Icing encounter, ATC negotiation, MVAs that are higher than MEAs in an area

[carusoam]

Welcome aboard @ZMERC!

It is great to have your experience shared here…

We have only a few ATC people form various areas and experiences… 

More experience is always welcome.

Best regards,

-a-

[Will.iam]

Out of this thread, no one mentioned the option for climbing to get to colder temps to where the precip will not stick to the airplane?  As long as my destination airport is warmer than freezing to melt the ice back off, I'd rather climb and get above the icing or get the temp down to where it no longer sticks.

Most icing encounters are only 5k in height before you get out of them because the temp is too cold or too warm.

[Ragsf15e]

16 hours ago, Will.iam said:

Out of this thread, no one mentioned the option for climbing to get to colder temps to where the precip will not stick to the airplane?  As long as my destination airport is warmer than freezing to melt the ice back off, I'd rather climb and get above the icing or get the temp down to where it no longer sticks.

Most icing encounters are only 5k in height before you get out of them because the temp is too cold or too warm.

I definitely use that technique in my work airplane but it’s got a PT-6 and pressurization.  Tough to count on climbing through a layer in a SEP if ice is sticking.  You can lose climb rate quickly.  
I base all my winter cruise altitudes off temps at altitude.  I want to see colder than -20c.  Hopefully -25 or colder.  Usually not a problem in Washington state in the winter.  Typically you’re safe above 20,000’ or so.

I believe the pilots guide to instruments (could be the weather one), says icing is typically found from +5 to -20c.  I have yet to see it above 0, but definitely all the way to -20, maybe slightly colder.

[Will.iam]

19 hours ago, Ragsf15e said:

I definitely use that technique in my work airplane but it’s got a PT-6 and pressurization.  Tough to count on climbing through a layer in a SEP if ice is sticking.  You can lose climb rate quickly.  
I base all my winter cruise altitudes off temps at altitude.  I want to see colder than -20c.  Hopefully -25 or colder.  Usually not a problem in Washington state in the winter.  Typically you’re safe above 20,000’ or so.

I believe the pilots guide to instruments (could be the weather one), says icing is typically found from +5 to -20c.  I have yet to see it above 0, but definitely all the way to -20, maybe slightly colder.

I have seen ice / snow at -20 but not sticking to the airframe. Maybe I just have not had that experience yet. 

[Ragsf15e]

2 hours ago, Will.iam said:

I have seen ice / snow at -20 but not sticking to the airframe. Maybe I just have not had that experience yet. 

Yeah it’s definitely more rare that cold, but I’ve seen it at -25.  A friend who has a cirrus got into a really bad ice situation (at night no less) and swears he was still getting it at -30.  He was pretty white telling the story and I believe him.  

Generally you are right that you can get out of ice by getting very cold though.

[Ragsf15e]

2 hours ago, Will.iam said:

I have seen ice / snow at -20 but not sticking to the airframe. Maybe I just have not had that experience yet. 

Speed depends a lot too… if you fly a jet you probably see less ice at different times than a slower prop.

[midlifeflyer]

@ZMERC, as a Center guy, how do your MIAs fit into this scenario? They are your rough equivalent of MVAs and also charted by sectors. I've seen some of those overlayed on en route charts. Airways with high MEAs but portions passing through or adjacent to lower MIAs. The discussion usually focuses on MVA so I'm wondering how much leeway MIAs give you in the situation of a pilot who is encountering icing (but not an emergency) at the MEA and for whom climbing is not a feasible option? 

[ZMERC]

@midlifeflyer MIA and MVA (in ARTCC) are effectively the same thing.  MVA "maps" are not displayed, what's displayed to enroute controllers is the MIA map.  So you may hear an enroute controller say "my minimum IFR altitude in your area is XXXX" or they may say "my minimum vectoring altitude in your area is XXXX"  In the enroute environment the only difference is a potential lower vectoring altitude carved out for vectors to approaches at outlying airports (not inside an approach control).

disclaimer: MIA in this description is NOT referring to MIAs published on a chart.  They refer to the controllers MIA in their sector.   Controllers know the MIA published on charts (and have been tested).  They have that info available to them.  Aside from that they also have an MIA "map" overlay on their radar display, which is NOT necessarily the exact same altitudes.  This is one of those things that always get confusing when pilots/controllers discuss MIAs in an area.  Bottom line, it doesn't really matter, if you file/fly what's published as an MIA, you will always be at or above what the controller knows to be safe.  For example, a route between A and B shows and MIA/MEA/MOCA, whatever of 4200, the controller may have knowledge that they can actually vector you and use 4000 in that area, but the fact that you believe 4200 when you file makes you safe.  I hope my disclaimer didn't make things more confusing.

[tls pilot]

On 11/9/2021 at 4:47 AM, Will.iam said:

Out of this thread, no one mentioned the option for climbing to get to colder temps to where the precip will not stick to the airplane?  As long as my destination airport is warmer than freezing to melt the ice back off, I'd rather climb and get above the icing or get the temp down to where it no longer sticks.

