|
|
Posted for "Mark & Lisa" <marknlisa@hometel.com>:
Rob,
I read something very similar to this in an article regarding landing on
water. The author noted that most fixed gear aircraft tend to nose down as
a result of the main gear dragging in the water first. Once the nose tilted
forward, the nose gear hits and the aircraft tilts farther nose down
allowing the entire nose section of the aircraft to plow into the water.
This results in a rather violent stop -- sometimes inverted. The author
referenced some WWII US Navy training material that recommended a shallow
banked approach allowing a wing to hit first (for fixed-gear aircraft)
absorbing energy while spinning the aircraft around -- much lower energy
transfer to the occupants and much lower chance of flipping over.
Another article I read in Aviation Safety last year (or the year before) was
an in-depth discussion of crash landings. The authors of this piece did
some research in the NTSB files and determined that the statistically safest
place to crash land (for occupant survivability without regard to injury or
saving the aircraft) was either on water, or into the tops of trees. They
also noted that pavement was much preferable to earth for gear-up landings
because of the tendencancy to dig in when landing on earth. For example:
you land gear up on an empty pasture. A piece of the bottom of the aircraft
breaks away exposing a sharp edge that can now dig in to the dirt like the
blade of a bulldozer--the stop will be quite sudden! Contrast that with a
gear-up landing on a paved surface where the aircraft just slides; much less
energy transferred to the occupant.
One thing made very clear (to me at least) is that the primary concern must
always be to save the occupants--they are the only non-replaceable parts!
It's been speculated that a fatal Lancair accident discussed on this list
could have been partly attributed to the pilot's attempt to "save" his
aircraft (he was also the builder) by overflying a suitable landing site
enroute to another with a longer runway. Whether he wanted the longer
runway because he thought he could save the aircraft there or because he
wanted access to the Fire/Rescue personnel remains speculation, but the fact
remains he never made it and crashed short of his chosen runway.
BTW, the Bold-Face crash landing emergency procedure (a procedure that must
be recalled from memory without reference to technical orders) for USAF
KC-135 aircraft is: FLAPS 50 (which is fully extended for this aircraft)
GEAR DOWN UNLESS OVER WATER...
Discussions with Boeing engineers revealed they intend the gear to shear
away (when not crash landing on water) absorbing energy and enhancing
occupant survivability -- no reference is ever made to saving the aircraft.
Mark & Lisa Sletten
Legacy FG N828LM
http://www.legacyfgbuilder.com
|
|