NTSB recommends immediate changes to Cessna 208B usage

[wmuflyguy]

I'll pass on what was told to me in a Winter Ops seminar at the school i teach at by the people from the NASA Glen Research Center in Cleveland. They are the guys that fly the Twin Otter around and look for Ice. It is a neat airplane they brought it up during the seminar and we got to look at it.

I'll try my best to recall what was said but sorry if anything is incorrect.

As i recall, they stated that the caravans wing is like that of a Skyhawk, it produces much of its lift between 25%-40% of its chord. As opposed to some aircraft wings which create lift much more uniformly over the entire length of the chord line.

This wing allows for more stability and control during stalls and lowspeed flight, so it is used alot in trainers.

The downside is that Ice builds up in the front part of the wing(25-40% chord) rapidly causeing the airflow to become turbulent over the portion that produces the majority of lift in the Caravan.

So with a small amount of Ice aft of the boots can cause a drastic loss of lift in an aircraft with this type of wing.

That is how i understand it.

I would really like to fly on still regardless

 

[KPTPK]

Sad news in Alaska and a little known fact about the Caravan.

http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/Calling_it_a_night-1.html

 

[FN FAL]

So you're saying that normal cruise is lower than min icing airspeed? Wow, that sucks. I've always wanted to fly one. I guess it's a good thing I live in Florida.

?????

 

[FN FAL]

Sad news in Alaska and a little known fact about the Caravan.

Yea, bad decision making skills can kill...you can find a ton of corporate jet crashes with frost on the airframe, the Caravan isn't the only plane that sucks when taking off with frost on it.

Company records indicate that the certificated commercial pilot completed his initial CE-208 flight training 2 months before the accident and had accumulated a total of 74 hours in this make and model of airplane. The airplane, with the pilot and nine passengers onboard, crashed shortly after takeoff from runway 01

I flew that morning, but we waited for the front to pass. This weather was easily aviodable and was clearly painted on www.intelicast.com and in the FAA weather briefings. It was a fast moving system and would have cleared this the area where this crash occured within several hours. This weather was so bad, it took me an extra 45 minutes to get into work, there were car accidents all along the way due to the freezing drizzle and the windows of my house were coated with at least a 1/16 inch of freezing drizzle. There's no way I would have flown a jet off the runway, much less a King Air or regional turboprop that morning...until the front passed. After that, it was not a bad saturday to be out flying.

The manufacturer of the plane that crashed last weekend into Lake Erie knew for years that model had flaws that made it dangerously susceptible to ice, says a lawsuit filed against Cessna Aircraft Co. The presence of freezing rain last Saturday about the time of takeoff of the Cessna 208B Caravan is being investigated by Canadian authorities. The crash killed 10 people.

 

[FN FAL]

I'm sorry, but the lake Erie crash had 10 people on board...this Alaska crash had 10 onboard as well.

Let's look at some figures. Icing weight in a 675 HP Caravan is 8,000 LBS. (in FedEx's 600 HP Caravans, it's 7600 LBS) 4500-4600 is an average weight for a Caravan. That means a 675 HP Caravan can carry 3400 lbs of fuel, people and gear...if it's flown at an icing weight of 8,000 lbs.

10, 200 pounders, is 2000 lbs...1400 lbs of fuel is 4 hours endurance, including taxi time (yea, the burn is 100 lbs or so in taxi, but we're talking conservative figures and we don't know how long he taxied).

The Canadian trip was to pick up hunters...hmmmm, how much did their bags weigh and how much game did they have with them? Lets figure conservatively at 50 lbs each. That would be 400 lbs additional weight...bringing fuel down to 1000 lbs. That's 2.5 hours of fuel in a Caravan, if it was flown at the highest of 1500 lbs torque, 700 ITT or 100% NG in cruise.

If your passengers only had 50 lbs of luggage each, as hunters that spent a week at a hunting lodge and their butts only weighed 200 lbs a piece and you only needed to fly about an hour, that would have been a good start. Add in the fact that they didn't get a deice or anti ice on the ground and that one of the passengers was a tag along girlfriend (dead freaking weight on an icing day in my book, I don't care how good her poontang looked)...plus the fact that it was freezing rain out...no wonder there was a crash.

 

[EagleRJ]

600 HP sounds kind of low for a Caravan! How many variants are there?

FN FAL- Have you ever seen/flown a 'van with the Soloy Dual-Pac (two PT-6s driving a common propeller)? 1300 SHP should be enough to drag it up through the ice without breaking a sweat!

 

[Kingairrick]

FN FAL,
I'm puttin' it together here. Do you lower the max takeoff weight in the Caravan in icing conditions? In the King Air, we just have to stay above the minimum icing airspeed (140KIAS) so ice doesn't form on the bottom of the wing behind the boots. That's what I thought you were implying in your previous post.

 

[Secret Squirrel]

I have never flown the van either but I knew a lot of guys in alaska who flew it. They always told me it was not the wing but the tail (horizontal stab) that was the problem. It was too small and because of the airflow around the plane when below min ice penetration speed was VERY suseptable to ice and would cause a tail stall. They said the caravans with the belly pod were more so because they only flew maybe 10 knots over ice penetration speed anyway. (The belly pod even has a deice boot on it)


The reason I am writing is the name of one of the pilots sounds familiar. Was this Fred Villanova who use to fly the 99 at Ameriflight in SLC?

 

[Checks]

You have to fly the caravan like it isnt certified for icing. At the first sign off ice start getting out of the icing conditions. As a general rule I always climb...you can always come back down and the increased speed in the descent will blow off more ice. If you jerk your chicken while picking up ice, that ice will bite you in the rear one day.

 

[Duderino]

So you're saying that normal cruise is lower than min icing airspeed? Wow, that sucks. I've always wanted to fly one. I guess it's a good thing I live in Florida.

Hey Eric, sounds like you are working at a company that has one.