Black Box and Voice Recorder have been recovered. Hopefully will give a bit more of an indication. Very sad..

Well, having flown Dash-8 100/300/Q400, I can say from experience that the aircraft can handle a LOT of ice. The Q400 also has an ice detection system, alerting the crew through the centre MFD (Engine Display). "ICE DETECTED" will flash in reverse video for 5 seconds, go to steady reverse video, then turn white/normal video when the "increased ref speed"-switch switched ON. The warning activates when either of the two ice detector probes (on on each side of the a/c nose) detect ice of more than 0.5mm thick, and are very sensitive.
The de-ice boots are, as per manufacturer´s recommendations, to be activated before entering icing conditions. These are very effective at removing ice. Never had any problems with this system during my 6 years on DHC8 models. Also, two small spigots (one on each wiper) will tell you if ice is accumulating. These are part of the certified ice detection system, and are lighted (on/off btn).

My speculation would be "Tailplane Icing", since everybody speculates.
Nose diving after changing configuration? Hard to recover if you do not expect it.

Anyway, lets wait for the FDRs.

Re: #51
 

In my opinion, I think that the latest generation of pilots are not educated/trained about how to handle icing conditions. Witness the latest NTSB recommendation about turning on the boots at the first indication of icing, and that "bridging" is a myth.

I also think that the newer generation of "smallish" commuter turboprops/regional jets are not capable of handling prolonged icing conditions because the designers figured that the aircraft would be through the icing conditions in short order.

I also think that the wing designs have a lot to do with ice carrying capabilities.

I spent many hours in DC-3s and DC-4s in moderate to severe icing conditions. We'd wait for about 1/2 inch of ice to accumulate on the wings and then we'd cycle the boots to break it off.

In the Winter, we carried extra alcohol for the props and windshield. If it was rough, half the alcohol ended up on the cockpit floor. The sound of ice hitting the fuselage as it slung off the props was reassuring in a strange way.

The main point is that the old prop-liners were designed to carry and shed ice for extended periods because they couldn't get above the weather. Those of us who flew them learned how to deal with icing. The wing and props were not as efficient. Airspeeds had to be watched. If we were still carrying ice during landing at SLC or DEN for instance, approach and landing speeds were increased.

Enroute, the general rule was to climb to colder air if possible. The ice that couldn't be shed by the boots and alcohol would shed by sublimation. If the weather was reported to be really bad, we just postponed takeoff until we got better reports.

The worst mistake was to turn on the boots and let them run in heavy icing because "bridging" was a very real concern. If the boots were cycling beneath the ice buildup, you were in big trouble.

...and you're around to talk about it so something must be right in what you did.

Dumb Q: any chance the anti ice wasnt turned on?

Anti/De-icing equipment are operated according to manufacturer recommended procedure and not seat-of-the-pants instinct. There have been many accidents because the ice systems weren't activated by the crew. Furthermore, on an airplane such as this the crew probably cannot see too well what is happening on the leading edge of the wing. They have to rely on electronic ice detectors and solid-state indicators like the windscreen wipers.

I'm beginning to see that much of the news stations want something almost anything from authoritative sources in the first 24 hours. Since the government investigation agencies have little concrete facts to go on, the newpeople turn to available "experts" with a proven record or a pretty face and demeanor.

I'm afraid that is the way it is and there is not a thing that bitchin about it is gonna change.

Fortunately we can all luck out when both a pretty face, demeanor and expertise end up in an interview at the same time.

I've come to find that PPRune provides as much as expertise as needed in the first 24 hours provided that one can read through the chaf.

So thanks for that:ok:

Of course there is that chance. There's a chance a flap failed, or there was a total or partial failure of the de-icing, or a crew member committed suicide, or they unintentionally allowed the plane to get too slow, etc, etc, etc, or any number of other "chances".

I'm not certain if the switch position will physically survive this crash, nor do I know if the FDR records that switch position. The heat of the fire also eliminated any chance to determine what ice had developed on the control surfaces.

The good news is that the FDR / CVR are both physically good shape. Answers will come.

I can only agree with crossunder. During the 19 years and more than 11000 hours on the Dash 8 100,300 I had a lot of flights in icing condition, up to severe. Just switch any deicing or antiicing equipment on and increase your speeds according to the book. You will never have troubles.

Lets hope that the DFDR and CVR are readable. NTSB will find the reason, all other things are more or less speculations.

"theory"
 

Witness looking up through auto windshield reported gear was not down.

