Megan/ Dave ReidUK , I agree,very possible loss of control on three Engines.
It was Cheshire who first noted that not many Halibags were coming back on three engines and conducted a test to find out why.
He struggled to regain control after a stall. Handley Page refused to modify production and it was only after a Polish test pilot was killed doing further tests, that they agreed to changes- according to Max Hastings Bomber Command.