No-one has mentioned the 'After Takeoff Cx List.' Does this not include 'Gear Up'? If so, then it is more than a little forgetfulness, but a lack of Cx List discipline. It also exposes a lack of problem solving culture/philosophy/training. Problem: the a/c is not performing as expected; Why? En-route fuel checks, (issue that is an SOP) we are using too much fuel; Why? The vibration & noise is more than usual: why? So many questions should have been buzzing around the flight deck. There are supposed to be 2 brains up there. One might fail, but the back-up system should have been working. Good job they were not trying to climb over the Himalayas.
Does India have an alternative day to April 1st?