Tail Stalls-EXCELLENT discussion worth reading

[kc1]

Without speculating, a good lesson for anybody interested in tail stall aerodynamics.

http://www.pprune.org/archive/index.php/t-153740.html

 

[Abernathy]

Also found this on google. Interesting video:

http://aircrafticing.grc.nasa.gov/courses/inflight_icing/related/3_2_3f_RI.html

 

[Talian]

Although it's really early on in the investigation, I can't help but wonder about tail icing considering that the CVR shows pitch and roll upset immediately after flaps we set .
I remember the Washington state crash of a Jetstream 31 operated by United Express in 89 or 90.
This specific accident was directy related to tail icing. In this case the aircraft stalled over the threshold when elevator was applied to transition from the descent into the flare.
This should be very interesting to see what the conclusion of this one reveals.

My thoughts and prayers are with all those directly involved.

 

[Oakum_Boy]

What's astonishing is that tailplane icing was only a brief mention in ground school a decade ago. Never saw it in the sim.

 

[spudskier]

What's astonishing is that tailplane icing was only a brief mention in ground school a decade ago. Never saw it in the sim.

Guessing that'll change.. maybe even a new ops spec that says no more than flaps 15 in icing?

 

[JettBoii]

The NTSB stating that the crew was concerned over "significant ice on the windows". Was the accretion rate so high that the window heat could not clear it? SLD? No idea. Very very scary indeed. As heartbreaking as this accident is I hope this investigation helps all of us no matter what we fly operate safer in icing conditions.

 

[CE750]

Here are a couple more videos that are very informative on icing.

http://www.part135.com/TailplaneIcing.html

http://www.part135.com/IcingForRegionalPilots.html

 

[Metrojet]

Here are a couple more videos that are very informative on icing.

http://www.part135.com/TailplaneIcing.html

http://www.part135.com/IcingForRegionalPilots.html

Those video's presented quite a bit of information that was very interesting. It has been a long time since I flew a turboprop - and the information in the video was extremely important if you fly an aircraft of this type.

Metrojet

 

[100-1/2]

NASA had an awesome article in one of the Pro Mags detailing the lengths they went in a Twin Otter to research Tail Ice and adverse flight regimes. Seem to recall T-tail aircraft were extremely susceptible to Tail Stalls after introduction of 20' or more of flaps. Don't know Colgan SOP's but speculate with most that landing configurations of Gear and final flaps would be elected just outside the marker or GS intercept where this Q4 lost it. I also could swear following NASA's research in the late 90's an AC was issued recommending minimal flaps for moderate/extreme Ice encounters to assure sufficient boundary layer flow across the tail. Anyone with any time or experience in the Q4 or strait -2's know they kind of fly like they are dragging their arse through the air. With that huge fuse out in front of the C(enter)P(ressure) on the Q4, if they were not anticipating the potential for atail stall, they would not have settled in their heads that when the extra flaps were thrown out that the tail stall would require pushing the nose forward to break the stall rather than fighting the tail stall through the nose dive.

Amazingly, Flightaware's ground track shows they actually spent little time in the arrival and feeder segments where they could have picked up a bunch of ice and the ATC tapes seem to reflect Colgan's sequence to be in the front of the pack, turning final about 5m(2-3 out of the marker) from the airport. That had to be some nasty stuff, particularly the way NWA alarmed of their concerns. Obviously, saturated with the events, ATC didn't quite pick-up the first pirep from NWA.

Nasa's otter conducted its exercises over 10k if my memory serves. Wouldn't beleive these poor souls had a chance <2k AGL.

prayers ya'll.

100-1/2

 

[clr4theapch]

As dispatchers do... I was looking at the weather during that time.. some of the graphics I have show that the area was ripe with liquid moisture from 12k down to 4K.. just north of BUF where is was light snow the waether was actually freezing rain and warmer than at the BUF airport.. so It seems to me that it may have been warmer in that 12k down to 4 k areas that they just decended thru.. once they got below 4K the air got colder and possibly run back water froze and the leading edges were fully contaiminated.. of course we know that they where using the autopilot for the apch so they would not have had any feel of impending control issues, once they got low and slow, and the auto pilot was kicked off when they lowered the flaps, the control forces where HUGH and maynot have been able to recover, they certainly were up against it being that they were low on the aproach.. prob no time to do much but try to fly out of the tail stall, thus the nose up, or Flat belly crash on that House....