Originally Posted by
The Ancient Geek
Much discussion has centred around heading changes and the complications of entering these into the FMS.
I am not familiar with Boeing practice (777 pilots please comment) but many aircraft have a large 4 position knob on the centre console which simply changes the current heading in 90 degree steps. This is used when flying a holding pattern.
In the event of a depressurisation or other serious event it would make sense to simply turn the knob 90deg right, wait a short time to clear the airway then right again to head for home. No complicated FMS entries required.
Is the heading flown to the Indian Ocean 180deg to a heading which the aircraft would be expected to be flying during its normal route ?.
If the aircraft was flown in any 'heading' mode then it would deviate by a large amount from a straight track due to the large change in magnetic variation. The aircraft was not in heading mode.
To fly a different mode requires specific inputs either track mode or to a specified waypoint. Someone needed to be there to make those inputs
after Malaysian radar had lost contact on the westward flying aircraft.