Two recent incidents

Sorry if this is boring, but the last discussion pretty much focused
on the release / rudder waggle. I can't get to the NTSB report just
now, but I seem to recall reading in the report on the OTHER incident
(loose hand held radio blocking forward stick movement) that the pilot
released, still couldn't get the nose down, then tried adding down
trim to bring it down. If the glider being flown at the time had a
spring trimmer, nothing will be gained by moving the trim. If the
glider had a tab on the elevator, pushing down trim effectively adds
more UP elevator. I often fly a Grob Twin Astir, and have played with
the trim quite a lot. Very useful in steep turns with a fat guy (me)
in the front seat. The trim tab has a surprising amount of pitch
authority. Spoilers might also be a way to get the nose down, but I
would hesitate to open them while the nose was in the process of
approaching stall attitude.
I read the NTSB reports because it makes me think about contingencies:
"what could/should/would I do if....."
I learned last summer that I won't think of something new while
experiencing a non-standard (hairy) situation, so playing 'what it' is
very useful to me.

Uncle Fuzzy wrote:
Sorry if this is boring,
Snip...
I read the NTSB reports because it makes me think about contingencies:
"what could/should/would I do if....."
I learned last summer that I won't think of something new while
experiencing a non-standard (hairy) situation, so playing 'what if' is
very useful to me.

There *may* be pilots around who think 'originally and well' under new &
stressful/hairy situations...but I've never encountered/heard/read of
one, yet.

Regards,
Bob - seeks to be mentally 'semper paratus' - W.

You will have the similar limitation.
Once the elevator hits the stop(obstruction) moving the trim tap further
has no effect if anything it will be reversed as the trim tab now acts
alone and is in a down deflection.(in case of a nose up trim)
Udo


At 19:35 08 September 2008, Uncle Fuzzy wrote:
Sorry if this is boring, but the last discussion pretty much focused
on the release / rudder waggle. I can't get to the NTSB report just
now, but I seem to recall reading in the report on the OTHER incident
(loose hand held radio blocking forward stick movement) that the pilot
released, still couldn't get the nose down, then tried adding down
trim to bring it down. If the glider being flown at the time had a
spring trimmer, nothing will be gained by moving the trim. If the
glider had a tab on the elevator, pushing down trim effectively adds
more UP elevator. I often fly a Grob Twin Astir, and have played with
the trim quite a lot. Very useful in steep turns with a fat guy (me)
in the front seat. The trim tab has a surprising amount of pitch
authority. Spoilers might also be a way to get the nose down, but I
would hesitate to open them while the nose was in the process of
approaching stall attitude.
I read the NTSB reports because it makes me think about contingencies:
"what could/should/would I do if....."
I learned last summer that I won't think of something new while
experiencing a non-standard (hairy) situation, so playing 'what it' is
very useful to me.

You will have the similar limitation.
Once the elevator hits the stop(obstruction) moving the trim tap further
has no effect if anything it will be reversed as the trim tab now acts
alone and is in a down deflection.(in case of a nose up trim)
Udo


At 19:35 08 September 2008, Uncle Fuzzy wrote:
Sorry if this is boring, but the last discussion pretty much focused
on the release / rudder waggle. I can't get to the NTSB report just
now, but I seem to recall reading in the report on the OTHER incident
(loose hand held radio blocking forward stick movement) that the pilot
released, still couldn't get the nose down, then tried adding down
trim to bring it down. If the glider being flown at the time had a
spring trimmer, nothing will be gained by moving the trim. If the
glider had a tab on the elevator, pushing down trim effectively adds
more UP elevator. I often fly a Grob Twin Astir, and have played with
the trim quite a lot. Very useful in steep turns with a fat guy (me)
in the front seat. The trim tab has a surprising amount of pitch
authority. Spoilers might also be a way to get the nose down, but I
would hesitate to open them while the nose was in the process of
approaching stall attitude.
I read the NTSB reports because it makes me think about contingencies:
"what could/should/would I do if....."
I learned last summer that I won't think of something new while
experiencing a non-standard (hairy) situation, so playing 'what it' is
very useful to me.

There was a story, for which I don't have a citation, about a checkride in a
piston airliner in the early 1950's. This shows that trim tab antics go
way back. I heard the story from one of the participants.

After settling in at cruise altitude, the check airman in the jump seat
decided to engage the control locks to, "see what the pilots would do". As
it happened, the control locks introduced a slight nose up elevator input.
The pilots started rolling in nose down trim to counteract the nose up trend
but, of course, this just made it worse. As the trim tabs reached their
nose down limits, the check airman decided his little 'joke' had gone far
enough and released the control locks.

The airplane now was configured with full nose down trim at cruise power
causing it to enter a screaming dive.

Only the captain was wearing his seatbelt so everyone else got intimate with
the overhead cockpits panels. The captain saved the aircraft, albeit with
structural damage, so the check airman lived to explain his actions to his
supervisors.

Bill D




"Udo Rumpf" wrote in message
...

You will have the similar limitation.
Once the elevator hits the stop(obstruction) moving the trim tap further
has no effect if anything it will be reversed as the trim tab now acts
alone and is in a down deflection.(in case of a nose up trim)
Udo


At 19:35 08 September 2008, Uncle Fuzzy wrote:
Sorry if this is boring, but the last discussion pretty much focused
on the release / rudder waggle. I can't get to the NTSB report just
now, but I seem to recall reading in the report on the OTHER incident
(loose hand held radio blocking forward stick movement) that the pilot
released, still couldn't get the nose down, then tried adding down
trim to bring it down. If the glider being flown at the time had a
spring trimmer, nothing will be gained by moving the trim. If the
glider had a tab on the elevator, pushing down trim effectively adds
more UP elevator. I often fly a Grob Twin Astir, and have played with
the trim quite a lot. Very useful in steep turns with a fat guy (me)
in the front seat. The trim tab has a surprising amount of pitch
authority. Spoilers might also be a way to get the nose down, but I
would hesitate to open them while the nose was in the process of
approaching stall attitude.
I read the NTSB reports because it makes me think about contingencies:
"what could/should/would I do if....."
I learned last summer that I won't think of something new while
experiencing a non-standard (hairy) situation, so playing 'what it' is
very useful to me.