Subject:  C.11.  Why do USAF aircraft have tailhooks?

To help stop the aircraft in the event of brake failure, or some similar
accident leading to a runway overrun.  Just past the end of many military
runways, you'll find an arrester cable strung across the field.  The cable
(unlike those on aircraft carriers) isn't attached to anything firm; instead,
each end is linked to a long chain, which just drags on the ground.  The idea
is to slow the aircraft down in a reasonable distance; the tailhooks on Air
Force fighters are smaller and weaker than the superficially similar hooks on
Navy planes.

The inevitable next question, "Does this mean Air Force planes could land on a
carrier in an emergency?", has been discussed at length in this newsgroup.  It
has been conclusively established that, no, an Air Force fighter could never
land on a carrier because, first, its landing gear is likely to break in the
much heavier touchdown required for carrier landings (sink-rate figures quoted
in the newsgroup give an F-15's main gear roughly a fifty-fifty chance of
taking a carrier landing without breaking); second, even if it could get on
the deck in one piece, the weaker AF tailhook would break when it caught the
Navy arrester cable; and third, even if the aircraft was physically capable of
it, Air Force pilots aren't trained in the highly specialised and difficult
art of carrier landings.

It has been pointed out that, if the USAF thought there was even the slightest
chance of ever being able to save one of its planes by landing it on a
carrier, it would have been tested on the mock carrier deck at Patuxent River;
the fact that this has never been tried is pretty solid evidence that the Air
Force engineers (who would presumably know) are certain it can't be done.

The F-16Ns used by the US Navy as adversaries in training have the standard
Air Force tailhooks and undercarriage, and are definitely not carrier
capable.

The RAF pilots who learned to operate from carriers in a few weeks on the way
to the Falklands are a different matter entirely; they were flying Harriers,
and of course most of the above is irrelevant to VTOL aircraft. Some training
was still required, of course, but the requirements are very different, both
for the aircraft and the pilots.  (As one Harrier pilot put it:  "It's much
easier to stop and then land, than to land and then try to stop.")

A few land-based aircraft have been flown from carriers with minimal
modification, notably the Lockheed C-130 Hercules and U-2.  Both of these were
fairly special cases involving aircraft designed for very low speeds (and, in
the case of the Hercules, rough landings) from the start.

On 30 October 1963, a USMC KC-130F made several carrier landings and take-offs
on the flight deck of USS _Forrestal_, in a series of tests intended to
determine whether it would make a good COD (carrier on-board delivery)
aircraft.  The only modification was an anti-skid braking system. The aircraft
made several landings and take-offs, with no use of arrester gear or
catapults, and performed well (the pilot, Lieutenant James H Flatley III, was
awarded the DFC for his part in the tests).  However, it turned out that the
Hercules would have been unable to fit in a carrier's hangar deck, so the
smaller Grumman C-2 Greyhound was developed instead.

Modifications to the U-2 involved the addition of an arrester hook and a
strengthened landing gear (the U-2 already had folding wings).  In 1964 two
modified U-2As, designated U-2G, were flown from USS _Ranger_; the tests were
successful, and several modified aircraft were apparently flown from carriers
by the CIA during the 1960s (the service version may have been designated
U-2J).  In 1969, a similarly modified U-2R was flown from USS _America_, but
this does not seem to have led to any service use.

Land-based aircraft have been successfully modified to be carrier-based; the
modifications involved, when the aircraft is a fast jet, are extensive. It
isn't just a matter of adding a tailhook and new landing gear; most of the
airframe needs to be redesigned.  The best known example in the West is the
BAe/MD T-45 Goshawk, the US Navy's new trainer, based on BAe's Hawk. The
Russians have had some success in adapting several fighters and attack
aircraft for carrier service.  Carrier tests were made by modified MiG-29 and
Su-27 fighters, and by trainer versions of the Su-25; the naval MiG-29K was
cancelled, but the Su-33 (based on the Su-27K) and Su-25UTG have entered
service.  A report of an early MiG-29K being torn in half on its first attempt
at a tailhook arrest gives a hint of the difficulties involved.

Please E-Mail me at johansson@ctrl-c.liu.se