twin otter landing on floats

[jxc]

if one was landing a Twin otter with floats on to a lake which is frozen I assume they land on the wheels but what happens if it is not frozen enough would it turn into a crash ?

[neilgeddes]

I wonder if with a light covering of snow whether a wheels up landing is possible and preferable?

[Pilot DAR]

Hmmm, Odd question. A few associated thoughts;

Very few Twin Otters are amphibious. I would highly doubt that the pilots of those few which are, would contemplate a landing on the ice of a frozen lake on wheels, unless that ice was so thick, and tested, that breaking through was not the least in doubt. Ice thicknesses exceeding 18 inches, with no change in characterisitics along the path, would be a safe number.

It is only under extreme circumstances that a floatplane is landed on snow or bare ice. Knowing the type of ice is vital under these circumstances. The explanation is too much for a post here. I have done this three times. Twice an amphibious landing gear problem where a bare ice landing had the least potential for damage to the floats (one side wheels up, the other side wheels down). It worked fine, but certainly has the potential for damage if you hit a frozen bump in the ice. My other time was landing a floaplane with a broken bracing wire (floats flopping) on the ice, then dropping it purposefully into the water at low speed to get to the dock for repairs. If the floats had collapsed, I could stop on the ice, and [hopefully] not sink. They did not, so I taxiied to the dock very gently with a sagging airplane.

Landing float planes in snow is permitted in Canada, but again rarely done. There is huge potential to damage expensive floats, and when the plane comes to a stop, there are rather challenging logistics as to how to steer and handle it on the ground, so it can be readied for takeoff. Such extreme operations are normally only done to fly a floatplane to or from seasonal changeover at an airport, with a known runway (usually grass under the snow) and only then with great caution.

Floats are easily damaged, and expensive to repair - particularly Twin Otter floats!

[RatherBeFlying]

In my faraway youth, I saw a TV news item where the floatplanes landed on wet grass for their changeover to skis. These were all SEPs. As PDAR observes Twotter floats are much too expensive.

[jxc]

I only ask as looking at a project where there are not many airfields but lots of lakes and in the north quite cold in winter and lakes frozen and the south mild so trying to work out how the Twotter could operate from a lake in the south then land on the lake in the north

[Pilot DAR]

These operations are very well planned, with lots of information. Added to that, certain times of the season, the operations are just not possible. If the lakes are open in the south, and floats are being used, the operations would not extend far enough north that frozen operations are considered with the same plane. If you have frozen lakes, it is extremely unlikely that an amphibious aircraft is being used. You would be on wheels/skis/wheelskis, and operating only from the hard surface.

Amphibious operations are not great when going from above to below freezing temperature zones in one flight, particularly if you've taken off from the water. The wheel gear can become less than dependable - ask me how I know!

[downnorth]

Up here we usually remove the float aircraft from the water just before freeze up. On occasion towards the end of the float season we land on lakes which are starting to freeze and are partially frozen. The ice is generally very thin, much less than 1 centimeter thick. You can taxi very slowly and do some ice breaking, no big deal. You just really need to know what you are doing and not recommended on an unfamiliar lake for obvious reasons.

As Pilot DAR mentioned landing a float airplane on thick ice is not a good idea. It can however be done in an emergency situation. If you are landing a float aircraft on ice, how did you manage to get it off a frozen lake in the first place? I guess this might be a situation an amphibian operator can run into. I cannot imagine being able to take a loaded Twin Otter from an area where it is warm enough to take off from a lake then land in an area where the lakes are completely frozen. Range is certainly not one of the aircraft's strengths.

We have several configurations for our Twin Otter operation. We use floats, small wheels, intermediate wheels, large tundra wheels, skies (planks) and wheel skies. We do not use amphibious floats due to the additional weight.

This time of year most lakes are now frozen but not frozen enough to land on skies or wheel skies. If a customer needs to get to a lake we try to find an esker to land on using the big tundra wheels. If the nearest esker is far from that lake, some customers choose to load a few snow mobiles or four wheeler ATV's and bushwhack to their location. By mid December/early January the lakes will be good and frozen and the ice will be thick enough for the ski aircraft operation.

The rule of thumb for our fleet in regards to landing on ice is as follows: Cessna 185 6 inches thick, Turbo Beaver 12 inches thick, Twin Otter 18 inches thick, Dash-7 33 inches thick. If landing on sea ice add 75%.

We do land wheeled aircraft on ice. It is not a huge deal as long as we know the exact conditions of the ice. In a few weeks ice strips will start appearing on many of the lakes. These strips are properly groomed and maintained and are ideal for wheel aircraft.

To give you an idea check out a few photos of our airplanes operating on lakes and the frozen ocean.

http://farm5.static.flickr.com/4061/5166530081_2da981c7ef_z.jpg (http://www.flickr.com/photos/downnorth/5166530081/)

http://farm5.static.flickr.com/4086/5167122786_93257b6fb5_z.jpg (http://www.flickr.com/photos/downnorth/5167122786/)

http://farm5.static.flickr.com/4104/5167122536_55c6867426_z.jpg (http://www.flickr.com/photos/downnorth/5167122536/)

http://farm5.static.flickr.com/4145/5166523621_09a1f6b9dd_z.jpg (http://www.flickr.com/photos/downnorth/5166523621/)

http://farm2.static.flickr.com/1367/5166523789_5c4af0bb5d.jpg (http://www.flickr.com/photos/downnorth/5166523789/)

http://farm5.static.flickr.com/4088/5166524035_e69c17c0c5_z.jpg (http://www.flickr.com/photos/downnorth/5166524035/)

http://farm2.static.flickr.com/1208/5167122980_e5984da232_z.jpg (http://www.flickr.com/photos/downnorth/5167122980/)

Last float trip of the season before heading to the airport for float removal and installation of wheels or skies:

http://farm5.static.flickr.com/4017/5167278254_7ec17dff94_z.jpg (http://www.flickr.com/photos/downnorth/5167278254/)

[jxc]

I like the 3rd photo looks like the FO is doing a mooney out of the window maybe a bit cold for that


Where I am looking it's not the distance as it is only around 200miles but in the north it is in the mountains

[treadigraph]

About 25 years ago I zapped past Popham on the A303 and there was a Cessna 180 on floats (G-BKMM?) sitting on the grass by the hangar. It had been landed on the grass for conversion to landplane config.