Originally Posted by
pattern_is_full
A full 90° bank in a transport aircraft? Not on my life. Not without a full understanding of a given aircraft's inertia, control response, rudder effectiveness, W&B etc.
But - see the note in the procedure posted by barrow
Some bank will A) spill some excessive pitch-up into turning moment, and B) turn the VS and rudder into an angled "half-ruddervator" as in a fork-tailed Bonanza, allowing some minor pitch adjustment via the rudder pedals (at the cost of a slip or skip).
It will require fine judgement if one is already in a near-stall attitude, since the banked turn will increase effective weight (G forces). Conversely, being able to input partial "bottom-rudder" with the pedals may help reduce AoA.
And it's still only a stopgap until the rest of the procedure can be completed successfully and normal control regained in all axes. One would have only a bit more long-term course control than the DC-10 at Sioux City - flying in circles or steepish S-turns all the way to the runway.
The aircraft itself doesn't care if it has a high bank angle or not, as you are aware. At low speed, there can be an over banking tendency on some aircraft, think B-52/ Fairchild AFB in 1994, but otherwise the aircraft will maintain it's composure. The advanced handling training resulted in unintended consequences, where inadequate knowledge of the structural protection through certification standards met aggressive control inputs, resulting in torsion bending loads well in excess of the structures ultimate strength. Rudders are extremely effective at high AOA, and do not need large deflections if used for roll. The rudder always places a torsion load on the rear structure as it is asymmetrical to the fuselage.