The B52 fin/rudder loss was not a straight forward failure. My B757 Instructor at Seattle in 83 was the pilot of the said B52. When showing me photos of the damage, he said they were searching for turbulence in the rockies as part of an underslung cruise missile mounting test when the incident occured. They certainly found what they were looking for! The B52 entered a vicious mountain wave, the rudder came off cleanly and the vertical stabilizer snapped off leaving about a quarter of it's area sticking up from the fuselage. He found it hard to control the airplane, expecially in pitch. An F100 was scrambled as a chase plane and confirmed the detached part of the fin was still lying across the horizontal stabiliser. Several violent manoeuvres succeeded in detaching the fin and they made a high speed emergency landing at Edwards AFB.