A Grumman Mallard (one of my favorite planes) operted by Chalks Ocean Airways has crashed. It is beleived all aboard (2 crew, 17 passengers) have died 
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Being a seaplane pilot is one of my “dream jobs” - something I think about but am unlikely to do anything about.
Chaulks is arguably the oldest US commercial airline, founded in 1919. This is thier 1st passenger deaths (in 1994 a pilot and co-pilot died)
Brian
Been watching the coverage on CNN. Well, not watching watching. But it’s been on. Seems they haven’t gotten the experts they had for other aviation (i.e. ‘plane in trouble’) stories.
Looked like a wing exploded?
New video. It looks like the starboard wing departed the aircraft, and was on fire.
I did a college internship at a company that builds floats and reconditions old DeHavilland Beavers. There’s a lot to know to fly off the water, but it’s fascinating stuff.
Let’s see,
Plane catches fire and may have broken up before crashing and killing all aboard.
It was a seaplane, one of the few commercial planes that doesn’t take off from an airport. The relative lack of formality and security was what makes planes like that appealing to some.
Christmas is just around the corner.
If the plane had headed towards downtown Miami maybe, but 20 people seems an awfully small target.
Brian
Uncontrolled engine fire burning through the wing would be a more likely scenario.
I agree that a problem with the aircraft is more likely than an intentional downing.
Question: What is the engine-fire record of the Pratt & Whitney PT6?
Okay, I think we all have our ratings here. Right? So you’ll understand if I do a bit of amateur post-crash analysis (with the caveat that we don’t know anything until the NTSB report comes out).
The smoke trail seemed fairly short. In my non-professional opinion I would guess that the aircraft suffered a sudden, catastrophic failure. If there had been a slow fire, I think one of the passengers (who were probably looking out the windows – I know I do) would have noticed something. I think the pilot may have had time to make an emergency landing. (Is it still ‘ditching’ in a seaplane?) But the short smoke trail and the seemingly immediate nature of the steep dive indicate, to me, a non-professional, that the failure was sudden. i.e., I’m guessing there was an explosion.
What would cause an explosion? Obviously a bomb would. Only as Ray points out, it’s a pretty poor target for a terrorist considering other available targets. Jet fuel is less volatile than avgas (lower ‘octane’, as it were – although kerosene doesn’t use ‘octane’) but as was seen in TWA Flight 800 its vapours are capable of an explosion under the right conditions. Why would Jet-A explode? An electrical fault, as in TWA 800? Maybe.
Or a catastrophic failure of the engine might cause a turbine blade to puncture the fuel cell. If that fuel sprayed onto the hot engine, I believe the result would be explosive. Which brings me back to the question of the P&W PT6. I have not made any studies, nor even casual observation of failures of these engines. AFAIK they are one of the most reliable powerplants in the industry. I personally have not heard of even one of them flying apart. I just don’t have the data.
I’m guessing that the fuel cell was punctured in some way, possibly by a turbine blade, causing fuel to spray on the hot engine causing a fast fire/explosion that severed the starboard wing.
I am not a crash investigator. The only data I have is the video I saw on the news. We really won’t know anything until the official investigation has been completed and the NTSB releases its report – which tends to take a rather long time. But that’s my non-professional theory.
The G73T seems to have the engines entirely forward of the wing. The PT6 isn’t all that long, being a reverse-flow design, and the hot section is up front anyway. A hot-section failure would involve the fuselage, not the wing, except for secondary damage from perhaps a severed fuel line.
This happened *right * after takeoff, for another thing, so a liquid-fuel-initiated fire doesn’t seem like it would have enough time to act. I’d vote for a fuel-vapor explosion as my top suspect. I’ve read elsewhere (can’t put my finger on it) that Chalk’s had a plane hijacked to Cuba once, and ever since their policy has been to never have enough fuel on board to get there (and it’s only a little farther than their normal south-Florida-Bahamas routes). That leaves a helluva lot of empty space in the tanks for fuel vapor to collect.
Just guessing, like everyone else, though.
Your theory sounds better than mine.
Only I can’t help thinking of the thousands of turbine-powered aircraft that fly with partial tanks. The only other aircraft I can think of whose vapour-filled fuel cell exploded was TWA 800, mentioned earlier. (Not to say it hasn’t happened to other aircraft, just that that’s the only one I can think of. Oh, wait. There was Apollo 13, after a fashion.) What could have caused the spark, if that indeed was the cause? The Grumman was an old aircraft, but the turbines are a more-or-less ‘modern’ upgrade. Being a relatively small aircraft, I would think that frayed wiring would have been spotted in the 100-hour or Annual inspections. OTOH, seaplanes operate in a fairly harsh environment. I’ve never flown a float plane, but I have the impression that the take-offs and landings – especially in open water – may be a bit bouncy. Severe vibrations or shocks can cause damage that may go unnoticed between inspections.
Does anyone (N91WP?) know the Mallard well enough to know what may have ignited fuel vapours, how the wiring goes, etc?
More.. There have been 2 737’s destroyed by center-tank explosions, one in Manila, one in Bangkok. I’ve seen references to a KC-135 having it happen in England, too. Other incidents that hadn’t, or couldn’t, have their causes determined might be added to the list.
Sorry, don’t know anything about the fuel / electrical system of the Mallard.
Brian
Video on CNN shows the seaplane falling into the water with the fuselage, tail, and at least one wing and engine intact. This was closely followed by flaming wreckage of what appears to be other wing and engine.
Paul Harvey, radio guy and amateur NTSB investigator, announced that he suspected metal fatigue, then said that the real investigation will not be finished for several months. I think I’ll wait for the feds to find out what caused the crash. For now, I will grieve for the 20 lives lost.
Before I looked at any fuel tank explosions, I would be more worried about structural failure. Remember the Aloha Airlines 737 with a sunroof? 
Seaplanes live in a very hostile corrosive environment. Salt water eats aluminum. Little bit of corrosion on this spar, that spar, and before you know it the wing fails. When the wing fails, fuel leaks, sparks fly, fire starts.
I was watching CNN when this happened, and noticed that for the first fifteen or twenty minutes, they kept talking about a “hydroplane” that had crashed – then they switched over to “seaplane” without comment.
Very confusing. It didn’t help much that they also had a guy from the Coast Guard on the phone and kept asking questions of him even though he clearly said that the only source of information he had at the time was the TV he was watching, tuned to CNN. “What can you tell us about the weather?” “Well, I’m nowhere near the scene, but from what I can see on the TV, it looks pretty clear.” Aye-yah.
Possibly, only AFAIK Mallards aren’t pressurised. Many pressurisation cycles is a contributing factor in metal fatigue. But yeah, spars have been known to fail through corrosion.
That really sucks. My thoughts are with those families.
Being stationed at the CG base there twice, I’ve watched that plane land and take off in the cut hundreds of times (and dodged it a few times as well). I was always amazed how they operated in one of the busiest waterways in the US as the least privileged ‘vessel’ on the water without any mishaps.
I suppose one small fortunate aspect of this tragedy is that it could have been much worse, given the volume of traffic in that waterway.
Suppose this crash will be the death knell for the already fast-disappearing flying boat fleet?
I don’t think so. They are really needed in places like Alaska. Hawaii, and the Caribbean. I go to the USVI fairly often and seaplanes are the best way to take quick trips to other islands. A boat is way too slow for a 50 mile trip and a real airport is too large, time-consuming, and expensive.