Originally Posted by
Flightwatch
The BAC 1-11 did not use water-methanol, it used demineralised water. Watermeth was used in the Dart engine to produce the same effect. I believe the JT9D used demineralised water also.
The methanol was there as antifreeze so the water injection could be scheduled for the baulked landing WAT case. Without the antifreeze all sorts of obvious problems would ensue.
The 1-11 did not need water for that WAT case and I understand that where it was scheduled for takeoff the water was selected "on" until it ran out - therefore no antifreeze required.