So whats too cold for the plane

[jlunseth]

13 hours ago, jlunseth said:

I just generally don’t like flying if it is below 20 dF, and you would have to drag me kicking out to the airport if it is below 0 dF, although I am going to go up today just to fly around the practice area.  It is going to be in the single digits below zero dF.

Well, after saying that I went up today for about an hour.  It was -7F on the ground and the OAT at 3,000 was -25C (-13 F).  I didn’t go higher than that.  My excuse was that the flaps stuck in the half-down position after my last flight, and I needed to go up and see if I could unstick them.  It is not a cold related issue, the contacts probably need to be cleaned, and since the belly panels need to be removed that is an annual chore. I succeeded with the flaps.  Even at 12.5 GPH and ROP, which is pretty much dead peak, the cylinders were only in the high 200s.  However, heeding my own advice about getting the engine compartment warm, I messed around on the ground until the oil temp was up around 120 when I started to taxi.  It went up some when I did my runup and In the air the OT was in the 140-150 range.  The flight was uneventful except for the fact that the cockpit never got warmed up.  The heater works fine, but you have to have some heat in the engine for the cockpit heater to do much, and although I was able to keep the engine warm with the mixture, it did not help me personally very much.  Dress warm.  Especially feet, the footwells are forward of the heater exit and never do get warm.  Boots and wool socks.

I never opened the cowl flaps at all, not on the ground or in the air. 

I forgot another reason to let things warm up a bit before taking off.  If you don’t, you shiver, your voice shakes, and ATC asks if anything is wrong.  Has happened more than once.  

Be prepared for a lack of cooperation by your nifty panel electronics. I had forgotten about that. My JPI is fine at any temp at which a human can survive. However my 430 takes some warming up.  It works, but it takes quite a bit of time to respond to any changes.  Don’t know how a G500 would react.  Steam gauges are perfectly happy.  

The pressure was 30.72.  My takeoff roll was about 50 feet, well, ok, that is a little bit of an exaggeration but not much.  It was probably 20 or 30 feet more than that.

Edited January 1, 2018 by jlunseth

[David Mazer]

Early in my Rocket flying I flew into very cold conditions where OAT was -40F at 15,000 ft. for several hours. I found the plane performed flawlessly and, most surprisingly, the heater kept the cockpit warm enough that we both took off our coats. I later learned the general rule of thumb in Alaska is no flying when ground temperatures are below -40F due to the temperature at which fuel freezes and the problems with oils and greases. On the flight back, ground temps around -10F, I kept the plane in the FBO's hangar over night, started up fine, warmed up fine, flew home fine.

One other suggestion that I have read about is to be sure to tap the breaks shortly after takeoff to warm and dry the brakes to prevent them freezing in flight and skidding on landing because they are seized up.

I am aware of the use of isopropyl alcohol to dry fuel but doesn't that have a negative impact on the fuel lines unless they are specifically rated for alcohol?

[aviatoreb]

On 12/31/2017 at 8:43 AM, jlunseth said:

I live in Minnesnowta.  The coldest I have been in the aircraft was a trip from Williston ND a few years ago, back to MN.  We were in the low flight levels, I think FL210, and it was in the minus 50’s.  That’s Fahrenheit.  The cabin heater could not keep up, all the windows frosted over, but the plane otherwise was fine, just me and the co-pilot who were suffering.  

That is getting pretty close to the freezing point of avgas.

[aviatoreb]

Isopropyl - we have reviewed how much and which isopropyl in a Mooneyspace thread-past:

One thing is I meant pure isopropyl vs the stuff you get at the drug store-rubbing alchohol which has a good bit of water in it which you don't want.

https://www.amazon.com/dp/B00ZSOO4UA?psc=1

but you can get good pure stuff at a paint shop for cheaper.  It doesn't take a lot.  They say "3% max" by volume.  It is an approved substance I have confirmed in continental literature.

 

[N201MKTurbo]

46 minutes ago, David Mazer said:

Early in my Rocket flying I flew into very cold conditions where OAT was -40F at 15,000 ft. for several hours. I found the plane performed flawlessly and, most surprisingly, the heater kept the cockpit warm enough that we both took off our coats. I later learned the general rule of thumb in Alaska is no flying when ground temperatures are below -40F due to the temperature at which fuel freezes and the problems with oils and greases. On the flight back, ground temps around -10F, I kept the plane in the FBO's hangar over night, started up fine, warmed up fine, flew home fine.

