Unusual A 340 departure

[zero-five]

As a very regular passenger I've got a good idea of what constitutes a "normal" takeoff sensation. What I experienced last week was a long way from that so I'd appreciate any logical explanations from the community.
It was a daytime, sea-level departure in an A 340. Wind was light / variable, temp 23C, runway 4000m-plus. The aircraft had a full passenger load but the flight was less than 3000km (so probably no-where near close to max weight). I don't believe the area is noise-sensitive.

The takeoff run appeared leisurely (nothing unusual for an A 340) but shortly after rotation there was about 10 seconds of severe vibration / rattling that really was most disconcerting and unlike anything I've ever experienced. There was no discernible pitch change and the climb rate looked normal. I was in row 32 so not close to a galley area (i.e it's unlikely to have been loose food containers etc.). Once it stopped there was no recurrence and the rest of the flight was normal.

Any ideas?

[22/04]

Where were you sitting? - I think I've experienced vibration towards the front of this aircraft as the brakes are applied to nosewheel before retraction. Similarly there is a centre wheel assembly that might do the same thing.

Remember that these days take offs are often de-rated to conserve engine life etc. So however heavy the aircraft was it might not change the perceived performance.

A340-300s in particularly are always leisurely.

[zero-five]

Thanks. I was in a window seat, 4 rows behind the trailing-edge emergency exit row. It probably was a de-rated departure. Apart from the vibration, everything else looked / felt normal. (It was a A-340-300).
The passenger sitting next to me (who, it turned out, travelled the same route regularly), spontaneously remarked, "that was scary". It wasn't quite worth a call to the Daily Mail but it was definitely unusual!

[togsdragracing]

"It wasn't quite worth a call to the Daily Mail"
-- But I trust that the flight crew steered away from the local nursery school at the last minute

[Hotel Tango]

From where you were sitting, it sounds like the main gear retraction process to me.

[SpringHeeledJack]

I recall the MD11 always gave me the heebie geebies on take-off due to the short but severe vibration felt a few moments after the aircraft lifted off the runway. The perceived wisdom at the time was that it was due to the main gear retraction process, with special mention to the doors, that disrupted the airflow noisily. Perhaps the OP has never slummed it down the back of the aircraft before ? ;-)

[DaveReidUK]

Where were you sitting? - I think I've experienced vibration towards the front of this aircraft as the brakes are applied to nosewheel before retraction.

Very few aircraft types have nosewheel brakes, and as far as I'm aware the A340 isn't one of them.

[zero-five]

Thanks for the feedback. Although I always seem to get allocated 32A on A 330 / 340's by this airline, I imagine that a particular combination of wind / weight / t/o performance etc. may have produced (or accentuated) an effect I've never noticed before.

And yes togsdragracing - with engines screaming, the crew clearly managed to wrest back control of the stricken craft, milliseconds from disaster :)

[Piltdown Man]

Maybe a puncture? Or a dreadfully unbalanced wheel? Shattered wheel bearing? A tyre delamination? There are a hole heap of things that could have given rise to this. What is really important is that you are here to ask what it could have been.

PM

[jackieofalltrades]

A340-300s in particularly are always leisurely.

Yes, it's a well known fact that the A343 only takes off via the curvature of the Earth.