* Posts by Don S

1 post • joined 22 Jan 2008

Computer system suspected in Heathrow 777 crash

Don S

about Airbutt and Boeing flght control issues

regarding the Airbutt flyover that wound up a crash. The major factor has to do with the design philosophy of Airbutt versus Boeing

Airbutt uses a 'hard limit" on software/hardware which absolutely prevents the pilot from " bending" the airplane in ANY situation

Boeing uses a ' soft limit " on ALL flight control software/hardware. Which means in the Final analysis- albeit with BUCU horns- whistles, lights, etc the PILOT retains the FINAL and ULTIMATE control with a HARD push or pull - even if it means "bending" the plane.

Check your avaiation history regarding a very early 707 transatlantic flight- within the first year it went into service.

Pilots were N OT minding the store- autopilot kicked off - at night - over the ocean - plane went into a diving spiral- eventually pilot pulled it out a few thousand feet above the ocean- but actually bent the wings and popped a few rivets.

The plane was repaired - but the slight increase in wing angle was never corrected. The plane after that had one of the better- lower fuel consumption numbers in the fleet.

Point is - had the airbutt version of FBW been in existance at the time - the plane would have simply disappeared- had Boeing FBW software been in existence then as now - the plane would be bent - but flyable.



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