Actually both the FAA and Transport Canada have recently come out saying they can not find actual information of 'ice bridging' be factual. The FAA and TC are now saying to activate the systems PRIOR to entering the conditions and to continue using the systems until one lands or exits the conditions.

And yes, I have for decades followed the old rule of wait.. no longer. NTSB now is saying as little as 1/4 in can increase stall speed 25-40kts.

A question, are the boots on the Q400 considered anti-icing or de-icing as there is a difference.

Gasbag

I followed the modern advice about ice bridging myself, pop the boots straight away. Changed my mind after a bad experience and now follow the old method again. So far so good.

I'm surprised that I've not read anything about the operator Colgan. Okay they've not had an accident since they lost that B1900 in 2002. That had the FAA crawling all over them. However the Q400 is a new machine for them and from what I gather needs a lot of TLC. I know several people who fly for Colgan and as of a few years back, none were complimentary about the way they maintained their aircraft.

In more than 6000 hours on DH8-300 and DH8-400 I have run into a lot of icing conditions some with heavy ice (Propellers throwing ice against the ice shields on the fuselage). Sometimes even level change would not help and we had to stay in these conditions for quite some time.

Never ever had any problems. Not even a noticable speed or climb performance loss during stong ice buildup. The Canadians certainly know how to produce planes who can handle ice.

The boxes just might be heat damaged though. It took the firemen some 13 hours to put the fire out. Black boxes can only take so much heat... Something like 1 hour @ 1100 degrees C or 10 hours @ 260 degrees C.

I know that this is my first post here and unfortunately it has to be on a subject caused by such a sad event, but I read earlier today on another aviation forum a post by someone (I presume a ramp worker or fellow pilot), who claims they saw the aircraft in question a few hours earlier in Newark doing ground runs on one of the engines, with one of the pilots outside looking at it, while the run was performed, thus delaying the boarding and subsequent departure.
Perhaps there was something that happened earlier yesterday, which contributed to this accident.

Anyhow, RIP to the victims and my thoughts go out to all those affected by this :sad:

in 1995 an atlantic southeast airlines turboprop lost a prop blade, the plane crashed...huge amount of drag as the engine changed its position in the mounting.

If a company Q400 was following, I'd think the NTSB would like to read out the FDR from that other flight and have pictures of any ice on the airframe after landing for baseline comparison.

With the caveat that icing conditions can change very quickly, if the following Q400 flight was uneventful, mechanical failure becomes a stronger possibility. Mind you, any mechanical problem with ice added to the mix is test pilot territory.

onfinals post
 

an engine run up is quite interesting in this case...I wonder if they were checking the prop and its governor.

looks like the WSJ might have gotten something from a controller:

@Robert Campbell:

While I was never privileged to fly the DC-3/4 I started flying turboprops a few years before the FAA de-/anti-icing review following the Roselawn accident. Waiting for ice to build up was what we were taught and did.

After the FAA review we "switched" to switching on the boots when entering icing conditions. While flying along and over the alps all year long I never saw any "bridging" and switching on the prop heat right away saved the pax a lot of "banging" from chunks of ice suddenly hurled against the fuselage.

The FAA review specifically differentiated between suction-powered "low power" boots on older piston A/C (some of them without ridges as far as I remember) and bleed-powered systems on turboprops the FAA found to be powerful enough to avoid bridging.

I too found the Dash 8 to be very capable in icing conditions and never encountered a situation where I would have been unable to continue on course due to icing.

Uncle Jay,

Having flown the type in question I can say that your "inviolate rule" is an inappropriate way to fly this particular aircraft except under completely smooth air conditions. It is not speed stable even with the flap in the 35 position. As you get into the lower power settings the TLA varies the propellor pitch and has a marked effect on the overall drag of the aircraft, especially at the standard 1020rpm landing setting.

A few further points:

Generally there are plenty of visual cues to when the airframe is icing up, namely the wiper spigot, under the wiperblade itself, the leading edge and the spinners all show ice up nice and clearly. As has been mentioned, the aircraft has a very good (flashing amber on the ED) attention getting display if ice has been detected by either ice detector and stall reference speed switch has not been selected on. This switch however is not in any way linked to the actual operation of the de-ice/anti-ice system; it reschedules the trigger alpha for stick-shaker and pusher.

The AOM mandates the disconnection of the AP under severe icing conditions to prevent any possibility of inappropriate trimming by the AP.

The de-icing system, though not perfect is very good at least at letting you know when there is a problem with it.

sr

NTSB live press briefing going on now...

NTSB reports excellent data on data and cvr. The gear had been lowered a minute before the data ended, and as it began large excursions, attempts were made to raise the gear and retract flaps 15.

