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-   -   Why isn't AOA on the panel? (https://www.pprune.org/flight-testing/240618-why-isnt-aoa-panel.html)

Mad (Flt) Scientist 26th Oct 2006 18:44


Originally Posted by Double Zero (Post 2930340)
Given that, how about a reliably informed & programmed ( ie. by Test Pilot / Flt. Test gen', not avionics types with computers in bedrooms ) - a decent Stores - ( weight / fuel Mangagement System, with civilian equivalent ?

Along with suitable decent sensors.

Seems to a pleb' like me a much more user - friendly way to do things, after previous users & systems required a lot of heads-down deciphering...

DZ

I think most TPs would run a mile if asked to actually 'program' an avionics system (and rightly so). All systems placed on aircraft and certified (at least by OEMs) are subject to test pilot assessment, but it doesn't make them the right people to design such, by any stretch of the imagination.

barit1 26th Oct 2006 19:21


Originally Posted by Mad (Flt) Scientist (Post 2930507)
I think most TPs would run a mile if asked to actually 'program' an avionics system (and rightly so). All systems placed on aircraft and certified (at least by OEMs) are subject to test pilot assessment, but it doesn't make them the right people to design such, by any stretch of the imagination.

This is perhaps a good distinction between an experimental TP vs an engineering TP. While there are TP's that excel at both, there are also TP's who consider themselves primarily engineers in charge of taking a state-of-the-art design and taming it into a production machine that any good pilot can fly well.

I'd nominate Per Pellebergs and his SAAB flight test crew in this latter role.

formulaben 27th Oct 2006 01:26


Originally Posted by Mad (Flt) Scientist (Post 2930502)
Also, give the 'worst case scenario' of being grossly overweight, there are warning systems or characteristics which will alert the crew to a too-slow approach; there's nothing to warn you that your calculated landing distance is too short (that I know of) except indirect clues. So to stall on approach requires the weight error and failure to respond to warnings. With an AoA approach, what's going to protect against overrun?

Well, that's my point! If you happen to be a a higher weight than originally caculated, then you'll SEE the disparity between your planned Vref versus your AoA. THAT is what will protect from overrun. A prudent (ahem, sane) pilot will note the difference and recalculate landing distance, as something is obviuosly wrong.



Originally Posted by Mad (Flt) Scientist (Post 2930502)
Scheduled speeds can also be affected by, amongst others, VMC (a, l or g), VMU or variations in stall AoA with conditions; none of which will be captured by a simple AoA target.

Well, you're throwing in conditions that were not part of the original debate! My point was that it was sad that Cessna chose to not make the AoA standard on a CE-750. My gripe was that a simple glance at the guage can be very helpful in quickly determining general climb ability, such as an ATC request...VMC (a, l, or g), 2nd segment, VMU, etc. are all different situations. To clarify, I was meaning that when I'm at FL430 (with both engines running!) and for some reason I want/need to go up, a basic AoA guage would be a simple reference, that in cooperation with an SAT guage, can quickly be used to determine if you're gonna make it.

PEI_3721 27th Oct 2006 21:51

I align my thoughts with those of MFS (post 40), particularly with the problem of avoiding runway overruns. Landing performance involves energy – speed. Thus without knowledge of a specific touchdown speed (target) how can the pilot relate his landing performance to the approach AOA. Note that carrier landings do not suffer this dilemma (and are the land based military less concerned?).
A related problem is how to deal with speed additives required for gusty wind conditions or specific additions for ice accretion; a performance decrement due to ice might not be detectable with AOA.


Originally Posted by formulaben (Post 2931016)
... then you'll SEE the disparity between your planned Vref versus your AoA.

Surely this detracts from the advantage of using AOA, you require both AOA and speed to complete a safe approach.

The compromise of using speed and AOA to alleviate the concerns cited above might increase workload and for the inexperienced pilot creates opportunity for distraction and error.


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