"JGalban via AviationKB.com" u32749@uwe wrote in
news:832e340dd3468@uwe:

Mike Isaksen wrote:

Here's a painful one to watch. Good vid to show students about why
airspeed is important.
It's a walkaway, but maybe not fly away:

http://uk.youtube.com/watch?v=lhUO4pdGCf8

That looks like a classic porpoise. I'll have to admit, I've never
seen an
airliner do one, though they're not uncommon if you hang around a GA
airport with a lot of training activity. On GA planes, the nose gear
will usually collapse on the third or fouth bounce.

Airspeed is not the only key to avoiding one of these. They're
usually
entered by touching down with a flat or nose low attitude.


Well, your airspeed will dictate your attitude at touchdown!



Trying to
force the airplane onto the runway before it's ready is good way to
get one started. =

Yeah. It's the best way, certainly.
Airliners do do this from time to time. I know of several. One, a 727
had massive damage done to the fuselage and had to have the entire top
of it reskinned from the leading edge to the cockpit. A 737 that bounced
off the nosewheel, then went around. the crew discovered they had no
ailerons once airborne since the nosewheel had punched the forward
bulkhead so hard into the belly that it slackened the aileron control
runs. I've seen both of these airplanes soon after the event as well as
several others. It should be harder to do in a jet than a light plane
since the attitude should be a bit more nose high for a given VS-Vref
ratio due to the leading edge devices, but some guys manage it anyway!


Bertie