few more questions

[rk772]

Icing in the hold at 7000 ft. Climb or Descend? and why

On a windshear escape, Why do you leave the gear extended?

The difference between type I, II, and IV deice fluids and when are each used

How are they applied

What do aircraft manufactures do to counteract dutch roll

Thanks

 

[jergar999]

On the windshear, if it is LOW (and I mean low) level wind shear, you leave the gear extended in case you meet up with the runway again.

Icing at 7000' - check the OAT first. Right at or above freezing, climb above the freezing level. Right at or below, descend.

In other words, if there is ice at 5 degrees Celcius try to climb first, you might get less above the freezing level as anything there will already be frozen/falling. If this doesn't work, try to descend into warmer air.

 

[leardvr]

Some answers?

I was always taught to climb out of iceing if you can, unless you know for a FACT that it is warmer lower or that you'll break out. The higher you get the colder it gets and maybe to cold for ice. And there is always the chance of an inversion sence cold air slices under warm air.

During a WS you don't want to change the configuration of the a/c. In most A/C the gear doors create a large amount of drag. Also in some A/C if you retract the gear and not the flaps you can get a horn which is distracting. That comes from the FSI manuel on WS.

De-ice fluids:
Type I is DEICING used to REMOVE ice, slush, and snow. Provides MINIMAL anti-ice protection.
Type II or IV ensure A/C remains clean after deiceing. Type IV is Gel Like and is thick, in many smaller A/C type IV is prohibited b/c of its weight.

As a caution type I, II, and IV are NOT compatible and can't be mixed.

Application of all 3 can be in spray form.
Type I is sprayed on to REMOVE contamination, and can be heated.

Type II is sprayed on to PROTECT from contamination, but is on a clean A/C. If type II is heated is will evoperate faster and in that case is considered Type I used again for REMOVAL.

Type IV is sprayed on to PROTECT from contamination, also on a clean A/C. It should be applied cold. Again it can be heated but in that case is considered Type I for REMOVAL only.

Confussed?
Type I De-Ice
Type II (cold) Anti-ice
Type IV (cold) Anti-ice

II or IV heated De-ice.

As a side note I suggest always de-iceing/anti-iceing starting at the cockpit. That way you can "assume" that if it remains clear so is the rest of the a/c. And don't forget your holdover times.



Dutch roll is fixed with yaw dampeners, strakes, V-tails, and I'm sure more. The first two you see on lots of A/C, some have both; CE 560XL, LR35(some), LR31, BE1900

Hope that helps.

 

[172driver]

So, for airline ops, what would be the typical deice/anti-ice routine if the a/c is carrying snow or ice on the ground? Heated type I followed by cold type IV?

 

[pireps]

In the US, normal procedure is to de-ice with hot type I fluid, and then cover with cold type IV if needed. A situation that would require type IV is falling precipitation (snow, freezing rain, etc.) that would cause the holdover time of type I to be exceeded. Flight crews refer to their holdover charts to determine how much time they have with the current fluid, outside temperature, type of precip. So let's say type I on a certain day gives you 20 minutes of protection in light snow (for example), you will probably not use type IV fluid unless you expect delays for takeoff or have some other reason. If there is no precipitation, but you get to the airplane and it's covered with snow
or ice, you would just use hot type I and skip type IV altogether.

Type II fluid is not used much, if at all, in the US. Does anybody here know who uses this stuff?

 

[atldc9]

1. I was always taught to climb, because if you are getting ice, you may not be able to climb later if you get too much ice.

2. Again, the reason to maintain configuration is most aircraft have an increase in drag as a result of the gear dorrs opening. In the MU2, I recall that it was around a 500 fpm loss of climb when you were on 1 engine and sucked the gear up, that was on the long body's.

3. Don' think I've ever seen type II. We always use the heated type I then if necesary the cold type IV.

 

[80/20]

Is there a difference between Type II & IV? - Both have at least 50% glycol.
Type IV has much better HOT under certain weather conditions & temperatures.
Type II was very common but is now prohibited of environmental reasons in many countries.

One way to explain de- & anti-icing:
DE-ICING = REMOVAL
Warm fluid melts ice & snow. (Typically hot water or a mixture of type I & hot water)
Pressure spraying helps to clear the surfaces

ANTI-ICING = PREVENTION
Glycol does not remove or melt it only prevents new accumulation and gives a HOT (hold over time).

Type I is thin and will drip off quickly which gives a short HOT. It is usually mixed with hot water for de-icing but will also work as anti-icing for a short period.

Unheated type II or IV are best for anti-icing when you need maximum HOT.

A two step process gives best results.

Don't spary fluid onto flight deck windows as this can cause damage to the windows and/or the window seals.

 

[jergar999]

I didn't know about the gear doors, you learn something every day.

 

[Cargoboy]

someone getting ready for an interview it sounds like???? good luck!