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So whats too cold for the plane


FlyboyKC

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Ordered some this morning off of Amazon after reading over this thread. I actually did a search on MS last night looking for anything related and came across this thread. 
 
-Tom
 


Tom - I’ve never used IPA for water in my fuel tanks. I used a product called Prist. It is DoD approved for jet fuel and can be used with 100LL (unless something changed with the formulation).


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13 hours ago, M20Doc said:

Applies to long bodies only.

Both cold and hot air are ducted to the box, but the cold air valve has 4 -1/2” diameter holes in it.  Kind of counter acts what little heat an Acclaim makes.

Many of the older airframes had avionics cooling ducts which were removed but never sealed.  They come from the right air scoop.

Clarence

 

5A83B60F-00BD-4A0C-BCE8-67885EF7B514.png

Clarence what 4holes, can you reference them by the number. I also have a new sponge I put in the heater outlet until the hot air starts coming out. If the vent and heater are off cool/cold air comes out the heater outlet, it seems to help quite a bit

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2 hours ago, Marauder said:

 


Tom - I’ve never used IPA for water in my fuel tanks. I used a product called Prist. It is DoD approved for jet fuel and can be used with 100LL (unless something changed with the formulation).


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Why not ipa?  I’ve used both.

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I've been using "ISO-HEET Premium Fuel-Line Antifreeze", when appropriate, since I first started winter flying back in Niagara Falls.  As previously mentioned, buy 100% alcohol in the RED bottle.  Their other formulation in the yellow bottle is a solution of IPA and water.  It's particularly important to use IPA when you're tankering fuel from a warmer area of the country, since the water solubility in 100LL is much higher when the fuel is relatively warm.

No need to spend money on Prist if you are a CB.  

The FAA allows the use of isopropyl alcohol as a fuel system icing inhibitor up to 1 percent by volume.  I usually add one 12 oz bottle of Iso-HEET to each tank.  One bottle in 25gal of 100LL is around 0.4% of IPA.  In Tom's case, where he pretty much knows he has water crystal potential, I might double that dose without exceeding 1%.

Edited by neilpilot
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Do you have a reference to the legality of pilot's (non-mechanics) adding additives to the fuel that do not meet the type cert of fuel spec itself? Is this something the FAA has an interpretation issued on? The type cert lists the fuel specs so I assume anything that meets that would be ok but I assume these additives do not.

 

-Robert

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5 hours ago, Danb said:

Clarence what 4holes, can you reference them by the number. I also have a new sponge I put in the heater outlet until the hot air starts coming out. If the vent and heater are off cool/cold air comes out the heater outlet, it seems to help quite a bit

If you take off clamp13 and duct 12 you will find a door controlled by 21. The door has the 4 holes, sealing them will dramatically help with heating.

 Of course you could die of carbon monoxide poisoning.

Clarence

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2 hours ago, M20Doc said:

If you take off clamp13 and duct 12 you will find a door controlled by 21. The door has the 4 holes, sealing them will dramatically help with heating.

 Of course you could die of carbon monoxide poisoning.

Clarence

A CO detector could help identify the presents of CO. If found turn off the heat and crack open the overhead vent. 

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4 hours ago, RobertGary1 said:

Do you have a reference to the legality of pilot's (non-mechanics) adding additives to the fuel that do not meet the type cert of fuel spec itself? Is this something the FAA has an interpretation issued on? The type cert lists the fuel specs so I assume anything that meets that would be ok but I assume these additives do not.

 

-Robert

Look for Mooney Service Instruction M20-64, issued in 1983, which references Lycoming SI #1070K and a similar Continental service bulletin.    FAA references ASTM D 910, Standard Specification for Aviation Gasolines, that permits 1% IPA, in at least one of their ACs.

M20-64.pdf

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13 hours ago, neilpilot said:

Look for Mooney Service Instruction M20-64, issued in 1983, which references Lycoming SI #1070K and a similar Continental service bulletin.    FAA references ASTM D 910, Standard Specification for Aviation Gasolines, that permits 1% IPA, in at least one of their ACs.

M20-64.pdf

That was great Neil.  I was aware of the ability to add up to 3% from the classes Bruce used to teach at the Mooney PPP, but not where it came from.  

I still don't think I will be adding IPA though.  I used to do it, but as I said, many hours in the flight levels not just below freezing, but down around -25C, and no hint of trouble without IPA.  

This thread did give me a thought though.  My fuel switch is right below the port where the cabin heat comes out.  When I first got the plane, that switch would get too hot to handle without something on your hand.  I eventually discovered you could mix in cold air by opening the Cabin Vent knob on the panel, and not heat that switch so much in the warm weather months at altitude.  But now I am thinking I will take all the heat on that switch I can get in the winter.  That will conduct heat into the gascolator and voila, no ice.  I have my own little fuel heating system.  Probably not designed that way, but works that way.

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12 minutes ago, jlunseth said:

That was great Neil.  I was aware of the ability to add up to 3% from the classes Bruce used to teach at the Mooney PPP, but not where it came from.  

