Skymaster Arctic Circle Ditching.
 

Amigos,

A 337 apparently just ditched south of the Anctic circle when both engines stopped turning. Both occupants survived, according to the BBC article at the following address:

http://news.bbc.co.uk/1/hi/world/americas/7773046.stm

Does anybody know what happened to cause both engines to stop?

purely speculation, and dependent on altitude, but Brian Von Herzon has said that if the temp is below -34, fuel does not flow. There is apparently a placard on Malibu Mirages limiting operations due to temp. That is because the Mirages don't have fuel heaters. Neither do Skymasters.

Larry,
I am not sure about that, only because I flew my P210 at FL230 at -40 ( C of F, your choice!) for 3 hours and had no problems. The P210 has no fuel heating either. I have read of dissolved water in fuel crystalizing out at very cold temps and clogging fuel systems though. That is why Cessna suggested Prist or Isopropyl Alcohol be added to the fuel if operations in very cold temps were anticipated. There were a few paragraphs about this in the P210 POH, as well as a graph showing how much Prist or Isopropyl Alcohol to add. The other Cessna P twins have oil heated fuel spiders I think.

As i said, it's speculation.
it's been so long since I heard Brian talk about that, my memory is hazy.
Maybe a brain cloud :D

This is really ironic because I sold a dozen or so SOAPA t-shirts from the 2008 fly in to Troels Hansen. The Skymaster was in Ohio having a major avionics upgrade. Troels had told me that he was going to be flying the aircraft back to Sweden. I assumed it was his Slymaster but appearently not. Nice guy, I am really glad to hear they are alive. They are really lucky. Too bad about the aircraft though.

http://www.theglobeandmail.com/servl.../National/home

http://www.avweb.com/eletter/archive...ll.html#199361

That just made my heart stop when I read his name.

The photo is just incredible

Maybe they will be in the states next year, and will come and talk about it.

They are two very lucky fellows. God was smiling on them that day for sure.

Daev

I agree they were so fortunate!!! Yikes!! I can't imagine a worse place to have to land, except the freezing water with no ice. It is too bad we will never know what really stopped both engines. Good comments on a lot of sites about being prepared for this sort of situation though.

Hello all Skymaster freinds.
I am presently in Iqaluit. I only have minor injuries. I will write my story in this forum when I get home to Sweden. Thank you for all the kind words and thoughts. I sure leaned about survival from this.
Regard Troels Hansen (former Skymaster owner)

we are all thankful you are alive.

From AOPA Online:



Arctic rescue saves ferry pilots
Skymaster makes forced landing on ice floe

By AOPA Publications staff

A Cessna 337 Skymaster on a transatlantic ferry flight made a forced landing on an ice floe near remote Baffin Island on Dec. 7, and the two pilots survived 18 hours in sub-zero temperatures by walking.

The twin-engine, centerline-thrust airplane reportedly lost power in both engines and went down on an ice floe. But the ice was less than a foot thick, and the plane broke through and sank, taking the pilots’ life raft and survival gear with it.

With no food, shelter, or fuel for a fire, pilots Oliver Edwards and Troels Hansen, who both live in Sweden, paced through the night as temperatures dropped to minus 20 C and into the next day before a shrimp trawler located them Monday. A Canadian military helicopter brought them to Iqaluit, a small town on the southern tip of Baffin Island, where they were reported in good condition.

“They were very healthy,” Bo Mortensen, captain of the Atlantic Enterprise, the trawler that located them, told the Canadian Globe and Mail newspaper. “One of them was frostbitten on his feet. They were smiling and crying.”

The pilots wore survival suits designed for water landings. They had taken off from Labrador for what they expected to be a two-to-three-hour leg on their overwater journey to Europe. When both engines failed, they made emergency radio calls, and a Canadian rescue center in Halifax coordinated the search. The Atlantic Enterprise was about 180 miles away from the place where the airplane touched down.

Both pilots escaped the sinking airplane through the side windows.

D

Considering the possible factors leading to ditching
 

Greetings fellow SkyMaster pilots:

Thinking about the double engine failure of the SkyMaster recently off Baffin Island, several thoughts come to mind.

The sort of things that commonly cause double engine failures include:

1. fuel contamination
2. fuel system icing
3. induction air icing
4. dual-engine vapor lock
5. fuel starvation

The distance from Wabush NL to Iqaluit is 652 nautical miles. According to Wunderground, surface winds were 10 knots out of the south or east, resulting in a tailwind or cross wind, not much to worry about. With 7-8 minutes to landing, they could have been at about 4500 feet when the engines stopped (the MEA for the region).

