Originally Posted by
Volume
Maybe they did run the L/H engine a lot during maintenance? An then topped up with Jetfuel?
Enough to cause knocking, not enough to be detected until too late in the takeoff run. Initial issues attributed to water injection by the pilots, but symptoms did not disappear after switching it off?
Normally each engine is fed from one tank only (by regulation), crossfeed is to be used in specific cases only.
All plausible suggestions, if a tad unlikely. Yes, my comment was predicated on the assumption that the crossfeed would be closed for take-off.
You're right to point out that recently-introduced contaminants take some time to reach the engine. One of my company's DC-10s received seriously-contaminated jet fuel at Lagos in the 1980s. Fortunately, one of the engines started to run down just before they turned on to the runway.
In an ideal world, the water drains at the bottom of the wing tanks are dripped before the first flight of the day, and - as
Dan_Brown points out - any kerosene would sink below the gasoline and sit on any water, given the time.