NTSB reports (from initial FDR and CVR readout) that plane was at FL160 and requested descent to FL120 to clear haze. ATC cleared them to FL110. Pilots discussed significant ice buildup on the wings and windshield. Aircraft deice was selected just prior to these comments.

1 minute prior to the end of recording, landing gear was selected down. 20 seconds later, flaps 15 were selected. Immediately following flaps to 15, a series of violent pitch and roll excursions occurred. The pilots tried to raise the gear and flaps prior to impact.

From the NTSB brief:

Both the FDR and CVR are in excellent shape and have had an initial read in Washington.

The crew discussed significant ice buildup on the descent, airframe deice was selected on.

About one minute before the end of the recording, gear was selected down, 20 seconds later flaps 15 was selected, severe pitch and roll excursions started almost immediately after the flap selection.

The gear and flaps were raised and the recording ended soon afterward.

The briefing is being conducted by Steve Chealander, a former American Airlines captain and USAF Thunderbird.

Did the ice buildup overwhelm the deice system?

NTSB briefing:

crew briefed ils approach to 23 Buffalo
discussed vis 3m snow and mist
at 16000 vis hazy so requested 12000
shortly after cleared to 11000
FDR showed airframe de-ice selected on, followed by a cockpit discussion of significant ice on windshield and leading edge of wings
final events timeline:
end-of-recording minus 1 min: landing gear selected down
eor minus 40 secs :flaps 15 selected
"within seconds of flap selection": "series of severe pitch and roll excursions"
"shortly after that" : crew attempted to raise flaps and gear "just before the end of the recording"

tailplane icing and upset...I think is now a reasonable thought as upset happened after flaps selected down...

jetstream 41 in cmh similiar?

Is there any deicing capablity in the horizontal stabilizer?

boots and horn heat on the tail section...

horn heat might only be on the 100/200/300 series...

Yes, there is.

http://aspenflyguy.files.wordpress.c...8/04/fox11.jpg

Question is, was it working and was it properly designed and certified. Everyone thought the ATR de-icing kit was good enough until Hallows Eve 1994.

Approach speed and conditions
 

Looking at the posts, and after hearing the NTSB presser, had a few q's.

- Are the ice detector or stall ref speed switch two of the parameters recorded on the FDR?
- What are the approach speeds for no icing vs. icing conditions in this aircraft?
- Is the pitch and roll "excursion" reported by the NTSB after flaps 15 a typical indication of an icing related stall event?

Sound similar to another turboprop accident in (Ohio?) a few years ago originating at DTW that I believe was caused by a misconfigured aircraft flying too slowly in severe icing...

Sounds like the Roslawn American Eagle ATR 72 accident!

The NTSB report exessive pitching and roll before this Q400 crash. The same thing happend to the ATR!! NTSB says it happend after selection or retraction of flaps. The same happend in Roslawn. The first roll came after the copilot selected a lower flap setting. ATR has since recommeded flying manually in severe icing, and if roll accurs, select more flaps.

The ATR also has a ice detector, and on that accident the equipment was on and working. The ATR, however, has a so called 'critical wing', which can lead to ice buildup behind the boots. ATR has after the Roslawn accident recommended all operators to install a new larger boot on the wings.

Q400 pilots; do the Q400 have a critical wing?

Caution!! This is just my speculation! Obviously we must wait for the final report!

Ice induced stall?
 

My prediction, based on what is known, is this Dash 8-400 iced up bad while on approach (with on auto-pilot on) then outright stalled, probably as it leveled off to it's assigned altitude. The engine power isn't coupled to the autopilot. The tail section is intact on the ground and the debris is hardly spread out.

Cause of the stall? Faulty deice boots on the tail or wing(s). Crew didn't
select wing/tail anti-ice. With integrated windshield heat nowadays always selected on, you don't necessarily suspect ice accumulation unless you turn on the wing inspect lights and have a look at the leading edges.

Having said this, question was asked if it may have hit migratory birds bad enough to cause a double engine out; although not probable it can't be
totally discarded. If we could see the props in all the pictures it would
confirm this right away.

Glad they recovered both the CVR and FDR to get to the bottom of it so we don't have to speculate too long. I'm sure Bombardier is in white knuckle mode. This airframe was a late serial number, i.e. fresh off the production
line.

Well, NTSB reports that the crew did select anti ice ON!

WilliJet, The Increased Ref switch increases the low speed awareness cue by 20 knots, so the approach speed is also increased by 20 knots.

There was no mention in the NTSB briefing about the air speed when the gear and flaps were selected. It would be nice to know that.