The 80 knot call - potential for confusion?
Cunning Artificer
Join Date: Jun 2001
Location: The spiritual home of DeHavilland
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Interesting point Hobo and probably right on, but our good old British Lancasters got their tails up a bit quicker than that.
When I cut my teeth as an Instrument Technician Smiths had recently introduced an ASI designed for 'heavy jets' - the Mark VI as I recall - on which the lowest reading was 60 knots and and the pointer didn't move at all until that speed was reached. In this case 80 knots, being at the three o'clock position, was a good speed to confirm that it was working. We did have a Vulcan get airborne with the Pitot-Statics inoperative and he got down safely but it isn't something you'd want to do on purpose.
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Through difficulties to the cinema
When I cut my teeth as an Instrument Technician Smiths had recently introduced an ASI designed for 'heavy jets' - the Mark VI as I recall - on which the lowest reading was 60 knots and and the pointer didn't move at all until that speed was reached. In this case 80 knots, being at the three o'clock position, was a good speed to confirm that it was working. We did have a Vulcan get airborne with the Pitot-Statics inoperative and he got down safely but it isn't something you'd want to do on purpose.
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Through difficulties to the cinema
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Hobo. Can you quote an authoritive source on this 80 knot thingy for Boeing? I find it a bit difficult to accept that Boeing would nominate a 80 knot call purely based on a 1943 vintage aircraft. My bet is that someone has heard this from someone in the industry and it gets passed down through history until it becomes "fact". Blacksheeps point about 60 knots being the lowest ASI reading before the needle comes off the stops sounds a more valid point of view.
In large tailwheel bombers - and I flew Lincolns - a slight forward pressure was kept on the wheel until the tail gradually came up. It was never done at any specific speed. One thing though about the Airbus 100 knot check and that is it sure removes any decision making about going or aborting if an ASI discrepancy is discovered at that point. It is go man - go!
In large tailwheel bombers - and I flew Lincolns - a slight forward pressure was kept on the wheel until the tail gradually came up. It was never done at any specific speed. One thing though about the Airbus 100 knot check and that is it sure removes any decision making about going or aborting if an ASI discrepancy is discovered at that point. It is go man - go!