Most icing encounters are only 5k in height before you get out of them because the temp is too cold or too warm.

There is such a thing as Super cooled water. 

Also from a FAA Publication

updrafts in cumuliform clouds carry large amounts of liquid water far above the freezing level. On rare occasions icing has been encountered in thunderstorm clouds at altitudes of 30,000 to 40,000 feet where the free air temperature was colder than minus 40°

A good refresher, especially this time of year. See:

https://www.faa.gov/documentlibrary/media/advisory_circular/ac 00-6a chap 10-12.pdf

[midlifeflyer]

2 hours ago, ZMERC said:

@midlifeflyer MIA and MVA (in ARTCC) are effectively the same thing.  MVA "maps" are not displayed, what's displayed to enroute controllers is the MIA map.  So you may hear an enroute controller say "my minimum IFR altitude in your area is XXXX" or they may say "my minimum vectoring altitude in your area is XXXX"  In the enroute environment the only difference is a potential lower vectoring altitude carved out for vectors to approaches at outlying airports (not inside an approach control).

disclaimer: MIA in this description is NOT referring to MIAs published on a chart.  They refer to the controllers MIA in their sector.   Controllers know the MIA published on charts (and have been tested).  They have that info available to them.  Aside from that they also have an MIA "map" overlay on their radar display, which is NOT necessarily the exact same altitudes.  This is one of those things that always get confusing when pilots/controllers discuss MIAs in an area.  Bottom line, it doesn't really matter, if you file/fly what's published as an MIA, you will always be at or above what the controller knows to be safe.  For example, a route between A and B shows and MIA/MEA/MOCA, whatever of 4200, the controller may have knowledge that they can actually vector you and use 4000 in that area, but the fact that you believe 4200 when you file makes you safe.  I hope my disclaimer didn't make things more confusing.

Thank you. And yes, I know which MIA you are referring to. 

The MIA you are describing don't appear on pilot charts (which is why some pilots want them). Our published IFR altitudes come down to MEA* , MOCA, OROCA, and the MSA for emergencies. It can be confusing because all of those are "minimum IFR altitudes" for certain purposes. Then to confuse things even more  there's the ultimate FAR definition - 1,000' (2000' in mountainous terrain) above obstacles within 4 NM laterally.

At this point it seems to be turning into research for an article but my guess is that the 1000/2000 definition is probably what the MIA maps show in smaller pieces than OROCAs so they can be used by you.

 

(*Then there's the SID/STAR MEA which is just a procedural altitude and may not elated to the definition of MEA at all)

[ZMERC]

3 hours ago, midlifeflyer said:

he 1000/2000 definition is probably what the MIA maps show in smaller pieces than OROCAs so they can be used by you.

yes, but.... of course there's a but.  The MIA a controller sees "could" also be due to radar coverage in an area.  Although that would be locally adapted by a center.  It's not typical to create an MIA for radar coverage.

[Ibra]

On 11/9/2021 at 10:47 AM, Will.iam said:

Most icing encounters are only 5k in height before you get out of them because the temp is too cold or too warm.

In stratus, that is the typical size of the band, there is a tiny observation of rime ice bellow -15C, some could make it in labs down to -40C but it’s not what brings aircrafts down at least not in the next one or two hours…in convective clouds, the band is higher but the ride is not comfortable neither (there is that thing that take a liquid water from near the surface and send it up to 40kft before it hit airframes and freeze)

Anyone who claims getting bellow -20C in a smooth ride is probably just allergic 

On 11/11/2021 at 2:00 AM, Ragsf15e said:

Speed depends a lot too… if you fly a jet you probably see less ice at different times than a slower prop.

+1deg TAT/OAT at 100KTAS but I gather you still have +4deg TAT/OAT at 200KTAS in a Mooney 

[Ragsf15e]

24 minutes ago, Ibra said:

In stratus, that is the typical size of the band, there is a tiny observation of rime ice bellow -15C, some could make it in labs down to -40C but it’s not what brings aircrafts down at least not in the next one or two hours…in convective clouds, the band is higher but the ride is not comfortable neither (there is that thing that take a liquid water from near the surface and send it up to 40kft before it hit airframes and freeze)

Anyone who claims getting bellow -20C in a smooth ride is probably just allergic 

+1deg TAT/OAT at 100KTAS but I gather you still have +4deg TAT/OAT at 200KTAS in a Mooney 

Ha, yeah, the Mooney is always super fast!!

I was thinking of those of us that fly other planes.  Say airline pilots or the turboprop I fly.  You can have airlines reporting negative ice during their 250+KIAS descent when I’m clearly getting ice in my 175kias descent and a SEP at 150 might be even worse.

Edited November 15, 2021 by Ragsf15e

[Delta]

To answer DXB’s question #2, WingX has a feature to display MVAs that may be of interest.  Tap on an airport in the area of interest, tap on “MVA – Not for navigation” at the bottom of the menu, and select the MVA depiction for the area of interest.  Below are a couple of screenshots from WingX.

I can’t speak for its accuracy or benefits, but I will add it to my pre-flight planning. 

 WingX MVA Depiction.pdf