Good post.
Thanks,
Michael
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From: Bud Yerly
Sent: Sunday, May 11, 2014 9:28 PM
Subject: Europa-List: RE: Europa-List: Re: Europa-List: Re: Europa crash
in L=C3=BCbeck/Germany
Graham and others.
Good comment on the leading edge curve. My Classic wing has that slight
cup sanded and filled off by my painter. It has a bit of a sharp stall
like a normal series 6 airfoil.
On the accident comments:
I hate to speculate, but the accident investigator training and
extensive flight envelope expanding time I have acquired, leads me to
use caution speculating at this time and to causes and early on
assumptions on should have had equipment, etc.
The initial test phase of the Europa (or any aircraft) needs to make
sure it is made in baby steps.
After building 18 aircraft 15 of which are Europas (yes I am starting
our 16th Europa in the shop) and test flying many other owners aircraft,
many things can cause a takeoff leg stall spin type accident.
My last call from a US accident inspector was a very long time ago.
Here is what we discussed on a takeoff leg, attempted turn back and high
angle impact deadly crash of an experienced pilot and seasoned aircraft.
Off the top of my fuzzy balding head:
On takeoff the Europa has a very good rate of climb and deck angle. In
testing of 12AY (a Classic) with 914, the full flap takeoff has a deck
angle of 10 degrees (and about a 12.5 degree angle of attack) at 55
Knots. When pulling the power back abruptly during test, at 55 knots, I
found only 3 seconds with the nose up pushed me into the stall warning.
Since the full flap approach angle power of the my old Classic is about
8 degrees glide slope or so, one can see that it requires a 13 degree
push over to try to preserve airspeed and control.
Lesson for everybody: Recovery from a takeoff engine failure requires
an aggressive nose down push to preserve airspeed.
Clean, it wasn't much better, in fact with the 914 at 65 knots the deck
angle is close to 15 degrees and the results were a very rapid bleed off
unless a push over to nose slightly below the horizon (about 5 degrees)
was necessary to preserve airspeed.
To the comments on the web regarding AOA and flight testing:
A new pilot checking his aircraft out is not safe by adding equipment to
help determine his AOA. These systems require calibration and testing.
I doubt these folks had time to test and calibrate aircraft systems in
flight test yet. Un-calibrated equipment often times leads to more
cockpit distractions early on.
I have no data on this accident and doubt I or we will get much other
than stall spin accident.
My flight test comments are as follows:
We know that in the preflight phase, Annex E for wing angles/tail plane
angles and control throws is not enough. Retract tests are essential to
verify gear lock, flap position/operation, and outrigger lock operates
full proof. The engine and fuel system must be bullet proof at level
and max angle nose up. The fuel system must be able to go from empty to
fully primed at max angle with only 5 gallons total (the main and
reserve side holding 2.5 each across the saddle) in 5 seconds or less.
Complete Wt. and Balance and a review of max forward, aft and test
flight loads and CGs verified on the Wt and Bal form. (I normally will
fly with a minimum of 10 gallons US on test flights.) The engine must
run flawlessly idle to full and not overheat on the ground for 20-25
minutes running at summer time temps.
The electrical system must be able to handle the load, and if there is a
cockpit smoke situation, battery off, the engine must run with ignition
only. (914s don't forget the Aux pump operation.)
All engine instruments and flight instruments/equipment (pitot and
static) must be verified for accuracy and operation prior to flight.
(Read as no red light distractions on takeoff or funky airspeed and
altitude indications). Trim must be checked and verified operational.
All aux systems must be operational or placarded and left off. (Radio is
a must, Transponder is often required, ELT operational, (I turn AOA and
Autopilots off).
The night before, I chair fly and prepare for the flight. I go over
aircraft systems, test parameters, panel layout and specifics of complex
electrical systems.
Flight one is 15 minutes to check for runs drips and errors. (Immediate
acceleration to 75 and climb at 90.) (Normally I can fly one of our
planes hands off, feet only, half way down the 4000 foot strip above 50
feet.) Climb to 2500 feet or so and check the trim and rig from 70 to
100 Knots. Return to the pattern, 80 on downwind, no slower than 75 in
the turns, and no slower than 70 on final. One of two low approaches if
in a mono is OK. Land and pull the cowl and inspect. Fix any and
everything you found abnormal.
