Fly By Wire

[JohnDixson]

Flight Global Info

HS,

Re the UH-60 anecdote reported in the Flight Global article: unfortunately typical of the apocrypha that went around for a few years in fact regarding the stabilator. There was only one stabilator induced crash, and that was the 1978 crash of one of the prototypes at Sikorsky. That had nothing to do with EMI or the like, but was incomplete maintenance done during an all-nighter to get the ship ready for a VIP ride in the morning, coupled with an inexplicable failure by the crew to utilize the dual, backup straight to the actuators DC manual controls. There was however, an event that took place in Korea in the 80's, wherein a 60A was flying by a Hawk Missile Battery, who thought they would practice on it using their radar, with the result being that the Stabilator electronics reverted from the auto mode to the manual mode.

The Seahawk story is news to me, but after reading the 60A inaccuracies, am skeptical. And skeptical not only because they had the 60A story completely wrong, but also because, being involved in the Seahawk first flight thru development, I am aware of the scope of the EMI invasive testing the USN put the machine thru at PXT. Given the mission of the machine, it was exposed to all of the naval electronic transmission equipment, from the carrier radars on down.
" never say never in aviation " the saying goes, but I would guess the real story about this Seahawk event might be different.

One other observation for HC and the EC community re redundant power sources etc.: it always surprised us at SA that EC never upgraded to installing an APU as standard equipment in the Super Puma line. It really does provide benefits across the board, not only for dispersed field operations and ease of maintenance, but well, take the blade de-icing system. If the ship has one main generator go down, the Hawk or 92 pilot can fire up the APU and continue. Not an end of the world difference, but sure nice to have the all around capability. In the Hawk, up to a pretty decent altitude/ temperature combo, the pilot can hit BOTH engine start buttons simultaneously and start both engines at the same time ( APU bleed air used for start ).