Dougdrvr

Don't worry so much about confusing the two, SAABaroowski, because when it happens you'll know the difference as it will literally snatch the yoke out of your hand. And the Saab is suseptable to it. I had a couple of good friends experience it during a training flight in the very early days of the Saab (do they still have chordwise boots on the stab?) Glideslope intercept, final flaps, moderate ice. The Captain/student was a BIG guy, built like a linbacker and he said it took ALL his strength to pull the nose up while the instructor took off a notch of flap. The IP later told me if he had been with someone weaker, they probably wouldn't have made it. They were hand flying at the time, but I would think that such stick force would dissconect the autopilot immediately.

Dougdrvr

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NuGuy

It's fairly complicated, BUT, the jist is that the wing LE has a larger radius, and thus creats a larger "bow front", which is strong enough to carry the water droplets around the wing.

Generally, the LE radius of the tail is much smaller, thus the bow front isn't as large, allowing the droplets to penetrate the airflow and contact the LE and freeze.

This is generally why you'll see antennas, and small, unheated parts of the airframe carrying ice, while there is none on the LE of the wing.

When I flew the Dash, we were told that's why you look at the ice probe on the wiper, versus the wing, since it was a MUCH better representation on what ice could be on the airplane.

Tail plane icing was BIG news back in the 1990's when I was flying t-props. Scary that it's been "forgotten". Look up the Jetstream crash in Washington State for another good example.

Nu

The Duke

I've flown all over the Rockies in moderate rime/mixed icing, have had the airplane so iced up the cockpit display shakes so badly it's difficult to read the instruments...condition levers max, 1200 RMP usually knocks this type off w/ a loud thud against the Kevlar shields. The Dash 8 Q200 does quite well in the ice, I feel like I'm in an industrial plow when I fly into the mountains and into the ice. I've never had any issues w/ flying in the ice in the Q200.

I've also shot numerous approaches to the FAF in what we'll call pretty impressive moderate...particularly going into ASE, remember one time while on the approach a KeyLime over Red Table VOR had to shut down an engine due to severe vibrations due to ice on one of the props...he was enroute to GJT, diverted single engine to Rifle.

I've never experienced anything like a pitch upset due to inflight icing in the Dash, I hope I never have to either. With that said, was the icing really that bad to cause a pitch upset? Were there any PIREPS of moderate mixed or rime in the area, or worse? Could the tail stall phenomenon be different due to fuselage length, etc? Could anyone who has flown both the Q200/400 chime in on this?

Typically Dash 8 operators will advance the condition levers to max after extending landing flaps, are there any possible scenarios w/ the Q400 that could lead to a failure of the prop assemply? I have a real hard time believing that, if boots were in fast, heck even slow, and the correct prop heat selection was made, that the sort of icing in the area would have brought down a Q400. This plane was built by people who live in the ice.

I'm both interested and concerned because I make my living in the Dash 8. I generally don't like speculating after accidents anymore that the next line pilot, but the fact that this is my plane has made this whole event even more personal.

Lindy

Yes, the pitching moment is that pronounced. Re-read LuckyDawg's account of the ATR.

Had a failure of tail de-ice (in another life-time) in a Corporate Aircraft, so I cannot comment on the Dash characteristics, but the moment arm is much longer on the Dash than what I used to fly and the Duke, you could definitely be onto something. We need a mechanical engineer to chime in.

Took pictures after landing of the ice build-up on the tail (one side worked, another side failed)...it was NOT an impressive build-up of ice. I would say less than 1/2" on the side of the stab which failed.

It doesn't take a lot of ice to affect and effect the flying characteristics of aircraft.

The video should be watched and KC10-FatBoy is correct about being a professional aviator.....

frequentflyer

This thread and its information has provided great knowledge that i was never really taught. Thank You All for all the great information that could potentially save my life as i am only a private pilot with little experience . Once again thank you all and take care ! May God Bless those Lost and Their Friends & Family

Dougdrvr

Hence the stipulation to initiate a tail cycle at least one minute prior to final flaps

higney85

Great thread for a knowledge base. All I have to chime is this- the CRJ-200 CAN develop ice on the tail, I have seen it in person and have had it fall in my face when doing the post flight walkaround. That being said I have never had or heard of control issues due to the ice on the tail. Typically even in icing conditions (with visible icing on the fuselage) there is none visible after landing, but occasionally (in more serious icing) there is some visible.