The weather at Wabush was light snow and -10 to -8 celcius. Assuming dry adiabatic lapse rate of 3C per 1000 feet, at 4000 feet they would have had temperatures of -22C, not low enough to gel the fuel. Minimum temperature at Iqaluit was -17C that day, or -29C at 4000 feet, probably still not quite enough to gel the fuel. Conditions were probably warmer than that, given the high level of moisture (enough for it to snow most of the afternoon). So gelling the fuel is improbable given the temperatures.

Cessna says to add 1% anhydrous isopropyl alcohol if the aircraft will spend much time at minus 30C or colder. Note that there is a lot of heat capacity in the fuel, so it takes a few hours to cold soak the fuel enough for it to gel.

The light snow for several hours before departure suggests the hypothesis that ice could have accumulated on the air induction system. I have never had a problem of this sort, even when flying for over an hour in ice accumulation regions (not recommended). Also it would seem improbable that the two engines would ice over at nearly the same time, especially given the assymetric configuration.

Fuel contamination would seem to be ruled out unless they had just started drawing fuel from alternate tanks, but even then you would imagine that all tanks were filled from the same source in Wabush, so the main tanks should have failed much earlier unless the contaminant was much more concentrated in the aux tanks than in the main tanks.

One other possibility is that of vapor lock. In the T337G modified that I fly, it is very common to have fuel interruption in one engine as we climb through 11,000 to 13,000 feet, especially at low fuel flows. The fuel seems to vaporize in the injector lines, even more so when the fuel flow is low as the fuel has more time in the line to vaporize due to the lower flow rate. Did the pilots turn on the low pressure fuel boost when the first engine lost power? Still, these heating effects tend to be assymetric on the front and rear engine, and would not typically result in both the front and rear engines quitting within minutes of each other after 3-4 hours of operation. The best timer of this sort are the fuel tanks themselves.

Pilots go to great lengths to match the fuel flows of front and rear engines. The fact that the two engines quit within minutes of each other provides a lot of useful information. Some SkyMasters have electromagnetic wiggle pumps for transferring fuel from aux to main tanks. I often have these freeze up on me in cold weather, especially if there is a bit of moisture in the fuel. Ice may accumulate in the pump itself (or water that freezes on takeoff). The net result is that it is common for these pumps to freeze within the first hour of operation (when you can't pump the fuel because the main tanks are too full). By the time the second hour rolls around, the wiggle pumps may be already frozen, resulting in dead fuel in the aux tanks.

Skymasters have so many tank configurations that it can be hard to determine how much fuel these main tanks had. However, based on where the engines quit, they were airborne for approximately 3 hours and 42 minutes. We should probably hear from the pilots themselves about their fuel management approach and what they observed.

Given that pilots tend to actively manage their fuel flows to keep them nearly equal, and given the short amount of time between the first and the second engine quitting, and given that fuel contamination, dual-engine vapor lock, fuel icing and induction icing seem improbable (and produce different symptoms), we should consider the possibility of fuel starvation more carefully. Such fuel starvation could of course be caused by the inability to transfer fuel from one tank to another. The pilots may be able to tell us in detail what fuel management they used, what tanks were available, and what the state of their fuel was on takeoff. From that information we might be able to learn more about the nature of the problems they encountered.

By the way, one thing I learned from reading about this experience was the essential need for good waterproof lighting around your neck (to signal the helicopter!). The best one I have found is a green laser flare from Greatland Laser. 30 mile range signaling to an aircraft at night! I am just blown away that you can actually see this pen laser from 30 miles away with the naked eye, but I believe it! Equipped has a good article:

http://www.equipped.org/rescuelaser.htm

https://www.greatlandlaser.com/index.php?productID=162

I haven't tried it yet and have no affiliation with the company.

