Skymaster Arctic Circle Ditching.

[Diamond Service]

Hello Karl.
Thank you very much for sharing your expirience. All information like this help me to find answers and to heal my wounds. I am quite sure that my engines had the red silicone seals under the valve covers. I need to look in a computer in my maintenance shop for the pictures.

Rgds Troels.

[ipasgas1]

I, too, had an engine failure but in a single engine aircraft. It had a Rotax 912ULS engine. But, I have often wondered if the cold had something to do with the failure. The NTSB and Rotax said it was due to oil starvation due to a "collapse" of an oil hose. It was MLK day, 4 years ago, and happened to be the coldest day of the year, around 0 degrees F on the ground. I had no warning of the impending failure, it was sudden and finite. The extreme cold sounds like a very likely culprit. I now fly a skymaster for the added engine but I still, and moreso after this, will not fly in extreme cold.

[Dave Underwood]

A thought on being prepared.

When I used to fly in Northern Ontario I was always reminded to be prepared and to make sure I could survive with only what I had on me as I got out of the plane. The reasons were simple. The float plane could sink or the aircraft could go up in flames.

These days with portable transceivers, Personal Locator Beacons, cell phones and multitools with powerful LED lights it is much easier.

Perhaps we should all consider what we need to have on us in that very worst case.

Can I also wish everyone a Very Merry Christmas and a Great New Year with bright blue skies and more reasonable gas prices.

Warm regards - Dave

[JeffAxel]

just looking at stuff and came across Cessna Service Bulletin ME79-2 which may have a bearing on this accident. It addresses use of Prist or Isopropyl Alcohol as a fuel additive in very cold conditions.

[atsiii]

The pilot's observed decline in oil temps followed by loss of pressure, caught my attention; as has the resulting discussion of possible oil loss. I'll offer my two-cents worth: one for each engine.

I had an oil separator installed on the rear engine of my '69 T337. Twice during long (3+ hour), high altitude, winter-cold cross-country legs, I lost four quarts of oil from the rear engine. The oil was literally everywhere. I finally determined that the probable cause was the breather running from the separator to where it vents by the prop had frozen, pressurizing the case and forcing oil out every available seal, gasket and orifice. It seems like there is or should be an alternate vent to atmosphere, but perhaps it was covered or plugged. At any rate, because it happened twice, I removed the oil separator, insulated the breather line and never had the problem again. I can't swear, however, that I again flew in as cold of temps.

The only oil anomaly I've ever had with the front engine was the result of the oil fill cap not being reinstalled properly after adding oil. The cap came off in flight (retained by its chain), and the engine proceeded to dump three-plus quarts of oil out the breather tube, completely coating the belly of the a/c. This occurred during a high altitude three-plus hour cross-country leg, but it was not particularly cold.

Like everyone else, I was relieved to hear that all were safe.

Allen

[billsheila]

I was speaking to my mechanic about this failure, so these are really his two cents: he suggests it is oil flow problem due to congealing (at the cooler, presumably?). Seems to make some sense given the temp indication followed by the pressure indication (followed by the failures)

[Dale Campbell]

I to installed M-20 air/oil seperators on my 337H 6 years ago. This was due to a oil slick found on the belly and tail area. I also insulated the breather line from engine to M-20 including M-20 down the exit pipe on both engines. My rear engine always ran much hotter than the front engine, which is normal for 337. In summer I fly with cowl flap door partially open when tempature above 85 degree. In winter rear runs about 180-200 degree. The front engine runs 180-200 in summer but ran 160-170 in winter. I now install a plate above front engine oil cooler for winter to get the engine above 180 degree. Without the plate I was holding water in oil and could see droplets on dip stick. No problem now with plate installed. My bird is normally asperated so anything above 13,000 feet is out of the question and I live and fly in Pennsylvania and mostly fly 500 mile radius of Pa, so I do not experiance any super cold air.

[sunnysky]

BILLSHEILA is on the right lines I think.
Several years ago I was flying my 337G from France to the UK. It was a much much colder than ISA day. Seem to remember something like minus 20c at 12000feet. We had been in the cruise for over two hours when I noticed the rear engine oil temp gauge "going off the clock". The problem was confirmed by low oil pressure. I reduced power on the rear and started a descent. The intention was to divert to Cardiff in Wales. At about 7000feet the oil temp started to reduce together with an increase in pressure. Power was gradually increased and the engine ran normally and the flight continued to Leeds Bradford.
I reported the problem to the Chief Engineer at Knight Air ( who were very "au fait" with the 337 ) and we concluded that there is a thermo valve in the oil cooler which stops oil going thro' the cooler when cold. In this instance because ambient was minus 20 or so, the cooler had shut off, then causing the oil to overheat then the low pressue. If there is then congealed cold oil in the cooler, the valve will not open to let the hot oil through. Then overheating. The only reason oil started to flow thro' the cooler again was due the the rise in ambient temperature.
Hope all this makes sense.!! It's my input for what its worth !!
Sunnysky

[Ernie Martin]

The report, however, is that they had a decrease (not increase) in oil temperature, which differs from your experience. Might be the same issue if oil temp was measured at the cooler in their aircraft and in the engine in yours.

