like the front of a shopping cart (or at least that what you can do in a 172)

Quote:

Additionally, didn't the pilot do a walk-around inspection on his plane before climbing onboard? Wouldn't the condition you describe be something that should have been seen?

he walks around.... then climbs aboard.... THEN the tug hooks things up... so hes already inside when they pushback..

MFAFF · 09-30-2005, 04:29 AM

Sing,

Much as I hate this I'm going disagree with you.

That' not the LA plane as its got snow on the ground.. go to PPRuNe to see other images of that jetblue A320 incident...

Secondly I don't see the scissor link as being detached....

Here's why, the upper porion is attahced to the top fixed section of the front u/c struct....and the bottom section is attahced to the lower pivoting from oleo,, the two seem to be jointed at the 'knee' joint, maybe not split pinned and all that but still attached.

You are right to say that thay link is 'openable' to allow full asteroing of the nosewheel whne neede on confinded are maneouvres.

It seems (and this from PPRuNe) that the failure occured within the steering pistons.. the two 'cans' above the scissor link, at 90 degress to the strut direction...an 'o' ring failed, hence the wheel, having been rotated tho' 90 degrees to retract, could not be rerotated back inline on extension....

928ram · 09-30-2005, 04:38 AM

Not to take this off the topic of the gear; is JetBlue the re-organized version of ValueJet?

Burnin' oil · 09-30-2005, 04:46 AM

Quote:

Originally posted by 928ram
Not to take this off the topic of the gear; is JetBlue the re-organized version of ValueJet?

I think JetBlue came from the remnants of Blue Star after Gordon Gecko tried to break it up and sell it off.

Teutonics · Teutonics's Garage

ValueJet is now AirTran.

fuelie600 · 09-30-2005, 05:01 AM

Blue Horseshoe loves Teldar Paper.....

911/914gary · 09-30-2005, 07:06 AM

I agree with MFAA that the scissor link or torque links are attached and that steering would be inoperative. The torque links are attached with cross bolts. This would not be removed by grounds crew.

Being involved with the landing gear engineering I have come across some inside info. There is a history of these nose gear failures.

The shock absorber assembly consists of two sections: a stationary inner cylinder (piston), which is mounted inside the shock strut assembly, and a sliding tube, which is the lower portion and contains the wheel axle. The upper portion of the inner cylinder contains anti-rotation lugs. During installation of the shock absorber, the anti-rotation lugs are aligned in slots on a backplate, which is mounted inside the top of the shock strut. A nut is then installed to secure the inner cylinder of the shock absorber/gear assembly to the backplate.

The bottom of the inner cylinder contains the lower cam. The upper part of the sliding tube contains the upper cam. This cam is held in place by eight dowel pins retained by a bushing and a retaining ring. During gear extension and retraction, the sliding tube extends down and the two cams engage, centering the nose wheel. When the strut is compressed on the ground, the cams are separated and the nose wheel is free to move for on ground steering.

Apparently if the mechanics are not careful the strut’s upper cam can be assembled with the dowel pins miss-aligned and still have steering if the strut is compressed. Because the cam is not secure the cam can rotate during steering operation. When the aircraft rotates the upper cam can react with the lower cam and shift the strut back to the proper position and center the steering. However , if the cam's shift is great enough, it is also possible to react with the lower cam by rotating the strut 90° out of phase. This is what has happened in 8 previous incidents!

stevepaa · 09-30-2005, 07:57 AM

Quote:

Originally posted by 928ram
Not to take this off the topic of the gear; is JetBlue the re-organized version of ValueJet?

Most of Jet Blue staff are older experienced personnel from other airlines. IMO, a good thing.

It would be interesting to see more photos of this. Does anyone have a reference for a final NTSB report on such an incident?

singpilot · 09-30-2005, 07:57 AM

Both Gary and MFAFF are correct. My Director of Maintenance sent me those pics, and after he showed me the rest of the pics, there was no doubt that they were not of the LAX incident.

I stand corrected. It does appear that this is an ongoing failure mode of a design issue.

Another thing came to light on this incident. The Captain that day at LAX had dealt with this exact same thing previously. Exactly the same outcome. What are the odds on that?

stevepaa · 09-30-2005, 08:02 AM

Quote:

Originally posted by singpilot

Another thing came to light on this incident. The Captain that day at LAX had dealt with this exact same thing previously. Exactly the same outcome. What are the odds on that?

As Jet Blue has experienced crew, not too surprising.
My wife had two emergency landings in 6 months as FA.

Joeaksa · 09-30-2005, 08:10 AM

Quote:

Originally posted by singpilot
Both Gary and MFAFF are correct. My Director of Maintenance sent me those pics, and after he showed me the rest of the pics, there was no doubt that they were not of the LAX incident.

I stand corrected. It does appear that this is an ongoing failure mode of a design issue.

Michael, I received the same photos via the internet and on the sidewall of one of the tires it was marked "jet blue" so the photos were of a jet blue plane and incident, just possibly not this one.

911/914gary,

Nice to see someone who knows landing gear operation! I am an A&P and have gone through these puppies more than I care to think about. It was easy to see that the "self centering" bits were not working correctly on this gear. Glad it has not happened to me in the air!

JoeA