Cruising Alt & Freezing Level.
 

hi all

Just trying to find some information on crusining altitudes in regards to freezing level. Ive search for a while and cant seem to find anything. :ouch:

Any advice or references would be much appreciated :ok:

Not in cloud above freezing level without de-icing gear...? :}

Or, if u got da white stuff building up on wings, props etc... go lower! If you cant go lower due lsalts etc you better hope theres a nearby airport with instrument approaches to land at or that whatever your flying has the nuts to get above the cloud!! :}:E

Hope ive helped... lol :ok:

Turbz :E

Just information of pre-flight planning of altiutudes and the freezing level is a few thousand feet above the LSALT. So in cloud and no de-icing equip.

Thanks for your help, ill remeber to take a plan with nuts when flying in cloud :}

The area forecast is a good place to look!

J:ok:

I guess if you cant get above the cloud ie. it extends above A100 and you cant get a hemispherical cruising level between LSALT and FZL you just have to plan non standard levels... or just cruise at LSALT if its that tight...
You just have to be careful of freezing rain etc, coz u can still freeze up a couple of thousand feet below FZL, one day i had about 2-3 inches of ice on my wings from only 5 or so mins popping in and out of cloud 4000' below the declared FZL so keep an eye on your OAT too if its close...

Turbz :E

Ummm, was the question how to work out Freezing levels in pre-flight planning ? or how to figure if you have ice build up? or what to do if you find yourself inadvertantly cruising in it ?

Having spent 90% of my flying career in the sub-tropics/tropics, I know all about flying in icing conditions! Yeah right!

I aversion to ice is right up there with my aversion to CBs.

Here's my approach for a GA aircraft not approved for flight into know icing conditions.

1) No flight in sustained cloud at or above the forcast freezing level.

2) If flying in IMC and icing occurs - immediate 180o turn and bug outta there. There was no icing in the air you just flew through so there should be no icing when you go back there.

3) Descend into warmer air if LSA allows, before returning to the desired course.

4) Take a different course that has a lower LSA - well below the freezing level

5) If in doubt - head for the nearest instrument approach behind your present position, with the lowest LSAs and land.

Nothing is so important that you should risk smacking in!

Dr :8

PS: I suspect that people who operate in southern Australia are considerably less averse than I am!

Icing
 

below -40 SAT we switch anti ice off..... :}

Yeah, what FTDK said... i should have stated that i didnt just keep going with that ice on either, i descended and it eventually broke up and allowed me to return to normal cruise IAS again...

Sometimes (especially around Tassie) you will have FZL much lower than your LSALTs... ive heard of the troubles other pilots have had but never had to plan around a situation like that before fortunately...

My experience is that young pilots starting out are weary of ice for a few hundred hours, and then once they have had trace ice build up and do very little to the performance of the aircraft a few times they get a bit bold and tend not to do that 180 turn straight away. Then one day the trace ice turns to three inches of rime in about 40 seconds and the airspeed indicators don't match and the airspeed drops way back .....then they rethink the 180 turn thing for their next flight. Human nature I suppose. It's like they (me included) have to see it for themselves before they'll believe that it can be scary stuff.
At the end of the day, if you have no anti or de ice and you can see ice building, get out of it.

I had a question in my IREX exam about pre-flight planning said something along the lines of the freezing level is 9000ft along route WXXX. What altitude should you plan your flight at: (LSALT was about 6100ft)
The track was a westerly heading
a) flight can not proceed,
b) fly above LSALT at 8000ft
and i can remeber the other two (im sure it would help a lot if i could :8)

Cloud should perhaps include any "VISIBLE MOISTURE"

You don't always have to go lower, you can go higher - just stay out of VISIBLE MOISTURE and you won't ice up, even if "above the freezing level"

Umm... same difference Atlas, and if you read the post, i didnt say stay below the FZL... i stated "not in cloud above the FZL"... it means the same thing... :ok: I mentioned rain also...
But thanks for quoting me anyhoo...

Turbz :E

Hey,

Does anyonone know the reference for not planning above FZL in IMC ?

Can't seem to find it in AIP, CAR's or CAO's or on the web :bored:

Cheers

Have a look and see what the Canadians do in winter ops. They seem to manage ok in the winter when the temps can be as low as -35 on the ground.

As icing is only a problem down to -40 C, the Canucks can probably climb a few thousand feet ASAP and have no worries!

Investigation: AO-2007-019 - Icing event - 50 km SW Canberra, 4 July 2007, VH-VEG, Beech Aircraft Corp B58

This ATSB is a good read regarding an icing incident in a Baron a few years back near Canberra.

Luke,

There is nothing stopping you planning to fly in icing conditions, ie ATC won't ask 'confirm you want 8000 as it is above the freezing level?'.

Flight in known icing conditions is an aircraft certification issue and as such you will find details in the POH for your aircraft. If your aircraft is not certified for something you are not allowed to do it. That applies to other things such as aerobatics, flight at night, or in IMC.

Also worth remembering that the freezing level on the forecast is just that, a forecast. The temperature in cloud can vary and cause icing when below the forecast freezing or you could be lucky and not encounter ice at the forecast level. If your not in an aircraft certificated for flight in known icing be conservative with your planning so you can descend out of icing immediately.

Bullsh!t. :ugh: CIVIL AVIATION REGULATIONS 1988 - REG 238 Icing conditions

Basically, if your aircraft is not certified for ice (that's certified, not just "hey I've got hot props, it'll be OK") then finding yourself flying in icing conditions means you have screwed up to roughly the same extent that a VFR pilot who finds themselves flying in cloud has.


... and case law shows that is exactly how the courts view it, for those found out. (As in managing to land after some sort of distress call to ATC, not just getting killed.)

It always amazed me that when hundreds of DC3's from the war were made available to civilian operators in Australia, one of the first "modifications" these operators made was to strip off the wing and tail rubber de-icing boots. This was done to save weight and make more money. DCA looked the other way and even approved the modification.

So for years there were DC3's and Bristol Freighters and other smaller twins and singles being flown in southern Australia and across to Tasmania hauling freight and passengers in mid-winter while braving ice. Sure there was sling rings to throw de-icing fluid into the props and squirty stuff to de-ice the cockpit the windshields. But the rules designed to prevent flying in icing conditions were regularly flouted and are still flouted to this day with Chieftains and their GA ilk which are not equipped for flight into known icing. There were many frights as aircraft were covered with ice but most managed to get away with it although the number of close calls were never recorded. The good old RAAF did the safe thing and kept their Dakotas with the rubber de-icing boots installed - and still did until the last Dakota was retired.