Water scooping Q

Let'sgoflying!

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Dave Taylor
Regarding firefighting aircraft that scoop water, ie the Canadair.
Is it the case that they scoop because a full water-load takeoff may not be possible due to weight?
I realize the main reason is probably to allow for the speediest turn-around - but I was wondering about take-off weight limitations.
(follow on Q’s might include, can they offload water if they find themselves on a lake, full?)
 
Let'sgoflying! said:
but I was wondering about take-off weight limitations.
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I dont know about the Canadair but the Air Tractor Fire Boss on amphibs is normally ground-loaded with water prior to take off. Helicopter ops would also usually keep a tank of water at the departure point so they could fill their Bambi buckets prior to leaving as well.
EDIT:
The Fire Boss has a max take off weight of 16,000lbs (land) and a max scoop weight of 16,000lbs.
The CL-415 has a max TO weight of 43,850 lbs (land) and a max scoop weight of 47,000 lbs.
 
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Speed. Faster to scoop than to land, fill, take off.
 
Let'sgoflying! said:
Regarding firefighting aircraft that scoop water, ie the Canadair.
Is it the case that they scoop because a full water-load takeoff may not be possible due to weight?
I realize the main reason is probably to allow for the speediest turn-around - but I was wondering about take-off weight limitations.
(follow on Q’s might include, can they offload water if they find themselves on a lake, full?)
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It could be, Dave. But I think the real reason is that it is faster to on load the water by scooping it. Not to mention the improved takeoff performance of a lightly loaded aircraft. Kind of like aircraft taking off from an aircraft carrier with minimum fuel and hooking up to the tanker to top the fuel off.
 
Large fires are rarely convenient to an airport and airports are rarely convenient to large water sources. It's a lot faster (gallons on the fire per hour) to scoop from a lake (or, for helicopters, a pond) near the fire than to fly back to an airport and fill up from a hose at the FBO.
 
Thanks - I was wondering how they loaded water; I happened to be in White Salmon and Hood River right when the "tunnel five" fire started and planes looked like the were almost certainly collecting water from the Columbia river, but the actual collection point and process was out of view for me. You can't see the river here but it's behind the building, between me and the fire.

t.jpg
 
Think about it, unless conditions were truly adverse, I don’t see how it would allow one to scoop more water/weight than the plane could handle. I will say it could be big weight changes, empty to full, then empty at release. Kinda like a jump plane, allowances figured out ahead of time.

There were some firefighter airplanes positioned at SAW near Marquette MI 6 weeks ago. They were newer models, capable of scooping water. I talked to one of the operators some, asking max wave height & some other details.
 
I was imagining a situation where the scooping failed, ie the pilot inadvertently allowed the aircraft to settle onto the surface when it was almost full, whoch I could easily see, especially a new pilot in training, and it might not have enough power to become airborne again.
 
Let'sgoflying! said:
I was imagining a situation where the scooping failed, ie the pilot inadvertently allowed the aircraft to settle onto the surface when it was almost full, whoch I could easily see, especially a new pilot in training, and it might not have enough power to become airborne again.
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All modern fire water tanks have an emergency dump system required by certification so even if they have a scoop failure all the water will dumped via the fire gate so no real issue. Even helicopters with onboard fire tanks have this system. As to the training at least on the Fire Boss each pilot is required to specialized training due to the type rating exemption for the Fire Boss given its max weight of 16,000lbs. I never worked on a Fire Boss but did work helicopter fire ops and shared a hangar or two with their mx guys. Definitely an interesting aircraft complete with computerized tank controls.
 
Let'sgoflying! said:
I was imagining a situation where the scooping failed, ie the pilot inadvertently allowed the aircraft to settle onto the surface when it was almost full,
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Or the possibility of accidentally picking up a scuba diver and depositing him in the middle of a fire...

(I know...:lol:)
 
The airplane uses the dynamic pressure of the water to fill the tanks.

:)The scoops are small and could never scoop up the scuba diver as per the urban legend. Maybe take a chunk out of him, though...


Apparently this one landed with the scoops down, filling the tank and then falling off plane and couldn't get back on plane again.
 
iamtheari said:
Large fires are rarely convenient to an airport and airports are rarely convenient to large water sources. It's a lot faster (gallons on the fire per hour) to scoop from a lake (or, for helicopters, a pond) near the fire than to fly back to an airport and fill up from a hose at the FBO.
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Exactly. It's VERY impressive to watch a fleet of these in operation and then imagine the volume of water being dumped on remote fires from remote lakes without the steps of transferring from a water source to a tanker then a tanker to an aircraft. There's a time-consuming, cost consuming set of steps in there that can be completely eliminated.
 