I still don't think I will be adding IPA though.  I used to do it, but as I said, many hours in the flight levels not just below freezing, but down around -25C, and no hint of trouble without IPA.  

As your fuel cools, water will come out of solution at about 1 ppm/1 degF, and if the fuel is well below 0C that water will freeze in a very fine crystals, and in large amounts can quickly blind a fuel filter.  The key variable in addition to how cold you will be in flight is how much SOLUBILE water is in your fuel, and how quickly your fuel is chilled.  If the temperature change is slow, and especially if the cooling occurs on the ramp, the free water may separate and drop to the bottom.  On the other hand, if you take on a relatively warm load of fuel and then immediately go fly in the cold, those fine crystals can form and result in engine stoppage if you don;t use a water scavenger such as IPA.

You can fly may hours around -25C and have no problem if you've fueled from a source that's already at cold surface temperatures.  However, if you fuel from a relatively warm storage tank and then immediately go fly in the cold for awhile, you may just replicate Tom Winter's experience.

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1 hour ago, neilpilot said:

As your fuel cools, water will come out of solution at about 1 ppm/1 degF, and if the fuel is well below 0C that water will freeze in a very fine crystals, and in large amounts can quickly blind a fuel filter.  The key variable in addition to how cold you will be in flight is how much SOLUBILE water is in your fuel, and how quickly your fuel is chilled.  If the temperature change is slow, and especially if the cooling occurs on the ramp, the free water may separate and drop to the bottom.  On the other hand, if you take on a relatively warm load of fuel and then immediately go fly in the cold, those fine crystals can form and result in engine stoppage if you don;t use a water scavenger such as IPA.

You can fly may hours around -25C and have no problem if you've fueled from a source that's already at cold surface temperatures.  However, if you fuel from a relatively warm storage tank and then immediately go fly in the cold for awhile, you may just replicate Tom Winter's experience.

Well, that's the thing.  The great majority of the hours I have spent in the flight levels have been during the summer.  Fuel gets put on board at ground temps which are warm, and in relatively humid conditions.  Then I go to altitude, stay there for 4 hours at -25C, and nothing happens.  As I said, I used to put in some IPA.  I actually attended one of the Mooney PPP's where Bruce talked about the advisability of putting IPA in the fuel during the winter, and I said, hey, what about those of us who fly around at -25C during the summer.  Everyone agreed it was a good idea.  So I started doing it.  Then had a couple of trips where I didn't have any IPA with me and there were no problems, so I quit worrying about it.  Now it is several hundred hours of loading the fuel on the ground in the summer and then going to minus temps in the flight levels, and nothing.  I am going to guess the turbo guys on this site will say the same thing.  If there were a problem we would have seen turbos falling out of the sky with regularity, because this is a truism of flight level flying for all of us who do it.  We will be in temps below freezing. 

Practice meets theory.  Now, don't get me wrong, if this appeared to be a real safety of flight issue I would be the first to jump on it, but I just have not seen it.  

I don't have a carburetor and screen, maybe that would be different.  

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On 1/2/2018 at 9:40 AM, Marauder said:

 


Tom - I’ve never used IPA for water in my fuel tanks. I used a product called Prist. It is DoD approved for jet fuel and can be used with 100LL (unless something changed with the formulation).


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17 hours ago, neilpilot said:

Look for Mooney Service Instruction M20-64, issued in 1983, which references Lycoming SI #1070K and a similar Continental service bulletin.    FAA references ASTM D 910, Standard Specification for Aviation Gasolines, that permits 1% IPA, in at least one of their ACs.

M20-64.pdf

For the normally aspirated Lyc IO-360's Mooney POHs, such as the J model, Limitations section allows 1% isopropyl alcohol and they also specifically prohibit other things such as EGME  or Prist because of concerns for fuel system compatibility. Although you'll hear arguments to the effect that as long as its well diluted/mixed when adding it, it should be okay. But I would avoid it as long as isopropyl alcohol is readily available and just use it carefully when its your only option.

But on Continental Turbo charged  Mooney's K's through Acclaim, Mooney POH's allow up to 3%  which is a huge amount. I did hear from someone that actually used 3% all winter and reported it very quickly wore out the seals in the fuel pump which was expensive so would really advise against using more than really necessary.

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7 hours ago, kortopates said:

 

But on Continental Turbo charged  Mooney's K's through Acclaim, Mooney POH's allow up to 3%  which is a huge amount. I did hear from someone that actually used 3% all winter and reported it very quickly wore out the seals in the fuel pump which was expensive so would really advise against using more than really necessary.

To get to 1% takes 3 pints per side in my aircraft (tanks are 37.6 per side).  3% would be 1 gallon + 1 pint per side, that’s alot.  For a while I would put 1 pint in per side, and had no problems with it, but I was dubious that small an amount would do anything.  

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[mention=7862]kortopates[/mention] Paul, where in the POH would this detail be found?
I was reading the POH for the M20R in search of that detail.  I am pretty sure I remember seeing it before...  no Joy!
Best regards,
-a-

See the Limitations section.