One other suggestion that I have read about is to be sure to tap the breaks shortly after takeoff to warm and dry the brakes to prevent them freezing in flight and skidding on landing because they are seized up.

I am aware of the use of isopropyl alcohol to dry fuel but doesn't that have a negative impact on the fuel lines unless they are specifically rated for alcohol?

I don't know about isopropyl but I have used ethanol to remove fuel tank sealant. It worked as well as MEK. I would be careful with that.

[aviatoreb]

Cold feet- in summer I fly in socks - I feel with my long legs I get more leg room since my feet fit deeper into the well, plus I feel I land better since I have more tactile feel of the controls.

In the winter, I have very thick sheer fleece booties - the kind with no rubber buttons but just the wool -leather bottoms.  They work great to keep my feet warm and still get good tactile feel.  Those slippers live in my airplane and I take my shoes off and put them on as I sit into the airplane.

[carusoam]

Not a chemist, but...

The common alcohols are very similar in chemical structure...

a short Carbon chain with one or more OH group(s) on it somewhere...

The Carbon chain mixes with fuels.  The OH group likes to blend with other OH groups... like HOH or aka H2O...

The alcohol is basically named after the number of carbons in the chain.  Ethanol, methanol, propanol... etc...

Where the OH group(s) is on the chain will get an additional part added to the name like iso, cis, trans...

Keep in mind, this is from a discussion of two chemical engineers, sitting at lunch, discussing stuff They new decades ago...

watch for purity... rubbing alcohols have a lot of water already blended in them. Reading the label makes a lot of sense for this.

Best regards,

-a-

[RLCarter]

So whats too cold for the plan? Screw the plane, I call no joy way before it would

[aggiepilot04]

My coldest flight to date was yesterday departing the Chicago area.  The cabin heat did not keep up (as you can tell from my daughter hiding under her ski jacket).  It finally caught up as the OAT increased to about -10C further south.

The friendly folks at Gary Jet Center (KGYY) were very accommodating though.  I was able to preflight, load the bags, strap the kids in, and even strap myself in while still in the heated hangar with the door closed.  Probably the best service and facilities that I've experienced to date, and the prices were relatively reasonable.

[Guest]

If you want to improve the heat in your long body Mooney, you can close off the four holes in the cold air door above the copilots feet.

Clarence

[McMooney]

34f TODAY 8)  Birdy jumped off the runway like there was a fire.

was really hard keeping the cylinders above 200 while descending.

[DualRatedFlyer]

9 minutes ago, M20Doc said:

If you want to improve the heat in your long body Mooney, you can close off the four holes in the cold air door above the copilots feet.

Clarence

What holes?  Froze my tail off the other day at 9k. 

[Guest]

1 hour ago, DualRatedFlyer said:

What holes?  Froze my tail off the other day at 9k. 

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

 

Edited January 2, 2018 by M20Doc

[yvesg]

When I woke up this morning, the OAT was at -30 C. Too cold for flying. I put some wood in the fireplace, light it up and did nothing else than warm up all day!

Yves

[L. Trotter]

Indeed, there are 4 small holes in the cold air intake flap that joins the common air mixture chamber on the long bodies. You will note that there is always a little airflow through the forward vents that can not be turned off. This continuous airflow is coming from the 4 small holes. In the winter this air is really cold and becomes a real problem as far as comfort is concerned. I found that the cold air intake for the mixing box originates from the forward side vent just in front of the door.

My solution was to "plug" the cold air intake vent with a small cloth. A 2 second fix. Ya, it worked and the cold air no longer diluted what hot air was produced. Additionally, no more continuous cold air flow.

Now for my schooling by a Mooney factory A&P....Apparently, the continuous air flow was needed to keep CO (carbon monoxide) levels low and safe with in the cabin. The unfortunate continuous air flow is a required safety element. I was advised to remove the cloth, wear a coat and enjoy the "clean air"!

