OK, time for a bit of a 'washup':
There seems to be an opinion that on some
specific types a small 'push', just before touchdown, can help turn a good landing into a 'greaser'. No-one yet has come forward with a cogent explanation as to
why this might be but I am prepared to take it at face value and not think of it as another 'urban myth'.
This 'breakaway' thread started when I described a heavy landing in which I was pretty much a passenger (for CRM reasons). At the last minute, well, second I started to go for the control column but we had impacted before I got there.
There were some replies saying that pulling back near the ground would make things worse and that pushing forward led to a better touchdown sometimes. I think the thread has embraced both scenarios (very high and very low ROD) and treated them in the same manner - which would explain some of the differences of opinion.
My conjecture is this:
>>>
If you are heading towards terra firma at a rate likely to cause damage to the airframe and/or occupants, the
ONLY thing that is likely to rapidly improve matters is to pull back on the controls to reduce the descent speed.
If you have got so slow that this technique is ineffective then you really
are a passenger.
<<<
We got sort of sidetracked into a discussion about using thrust to reduce the high rate of descent. I argued that the actual thrust itself had a much smaller influence on the outcome than might be expected, most of the positive influences were secondary ones and you had to wait some time for the effects. This is not to say that adding thrust isn't a good idea, it's just not much of a solution
on it's own at a late stage.
As has been pointed out by some respondents, you can recover from a high rate of descent near the ground if you have enough airspeed to give you good control authority and a decent stall margin. If you have allowed the speed to decay unnoticed then you have effectively 'painted yourself into a corner' when it comes to dealing with an excessive sink rate.
(I remember being at Farnborough one year when a ?Dash-8? was demonstrating 'short field landings'. He came in slowly at a high rate of descent and basically crashed on the runway. Video footage showed full up elevator for the last couple of hundred feet but he was semi-stalled, so no effect... Impressively short landing, though.
)
P.S. I'm off to darkest Africa this afternoon (Nigeria
) so will be incommunicado for a few days. Please talk amongst yourselves while I'm away.
