Primary Flight Display........

[bgyuk]

Does anyone know what the following reading on the PFD is for? I have looked all over, and i can't for the life on me work it out. The one circled in red, not the localisers.

[Knick]

Isn't that angle of attack?  :-/

[pete]

This 1st obvious Q is 'how can you make it change?'

If I get a chance I'll take a look at this ..... (meanwhile someone else will probably have the answer)

[pete]

Kick is right. AoA.

More info

http://www.b737.org.uk/flightinsts.htm


Thanks for the question - learned something ...  8-)

[Dave71K]

I've wondered this myself for a while so thanks for finally finding the answer!!

However one thing I don't understand is how AOA relates to Pitch. In the example below my pitch was about 10 degrees but my AOA is 4.4.

How do these relate to each other?

[Hagar]

However one thing I don't understand is how AOA relates to Pitch. In the example below my pitch was about 10 degrees but my AOA is 4.4.

How do these relate to each other?

This should explain it. http://www.smartcockpit.com/data/pdfs/flightops/aerodynamics/Understanding_The_Angle_Of_Attack_%28Part1%29.pdf

[Dave71K]

However one thing I don't understand is how AOA relates to Pitch. In the example below my pitch was about 10 degrees but my AOA is 4.4.

How do these relate to each other?

This should explain it. http://www.smartcockpit.com/data/pdfs/flightops/aerodynamics/Understanding_The_Angle_Of_Attack_%28Part1%29.pdf

Thank you very much!

Basically AOA is the difference between your attitude (pitch) and you actual vector.

Just because your pitched up 10 degrees doesn't mean the aircraft is climbing at 10 degrees.

This clears up what confused me because now I see AOA is relative to airspeed. Hence why on the ground stationary AOA and Attitude are equal but at speed they are not.

Thanks!

[EVVFCX]

I only quickly scanned through the smartcockpit article, I didn't notice it mention changing air movement/airflow, only still air.

Presume most of of us have flown, either as pilot or passenger; ever notice the aircraft drop because the AoA has changed so far as to cause sudden loss of lift, either caused by sink or sudden updraft, the AoA has either gone negative or positive so far as to loose the flow of air close to the wing, set turbulence on and hopefully the gauge will change.
The article is good reading.

[bgyuk]

Thank you for the answers, I initially considered it could have been the AoA but then when i messed about with the pitch it didn't seem to make sense. However as pointed out there are many factors at work. Thanks for the links, i hate not having a full understanding of a plane/instruments  . I will be reading both of them.