Flight two expands the envelope to check engine climb temps and
performance. Check CS prop operation, and climb 3 mistakes high and do
A/S verification, stalls, falls and pitch and roll stability. Typically
our engines are flawless so it is only a 45 minute flight. If all goes
well and we have good stall characteristics, go back and review the
flight. (I have needed stall strips on the root to get a good early
burble feel prior to stall.
Once I am convinced the pilot (who has normally flown in my aircraft for
about 5 hours and is very current in other types) is ready, I prebrief
with him and hand him the keys for a test hop.
However, I have been guilty of flying a test flight early into the
flight phase dual. Confidence in the aircraft has to be extremely high
to do this. A thorough brief of what will happen if the engine quits on
takeoff is a must. The aircraft is the last thing I will attempt to
save. Two people flying an untested aircraft is too much exposure and
sometimes weight. ( My rule is the plane is not ready for test flight
unless you are prepared to knock on the test pilots door and explain her
husband is dead, and there was nothing that you could have done to make
the aircraft safer.)
Typically in the flight phase we go out dual and do stalls, slow flight,
advance handling at minimum speeds and ascertain if the pilot is
comfortable, the stalls are predictable and easily recognized. ( I am
the technical observer who is verifying airspeeds, pitch angles, stall
buffet, system operation and calibration while the client flies.) This
is where the AOA, Autopilot etc. gets calibrated or rung out.
Frankly, my opinion is that an AOA systems in straight wing aircraft is
a waste of money for me and I prefer a well installed stall strip (swept
wing aircraft are different). That said, after the 3rd 300 mile leg in
90F degree weather, sometimes it is nice to have "Bitching Betty" remind
me that I am not paying attention. Fatigue and complacency do set in to
us all.
If one adds my vortex generators for STOL capability, watch your speed
as the aircraft handles so well down to 50 Knots clean, you could be
falling with style and not know it unless looking at the airspeed. Here
is where an AOA, Airspeed Warner like the Europa Stall indicator, and
proper stall strip can be handy.
Right now all I can do is pray for the families heartbreak and learn
---From the lessons hard learned from previous aircraft accidents and my
own experiences. Then when appropriate, pass on the hard learned
lessons to those who may benefit.
Regards to all,
Bud
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Date: Sun, 11 May 2014 23:03:53 +0100
From: grahamsingleton@btinternet.com
Subject: Europa-List: Re: Europa-List: Re: Europa crash in
L=C3=BCbeck/Germany
Graeme
I was refering to the Classic Europa wing. The section has a slight bump
just
under the LE which is very easily sanded off. The nose radius is also
quite small,
again easy to sand off even with a sheet of fine abrasive round the
LE.Accurate
templates are essential and the plans version isn't accurate enough for
these subtle
curves. That's what was wrong with G-KWIP's wing. Always dropped L wing
in a flaps down
stall.
Graham
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From: graeme bird <graeme@gdbmk.co.uk>
Sent: Sunday, 11 May 2014, 18:57
Subject: Europa-List: Re: Europa crash in L=C3=BCbeck/Germany
Interesting to hear that you can fly with a flap down; but for me a lot
is going on just after take off, watching the gauges, the speed the VSI,
changing prop pitch, unlocking to get the wheel up and pushing the
leaver with the right hand etc - maybe the spring/tension is a bit off
if its first flight, I am not sure how I would cope if there were to be
a sudden roll at that point.
Yep I also value Grahams wisdom and contributions; I am just thinking of
the message, unintentionally, its sending to current builders. The fact
is hundreds have been made by imperfect amateurs and the stall
characteristics are one of the first things explored during the test
flights.
--------
Graeme Bird
G-UMPY
Mono Classic/XS 912S/Woodcomp 3000/3W
Newby: 105 hours 26 months on the Mono
g@gdbmk.co.uk
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