Flight Control Failures

Following the thread on landing with one spoiler, I wonder what
proportion of landing accidents result from mechanical failure or
jamming of primary flight controls and spoilers/dive brakes. I
personally know of a couple of failures - one spoiler handle sheared
off as the pilot did his pre-landing checks and he landed safely
off-field and another had a pencil jam in controls, limiting control
movement, but again landed safely.

With the exception of incorrect assembly, I have to believe that
asymmetric control failure or jamming must be an extremely rare cause
of landing accidents compared to the more common reasons we all know.

Any actual data or good anecdotes?

Mike the Strike wrote:
Following the thread on landing with one spoiler, I wonder what
proportion of landing accidents result from mechanical failure or
jamming of primary flight controls and spoilers/dive brakes. I
personally know of a couple of failures - one spoiler handle sheared
off as the pilot did his pre-landing checks and he landed safely
off-field and another had a pencil jam in controls, limiting control
movement, but again landed safely.

With the exception of incorrect assembly, I have to believe that
asymmetric control failure or jamming must be an extremely rare cause
of landing accidents compared to the more common reasons we all know.

Any actual data or good anecdotes?

I read a story, in a Canadian soaring magasine about 20-25 years ago,
about a girl forced to bail out of here glider (HP-14?) because a loose
item in the cockpit had jammed the stick. Landed in a river and almost
drowned.

Anyone have the original article?

"Sid" wrote in message
...

I read a story, in a Canadian soaring magasine about 20-25 years ago,
about a girl forced to bail out of here glider (HP-14?) because a loose
item in the cockpit had jammed the stick. Landed in a river and almost
drowned.

Anyone have the original article?

This one?
http://www.soaridaho.com/Schreder/Stories/Bailout.htm

--
Geoff
the sea hawk at wow way d0t com
remove spaces and make the obvious substitutions to reply by mail
Spell checking is left as an excercise for the reader.

You don't have to look far from home. A Grob 103 had complete aileron
failure in flight after the arm broke off a torque tube at the weld
line. The rear seat pilot opened the inspection hatch and flew it to a
safe landing by working the aileron pushrods with his hand behind his
back. Afterwards he said he would have done a better job if he had
asked his into ride passenger to operate the airbrakes.

Andy

"Mike the Strike" wrote in message
oups.com...
Following the thread on landing with one spoiler, I wonder what
proportion of landing accidents result from mechanical failure or
jamming of primary flight controls and spoilers/dive brakes. I
personally know of a couple of failures - one spoiler handle sheared
off as the pilot did his pre-landing checks and he landed safely
off-field and another had a pencil jam in controls, limiting control
movement, but again landed safely.

With the exception of incorrect assembly, I have to believe that
asymmetric control failure or jamming must be an extremely rare cause
of landing accidents compared to the more common reasons we all know.

Any actual data or good anecdotes?


Rare, but not unheard of. Let's see: (Some of the following pilots prefer
to remain anonymous. I don't believe any of them practiced for these
eventualities.)

The owner/builder of an experimental glider that I am to test fly assures me
that a lead shot ballast bag in the tail is properly secured. However,
turbulence on short final tosses the unsecured shot bag into the control
mixer jamming the ailerons and elevator while shifting the CG forward. I
manage to hit the grass between runways at 70 Kts plus using rudder alone.
After a few bounces, I slide to a stop unhurt and without damage to the
glider. Damage to the relationship with the glider owner took a while to
repair, however.

Not directly glider related but perhaps of interest; after climbing through
a nimbostratus layer to subfreezing clear air above, I notice my ailerons
are frozen. Rainwater had frozen the aileron gap seals to the ailerons. I
flew on above the undercast using rudder to warmer air that thawed the
ailerons. I still worry about wet control gap seals. This could be a cause
of otherwise unexplainable mountain soaring accidents.

Zigging when I shoudda zagged results in a mid-air while flying a Pratt
Read. The wing damage produces significant asymmetrical lift and drag which
full aileron and rudder won't correct. Experimenting with spoilers restores
partial symmetry and sufficient control authority to land safely. The pilot
of the other glider, a 1-26, managed to land without a fin or rudder and
with impaired elevator control. I still get spooked when another glider
gets near me.

