'suspended' takeoff: is this normal?
 

Just flew LanChile from Santiago to Auckland on a A340. The plane was almost full and this is a long flight (13 hours) across the Pacific. I guess the plane must have been very heavy.

Roll-off took very long and as the front wheel was pulled up nothing happened for a long time. We just sort of 'sat there' until finally, and very slowly, the rear wheels came off the ground too. Maybe this happens all the time but I had never noticed it (and I fly a lot). It normally feels pretty much like one fairly smooth action - front wheels up, nose of the plane comes up, soon after the whole thing is in the air.

Airspeed seemed very low and it took ages to really get any height. I must say I felt rather uncomfortable.

I was just curious as to whether this is normal.

I think it is normal, and probably a combination of Airbus programming (the 340 being the largest, it's the most noticeable) and the flight paths around SCL.

I noticed this too, when switching from KLM (734) to bmi (321) on LHR-AMS. You seem to spend quite a lot of time under the clouds departing from LHR, and the 321 seems at times almost to be drifting. I understand that one of the attractions of Airbus for airlines is the fuel economy, and that part of this is the ability to calculate the minimum thrust needed for take-off (with a safety margin, of course) and stick to it.

It's extremely unlikely that rotation occurred (that is, the front wheels came off the ground due to elevator pressure having been applied) and then the main wheels remained on the runway. When the front of the aircraft lifts up, the relative position of the wings (and flaps of course) changes, providing enormously more lift, and the a/c becomes airborne virtually simultaneously.

Although I'm sure that you perceived the front wheels to have lifted up, and I obviously can't sit here and disprove that they did, it is far more likely that the change in G-force that pushes you back in your seat caused you to believe that the aircraft had rotated.

The 340-300 (assuming LA doesn't have -500s or -600s, or even -200s) is known for lacklustre takeoff performance (i.e., it is underpowered). The full load and relatively long range may account for the slow and hence less noticeable rate of climb.

Not when you're heavy. Even in the DC9 that I fly the delay from the beginning of rotation until the main wheels liftoff can be up to about three seconds. We rotate initially to about 10 degrees aircraft nose up (ANU) then wait for the mains to lift off before continuing the rotation to a taget of about 18 degrees ANU. The target rate of rotation is 3 degrees per second so it would ideally take just over 3 seconds to hit the 10 deg ANU mark and almost 3 more to reach 18 ANU.

Exactly what I thought on AC's 343 taking off at YVR for HKG.

Interesting to hear your thoughts on this, thanks!

It's said that the 340-300 doesn't climb, anyway, in the traditional sense - it only gains altitude because of the earth's curvature.

Underpowered may be the wrong term. Suggest that the aircraft is poorly designed.

The 340 is designed to use minimal power for takeoff (less stress on the engines) so that it appears sluggish. Nothing wrong with the aircraft.

Underpowered may be the precise term. Apparently the 340 was designed around a P&W geared turbo fan - which never was produced. The only suitable replacement engines available then was what was being used on 737s and A320s which left a little to be desired.

I noticed this phenomenon on my flight from EWR-SIN, but I assumed it was because the aircraft was heavy with fuel due to the 18 hour flight.