This is what i found
“According to my MD manual the device is properly called a spray deflector and is one item on the exterior preflight inspection.
I have the video of the wet runway tests with and without this device. It is quite a difference. The spray is thrown in a much lower arc with the deflector attached and it makes ingestion by the engines much less likely.
Without the deflector the material would not travel much farther, mostly just higher. And if it goes higher it takes longer to arc over the top and fall back to the runway. Longer time = more opportunity for the engines to get there and ingest it.
At 120 knots a plane is traveling just over two hundred feet per second. Let’s picture a nosewheel tire with a tread width of ten inches, rolling 200fps through slush lying one-quarter inch deep on the runway. The tire will throw six thousand cubic inches (that is about 26 gallons) of slush per second up, and out to the side. Well, since the engines will arrive where the nosewheel is now in less than one second. The need to keep the spray low becomes pretty obvious when you think of it that way.
Forget gravel and other FOD, I don’t think jet engines would be happy being fed 26 gallons of water per second.
When the DC-9-80 entered line service this spray deflector created a small problem. The standard DC-9 towbar was about an inch too narrow of throat to fit over it. A whole new series of towbars was distributed.”
Thank you for the information flcriminal 😎 and some more great shots there like the AC A330
James
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