[jlunseth]

10 hours ago, RLCarter said:

So whats too cold for the plan? Screw the plane, I call no joy way before it would

Simple rule of thumb.  Flying should be fun.  Its less fun under 20F, and no fun under 0 dF, there needs to be a reason other than enjoying yourself to fly in temps like that. 

Those of us with turbocharged aircraft routinely fly in negative temps.  It is not at all uncommon to be cruising at -25C even during the summer up in the flight levels.  The main difference is that the thin air up there does not cool nearly as quickly as the dense air near the ground.  So the engine is able to stay toasty warm and the cabin heater is able to generate all the heat you need in the summer.  But after four hours at -25 at altitude the tanks, airfoils, etc. are not any warmer than they would be if the plane were cold soaked at -25 sitting on the ground, and the flight controls and trim equipment are only a little warmer.  The plane is not going to fall out of the sky because of the cold.  The big things in my experience are (1) be nice to your engine and pre-heat, (2) get an oil cooler block installed, so the OT stays reasonably warm, (3) let the engine and engine compartment warm up before you take off and the engine gets blasted with dense cold air, (4) wear warm footgear.  Everything else you can manage.  

[Mark89114]

8 hours ago, L. Trotter said:

Indeed, there are 4 small holes in the cold air intake flap that joins the common air mixture chamber on the long bodies. You will note that there is always a little airflow through the forward vents that can not be turned off. This continuous airflow is coming from the 4 small holes. In the winter this air is really cold and becomes a real problem as far as comfort is concerned. I found that the cold air intake for the mixing box originates from the forward side vent just in front of the door.

My solution was to "plug" the cold air intake vent with a small cloth. A 2 second fix. Ya, it worked and the cold air no longer diluted what hot air was produced. Additionally, no more continuous cold air flow.

Now for my schooling by a Mooney factory A&P....Apparently, the continuous air flow was needed to keep CO (carbon monoxide) levels low and safe with in the cabin. The unfortunate continuous air flow is a required safety element. I was advised to remove the cloth, wear a coat and enjoy the "clean air"!

Well hell....i just wrote this "squawk" on my non essential list of things to look into.  I assumed the valve was worn somehow and letting too much air into the cabin, which is good and fine when it is above 60dF but when it is 10dF any air is too much.  And itis not the jacket i need, my feet end up freezing.  First world problems.  

[mike20papa]

There are some cold weather operational limits regarding the propeller - relative to the type of grease used (I think you can use either Aeroshell 2 or 3 and that sets a temp range)  anyway down here in Texas, I didn't pay it much attention.  The freezing crankcase breather would be a real concern - even for autos.  Ditching in sub zero weather would DO IT for me.  Of course I could build a camp fire out of my A model wing!?

[TWinter]

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 

 

[Bartman]

17 minutes ago, TWinter said:

Interesting start to 2018.

-Tom 

 

Wow we are all happy to hear no broken bones and no bent metal !!!

sure sounds like some frozen water somewhere. Maybe a good time to get some of that 100% Isopropyl and add to each tank. I think I'll do the same. 

[Little Dipper]

Many years ago in a PA28R-200  I had a Lifeguard flight in the wee hours of the morning with a lung/liver transplant patient to Pittsburgh Pa.  I flew at 7,000' and it was -25F at altitude   I descended straight into AGC landed and the ambulance picked up the patient.  It was early in the morning and I requested for fuel for a quick turn.    It was somewhere around -5F on the ground.  I checked the fuel and departed for home. I was IMC in the clouds/dry snow and my engine started sounding funny and I was losing fuel pressure and asked for the nearest airport.   ATC cleared me direct to Johnstown  and gave lower which I declined. I ended up circling the airport dead sticking it IMC.  I broke out about 2500 AGL and landed at JST.   

When I landed and checked my fuel it looked like there was major amounts of dandruff floating in my tanks.   Long story short  the fuel truck was in a heated hanger prior to filling  up my Arrow.   It was first thing in the morning and the fuel was nice and warm.   When they filled up my cold soaked air frame I believe it created steam which stuck to the linings on my tank.  I did not see any sign of this when I checked my fuel sample.   The frozen steam broke off in flight blocking my fuel filter.    Six or so hours later sitting in a heated hangar after sumping and re-sumping my tanks I was back in the air safely on my way home.  

