Originally Posted by
BOAC
Without the excessive tailplane trim this aircraft should have been recoverable, albeit via a hairy ride. Surely the focus should be on ensuring that it does not happen and that when that defence fails - as Murphy states that it surely will - that crews are able to cope.
Couple of questions (being as I am more on the sliderule side of things...):
- given the test being conducted, shouldn't the tailplane trim be entirely expected ? Isn't the whole point of the test to reduce the speed so the a/c pitches up to hold altitude (on A or B) right until the envelope protections kick in (A) or stick shaker (B) ?
- or put another way, how would you / could you do this test
without the a/c trimming up ?
- and if the trim was expected, surely recovery
with that trim would have been planned ? [ assuming you plan for a test failure... ]
Also, I think that from other posts you think the a/c should have flagged "AoA disagree" or similar, at an earlier stage ?
Presumably that's on the basis that you wouldn't test (or would abort test of) AoA protections when faced with reported AoA disagree, right ? ... but then, you wouldn't conduct a lets-see-if-we-can-stall test at 10k less than specified altitude, right ?
[ Note that I'm not at odds with the idea of flagging the disagree, just not sure it would have made any difference here ]