What was that Vibration?!
 

I was on a flight from Denver to O’Hare on a Boeing 757. On our take-off roll, the front of the plane was <b>seriously</b> vibrating.(I say the front was vibrating, but that’s where I happened to be, in row eight. For all I know, it as all over the plane.)

I glanced over at the man across the aisle and he was looking at me. Both of us had the same unsaid question to each other: “What the heck is THAT?”

The best way to describe it is as if you your driving your car over the bumps that are sometimes on the shoulder of highways. Only imagine doing it at 180 mph.

I thought the pilot would abort the take off - it was that bad in my mind. An instant later the plane lifted off. I, in my now nervous mind, imagined that we would return to the airport and make an emergency landing.

The pilot retracted the wing flaps, great flight, all was well. There was no announcement and the attendants didn’t seem to notice what a lot of us sure did. I took their indifference comforting.

Help me out, rkkwan, AAFreq, et all. What was THAT vibration?

The were shaking the martinis up front?

Sorry-should have said THEY were shaking the martinis up front!

I am still thinking of a smart answer. Give me some time... :p

If you truly want to know I'd post this question at this forum: www.fearofflying.com/

I check it out a lot b/c I am a very, very, very, very nervous flyer -- the reason I pass it on to you is b/c the forum is filled w/questions like this and since the site is run by Capt. Tom who is a 30 year veteran pilot who now is a therapist dealing with ... yes, fear of flying -- you get real answers.

But he and some of his pilot buddies are always on that site answering tons of questions just like this. It's actually very fascinating b/c someone will ask a question just like you have and they'll tell you something extremely specific about a certain airport.

sorry RRkwan-just got in from Roma and have been up way too long. Scuzi!

The landing gear coming up often makes a few interesting sounds. The engins also slow down a bit after take-off. When I first started flying, I thought there was an engine problem and the plane was going to crash.

A runway badly needing resurfacing? Or did it keep on after you lifted off the runway?

Usually the culprit is nose gear &quot;shimmy&quot; vibration which can be caused by the same sorts of things that cause your car to shimmy - wheel alignment, flat spot on a tire or wheel imbalance, things like that. Commercial aircraft have &quot;shimmy dampers&quot; that help to reduce the shaking, but it sounds like your plane was ready for an inspection of the nose gear, which it probably got after landing. The cockpit crew would probably write it up for inclusion in the aircraft's maintenance log if they felt it was out of normal ranges.

As it was Denver, and (guessing here) on a warm day (?) I could also imagine that they needed to go really fast for takeoff, as warm air and high altitude (Mile High City and all) lead to high &quot;density altitude&quot; meaning planes have to roll faster and farther to get the equivalent amount of lift they'd get on cooler days or at lower altitude. Imperfections in the runway (expansion joints) coupled with nose gear shimmy may have joined together to make it really rattle. It probably didn't shimmy on landing (lower altitude, slower speed,) right?

I have no idea, but when I hear some scary noise on a plane, I check the flight attendants - if they look surprised or concerned, then I can panic. If they don't, I figure it is just some normal variation. And I am someone who needs little provocation to panic on a flight.

I've had the same experience, exactly, on at least a couple of flights and always assumed it was the runway condition.

Hmmm. Not sure I'm comforted to think it might be a nose gear issue! :)

Big airplanes are complicated things, and require regular maintenance. Ever seen the smoke that the wheels make when planes land? That's a little bit of the tires getting rubbed off when they suddenly have to start going round real quick when they hit the runway. Nothing to be alarmed about, but obviously after a certain number of landings the tires need replacing. Same with the nose gear - after awhile wheels get unbalanced or flat spots where they too &quot;smoke&quot; on landing... that's what maintenance is for.

Planes get way better maintenance attention than 99% of car owners give their own cars, and yet we put our lives on the line every time we pull out of the driveway.

&quot;What was that Vibration?!&quot;


When I saw this title, the devil on my shoulder told me to post a very obscene answer. &gt;:-)

But the angel took over so I didn't. ((a))

LMAO P_M!!!!