Seaplane down off Miami Beach....

The Chalk Island web site says that their airplanes were in
the shop for the engine changes and complete mechanical
refurbishment and new paint/interiors.

There should be some preliminary data released by the NTSB
before Christmas or New Year, I would expect.


--
James H. Macklin
ATP,CFI,A&P

--
Merry Christmas
Have a Safe and Happy New Year
Live Long and Prosper
Jim Macklin
wrote in message
ps.com...
| This news article
| (http://www.breitbart.com/news/2005/12/20/D8EKBRTG0.html)
says that the
| wing was recovered from the water today, and the engine
and prop are
| still attached. There's even a photo showing it. Looks
like the wing
| separated pretty well inboard of the engine. At this
point,
| speculation seems that either a fuel leak/fire melting the
spar... or
| perhaps just simple plain structural failure of the spar
with the fire
| happening afterwards could both possibly explain the wing
separation.
|
|
| Jim Macklin wrote:
| More likely that a fuel line was not properly safetied
or
| otherwise failed. Turbine engines have fuel pressures
as
| high a 1,000 PSI, so the fuel system in the engine is
highly
| stressed. The fuel supply pumps are high capacity and
50 to
| 100 PSI, so again, the fuel connections and lines are
| stressed.
|
| If there was a fuel leak into the nacelle, wing root
area,
| any source of ignition could cause an explosion and the
| resulting fire would soften the aluminum spar quickly.
The
| emergency procedure for a fire is to shut off the fuel
| valves, but if the failure was between the tank and fuel
| tank or the valve was damaged, it might not be possible
to
| shut the fuel off.
|
| The NTSB is very good at investigating this type of
failure,
| the will track melted and bent metal, see the pattern of
| soot and follow the fractures in the metal.
|
|

I'm wondering if fitting turbine engines on the old airframes
didn't pull something loose in the wing/mount.

Turbines run a whole lot smoother than the round Pratts that were on
originally. They don't have the power pulses that radial engines have.
I'd agree with the other posters that it sounds more like a
leaking/broken fuel fitting that went bad, ignited and led to
structural failure.

wrote in message
ups.com...
I'm wondering if fitting turbine engines on the old airframes
didn't pull something loose in the wing/mount.

Turbines run a whole lot smoother than the round Pratts that were on
originally. They don't have the power pulses that radial engines have.

I assume he was referring to the increased thrust that was probably obtained
with the turbine installation, which would create higher forces on the
structure transmitting that thrust to the airframe.

Of course, one would think that in a turbine retro-fit, that structure would
be upgraded to compensate. Hopefully, that's not actually the problem.

But I don't think Otis was suggesting that turbines would cause more fatigue
due to vibration than the original engines.

Pete

I assume he was referring to the increased thrust that was probably obtained
with the turbine installation, which would create higher forces on the
structure transmitting that thrust to the airframe.

I assumed the same. The round Pratts were 550hp engines, and the STC'd
PT6A-27 engines are flat-rated to 650hp. While the increased thrust
might add stress, my assumption was the weight reduction of the
turbines and their much smoother operation might nullify the power
increase as it relates to airframe stresses. It seemed a safe
assumption that that's what he was suggesting.

wrote:
I'm wondering if fitting turbine engines on the old airframes
didn't pull something loose in the wing/mount.

Turbines run a whole lot smoother than the round Pratts that were on
originally. They don't have the power pulses that radial engines have.

Not that they aren't subject to resonance issues. Remember the Electra?

Reports I saws this morning said that the NTSB said they
found a fatigue crack in the main spar, maybe the conversion
was not done well or the maintenance was not though enough.
I'll bet the fleet is grounded and they require immediate,
"before further flight" NDT inspections of the wings, etc.


--
James H. Macklin
ATP,CFI,A&P

--
Merry Christmas
Have a Safe and Happy New Year
Live Long and Prosper
Jim Macklin


"Ron Natalie" wrote in message
m...
| wrote:
| I'm wondering if fitting turbine engines on the old
airframes
| didn't pull something loose in the wing/mount.
|
| Turbines run a whole lot smoother than the round Pratts
that were on
| originally. They don't have the power pulses that radial
engines have.
|
| Not that they aren't subject to resonance issues.
Remember the Electra?

Jim Macklin wrote:
My guess is that they had a loose or broken fuel line,
caught fire and the fuel vapor exploded and the fire melted
the spar enough for it to fail.. The airplane seems to have
been very sturdy, since the fuselage is intact after the
impact.

Any information as to what altitude they were cruising at? It seems
like it would take a minute or more to soften a spar enough to fail, but
maybe the pilot wasn't aware he had a problem in time. Then again, it
may have been something else entirely. I wonder if they could have hit
a gull or something like that also and cause a problem.


Matt

Bird strikes are common, but Grumman was called the Iron
Works for a reason, they built tough airplanes. Aluminum
melts at 1100 degrees F and has lost most of its strength at
500 degrees. Kerosene fire is high heat and energy, failure
could happen in 10-15 seconds [guess].


--
James H. Macklin
ATP,CFI,A&P

--
Merry Christmas
Have a Safe and Happy New Year
Live Long and Prosper
Jim Macklin
"Matt Whiting" wrote in message
...
| Jim Macklin wrote:
| My guess is that they had a loose or broken fuel line,
| caught fire and the fuel vapor exploded and the fire
melted
| the spar enough for it to fail.. The airplane seems to
have
| been very sturdy, since the fuselage is intact after the
| impact.
|
| Any information as to what altitude they were cruising at?
It seems
| like it would take a minute or more to soften a spar
enough to fail, but
| maybe the pilot wasn't aware he had a problem in time.
Then again, it
| may have been something else entirely. I wonder if they
could have hit
| a gull or something like that also and cause a problem.
|
|
| Matt

Merry Christmas
Have a Safe and Happy New Year
Live Long and Prosper
Jim Macklin


Go **** yourself

Matt Whiting wrote:

Merry Christmas
Have a Safe and Happy New Year
Live Long and Prosper
Jim Macklin



Go **** yourself


I've reported this impersonater to hotmail, but who knows if they will
do anything about it.

Hopefully, anyone who has read my posts in the r.a.* newsgroups over the
years, knows that I don't use language like this.

Matt