"Check GW" message on A320 MCDU

[tayyareci]

Hello,

I do not have the reference book with me and cannot remember the exact conditions for this MCDU message to come up, could anybody please help me?

[salvation]

It is when the aeroplane 'weighs ' itself when airbourne by comparing angle of attack to airspeed. If it's figure differs from your inputted ZFM by I believe 5 tonnes, it flags the message up as a gross error check.

Normally only seen out of LCA or DLM when returning to BFS or GLA :E

[Speedtape]

If all the info is correct and you still get this message, its probably due to a dodgy AOA sensor;)

[Tonic Please]

This should go in tech I suppose but what method does it employ to weigh itself by AoA and Airspeed? Can't get past that logic :confused:

[Clarence Oveur]

To put it very simply.

Imagine you are flying along, straight and level, at 100 kts in your Cessna. At this point lift equals weight.

If you now increase the weight of your Cessna, but still fly at a 100 kts, you can only maintain level flight by increasing your lift.

You would do this by raising the nose of your Cessna, and thereby increase the AoA, until level flight is achieved.

You could also do the opposite, maintain AoA and increase airspeed.

In any case it shows the relationship between weight, airspeed and AoA.