Weather at Wabush NL(departure) the day of the ditching:

10:53 AM 14.0 °F / -10.0 °C 10.4 °F / -12.0 °C 86% 29.75 in / 1007.3 hPa 1.5 miles / 2.4 kilometers ESE 6.9 mph / 11.1 km/h / 3.1 m/s - N/A Snow Light Snow

11:00 AM 14.0 °F / -10.0 °C 10.4 °F / -12.0 °C 86% 29.86 in / 1011.1 hPa 1.4 miles / 2.2 kilometers ESE 6.9 mph / 11.1 km/h / 3.1 m/s - N/A Snow Light Snow

12:00 PM 15.8 °F / -9.0 °C 12.2 °F / -11.0 °C 86% 29.84 in / 1010.3 hPa 2.0 miles / 3.2 kilometers SE 8.1 mph / 13.0 km/h / 3.6 m/s - N/A Overcast
12:05 PM 15.8 °F / -9.0 °C 12.2 °F / -11.0 °C 86% 29.72 in / 1006.3 hPa 2.0 miles / 3.2 kilometers ESE 6.9 mph / 11.1 km/h / 3.1 m/s - N/A Snow Light Snow

1:00 PM 15.8 °F / -9.0 °C 12.2 °F / -11.0 °C 86% 29.81 in / 1009.4 hPa 1.2 miles / 2.0 kilometers ESE 9.2 mph / 14.8 km/h / 4.1 m/s - N/A Snow Light Snow

2:00 PM 15.8 °F / -9.0 °C 12.2 °F / -11.0 °C 86% 29.79 in / 1008.6 hPa 1.1 miles / 1.8 kilometers ESE 9.2 mph / 14.8 km/h / 4.1 m/s - N/A Snow Light Snow

3:00 PM 17.6 °F / -8.0 °C 14.0 °F / -10.0 °C 86% 29.77 in / 1008.0 hPa 2.1 miles / 3.4 kilometers ESE 10.4 mph / 16.7 km/h / 4.6 m/s - N/A Snow Light Snow

4:00 PM 17.6 °F / -8.0 °C 14.0 °F / -10.0 °C 86% 29.76 in / 1007.8 hPa 0.6 miles / 1.0 kilometers ESE 10.4 mph / 16.7 km/h / 4.6 m/s - N/A Snow Light Snow

4:19 PM 17.6 °F / -8.0 °C 14.0 °F / -10.0 °C 86% 29.65 in / 1003.9 hPa 3.0 miles / 4.8 kilometers ESE 10.4 mph / 16.7 km/h / 4.6 m/s - N/A Snow Light Snow

Brian - thanks for the work. Interesting to me in that Im not used to flying in such cold weather and have wondered what could happen in bitter cold weather. Encounter low temps over Rocky mts occasionally but its usually bone dry and not up there all that long. Also interesting to read the AOPA post that they exited the side windows. Side window exit has been my plan for a long time cause its pretty clear that a bunch of people and stuff just arnt going out the one door very fast - glad to hear it works.

For those relatively new to this forum, Brian von Herzen has been a member for many years, has crossed the Atlantic in his Skymaster via the northern route many times, and we were fortunate to have him speak of his crossings at the 2004 Skymaster Meeting and Fly-in held in Oklahoma City. An annotated group picture of that meeting may be found below, which allows you to put faces to names.

Ernie

Cold Air, side windows, ditching procedure modifications
 

John, I have actually encountered -32C in California of all places in the spring! It was just a cold day with a norther jet stream coming straight down from Alaska! I was only up there for 45 minutes so did not worry about cold-soaking the fuel, but 2-3 hours in that weather would be enough to increase my pucker factor and consider using isopropyl! So you could definitely encounter such cold winter temperatures in the central US at altitude.

Side window exits in unpressurized craft are a good idea. Sadly, in my P337G the only solution is to jam the clamshell door open before landing using the door handle as the jamming mechanism. Any racking of the doorframe after landing would otherwise jam the clamshell shut. While this would result in a lot more float time, the exits would be highly problematic.

Ironically, it may have been the side windows that caused the skymaster to sink so quickly. (although there was some mention of window breakage on this ditching). Most planes float at the level of their wings. for a low wing, this is no problem. For a high wing, it means that most if not all of the cockpit may be underwater. We should get the story from the pilots as to where the cockpit floats. Open the windows and the water will fill the cockpit in seconds. So we are left with a real tradeoff. Windows open, you can get out but you will only have seconds to do so. Windows closed, you will have minutes to ponder a watery death, but with 1 pound per square inch covering all 300 square inches of your window, you are unlikely to get that window open with anything less than a hydraulic press.

Given the importance of the life raft and the water bag, I am considering modifying my procedures to have the copilot hold the life raft in his lap before ditching, and have the waterbag in my lap before reaching the surface. Downside is that the life raft will hit the yoke and force a nose first second impact after first bounce. Upside is that the life raft will be with you when you egress, like it or not.

Green laser flare around my neck is the other modification to my procedures. There are just too many ways of not being found out there to not have one!

Cheers,

Brian