misd-agin says:
"so at 120-140 kts weīre supposed to pick out a 20ī difference? Mind you we have to have this point identified 1, 2, or perhaps 3 thousand feet away when you compute the slant angle..."
Yes at those approach speeds you're doing around 75 metres per second. But your question is like asking " I'm driving on a highway at 120 km/h and you expect me to read an off-ramp direction sign?"
Well not if you're looking out the side window just as you pass by the sign. But if you are looking out the front window and the sign is hundreds of metres in front of you and only a couple of degrees away from your aiming point, well then yes. If you recall the length and spacing of all the markings on the runway including the centreline markings, it's actually quite easy to work out where the reference point is in relation to your aiming point on the runway surface.
"Only 5'? Dónīt know about you but a landing height misjudged by 5', or even 2' feet, is not one I would be proud of. And youīre sink rate at touchdown is much lower so itīs not .4 of a second. Flare typically starts around 20', or slightly higher, but takes several seconds to complete."
It's all about when to
start the flare manoeuvre, not where the flare ends up once your vertical speed has reduced to zero! (That is [from flare initiation to touchdown] the subject of the second article I read in that same publication that I found invaluable. That one was written by an ex-airforce test pilot by the way.)
"This theory ignores sink rates and the actual arrival weight of the arriving aircraft. Landing an airliner at light weights typically needs a later and or slower flare vs. landing one at max gross landing weight. Thatīs for a normal approach. Have a 'sinker' like the FO had this afternoon and your theory would have left him humbled."
I agree with you on the point you make regarding landing weight, undershoot shear etc. and how these will vary the rate and amount of attitude change required during the flare manoeuvre, but I still think there is much merit it keeping the flare height consistant for each aircraft type. Again I haven't included it in this thread, but the other article that talks about the actual flare manoeuvre found in the 1987 Aviation Safety Digest, looks after all of those variables.
Hello brain fade. Thanks for that.
