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Lunar Landing
24th Apr 2002, 12:31
Was speaking to a friends dad the other day about the triple seven he works on at LHR, and he was telling me about the new 'enhanced' GPWS (ground prox. warning syst.) and something about a windshear predictor. Scuse the lame terminology. Could anyone explain what he meant as i did not quite understand what he meant. Be good for others to learn about it too thats why i posted here.
Just to be more clear, it is a sysytem which predicts when a windshear is possible so the pilot can take action just before it happens as to not be caught off guard. Very clever but no idea how it does that.

Smooth skies

Dan :)

777AV8R
24th Apr 2002, 12:58
Yes, the 777 does have the predictive windshear system (PWS). It is part of the wx radar and uses radar imaging to detect air movements (precipitation rates) prior to entering the windshear area.
The system is activated on the ground, when the wx radar is activated or automatically on ground when thrust levers are set for takeoff or automatically in the air below 2300 ft.

There are two aural warning alerts for takeoff and approach and a caution alert to monitor radar display. The cautionary alert and warnings have visual cues provided on the ND as well.

FlapsOne
24th Apr 2002, 13:03
This is a function of Radar rather than EGPWS. It's fitted to many aircraft now (all of EZYs 737NGs for example).

A predictive windshear system uses colour displays to alert crews. Using weather radar, the system looks for downbursts of air which indicate windshear conditions that the aircraft might encounter when landing or taking off. When a downburst is found, the system sounds a voice alert and also provides a red or yellow icon on the display screen.

Since the windshear hazard is greatest on approach or takeoff, the weather radar’s windshear mode automatically activates when the aircraft is below (typically) 2,300 feet. The radar adjusts all parameters required for windshear detection and alerts the pilot through an icon displayed on his weather radar screen and through an aural warning.

Information is displayed either on a stand-alone weather radar indicator or on a flight instrument—usually the navigation display.

The radar must have some weather to look at - ie it is not capable of 'seeing' CAT. I know this is in the development stage but not sure if they have actually produced a working model yet.

Lunar Landing
24th Apr 2002, 13:29
This is clever stuff. What do you think, or would you like to have in cockpits of aircraft which are not already there, which will improve the safety of an aircraft...not that it is not already safe.?.