Ever since then I've been extremely sensitive at to the variances temperature of the air frame in the winter when I  fuel.

[DXB]

33 minutes ago, Little Dipper said:

Ever since then I've been extremely sensitive at to the variances temperature of the air frame in the winter when I  fuel.

This is a very informative post!  It makes perfect sense not to fuel with stuff that's a disparate temp from what's in your tank.  

On another note, I wonder how many people put a winter plates over the oil cooler and what temps lead them to do so. It seems a pain to take it on and off frequently based on temp fluctuations, but otherwise I'd worry about the risk of overheating if leaving on all the time. I've been ifr training this winter pretty regularly so far this winter but have only encountered OATs of -18C so far in flight.  At that temp at cruise power, my oil temp barely touches 180F, the desirable magic number to get all the moisture out of the oil.  But a frigid day is the last time I want to spend extra time messing around in my unheated hangar to cover the oil cooler.  I'm liable to make a mistake and do something more risky than not get the oil warmed to 180F.

 

[TWinter]

1 hour ago, Bartman said:

Wow we are all happy to hear no broken bones and no bent metal !!!

sure sounds like some frozen water somewhere. Maybe a good time to get some of that 100% Isopropyl and add to each tank. I think I'll do the same. 

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

 

[kevinw]

14 minutes ago, DXB said:

This is a very informative post!  It makes perfect sense not to fuel with stuff that's a disparate temp from what's in your tank.  

On another note, I wonder how many people put a winter plates over the oil cooler and what temps lead them to do so. It seems a pain to take it on and off frequently based on temp fluctuations, but otherwise I'd worry about the risk of overheating if leaving on all the time. I've been ifr training this winter pretty regularly so far this winter but have only encountered OATs of -18C so far in flight.  At that temp at cruise power, my oil temp barely touches 180F, the desirable magic number to get all the moisture out of the oil.  But a frigid day is the last time I want to spend extra time messing around in my unheated hangar to cover the oil cooler.  I'm liable to make a mistake and do something more risky than not get the oil warmed to 180F.

 

This is the winterization plate that an A&P made for me a few years back. I put it in every year once it gets below 30F. The placard reads to remove at 50F but it's out well before it gets that warm. Easy to install and works well.

[TWinter]

54 minutes ago, Little Dipper said:

Many years ago in a PA28R-200  I had a Lifeguard flight in the wee hours of the morning with a lung/liver transplant patient to Pittsburgh Pa.  I flew at 7,000' and it was -25F at altitude   I descended straight into AGC landed and the ambulance picked up the patient.  It was early in the morning and I requested for fuel for a quick turn.    It was somewhere around -5F on the ground.  I checked the fuel and departed for home. I was IMC in the clouds/dry snow and my engine started sounding funny and I was losing fuel pressure and asked for the nearest airport.   ATC cleared me direct to Johnstown  and gave lower which I declined. I ended up circling the airport dead sticking it IMC.  I broke out about 2500 AGL and landed at JST.   

When I landed and checked my fuel it looked like there was major amounts of dandruff floating in my tanks.   Long story short  the fuel truck was in a heated hanger prior to filling  up my Arrow.   It was first thing in the morning and the fuel was nice and warm.   When they filled up my cold soaked air frame I believe it created steam which stuck to the linings on my tank.  I did not see any sign of this when I checked my fuel sample.   The frozen steam broke off in flight blocking my fuel filter.    Six or so hours later sitting in a heated hangar after sumping and re-sumping my tanks I was back in the air safely on my way home.  

Ever since then I've been extremely sensitive at to the variances temperature of the air frame in the winter when I  fuel.

This is interesting. When I went to top off at the FBO the supply tanks had a malfunctioning pump so they had to fuel me from the fuel truck. The had fueled the truck early this morning from the big tanks before the pump broke..Could have been many variables since the truck is parked inside sometimes and outside. Maybe water in the fuel truck tank, maybe the fuel in the truck was affected by the cold temps..idk.

I do know it made for a interesting couple of minutes.

 

-Tom