It depends upon the ops specs and the airport. Many airlines require Type 1 and 4 if there is any active precip below 0. "nothing sticking to the aircraft" doesn't apply to operations when the FOM overrides it.

 

To add my two cents... most operators out there don't offer any sort of guidance to crews or training on deicing and deice judgements. One factor that comes into play is holdover times.

There are many times when a type one deice will do, and an aircraft doesn't need type 4, particularly if there is no wait to depart and the deice location is near the runway. Don't have the charts infront of me right now, but IIRC light snow type 1 holdover time is around 7-11 minutes. Why get type 4 if you can get off the ground in that time? (And it's certainly not impossible to get deiced and off the ground in 7 minutes if the deicer is experienced or there are two or more trucks working).

Many folks have no clue how much deice fluid costs. Here's a rough idea... Type 1 is about $9/gallon in bulk. Type 4 is close to $15/gallon. If you don't have a bulk rate, it's even more (I've seen FBOs charge as much as $25/gallon for type 4).

Just food for thought. That said, as has been stated before, if in doubt, deice/antiice. However, I've seen many instances of deice "lemmings"... when it's not really necessary.

 

How many gallons does it take roughly to deice an RJ or even 737? Sounds expensive

 

uh Air Florida was deiced.

 

I was told Type 1 sprays at 3 gallons/second. FWIW.

 

I thought Air Florida was the aircraft that had snow on the wings and the crew decided not to de-ice because the snow would blow off. Then the snow at the wing root supercooled and froze to the wing. Or am I confusing that with a USAir accident?

 

Agreed. Deicing is a cost of doing business, but many pilots have no idea how much getting sprayed costs. When one gets a bill for $1000+ to deice a King Air, you can only imagine how that adds up for anything bigger than a Saab.

You never, ever compromise safety on that principle but at the same time, one should always use common sense. When in doubt, get deiced...but don't do it just because "everybody else is doing it".

 

Air Florida was deiced. They then proceeded to have several procedural failures that resulted in the final accident... (Powerback, extended sit after deice, positioning (close) behind another aircraft, failure to properly set deice/antiice, etc)

http://www.ntsb.gov/ntsb/brief.asp?e...17X01907&key=1

 

I don't think that it's that much, but I would say that it's somewhere close to around 25-30 gal/minute with the hose wide open... Thats why you usually (hopefully) see smaller streams or hoses used for the application of type 4, and short bursts when they are applying type 1.

 

hahahaha! I know Colgan better than that. When I worked line everytime I turned around I was deicing a Colgan 1900. Got paid $25 for every deice though, so it was worth it.