Dan Thomas said:
this one landed with the scoops down,
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Looks more like his floats were flooded or his gear was partially down. Takes at least 60 mph and 10 seconds to scoop fill the hopper which he could dump if that was the case. Regardless, to continue his taxi wasnt too smart unless he was sinking.
 
Some planes have larger scoops.

en.wikipedia.org

Canadair CL-415 - Wikipedia

en.wikipedia.org en.wikipedia.org

Most of the scoop planes I have seen are basically an amphib, so scooping is a touch and go on the water.
 
Bell206 said:
Looks more like his floats were flooded or his gear was partially down. Takes at least 60 mph and 10 seconds to scoop fill the hopper which he could dump if that was the case. Regardless, to continue his taxi wasnt too smart unless he was sinking.
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aha.
can they sink if on water and a full load?
 
Let'sgoflying! said:
can they sink if on water and a full load?
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If the float(s) were physically compromised sure. Other than that doubtful. However, a quick look at the specs shows the Fire Boss max take-off weight is limited to 11,500 max wt on water and 16,000 max on land. Landing weights are 11,500 on water and 12,300 on land. Given the scoop ops are normally automated the pilot would have to be intent on screwing up to take on a full water load that exceeded those limits. Regardless, he could still dump the entire hopper via the normal or emergency gate systems.
 
deyoung said:
Thanks - I was wondering how they loaded water; I happened to be in White Salmon and Hood River right when the "tunnel five" fire started and planes looked like the were almost certainly collecting water from the Columbia river, but the actual collection point and process was out of view for me. You can't see the river here but it's behind the building, between me and the fire.

View attachment 118859
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When we landed at The Dalles, Sunday around noon, there were no SEATs at the airport. I am guessing they were fighting this fire. Early Monday am there were three on floats. Early to mid Tuesday am there was two plus a twin commander that I guess was an observer.
 
Let'sgoflying! said:
aha.
can they sink if on water and a full load?
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The AOPA article made it sound like that was a certainty if they took on a full load and didn't stay on the step. If that happens, you dump the load (which lives in the nose, not in the floats, so it can still dump), take off empty, and try again.

So, either the pilot in this case didn't know that, or @Bell206 was right and the floats were flooded or something else caused them to not be able to dump. In any case, I think I'd have probably quit trying after the *first* time the prop hit the water instead of continuing the futile attempts until it sucked in enough water to kill the engine. That can't be good for it...
 
I saw a Blackhawk fire fighting machine and talked to the pilot, was a really cool piece of equipment. IIRC it picks up 1000gallons of water in seconds or a minute. It was fast.
 
flyingcheesehead said:
The AOPA article made it sound like that was a certainty if they took on a full load and didn't stay on the step. If that happens, you dump the load (which lives in the nose, not in the floats, so it can still dump), take off empty, and try again.

So, either the pilot in this case didn't know that, or @Bell206 was right and the floats were flooded or something else caused them to not be able to dump. In any case, I think I'd have probably quit trying after the *first* time the prop hit the water instead of continuing the futile attempts until it sucked in enough water to kill the engine. That can't be good for it...
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How else do you clean the inside of the engine?
 
Plano Pilot said:
When we landed at The Dalles, Sunday around noon, there were no SEATs at the airport. I am guessing they were fighting this fire. Early Monday am there were three on floats. Early to mid Tuesday am there was two plus a twin commander that I guess was an observer.
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Yeah, when I took this picture there were at least 5 planes dropping water on it. Their round trip time was under 10 minutes, I'd say, though I didn't time it.
 
deyoung said:
there were at least 5 planes dropping water on it.
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They use the FB 802 aircraft in groups for the best attack profile with some missions they're able to put more water/retardent on the fire than larger airplanes for the same cost. And in some areas those 802s have replaced helicopters for initial attack runs. An interesting aircraft that changed the rules some thought couldnt be changed when fighting fires from the air.
 
The Commanders are popular with the firefighting companies as "bird dog" aircraft. They're fast enough to stay up with or ahead of the big, fast bombers. A company pilot flies it, and a trained fire control officer is in the right seat. He directs the bombers from above, and often the bird dog will make a run along the path and altitude that the officer wants the bomber pilot to do.

The big bombers cost a fortune to operate, and the red fire retardant compound is fearsomely expensive, too.
 
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