A near head on collision between a Libelle and a Foka destroys the Libelle
but does minor damage to the Foka. The Libelle pilot parachutes to safety.
The damage to the Foka includes a jammed canopy latch and release so the
pilot, having no other choice, lands safely.

A lady flying a 1-26 has the release knob come off in her hand. Taking a
few seconds to think about the situation, coolly reaches under the panel and
pulls the release cable.

Not directly controls related; an owner of a kit built 1-26A makes a first
flight after covering the glider. The poorly cemented top and bottom fabric
on the left wing departs leaving only a skeleton. The pilot lands saying he
didn't feel much asymmetry. This leaves me unsure just what parts of a 1-26
are actually needed for flight.

A ride pilot flying a 2-32 from the back seat draws a mental blank when he
tries to remember if he secured the rear control stick with the bolt and
safety pin. For a fleeting moment he considers pulling up on the stick to
see before thinking better of it. (The rear control stick of a 2-32 is
often removed to allow two small passengers to ride in the back seat.)

A USAF general officer riding jump seat in a B-36 fiddles with a lever
asking as he does, "What does this gizmo do?" thereby dropping three unarmed
nuclear weapons on Albuquerque, NM. Source: Kirkland AFB Nuclear Weapons
Museum.

There are many sagas of military pilots landing aircraft with jammed
controls and/or major parts of the airframe missing. The entire left wing
of a F-15 for example.

Of course, there's the DC-10 over Iowa.

Bill Daniels

I have had a pair of unused headphones wedge below a collective on a
helicopter. Learned real quick. There may be a number of cases where
non-attached items wedge themselves in to cause problems with controls.

Glider pilots often carry loose water bottles, gps receivers or cameras that
are waiting to find novel ways of lodging themselves.

Colin

Mike the Strike wrote:
With the exception of incorrect assembly, I have to believe that
asymmetric control failure or jamming must be an extremely rare cause
of landing accidents compared to the more common reasons we all know.

Any actual data or good anecdotes?

I did have the spoilers on a Libelle freeze shut in flight until shortly
before landing, and had a pushrod fail between the front and rear rudder
pedals on a Blanik L13 (we landed before it did any mischief). Dave
Noyes had a serious accident when a bolt in the elevator circuit of his
new DG 800 fell out.


--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

A story related to me from the east coast site where I once flew but after I
left there.

A 1-26 pilot wrecked the glider and had major injuries. He rebuilt it then
recovered it. They did a very thorough preflight as is required after doing
that type of thing. Only problem is that they confirmed the ailerons were
connected but didn't notice that they worked opposite of what they should
have. Pilot took off and released soon thereafter again wrecking the
glider. Pilot (different person) was uninjured. Cables were "crossed".

Casey Lenox
KC
Phoenix

As an 18 year old, I washed and waxed a J-3 for 2 hours
of instruction. After takeoff and turnout to the
left I discovered that the stick would not move to
the right. After landing, the instructor and I poked
around below the floorboards and found the cap to the
can of Johnson's wax jammed in the controls. We had
cycled the stick all around before takeoff, so it worked
its way into the jamming position somewhere between
the initial roll and the first turn.

At 01:30 01 October 2005, Kilo Charlie wrote:
A story related to me from the east coast site where
I once flew but after I
left there.

A 1-26 pilot wrecked the glider and had major injuries.
He rebuilt it then
recovered it. They did a very thorough preflight as
is required after doing
that type of thing. Only problem is that they confirmed
the ailerons were
connected but didn't notice that they worked opposite
of what they should
have. Pilot took off and released soon thereafter
again wrecking the
glider. Pilot (different person) was uninjured. Cables
were 'crossed'.

Casey Lenox
KC
Phoenix

"Bill Daniels" wrote in message
...
snippage

Not directly controls related; an owner of a kit built 1-26A makes a first
flight after covering the glider. The poorly cemented top and bottom
fabric
on the left wing departs leaving only a skeleton. The pilot lands saying
he
didn't feel much asymmetry. This leaves me unsure just what parts of a
1-26
are actually needed for flight.

more snippage

Gee, Bill, I thought everyone knew that in a 1-26, it's all the pilot!

Tim Ward