Thread creep is often frowned upon but I must say that the discussion here about AOA had been fascinating. Some great contributions.
Regarding the use of AOA indicators by the military (at least by the fast jets, especially in the navy) and its rejection by civil transports I'll add this:
When I left the navy for airline flying I was not surprised to see a little instrument on the early model DC-8 captain's glareshield since it was identical to one fitted in the Grumman S2F Tracker. We called it an SFI because it was manufactured by a company called Safe Flight Instruments. While it was not calibrated in units (just fast,OK & slow) I believe that it was an AOA indicator and we used it for carrier approaches. I was surprised to find that the airline told us to ignore it, did not maintain it, and eventually they were removed. Check the next post for a link to a related page.
Then came the DC-9 with its Collins FD-109 flight director and the Fast/Slow indicator on the right side of the attitude indicator. I know that this was not driven by the pitot-static system but got its input from the vanes mounted on the fuselage. Once again we were told to ignore the information provided and fly airspeed on approach. I think that one reason might have been because you were "on speed" when the airspeed was at Vref and of course we always carried additives - 5 knots minimum with wind added to that. Not sure how the thing was calibrated but it was a nice visible backup to the ASI even though we were not supposed to use it.
My mob was strictly an airspeed bunch.
Edited to remove faulty link. Thanks Machaca, I'm not too adept with some of this stuff!
Last edited by Idle Thrust; 29th Mar 2010 at 20:00.