Sorry I can=92t get the list yet in my Windows 10-Outlook.
I have never seen runaway trim. A momentary trim stick and trim failure ye
s. But a runaway trim button did happen to a friend of mine in a T-33 (Butt
on stuck).
The Europa has sufficient stick authority to fly regardless of trim positio
n. Unless one has limited the stab throw due to a grievous building error,
+12to 13 and -4 to 5 gives adequate control.
Building conventions are to install a trim CB where it is easily reached.
There is not a snowballs chance in you know where, you will recognize the p
roblem then get to the trim CB in time to stop a runaway trim. Practice an
d find out what the control pressures are for various configurations. Toda
y folks install fully self contained power boxes for power distribution, so
no trim CB. I suppose I am guilty of not installing a paddle switch on th
e stick for a quick trim/autopilot cutout as was military standard back in
the 60s for these power boxes.
Trim failure occurs most often with those with the trim button conveniently
on the top of the stick=85 A size 10 boot can break the button and cause
it to jamb or be damaged. Flying with a damaged trim button is asking for
trouble. Always have a plug at the base of the stick to disconnect the sti
ck. Then use the copilot stick.
I=92ve never had the actual trim motor fail, but like all electrical equipm
ent, it can fail.
Wiring gets damaged or disconnected normally. I had an A&P put a drill thr
ough a wire bundle one time putting the top on with clecos and hit the trim
wire dead on. Found it and fixed it during the build. Normally it is a b
ad solder joint or poor crimp causes the trim to fail.
If you have never practiced trim failure in your flight tests in any airpla
ne, you are in for a surprise. It can be fatiguing. Plan to land as soo
n as conditions permit due to fatigue.
Normal trim failure is not runaway, but a trim failure to work (i.e. dead).
Start three mistakes high to practice.
>From cruise trimmed up (Fairly nose down trim), try to come in with that tr
im setting and do a low approach/landing.
>From stall or slow flight practice (Nose Up), try that same drill.
Let your imagination run wild. Fly with full nose up or full nose down.
General Rules with full up or down:
Full nose up, cut speed, slow and lower flaps to see if it eases control at
approach speed. Do a flapped landing at a speed where you are near neutra
l stick pressure. With a nose heavy aircraft (forward CG), a no flap land
ing may be at or near zero stick pressure and be more comfortable. Caution
: On go around with full flaps and full up trim, the plane will violently p
itch up so use forward stick to keep a steady climb attitude, then bring th
e flaps up if down to prevent ballooning.
Full nose down, depends on the aircraft. Hold back pressure and slow to do
a flapped approach at higher than normal speed near flap limiting speed to
ease pressure. You will tire rapidly in some aircraft with full nose down,
so flaps at speed will ease your stick pressure enroute to a safe airfield
. Eventually you will have to hold some pressure to land.
The old wives tale that the trim can be overridden by stick pressure on a s
tabilator like the Europa is false. The only possible way for override is
if the trim motor mechanism breaks off where it connects to the TS03. Fat
chance of that happening.
Others may have found other techniques but practice at altitude and see for
yourself what happens with your trim and configuration. Some variations i
n stab setup causes some planes to have slight differences in trim authorit
y. Same hard over trim situations must be checked for aileron and rudder
trim (autopilots too). Older autopilot systems don=92t trim so when the au
topilot is shut off or fails, surprise!
Those folks who have always controlled pitch with trim rather than setting
a pitch attitude then trimming are most susceptible to run away trim out of
control situations. I feel it is imperative to know the pitch and power s
ettings and regardless of trim, set the picture, trim it, and then crossche
ck it.
My opinion on the 737 Max: Anytime you have an automatic system, those who
fail to know their airplane, are at extreme risk. When one is in a new ai
rplane or a modified one, absolute knowledge of what has changed must be co
mmitted to memory.
My friends flying at Southwest (at least for another year until forced reti
rement), had no issues with the Max. Gear Up, Flaps Up, Autopilot On befor
e the plane is stabilized causes automatic stability equipment such as auto
pilots and the like to misbehave. They simply cut off the auto stabilator
incidence stall/trim to reset. This is widely know in the US. Foreign tra
ining standards I won=92t get into as it is beyond this forum. I was train
ed to get the plane stabilized, trimmed then hit the autopilot. Fly the pl
ane. Hit the paddle switch (auto system cutout) if the plane misbehaves.
Then analyze the situation and take proper action. Know your airplane and
practice emergencies. It is just common sense.
Just my opinion.
Best Regards,
Bud Yerly
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