I have dealt with SEVERE icing only once and it was in the -200. Climbing up through FL230 we had already been in icing conditions but received the EICAS ICE message and selected the wing on. From FL230-240 we were able to see some ice accumulation on the wipers (normal for some light-mod icing). From 240-250 we realized this situation was taking a turn towards a worse issue than a little ice collecting at the top of the clouds.... From FL240-250 we were now collecting ice ON THE WINDSHIELDS (yes they are heated) and also visible increase in ice on the winglets and wipers. We were starting to break out and I became very concerned very quickly. I was the PF and had already selected the windshield heat to high, our airspeed had already began deteriorating from 290(indicated) in an effort to go on and climb up since we could tell we were reaching the tops and the reported tops were ragged from FL250-260. Looking over at the instruments we were still doing 1000fpm in a climb, now bleeding off through 280kts, but the engine gauges really got my attention- our N1 advisory carats were literally ticking down .2% every 2-3 seconds WHILE our engine VIB gauges (both) were climbing in .1 increments. I decided this was a no-bueno situation, CA agreed (at least I am pretty sure he was agreeing with the 4-letter words that were escaping his mouth). We were at the very tops of the cloud deck and he had me talk to ATC while he was fumbling through the book looking for the ice dispersal procedure- so we were reporting severe icing while I turned us down to 300fpm while adjusting the engine power to keep out of the yellow VIB indications (that we now hit). Within 15 seconds we were clear and leveling off at FL260 (which I requested to do since it was clear). We was able to accelerate to just shy of the redline and we were clear on top so with time we shed some of the extra ice we were hauling around. With the higher speed, increased N1 application (as we shed what we believed was ice on the blade tips), with all the anti-ice and continuous ignition being turned off, we were able to continue a normal flight. The most interesting sound is the change in engine sound when you have ice on the blades....loud and enough to get your attention through ANR's. I happen to have been with a check airman who has been flying for more years than I have been alive. He said that was his first experience with severe icing of this nature. In hindsight and once our heart rates returned to normal we discussed what we should or could have done differently. There had been pireps about light and mod icing from various altitudes in the climb- I had elected and briefed to keep the speed up through FL180 so we could climb quick through layers if need be, out of FL180 I had selected 1000fpm and our speed had climbed up to 320 before we began losing steam at about FL220-230. We had the cowls on from the beginning of icing conditions and selected on the wing at the first indication of icing (happened to be the ice detector just prior to our visual cues from the cockpit). We selected on continuous ignition when we say the VIBs increasing and reduced power (we assumed we were picking up ice on the end of the N1 blades). We were lucky to get out when we did, we were lucky to be in daytime, we were lucky to have a light load and it was obviously cold (-isa day). If we had not tried a "momentum climb" and had the airspeed above profile would we have collected more ice and had further issues? When we were trying to level off and get rid of some ice we had discussed possibly diverting- we never agreed on a term to have to divert but mentally I believed it to be if we could not shed the ice and be able to get the VIBs down to normal. It was above freezing in MEM and BNA was also warmer than freezing so we would have been able to get in most likely but we had 20+ thousand feet to make it work. Live and learn I guess. Only other thing I will do in the future is to handfly when the icing gets to be significant enough to warrant concern on visual cues (most likely the windshield ice accumulation as a heads up to take over from george). I am very interesting as to what the tail looked like when all this happened.


It's still unknown about the Colgan crash, but the arrows are beginning to point to a weather issue over anything else. As a person who trained in the south I dealt with 2 run-ins with icing in college in a cessna 310 that was not a known ice approved aircraft. Both flights were not expecting ANY ice but forecast temps on one flight turned out to be off by a few degrees, and another flight had us in clouds that were not forecast to be there for another 4K feet higher. Both times were enough to teach me to avoid icing- I collected trace ice both times and found my way out, ATC was helpful in asking pilots of other altitudes of flight conditions. Icing is something that I hate dealing with, but have come to one conclusion- stay out of it if you are collecting and have a choice. That being said, don't be afraid of icing conditions, just have the proper equipment and get deiced if need-be. "De-icing for dollars" is the term....The -200 is NOTORIOUS for throwing a WING A/I OVERHEAT warning in icing conditions when nothing is wrong- but the message is a message, a red one. Stay out of it if you have a choice. Abide by your training, manuals, and limitations for your airplane.

Sorry for what may be a bunch of rambling, but I feel better typing out my thoughts opposed to seeing CNN tell me stuff that is only close to right and I think my dogs have had enough of me telling the TV it's wrong.

dash2121

The Duck,

Though i also fly the 200. One of my good friends flies the q400. The tail difference in the 200 and 400 are huge. The 400s elevator is more like a crjs then the older dash series aircraft. I am starting to wonder if that makes it more likly to get ice up there. I swear when I have taxied behind one it looks alot thinner then the 200s elevator.

Dougdrvr

[quote=UAL T38 Phlyer;558911]


As to why the tail may or may not develop more ice: I've never heard the pointy-er, the more ice. I would have believed just the opposite. The boundary layer increases in depth from nose to tail of fuselage, or leading to trailing edge of surfaces.



quote]

Excellent explanation. Not many people know that about the Stearman and I didn't know that about the F-16. The "pointy" problem I think is more that the resulting ice shapes are so unpredictable. I remember the tip tanks on older 402's would start to look like flower petals, and the original wooden mockup of the Citation had a sharp pointed nose but was reshaped to the more bulbous design for fear that unusual ice patterns would break off more unpredictibly and FOD the engines,