Ex Cargo Clown,
Surely the PNF calling out rotate at a speed that was clearly insufficient would have rung alarm bells.
The PNF called rotate at the bugged Vr, where he was supposed to. This call is a backup call & the PF is required to commence rotation at the bugged Vr, whether the call is made or not. Therefore, he/she is required to monitor the speed during the take-off as well as the PNF. I put it to you that the speed wasn't
clearly insufficient, as there are a number of occasions where the speeds are discussed prior to the aircraft commencing the take-off roll, & the crew obviously thought that they were sufficient at these points in time! They are only
clearly insufficient with 20/20 hindsight. However, the fact that 4 pilots did not feel that the v-speeds that were generated were somewhat low is something that should be looked at. Many things could lead to this, including cross-type qualification, distraction, inadequate cross check & fatique, to name just a few. To try & pin down a reason at this stage would be pure speculation.
There are definitely some serious human factors involved in this, I cannot believe fatigue does not play a part.
Of course there are human factors involved in this error. I would put it to you that this part of the accident chain is purely human factors related, as opposed to a technical issue.
JulieFlyGal,
Wouldn't increasing the pitch aggravate the situation even more, ie, cause airspeed to decay? Would have thought the first reaction would be to apply full throttle if the aircraft didn't lift off at Vr.
This is a very good question. From the preliminary report the aircraft started to rotate at 152 kts. 8 seconds later the aircraft was still accelerating as the speed was 156 kts when the tail contacted the runway. A slow acceleration for sure, but still an acceleration. However, from this point, the aircraft did not get above 157 kts until after it was airborne. So even though maximum thrust was applied, the aircraft did not continue to accelerate - possibly due to excessive pitch, or due to the extra drag from the tail scrapes & the main gear rolling over grass rather than paved runway, or a combination of both. Perhaps someone with a good knowledge of the theory of flight could shed some more light on this.
YoDawg,
Since the thrust is appropriate for the wrong weight, the aircraft will not even accelerate correctly to that incorrect VR
I agree, but still feel that the difference to the physical position on the runway that Vr was reached wouldn't have been large enough to have a visual impact on the pilots during the take-off roll. Particularly at night & if they hadn't flown this sector off rwy 16 at Melbourne for a while. My reasoning for this is based on the position on the diagram in the preliminary report that shows the location of the start of the first tail strike & guessing how far before this point the crew commenced the rotation, given the fact that the rotation was commenced 9 seconds before this point.
Perhaps some of the geniuses on this forum could compute the distance from the commencement of the take-off roll to the rotate point, using the figures that the crew used & also using the correct figures. I would be interested to see what the difference in distance would be.