Ernie

[sunnysky]

Hmm. Must say I didn't understand the bit about decreasing oil temperature in their report. Usually when you have decreasing OIL PRESSURE (as they state) you have a high oil temp ?
Maybe some clarifacation on the oil temp situation would help.
Your point Ernie on on where the oil temp is sensed. Surely its the same in all 337s ? Apart from the turbo ones maybe ?

[Ernie Martin]

I assumed the same, that all 337s measure oil temp at the same location, BUT a different measuring point seems the only way that your experience and theirs has the same cause. Also, is it possible that electronic engine monitors put the probe at a different point than the stock gauges?

Ernie

[Skymaster337B]

I'm starting to like the oil cooler theory. My question is, what type of oil was used? Straight weight or multi-viscosity synthetic oil? Personally, I only use synthetic oil and it makes a big difference how fast the oil pressure rises on a very cold day.

I also find it rather odd that the operator and maintenance manuals don’t establish a cold weather limitation…they both generally discuss colder weather starting procedures. There is an option for an oil dilution system, but that is for starting during cold weather and not while operating at altitude. The operator's manual says to watch engine temps during a cold weather descent…i.e, don’t chop the throttle. But the big paradox is I remember seeing optional cold weather plates the restrict airflow thru the front cowl and also out the rear cowl…but can’t find any info about it in either the operator or maintenance manual. It makes me wonder if Cessna really didn’t even want to mention cold weather flying for some reason.

[sunnysky]

Yes. I;ve heard about "winterisation" kits, but can't find out much about them.
Sunnysky

[Diamond Service]

The aircraft just had an annual done. The DAR can not issue an export C of A unless the annual is no more than 30 days old. The magnetos,prop governor and propeller were overhauled on both engines. The engines was serviced with Aeroshell 15W50.

During the cruise at 11000 feet the oil temperature was pretty much in the middle of the green arc. I was not concerned with the OAT being -30C since I have flown several pressurized twin Cessnas and Malibu 310 in colder conditions.

I did two test flights in Ohio. Some oil was noticed on the prop blades and I discussed it with the owner of the maintenance shop but we both considered it to be normal for a newly overhauled prop. We agreed that the seals in the props need some hours of operation and they will stop leaking. I did not notice any major oil leaks on the blades later on. I monitored the oil consumption on the engines very closely and they were not using much.

It feels to me like there was no oil left in the engines. The oil temperature decreased because there was no oil flowing past the sensor,but just enough to hold the pressure up a little while longer. There is a lot of ways to lose engine oil and I can only speculate. Why this happened to both engines within such a short period of time is also hard to answer.

I have more than 12000 hrs in the air. I have flown a lot of piston powered aircraft. I got my aircraft mechanic license in 1984. I am the owner of an aircraft maintenance shop that serves light aircraft. I search hard for some answers on what happened to my engines that night over the Hudson Strait. I am thankfull for all your comments but I also accept that I will probably never know for sure what happened. I want to buy another Skymaster but my family has suffered enough and for them the aircraft is a symbol of misfortune. I learned a lot from this accident. The equipment we had and the skills we had saved our life. My advise to pilots that fly over remote areas is to have the right equipment and use it. I also learned that what you have inside your suit is what you have left after a ditching. I know that the people that searched for me that night and the people that took care of me after I was saved is probably not in this forum but I want to thank them anyway. I am touched and lost for words on what they have done for me.

Troels.

[hharney]

In the POH of my 1968 Super Skymaster (lots of emphasis on the SUPER) Section VII on Optional Systems contains "Cold Weather Equipment" and says:

WINTERIZATION KIT.
"For continuous operation in temperatures consistently below 20 degrees F, the Cessna winterization kit, available from your Cessna Dealer, should be installed to improve engine operation. The kit consists of two baffles for the front engine, one baffle for the rear engine, and crankcase breather insulation for both engines. Once installed, the crankcase breather insulation is approved for permanent use in both cold and hot weather."

Attached is a photo of the front baffles but I have never seen the rear engine baffle. The rear engine baffle is attached to the lower outside ring below the prop on the exit end of the airflow. This statement is pretty standard in most all the Cessna piston Pilot handbooks except for the Turbo models. Maybe the Turbo models generate enough heat and do not require this?