(Frank May) wrote in message ...
Also, the cable(s) are at the end(s) of the runway, where the a/c would
be on rollout, not used during the touchdown. Usually in the over-run
sections, IIRC. The a/c would have slowed probably quite a bit from
approach speed by that point & the stresses on the airframe are nothing
like those on a carrier trap.

Well, this is partially correct. The Air Force (and also Navy and
Marines at their land bases) use several kinds of cable arrestment
systems, both approach end and departure end. A typical USAF base will
have 4 cables on each runway: MA-1As (I think) in the overrun on each
end, and BAK-12s (or similar) about 1500 feet from each end. The
MA-1As are cables attached to anchor chains, and are for one shot last
resort use, since they take a while to reset and close the runway when
they are being reset. They can only be used in one direction (at the
departure end) since they work by picking up progressive numbers of
chain links to provide gradual decceleration - if they are taken the
wrong way you pick up the weight of all of both chains all at once!
Because of this, the approach end MA-1A is usually disconnected. I
did see an AF F-4E (utility hydraulic failure after takeoff, loaded
with 6 inert MK-82s) take one by accident at Myrtle Beach - and it
stopped really quick - but surprisingly the Rhino wasn't damaged
(although the MA-1A was!). The crew was REALLY surprised, since they
were looking at the BAK-12 cable they were supposed to engage and
suddenly STOPPED! The other cables are bi-directional, and can be
used for either approach end arrestments, where the plane tries to
land 500 to 1000 feet in front and immediatly engage the cable at high
speed; or for departure end arrestment, which can be at any speed
(high speed abort, or loss of brakes on landing, etc). Finally, due
to the low clearance under F-16s, their bases use a recessed cable
(BAK-14 or 16 I think - someone out there in barrier maintenance
correct me please) that is set in a groove in the runway and has to be
raised by the tower when needed (the call for it on the radio is
"CABLE CABLE CABLE").

AF F-4s had bigger (lower pressure) main tires (Marine F-4s too?) and
probably slightly different landing gear (no extendable nose strut,
for example) but I doubt the arresting hook was different - there was
absolutely no speed or weight limit on it's use. Compared to the
hooks on F-15s and -16s, the F-4 hook is HUGE. And it got used often,
usually for some sort of hydraulic failure. Usually an approch end
arrestment, by the way.

Other air forces have started using emergency hooks, too - Mirage
2000, Rafale, Typhoon all have them, I believe, and all NATO fighter
bases have cables.

Kirk
F-4 WSO (ret)