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What about the gascolator and sumps under the wing ? After sumping the tanks in cold temps and resulting continous drip I had to replace one of the sump drains a few years ago. Granted, that sump was probably installed in Kerville and was 30 years old but it didn't leak until I sumped the tank in the winter. Since then the tanks have been sealed and no problems, but I keep my plane in a hangar except when on a trip. Since then I keep new o-rings in the caps and if it's going to be cold I sump my tanks ahead of planned flights, but if it's really cold I don't check it again before hopping in the plane. 

What do you guys do about sumping the tank in cold temps like we have this week ?

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On 1/2/2018 at 6:52 AM, TWinter said:

First flight of 2018..It has been cold here in TN. I wanted to do my traditional New Year's Day flight. Pulled the plane out and it was 12F outside. Taxi to the FBO tanks and topped off, took 29 gal. My last flight was about two weeks ago to and from Jack Edwards.

Here is the kicker..Not a great way to start the New Year.

Did my usual pre-flight etc..Took off and flew about an hour staying below 3000' along the Mississippi River. Thought I'd do a few practice GPS approaches at Blytheville, AR (about 20 miles from my base). Did the approaches from 2500' down to approaches and flew the missed. Did this about three times and decided to head home. 

Now is when it gets interesting... I'm headed home and decide to do one more practice GPS approach at my home field. Did the approach and just over the flew the runway. Start to climb out and turn crosswind for downwind. My final pattern before I call it a night. As I start to set up the engine loses all power and goes to idle. I do a quick scan and gauges look okay other than everything was where it would be as if I was sitting idle on the ramp. I push everything to the firewall, check the fuel gauges, turn mag left to right (no change). Scoping my landing position for a glide-in and starting to set up for no power landing. Gear down, another scan across the gauges and flip the boost pump on. All of a sudden the engine comes to life. I get reconfigured for a landing and all ends well. After I land and am taxing I switch Boost pump back off and everything is fine, engine stays alive and is running perfect. Taxi back to the ramp, shut down and get my thoughts together.

Decide to fire it back up and do some high speed passes on the taxi-way. They all check-out fine. All pressures are good. Fuel pressure is stable. Boost pump increases FP as it should.

Since everything looked good I decide to make another loop in the pattern staying tight and see what happens (staying in the pattern and within glide). I take off and level out and shut boost pump off. Everything is perfect and reading correctly. I'm wondering if there might have been some frozen water in the fuel and since all my maneuvers were low altitude at 12F temp and less as it was late in the day and getting colder..Maybe some frozen debris or water blocking the fuel flow? and when I bumped the BPump it cleared. The last test flight was 15-30 minutes around the pattern after it cleared and all were normal. No visible water in the sumps, but still think it was related to low altitude maneuvers and extreme temps. Thoughts? I have a JPI and plan to have my guy pull the data and see what was going on in that what seemed like forever, but in reality was couple of minutes.

Interesting start to 2018.

-Tom 

 

This reminds me of an article I read a year or so ago. They had similar problems with losing power. From the article:

"When an airplane—even one using avgas—flies at altitudes where it’s very cold, the water that is regularly dissolved in the fuel precipitates out in the form of ice crystals, which then can block your fuel system. Then as your fuel system warms up, the ice melts and the water dissolves back into the fuel. When you drain warm fuel from the sumps, you won’t find water, because it is dissolved in the fuel. The solution is to use a fuel system icing inhibitor like the product called Prist, or isopropyl alcohol."

http://johnandmartha.kingschools.com/2015/11/09/losing-them-both-flying-in-new-environments/
 

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12 hours ago, carusoam said:

@kortopates Paul, where in the POH would this detail be found?

I was reading the POH for the M20R in search of that detail.  I am pretty sure I remember seeing it before...  no Joy!

Best regards,

-a-

See Limitations Section Page 2-6 in the O2 POH, your IO-550 has the same constraints as the Turbo Continentals allowing up to 3% IPA giving all the Continentals the same limit at 3%; leaving only the Lycoming engines with the 1% limit (which of course is plenty). But all Mooney's prohibit Prist/EGME because of our fuel system.

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Some years ago I was landing at -32C in Iqaluit on a ferry flight. The aircraft was parked outside that night. At departure next morning the temperature was -35C.  The  Mooney M20E started fine after 30 min preheating of engine and cockpit. I remember the AI needed some time to stop tumbling after engine start. The cockpit warmed up quickly after takeoff.

I felt the limitation was more the pilot's performance at that temperatures and not the technology...

Iqaluit.JPG

Iqaluit 2.JPG

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Reading the Continental link posted above I thought I would see what Lycoming has to say.

"For most Lycoming models, preheat should be applied anytime temperatures are at 10˚ F or lower."

https://www.lycoming.com/content/operating-cold-weather

That's lower than the "preheat when below 40˚ F" that i have seen mentioned from time to time.

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